Way I understand the world

Wonders of the world: Spiders

2013-04-22T19:40:00.002+05:30

Tree spider

When I was a child like my other friends, I was scared of spiders. Even now when I see a spider in my room, certainly I do not scream, but yet, I avoid them and try to chase them out from my room. When I grew up little by little, I wanted to get rid of this fear and crazy imaginations about spiders, so I started reading about spiders in order to get familiarize with these little fascinating creatures.

We all know that spiders are disliked by many people due to their lack of knowledge about spiders. According to the taxonomy of spiders, they belong to the class Arachnida Phylum Arthropoda. These spiders are carnivores which mean they feed on small insects or flesh. They do it by trapping their pray using their web or by hunting on ground. In addition, these spiders can be seen all over the world except in air since they do not have wings to fly and in ocean since they are air-breathing animals. Yes, there are some spiders who can live under water such as Diving Bell Spider ( Argyroneta Aquatica) but they also need air. In this case they trap air in a bubble held by hairs on its abdomen and legs.

Another reason is their size and the appearance which give an expression that they should not be petted or loved, they are venomous and dangerous. When we consider about their size, most spiders are relatively small (2-10 mm) but there are exceptions like Tarantula whose body length will extend up to 80-90 mm. Even though size varies from one spider species to another, their body consists of two main parts. First part is the “Cephalothoraxe” (Prosoma) which is the anterior part and the other part which is the posterior part, known as “Abdomen” (Opisthosoma)

Parts of a spider (www.biological-diversity.info)

All six pairs of extremites which control the movement, food uptake and nerve interactions of the spider are located in prosoma. This anterior part, Prosoma Consists of two plates, upper plate or the dorsal plate is known as “Carapace”. Carapace is formed by six fused segments which bear the dorsal mussels and most importantly eyes of the spider. Ventral side of the cephalothoraxe is called “Sternum”. Usually, sternum is derived from four fused sternites. Both “sternum” and “carapace” are connected by soft pliable tissues called “Pleurae” and form prosoma exoskeleton.

Anterior median (AM) and Anterior lateral (AL) eyes of Maevia inclemens
(www.arthropodawordpress.com)

As I mentioned earlier, the most important organ located in carapace is the eyes of the spider. These eyes are important because they not only give a visionary aid but also they are very useful in spider classification. Usually, a spider has eight eyes which are located either in the anterior row or the posterior row. According to the position of the eyes they can be categorized in to four groups. They are, ALE, AME, PLE and PME (i.e. A= Anterior, P= Posterior, L= Lateral M= Median, E= Eyes). Although spiders have eight eyes, sometimes the number of eyes can be reduced to six, four and even two. Some spiders like Hawaiian cave wolf spider (Adelocosa anops) don’t have eyes at all.

Six pairs of extremities consist, “Chelicerae”, “Pediphals” and four walking legs. These “Chelicerae” have two parts, a movable articulated fang and a stout basal part which act as resting place for the fang. When a spider bites, the fang moves out from the basal segment and penetrates the pray. From the small opening at the fang, venom is injected to the pray. “Pediphals” and the mouth parts are the second pairs of appendages. These pediphals look similar to legs in appearance but they are only used for pray catching activities. Besides that, male spiders use their pediphals as copulating organ. This special feature of male spider is unique to them whereas pediphals are used only for pray catching by other Arthropods. Last extremites that are connected to the pleura is four pairs of walking legs. Each leg has seven segments which are, “ Coxa”, “Trochanter”, “ Femur”, knee like “Petella”, ”Tibia”, “Mettarsus” and finally “Tarsal” with two claws, which are known as “tarsal claws” which are serrated like a comb. In some spider species another additional middle claw is present, whereas this third claw is used to catch and hold the silk threads of their web. But in some hunting spiders beside these “tarsal claws” there is a dense cushion of hair on their feet which is known as “scopulae”. The spider walks with the help of these scopulae hairs, whereas these scopulae hairs split in to thousands of fine cuticular extensions called “end feet” which act as suction cups. According to the Homon, Roscoe and Walke (1991), these microscopic end feet structures use to achieve physical adhesion which is enhanced by the capillary force of the extremely thin water film on the substrate so that spider has a “surefooted” grip while walking on vertical walls, window planes and other smooth surfaces. Other than walking these legs act as sensory organs of the spider since sensory hairs are located in legs. These sensory hairs are mechano sensitive “sensilla” which is used to sense the touch and the vibrations. Besides mechano sensitive sensilla, chemo sensitive hairs are present which nerve fibers are exposed directly to the environment to sense the changes in chemical compositions in the environment. Except mechanical and chemical sensitive sensilla, another group of sensory hairs are present to sense the humidity level of the environment.

Spider Scopular (www.howstuffworks.com)

Another interesting fact about spiders is the way of food intake; mode of food intake differs from spider species to species. But the common way is the pre-digested method which happens in the following way. The spider releases digestive fluid on to the pray which is wrapped with silk or pray that subdued with a venomous bite. And then it sucks the pre digested liquid. This method is used by the spiders that don’t have cheliceral teeth whereas spiders with cheliceral teeth mash up the pray.

Blackwidowspider (animalsnationalgeographic.com)

For a spider, venom is the most important tool in their survival. Spider venom is used for immobilization of the pray. Even though it immobilizes the pray, as a secondary action of the venom it can cause death to the pray. Spider venom is produced in venom glands of the spider which is located in prosoma and it contains large amount of neurotoxic peptides which paralyze the pray and biogenic amines and amino acids which may have a potential threat to human. But out of more than 40000 spiders around 200 species are poisonous to human and they belong to Atrax, Latrodectus, Loxosceles and Phoneutria genera whereas these genera include, Black Widow, Brown recluse spider and Certain ctenid. But well known Tarantulas are not lethal to human but they are lethal to small animals such as frogs. This is because their venom is designed to paralyze their pray and as a defensive bite against large animals.

Spider web

Spider web is another beautiful thing about the spiders where spiders use proteinaceous silk which is produced in their spinning glands to build the web. This proteinaceous fibrion Spider silk scientists believe that water soluble, and when the change of orientation of polypeptide chain from an alpha configuration to beta configuration silk solidify make the web. Change of configuration of polypeptide chain simply by pulling it while weaving the web. Spider silk proteins contain different amino acids such as “Alanine”, “Glycine”, “Serine”, “Glutamic”, and “Proline”. The presence of these amino acids makes the spider web serve as a wound dressing in folk medicine. In modern medicine, spider silk is tested as a natural material for regeneration of nerve fibers. Spider cocoon threads are used in cartilage regeneration, and new material called silk bone is now developed to regenerate bon tissues.

Daddy spider (www.lucianabartolini.net)

Although we notice spider webs everywhere, not all spiders are capable of weaving a web. Only web spiders can weave a web. Depending on the web spider, they develop different webs. Funnel web spiders and sheet web weavers weave horizontal sheets, and cob web and daddy long legs spiders build irregular meshes. Spiral orb webs are usually built by family Araneidae, Tetragnathidae and Uloboridae. Spiders belonging to the family Theridiidae weave tangle webs or cobwebs. Funnel webs are usually weaved by the families of Agelenidae, and Hexathelidae.

CONSTRUCTED WETLANDS AS A METHOD OF WASTEWATER TREATMENT

2012-08-20T22:49:00.002+05:30

Since most chemical reactions take place in water based medium, water plays a major role in industrial world. With the polar nature of water it easily gets polluted from those chemical and biological ingredients use in manufacturing process. This polluted water is called industrial effluents or simply the wastewater. Since industrial wastewater contain toxic chemical compounds like Cyanides, biological waste like plant materials and pathogens, toxic heavy metals like Cadmium, Lead, exceeding the accepted levels for human use. When this wastewater released in to natural water bodies it may result social and health problems to the people living around the water resource and also to the people who use it for day today work.

Minamata Disease (methylmercury poisoning) on Public Health & Social Justice

socialmedicine.org

In early days people tends to release this waste water to natural water bodies without a proper treatment. Therefore in early days outbreaks due to hazards waste were common. Minamata outbreak in Japan is such a disaster coursed by not having a proper treatment for wastewater. Wastewater treatment is an expensive process, if we are using conventional methods like chemical precipitation, Ion exchange; Reverse Osmosis and Electro dialysis. Not only they are expensive but also they produce toxic sludge therefore small industries won’t consider about having a wastewater treatment plant within their manufacturing plants due to the high production cost. Instead they release wastewater to the nearby water stream without treating it.

Constructed wetland (vertical flow) in Shenyang (China)

blumberg-engineers.com

With the development of the science, scientist comes up with an eco friendly and economical friendly two methods to treat waste water by combining knowledge of botany and the knowledge of Chemistry. Those are phytoremidation which use living plants and Biosorption which use dead plant materials. Even though phytoremidation consume much time than Biosorption it is easier then biosorption. Therefore phytoremidation technique is used in initial process of wastewater treatment. And constructed wetlands are use in phytoremidation technique where plants are growing in the artificial wetland.

According to the US-EPA and Ramsar Convention Wetland is an area where area is saturated by surface water, ground water, flowing fresh or brackish water, permanently or temporary and characterized by a prevalence of vegetation that is adapted to the environmental conditions. Therefore wetlands contain three significant characters such that presence of water, unique soils that differ from upland soil and the presence of vegetation adapted to saturated conditions. Natural wetlands has a great capability of improving the water quality, this feature of wetlands is use in constructed wetland to treat wastewater. With the high demand for water quality, neediness of constructed wetland for wastewater treatment becomes high.

Subsurface Flow Wetland design

Maintaining a constructed wetland require less technology, less capital cost but to contract a wetland for wastewater treatment require some engineering and hydrological knowledge. Since fundamental biological processes like nutrient content, soil pH, water pH, species density, productivity, nutrient cycling which are important to pollution control are depend on the hydrology of the wetland. Furthermore another important factor is the Hydraulic Retention Time and the Water Budget, where treatment performance directly related to the time which wastewater is in contact with the plant species since plants need some time to absorb the pollutants. Taking all this to account engineers can construct two type of Constructed wetlands

Free Water Surface flow wetland design

First one is Subsurface Flow Wetland design (SSF). In this method gravel substrate is used as the filling medium of the wetland and plants are growing on it. Second one is the Free Water Surface flow wetland design (FWS). In this method waste water is retain as shallow water. Other than these two designs constructed wetlands can be categorized according to the flow direction of the wastewater. They are,

Horizontal- flow Wetlands.

Vertical – flow wetlands.

When constructing a wetland for wastewater treatment, scientists use two type of model to achieve the maximum usage of the wetland. One is the UK model of constructed wetlands. And the other one is The First order Plug-Flow Biokinetic model. In brief UK model is the simplest model used in domestic wastewater treatment in UK. In this model horizontal flow system for SSF system is designed. On the other hand, in first order plug-flow biokinetic model, both SSF and FWS systems can use and this model is more complex than UK model since it involves Organic denegation, nitrification, adsorption, disinfection and other biologically driven processes.

Spreading of gravel in the horizontal flow constructed wetland

athene.geo.univie.ac.at

References:-

1.Subsurface Flow Constructed Wetlands For WasteWater Treatment A Technology Assessment; United States Environmental Protection Agency Office Of Water EPA 832-R-93-008 (4204) July 1993.

2.Seswoya. R , Zainal. M,Y. ;Subsurface - flow constructed wetland: Proposed design area for high strength effluent domestic wastewater;

3. Akvopedia. (http://www.akvo.org/wiki/index.php/Free-Water_Surface_Constructed_Wetland)

German Shepherd Dog (GSD)

2012-07-09T20:34:00.002+05:30

Since Interesting fact about cats’ post I haven’t wrote about animals. So I thought to write about dog which I love to have around me all the time. From cunning fox to dreadful wolf, and to African wild dogs which are hunts in packs, are belong to family Canidae or simply dog family.

German Shepherd Dog is one of my favorite dog breed. And I think every dog lover know the answer why I’ am so much interested about them. German Shepherd Dog is a large size dog breed originated from Germany. Height: 60-65cm. Weight: 35-40kg (Dog breed info center). Since these dogs are strong, intelligent and loyal, initially they used to herding and guarding sheeps. After people get familiar with this breed people use this breed for police and military roles around the world (Wikipedia)

According to the Wikipedia German Shepherd Dog is created or in other word, creater of GSDs is Von Stephanitz, former German Veterinary student from Veterinary College. First he was a member of local dog breed society called Phylax Society. In 1899 he founded his own dog breeding society called Verein für Deutsche Schäferhunde. He started this society with one dog (Hektor Linksrhein later changed its name to Horand von Grafrath) which he believed it has the ideal characteristic of working dog. And this dog was the first GSD. After so much breeding processes society succeed in breeding a best working dog. And they are German Shepherd Dogs

Now we know the history of the GSDs. But what make to attract so much attention of us. Even Adolf Hitler is GSD lover that mean these dogs must have some special features with them. Let’s look at those interesting features. As I mentioned early these dogs are strong, intelligent and loyal. Other than these, there are some special physical features those are; they have a domed forehead, a long square-cut muzzle and a black nose. The jaws are strong, with a scissor-like bite. The eyes are medium-sized and brown with a lively, intelligent, and self-assured look. The ears are large and stand erect, open at the front and parallel, but they often are pulled back during movement. They have a long neck, which is raised when excited and lowered when moving at a fast pace. The tail is bushy and reaches to the hock. Also German Shepherds are direct and fearless, eager and alert. Bold, cheerful, obedient and eager to learn. German Shepherds love to be close to their families, but they are very wary of strangers. This breed needs his people and should not be left isolated for long periods of time. They only bark when it is necessary. German Shepherds have a very strong protective instinct, so they should be extensively socialized to prevent over-guarding when they are an adult. Aggression and attacks on people are largely due to poor breeding, handling and training. A well bred, well-adjusted, and trained dog is for the most part generally good with other pets and excellent with children in the family.
These dogs should look after well, because as any other dog; they also got some diseases, like hereditary diseases such as hip and elbow dysplasia, blood disorders, digestive problems, epilepsy, chronic eczema. Those will reduce the 13 year lifespan of them.

MOON PLAINS SANITARY LANDFILL

2012-06-20T19:21:00.000+05:30

In Sri Lanka, disposal of waste is a major environmental and social problem, which leads to several health problems like dengue in urban areas. As responsible government, Sri Lanka should have a proper way of disposing of waste. But in Sri Lanka, disposal of waste is mainly done by maintaining an open dump site, which will cause many environmental and health problems. Instead of open dumpsites, one proper way of deposing waste is maintaining a sanitary landfill. Moon Plains is one such sanitary landfill, which is started in 1996 by the Nuwara Eliya municipal council as a normal dumping site, and converted in to a sanitary landfill in 2003 with the help of JICA foundation. This land fill is located in a valley surrounded by a cultivated Eucalyptus forest, which is owned by the forest department, outside the Nuwara Eliya municipal council. And it is close to a water stream which provides water to a reservoir called Bomuraella which used for domestic and agricultural purposes by the people who are live around the reservoir. Initially this valley is used as an open dump site by the Municipal council without taking any environmental protection measures.

This valley which is 400m long and 30-40 meter deep is a part of 5.8ha catchment. And this valley consists of sandy clay soil and bed rock is a hard rock. Since Nuwara Eliya located in wet zone annual rain fall is around 2700mm therefore it gives rice to a seasonal stream which connects to the close by stream. When all the Municipal waste, Hospital waste and industrial waste is dump without any environmental protection measures it can easily contaminate that water stream and the reservoir causing serious environmental and health care problems to the society.

Nuwara Eliya municipal council used 2.0ha from the 5.8ha catchment as the dumpsite. Earlier this landfill did not contain any environmental protection methods like fence, gate, and other necessary facilities that should be in a landfill like weigh bridge, leachate treatment method, buffer zone and water supply. To have a proper waste disposal open dumpsite should convert in to a sanitary landfill like in Moon Plains now. And the total open area which is 2.0ha is now has been converted to controlled sanitary landfill.

Moon Plain landfill has designed under a level 3 sanitary land fill which use semi aerobic landfill method. And it involves leachate control facility, leachate treatment facility. Drainage facility, a Gas venting facility as sanitary waste disposal facility and other required facilities, for education, for security and for Maintenance.

Leachate Collecting Facility

Leachate collecting facility is a pipe network that has installed underneath the landfill area which uses to collect the leachate. Pipe system used hard concrete pipes with relatively high diameter and with pores around the wall. This leachate collection facility will collect the leachate and guide it to the leachate treatment faculty.

Leachate Treatment Facility

Usually leachate coming out from the landfill contains significantly elevated concentrations of undesirable material derived from the material that it has passed through like organic acids, aldehydes, alcohols and simple sugars from municipal waste and heavy metals and halogenated organics from Industrial waste. Therefore leachate should treat before releasing it to the environment.

For that in Moon Plains there is a leachate treatment facility located at the down end of the valley. Leachate treatment facility contain combination system of coconut fiber a biological conductor for aerobic and anaerobic bacteria, Charcoal filter for remove suspended particles and heavy metals. And Wet land for filtration.

Gas Venting Facility

Since this landfill use semi aerobic conditions gas venting facility is much needed in Moon Plain sanitary landfill. Gas venting facility help, aerobic bacteria to degenerate solid waste easily. Gas venting facility also includes pipe system that underlying the landfill which is end up with a perforated oil barrel filled with rubble stones. This gas vent will release CH₄ (methane) and CO₂ (carbon dioxide) to the environment without accumulating inside the landfill. By measuring the gas composition it is possible to predict the age of the landfill and the current status of the decomposition such like aerobic decomposition or anaerobic decomposition stage

Disposal pit for infectious waste

Disposing of Medical waste or the infectious waste should be done separately with care minimize the contaminations. Therefore in Moon Plains, Hospital waste is dispose in to separate pit located away from the dumping site, which would not contaminate ground water or any other wastes.

Storm water Drainage

Moon Plains sanitary landfill consists of two types of drainage systems. First one is Rip rap type along the waste filling slope and second one is Earth drain type along the access road to intercept all runoff from the out side from the access road. Storm water drainage system is designed to drain excess rain and ground water from the dumping site.

Tire wash pit

Tire wash pit is located away from the dumping site in the access road. This help tractor to wash their wheels, after dumping the waste to dumping site. From this it is possible to avoid contaminating the road with waste.

Other than these facilities as sanitary waste disposal facilities, there are some other required facilities that has been fulfilled by the Nuwara Eliya municipal council, which are, two Access roads are constructed using asphalt paved for long term use, and using gravel for short term use. Gate for control the entry of vehicles. Movable fence to for prevent waste scattered to outside of the site during landfill operations. And a fixed type fence to control the entry to the site.

As Educational facilities to illustrate how landfill operations are carried out in a sanitary landfill for students. And there is control room and a garage for bulldozer as the administration facility to administrate the work of the dumpsite.

For proper sanitary landfill it should be monitored frequently and should control its activities as required. Monitoring and control of the landfill is do under the supervision of the monitoring committee which is chaired by the Chairman of the health committee fallowed by a municipal council member elected from the ward near the landfill site, member from a municipal council staff in Health Department, a member from municipal council staff in Works Department, A member from Central Environment Authority staff, member from the staff in local environmental NGO rand a representatives of neighborhoods. Monitoring is done frequently in early stages or the first six months, it is monitored every month and after first six month land fill is monitored after every three month this was done with the permission of the monitoring committee, permission is issued after six month from the starting date. For this purpose there is monitoring well located in the landfill. And monitoring is done according to a check list which is executed by the monitoring committee.

Problems associated with the Moon Plains sanitary landfill

This land fill is classified as a level 3 sanitary landfill even though this is classified to a level three sanitary landfill there are some major problems with it, one is the discontinuous of the bed rock where bed rock plays a major role in preventing the contamination of ground water and since there is underground spring located in the site. Because of not doing a complete geological survey, authorities was not able to avoid the contamination of the underground spring hence Bomuraella reservoir unless use of a cement mortar, but they are fail to use cement mortar for entire area which cause leachate to penetrate through cracks. Second deficiency of the landfill is that they release the leachate without continuous analysis for BOD₅ and COD levels which should be in the range of 30ppm and 250ppm respectively. And leachate collecting facility is good place for mosquito breeding and may lead to other health problems like Dengue epidemic. Third deficiency is that there is a lack of infrastructure facilities such as electricity, water and telephone facilities, which make administrating processors, are more difficult. By avoiding and completing those deficiencies Moon Plains sanitary landfill can improve more to achieve maximum use of the invested money and the time on it.

References

1. Asanga Manamperi, L.C. Jayawardhana, Ajith de Alwis, Sumith Pilapitiya; Usefulness of best fill expert system: a case study of three landfill sites in Sri Lanka,

2. NA, Leachate,”Landfill leachate treatment expert website” ,Web 2012/ 5/6.

COAL FIRED ELECTRICITY GENERATION.

2011-11-02T23:07:00.000+05:30

Energy, we all need it to do a work. As humans we use energy stored in our body. But most of the time energy stored in our body is not sufficient enough to finish the required work. Therefore we use machines to do our work. Most of these machines driven by electricity which makes electricity to play a major role in the form of energy for development of a country. Electricity generation required an efficient energy source. Energy sources that we use today is limited resulting a global problem called energy crisis.s

Hydro power is the most common energy source that people familiar with the electricity generation in Sri Lanka. Other than that developed countries use nuclear energy to generate electricity. Fossil fuels, geothermal energy is also using for electricity generation. Due to the modern climatic changes hydro power stations cannot operate at their maximum capacity. And Nuclear power plants need more advanced technology and more capital which cannot afford by developing country like Sri Lanka, which lead to find a convenient alternative energy source to generate electricity. Such convenient alternative energy source is Coal. Coal is a solid fossil fuel which containing Carbon and it is the most impure of fuels, its impurities range from trace quantities of many metals including uranium and thorium to much larger quantities of aluminum and Iron to still larger quantities of impurities of such as Sulfur.

In a coal power plant have some kind of rotating machinery to convert heat energy of combustion in to mechanical energy which then operate an electrical generator. This energy conversion is done by using several steps. First step of this energy conversion is burning the coal in boiler furnace to produce heat In second step include thermodynamic process which are.

The heat from combustion of the coal boils water in the boiler to produce steam. In modern power plant, boilers produce steam at a high pressure and temperature.
The steam is then piped to a turbine.
The high pressure steam impinges and expands across a number of sets of blades in the turbine.
The impulse and the thrust created rotate the turbine.
The steam is then condensed and pumped back into the boiler to repeat the cycle.

In third step rotation of the turbine rotates the generator to produce electricity based on the faradays principle of electromagnetic induction. In practice to effect these three stages of conversion, many systems and sub systems have to be in service. Also involved are different technologies, like combustion, aerodynamics, heat transfer, thermodynamics, pollution control, and logistics. Leading to much complex tasks in coal fired electricity generation.

When a country involves in coal fired electricity generation, Country will have the benefit of generating large amount of electricity in one place. And much more advantages. Coal fired electricity generation also has disadvantages and some threats to the environment and to the people living around it. Those disadvantages and threats can be avoided using proper techniques which will discuss in my next post.

Interesting Facts about Cats II

2011-07-24T12:17:00.003+05:30

Saber toothed cat

In my early post we talked about some common facts that are shared by the whole cat family. Now let’s talk about domestic cats. These Cats have a long history; their prehistoric member was SABRE TOOTHED CAT which is very much similar to the tiger and about the same size. This Saber toothed cat developed six inch long canine tooth extending from its upper jaw. scientists believed this development of over sized tooth led to extinction of these unusual cats where as they could not open their mouth wide enough to bite well.

Kaffir cat

While Saber toothed cat is the prehistoric member of the cat family KAFFIR CAT an African wild cat was probably an ancestor of the domestic cat. They still live in North Africa and look very much like Tabbies (domestic cat breed). Egyptians were the first to tame and domesticate these small wild cats and it is thought that Phoenician ships calling at Egyptian ports traded them and carried cats to Greece and Italy. And Roman armies marching in to Spain and Northern Europe took cats with them as pets. Probably some of these cats may have mated with European wild cats, which still exist in wild in Scotland and in wooded Northern Europe. These domesticated cats became the most sacred of the Egyptians and this may be the reason for the Egyptian moon goddess to have a cat’s face. In Egypt some cats were mummified and buried with their owners when they died. And it was a crime to kill or steal a cat. And they were the inspiration for statues, jewelry and many other forms of decorative arts. Not only in Egypt, in China cats have been valued for many years. Their job was to protect the cocoons of silkworms from being destroyed by rats.

Angora

Persian cat

The varieties of domestic cat that we know today are all of one species, differing only in length of hair and in colour. The first long haired cat imported in to America was the ANGORA. One type of Angora, now called the MAINE COON CAT, is still found in Maine. Very much like the Angora is the PERSIAN. The Persian is one of most popular show cats. These Persian cats are long haired cats that have more compact body, smaller ears, a round head, and shorter legs than the Angora. Persian cats also have a pronounced ruff around its neck and a bushy tail. White Persians have blue eyes and black ones have deep copper or orange eyes.

Tabby cats

Tortoiseshell cats

Another common breed is TABBIES. Tabby cats have either long or short hair. These cats are with all kinds of markings that can appear in tabby’s litter. These makings can be strips or spots. For show purpose there are definite types. Most common Tabby is striped tabby often called the tiger cat, which may has a grey coat with black vertical stripes. And the latter “M” on its forehead; the Brown Tabby, with black strips on its tawny body; the Silver Tabby with tabby marking on silver ground. Sometimes we can find pure Black or White Tabbies without ant tabby markings. Another interesting short haired cat is the Blue cat or Maltese. Which may vary in colour from slated blue to pale lavender. And TORTOISESHELL CATS (there coat is like tortoise-shell) are produce by cross breeding as male tortoiseshells are extremely and cannot reproduce as they are sterile. Cat breeders are always trying to produce improved strains in the different varieties of cats.

Manx cats

Other famous breed is MANX CATS which can be black, white or any colour, come from the Isle of Man, off the North West coast of England. It normally has no tail and has especially long back legs. It is not known how these unusual cats got developed from ordinary cats, nor do we know how they come to live on the Isle of Man. Some Manx cats do have a very short tail, but for show purpose they must have a hollow at the end of the backbone where the tail should be.

Siamese cat

SIAMESE CATS are also common domestic cats that come from Thailand. They have a pale fawn coloured body, with either dark brown or grey-blue feet ear tips, tail and muzzle. According to the colour of these darker portions, the cats are called seal points or blue points. Kittens are born white and acquire their adult markings within a year. Siamese cats tend to grow darker coats if they are kept in cold climate. BURMESE CATS are very like Siamese with a rich, dark brown coat, lighter on the underside and darker where Siamese are tipped. Siamese cat have deep, hoarse voices. These are only few cat breeds but in the world there can be so many cat breeds which I or for that matter nobody has ever talked about.

Siamese cat

Interesting Facts about Cats I

2011-07-24T11:42:00.001+05:30

Cats! every girl and boy like cats. So what makes them so interesting and so lovable? Why do people love them so much? So it is better to know some facts about cats.

Cat family includes more than 50 species which greatly differ in size, from small domestic cat to the magnificent Siberian tiger which may be 10 feet long and weigh over 200kgs. They live in various habitats that vary from tropical jungles to the Arctic. So one or more of these wild species are found in every country of the world. And these cats share many characteristic features, so their behaviors are somewhat alike to what we find in our domestic cats.

All cats, wild or domestic are mammals, which give birth to the young and feed them with milk from their own bodies for some time. And cats belong to the group of carnivore/ flesh eating. But our domestic cats might eat anything and we all know that they prefer flesh. Cats’ eyes are specially suited for seeing in dim light so that they can hunt effectively at nights or at dusk and dawn by adopting their eyes to very little light by enlarging the pupil (opening). By doing so they can gather much more light than we humans do and thus they can see
more. This adaptation leads cats’ to be good hunters at dark. When light gets stronger the pupil decreases in size until it is the black slit that we see when cats face strong sun light. The eyes of a cat glow in the dark because the black surface of the eye is coated with tiny particles call guanine. When light strikes these particles they amplify and brighten the dim picture focused on the retina.

Another interesting fact about cats is that they can jump well as much as four times their own length and have delicate sense of balance and grate natural grace. Cats place their hind feet exactly in the track of their front paws, which test the path and this makes them both sure footed and silent as they stalk their pray. And cats have powerful muscles which lie under the skin which are used in leaping, running and in twisting to a good landing position when they fall. And it gives a very flexible body and its movements whether fast or slow are always graceful. Cats’ tail is a help in balancing and speeding up the twisting action as a cat jumps in mid air.

Other than these two facts the noise cats’ make vary. When small cats purr and large ones roar; leopards make an abrupt coughing noise. And Siamese and some wild cats have penetrating cries. Cats’ have rough tongues which are very useful for them to scrap meat from bone or plate and can wash and brash its coat. Soft pads under the cat’s paw are both sensitive “feelers” and cushions of fat which being poor heat conductors help to protect them from the cold. And all cats except cheetah have claws that can be extended or retracted. The most Interesting fact about cats is that they have the longest and sharpest teeth of all carnivores. These are some few fact that cats family share to make them so interesting, and in my next post I'll tell you about domestics cats and their interesting facts.

Salt and Heart diseases

2011-07-11T19:13:00.004+05:30

In modern society most people tend to have low salt diets. When we questioned about it they use to tell that one of their family members is suffering from a cardiac disease. So what is the relationship between salt and heart diseases? First I was confused by it because people started to use salt in their foods thousands of years ago. And salt contains Na⁺(sodium) which is an important element in human body.

Salt or Sodium chloride (NaCl) is used as a preservative as well as a seasoning in the ancient time. And by now we know that Sodium is an essential element in human body where as having Sodium in the fluid outside cell as the major cation, is important to a correct functioning of the nerve system since action potential occurs due to the Na⁺ (Sodium) K⁺ (Potassium) ion distribution across the cell membrane. And Sodium helps to maintain electrochemical balance in the body. This important element of Sodium (Na⁺) gets in to the body mainly through salt.

So how can this important element cause serious heart diseases? Is it possible? The answer is yes, salt can cause heart diseases. When Sodium (Na⁺) is present in blood in excess levels it causes retain fluid from the kidney, by secreting more ADH (hormone) from pituitary. Retaining more fluid from kidney increases the blood pressure. You all know that high blood pressure leads to several cardiac diseases where heart has to put extra effort to pump blood to organs and this will lead to several other health related problems if you are having high level of cholesterols. So what should we do? Do we have to stop the usage of salt? If we stop using salt in food what will replace the Sodium (Na⁺) that is excreted from our body with urine. So it is better to reduce the salt consumption. But it has to be done with care because less salt in the body can increase the stress in the body systems thus reducing insulin sensitivity and affecting the hormones that control blood pressure.

Now you might get confused by this because the consumption of both more and less salt can cause heart diseases. What is the correct level of salt that we have to consume? It is generally recommended that we should consume 24000mg of Sodium (Na⁺) for a day and to obtain that much of Sodium (Na⁺) people should use about 6g of salt which is nearly a full teaspoon of salt. For that we have to prepare our foods by ourselves. And we have to reduce the use of process food items like sausages and instant noodles since these process foods contain salt that is beyond the required level of the human body. So it is better if you can use process foods which are low salt foods (120mg/100g). through that usage I’m sure everyone can spend a fairly healthy life thus controlling the risk of having a heart attack in near future.

Wonders of the world (Firefly bug)

2011-07-03T19:15:00.003+05:30

Few years back when I was in grade one, me and my friends used to collect Tortoise beetles as our hobby. Whenever we caught a new Tortoise beetle which differed from others we brought them to school and showed them to others by saying that we got a new Tortoise beetles that you guys don’t have. And we explained how we caught them, from where we caught them, things they eat and that kind of funny stuff. Those are wonderful memories and i'm sure you also have those kinds of sweet memories with you. Back to story, but one day I caught a bug little bit different from Tortoise beetles. Usually, Tortoise beetles are hemispherical in shape and have bright colors. But the one that I caught was little bit elongated and thin. So I thought I caught a new Tortoise beetle that none of my friends have caught early. Since my friends don’t have such a Tortoise beetle with them, I was so happy. So that I can show my new Tortoise beetle and tell them about it.

I put my new friend with my other Tortoise beetles. So that I can take it to school on the next day. But at night I suddenly got waken up by a strange light emitted from my Tortoise beetle container. I was afraid and I called my mother to tell about this. She told me that she will explain it in the morning and asked me to sleep. But I couldn’t sleep all that night.

Next day morning I hurried to my mother and asked about the last night incident. She told me that I have accidently caught a fire fly not a Tortoise beetle. Then I wanted to know how living animals emit light without having a bulb and a battery. I asked from my mother how it can happen. She replied with a smile and told that I'm too small to understand that therefore I have to be patient till I find the answer in future. Since then I wanted to know how this little tiny bug emitted light at night.

With the grade five scholarship examination, me and my friends were busy with studies and so was our parents. So when I passed grade 3 my interest about collecting Tortoise beetles and knowing about fireflies faded away. At that time the only thing in our mind was to pass the scholarship examination and make our parents happy. Even after scholarship examination we were forced to go for classes to have 10 A’s in O/L examination. What we will be doing in the future depends on our education. So we let our other interests lay beside and hurried to school then to classes and back home. After finishing the O/L again had to study for A/L. Luckily I did Bioscience for A/L’s, there I learnt about insects and light emitting chemical compound. So I tried to combine what I learnt and tried to come up with an idea to explain how fireflies emit light. But I was failed. But when I got selected to the university I had a chance to learn about advance scientific concept such as biochemicals and mostly about enzymes that emit light that I haven’t learnt for A/L. With those advance concepts in hand I searched about fireflies in internet.

Firefly bug is an insect which belongs to the family Lampyridae order Coleoptera. Now people who don’t have a background on biology might get confused. For them just think those fireflies are insects. Most firefly species are form larviform (like a worm) females which differ from larvae (young stage in life cycle) by having compound eyes, and beetles like males whereas males can fly but females cannot. But in some firefly species both males and females can fly. Most of firefly species are nocturnal (active in nights) they emit light with great intensity, some fireflies are diurnal (active in day times) usually they don’t produce light but some diurnal fireflies also produce light not in great intensity but in low intensity. These adult fireflies produce light in light organs that are located under their abdomen. It occurs through a bioluminescence process which is a biochemical reaction which involves enzymes and several bio molecules and other chemicals. This is how it happens; fireflies produce an enzyme called luciferase in light emitting organs. This luciferase acts on luciferin to give out the light when cofactors like Magnesium (Mg²⁺), ATP (Adenosine Tri Phosphate) another bio molecule and Oxygen (O₂) are present.

It happens in two ways one is Oxygen can directly react with luciferin to give oxyluciferin and light

lucifarin

luciferin + O₂ → oxyluciferin + light

If not initially luciferin reacts with ATP to give luciferyl adenylate and two phosphate groups. Then this luciferyl adenylate react with oxygen to give oxyluciferin, AMP (Adenosine mono phosphate) and light

luciferin + ATP → luciferyl adenylate + PP_i

luciferyl adenylate + O₂ → oxyluciferin + AMP + light

Fireflies use this bioluminescence process throughout their life cycle in many ways. When they are in larvae form they use this bioluminescence as a warning signal to predators since many larvae contain toxic and distasteful chemicals. In adult stage they use this processes in mating selection and some use to attract prey. I told you that fireflies that are diurnal usually do not emit light so how can they use light in mating selection; instead of light they use pheromones. That’s why firefly bug is a wonder of this earth. Firefly bug is only one wonder of the nature; there are so many beautiful creatures on earth so love them, care for them, study about them and preserve them for our future generations.

e-Waste/ Waste Electronic and Electrical Equipment

2011-06-17T19:14:00.002+05:30

e-Waste or waste electronic and electrical equipment is a major environmental issue that is faced by developing countries even though they produce a small amount of electronic products. These e-Wastes can be either electronic items such as computers, televisions that are discarded, donated or sold by the original owner.

These e-Wastes contain several harmful pollutants like large quantities of epoxy resins, fiberglass, PCBs, PVC (polyvinyl chlorides), thermosetting plastics, lead, tin, copper, silicon, beryllium, carbon, iron and aluminum and also elements found in small amounts like cadmium, mercury, and thallium. They also contain elements found in trace amounts like americium, antimony, arsenic, barium, bismuth, boron, cobalt, europium, gallium, germanium, gold, indium, lithium, manganese, nickel, niobium, palladium, platinum, rhodium, ruthenium, selenium, silver, tantalum, terbium, thorium, titanium, vanadium, and yttrium.

With the technical development, scientists invent new electronic devices that can be handled and used easily than old devices. When the old electronic devices are damaged, people purchase new electronic products while giving away the old electronic products to others or discarding them to the environmental without a proper disposal method. Some developed countries export these e-Wastes to developing countries in Asia and Africa through brokers who export these e-Wastes without recycling thus making e-Waste a global environmental issue.

Like I have mentioned earlier, these e-Wastes contain harmful environmental pollutants like heavy metals and plastics which produce unfavorable conditions to human and animal existence by ground water contamination, atmospheric pollution, water pollution and surface runoff. Sometimes these e-wastes cause sanitary problems in developing countries due to their ignorance of the proper techniques required for recycling, reusing, refurbishing, repairing and remanufacturing.

Since e-Wastes cause several threats to the environment, e-waste disposal undoubtedly needs a proper management. Therefore many countries, including both developed and developing countries have taken several precautions to manage e-waste disposal in order to not to make further environmental issues. One such precaution is proper recycling of e-waste. In this process, electronic wastes are converted in to their raw materials like gold, silver, copper and are reused in manufacturing. Even though recycling of e-waste leads to conservation of intact natural resources and minimizes air and water pollution caused by hazardous disposal, it can cause serious health care problems to the people who are involved in the recycling process and to the people who live around recycling process take place. Therefore the recycling process should be done with extra care and attention because if not acids and acidic sludge which are recycling inside the waste can pollute the surface water and ground water by leaching. Toxic flames and gases that are emitted during the recycling process can go in to the air and pollute the atmosphere. When e-waste gets stored in lands (landfills), toxic substance like PCBs, lead, and mercury in batteries and in other electronic products gradually leach in to ground water thus causing a deadly impact on the environment as well as on human sanitation.

Other than recycling we can introduce production process modifications to reduce the waste generation. We can also organize consumer awareness programs using mass media. Several laws, rules and regulations to electronic waste pollution can be also introduced as a measure to reduce this generation of e-Waste.

By minimizing and managing the e-Waste, waste electric and electronic equipments it is possible to reduce these environmental issues which make earth a nefarious place for living.

PCB (Poly Chlorinated Biphenyl) Pollution

2011-05-31T14:46:00.003+05:30

PCBs or in other words, polychlorinated biphenyls are widely used as organic compounds and as dielectric fluids in transformers and capacitors. PCBs are organic compounds that contain 1-10 chlorine atoms attaché to biphenyl group (C₁₂H_10-xCl_x) and they are formed by electrophilic chlorination of biphenyl with chlorine gas. PCBs or Polychlorinated biphenyls were first commercially used in 1929 as a “safer” cooling and as an insulating fluid in electrical industry.

These PCBs are not only used as coolants and insulating fluid but they are also used as components in early light fittings and in electrical transformers. Besides all these usages, PCBs are also used as plasticizers in paint and cement, as stabilizing additives in flexible PVC coating, in electrical wiring and in electronic components. Since PCBs have high viscosity, high flashing point and high thermal conductivity they can be used for cutting oils, as reactive flame retardants, lubricant oils, hydraulic fluids and sealants. And PCBs are organic compounds that contain Chlorine in it and therefore can also be used as pesticide.

These harmful PCBs got entered to the environment through illegal waste disposal and the use of PCB products. They also reached through spills of PCBs containing oils like hydraulic oils and through Industrial effluents containing PCBs. When these PCBs entered the environment they produce harmful effects in several ways. Hence, PCB pollution has already created crucial problems to several developed countries since they use more electronic equipments containing PCBs in order to accelerate their economic development. With the development and wide usage of electronic products, not only developed countries but also the developing countries face the same environmental problem thus making PCB pollution a threat to the whole world. PCBs being less soluble in water and highly soluble in organic solvents and in fats, when they are released to the environment they get accumulated in animals through the biomagnifications. Further, PCBs are fairly chemically inert and they are resistant to oxidation, reduction, addition, elimination and electrophilic substitution. Therefore once they are emitted to the nature, it certainly takes a very long time to get decomposed.

As a result, these PCBs create many environmental issues causing many health care problems to humans and other animals. One of the major environmental issues that arise due to PCB is toxicity which is associated with it. This was first reported in 1970’s in seabirds. Depending on the number of chlorine atoms, some PCBs tend to have dioxin- like properties that cause health problems to humans.PCB can also cause genetic mutations. Sometimes, these PCBs can affect the estragon and thus cause serious development problems in both males and females. It can also lead to cancers. In addition to all these, when a person is exposed to the PCB by breathing contaminated air, by consuming contaminated food or by breast feeding, it can cause sexual, skeletal, and mental development problems. Some people might show certain symptoms when they are exposed to PCBs, like skin rashes, changes in blood and urine due to liver damage and irregular menstrual cycles. And sometimes the PCBs affect the immune system as well. When the exposure to PCBs takes place in pregnancy period, it may cause low weight child births, babies with problems in motor skills and problems in immune system. When considering animals, mostly sea animals are affected by PCB contamination. Even though, PCB is less soluble in water, a large amount of PCB is present in sea water thus causing biomagnifications in sea mammals like whales which ultimately lead to mass death due to low immune defense.

Because of these critical social issues created by PCBs, PCB is considered an environmental pollutant and several attempts were taken to ban the use of PCBs. Even if we are to stop the use of PCBs, due to the chemically inert nature of PCBs, they remain in the environment for a long period of time without getting decomposed and thus causing environmental issues. Therefore we, as the affected lot have to decompose PCBs in every possible way, either chemically, physically or biologically.

For chemical decomposing we can use Neucleophylic aromatic substitution or cleave C-Cl bond by Hydrogen gas which is more expensive. Other than that, reactions with strong reducing agents or reactions with highly electro positive metals can be used, and there are many more chemical decomposing methods as well. For physical methods, incineration, ultrasound, irradiation, pyrolysis can be used. As biological methods we use microbial activities for the biodegrade of PCBs hence, microbes use PCBs as their carbon source. And their enzymes and vitamins are also helpful to stop the PCB activities in the environment.

Since, the use of PCB is a burning environmental issue some countries have prohibited the production while some countries have stopped using equipments that contain PCBs, like capacitors that are used with florescent lights. And also PCB storage and disposal are done according to the EPA (Environment Protection Agency) and under the TSCA (Toxic Substances Control Act) rules and regulations. Hopefully, these measures will help us to live in a healthier environment with minimal threats from Poly Chlorinated Biphenyls (PCBs).

Greenhouse effect and Global warming

2011-05-24T13:30:00.006+05:30

Global warming is one of the worst environmental problems that the modern world is facing due to several unfavorable human behaviors. According to scientists and scientific research, global warming increases the average temperature of the earth’s near surface, air and the ocean. As a result of global warming unwonted environmental effects take place, such as the rise of sea level which causes several problems to small islands like Maldives islands. Because of the global warming, there can be changes in the amount of precipitation, extreme weather conditions like droughts and heat waves. And also global warming can affect the biodiversity of the world by eliminating animal and plant species due to the shifting of the temperature.

For this worst environmental effect, the main reason is the human activities. For instance, after the industrial revolution, people started to use more fossil fuels which gave rise to greenhouse gases. These greenhouse gases lead to a natural phenomena called greenhouse effect, which helps us live in a warmer place or on the other hand which warms the earth beyond its effective temperature. Without greenhouse effect the earth surface will be much cooler than what we are experiencing today.

This is how it happens; when sunlight or solar radiation reaches the earth’s atmosphere, part of the radiation will be absorbed by the earth’s surface and the rest of the radiation energy will radiate back to the space. When there are greenhouse gases like CO₂, H₂O, CH₄ and O₃which are hetero nuclear molecules having permanent dipole moment, they trap the reflected radiant energy (IR)which is equal to their rotational and vibrational energies, before the radiation leave back to the space. Thus they will increase the temperature of the atmosphere by creating warm conditions.

But after the Industrial Revolution with the use of fossil fuel, emission of CO₂ gas has gradually increased. CO₂is a major component of greenhouse gases, which contributes about 9-26% to the overall greenhouse effect. Therefore, the naturally occurring greenhouse effect thus becomes an adverse effect to the earth because of the nefarious behavior of the human. Not only combustion of fossil fuel will increase the CO₂concentration in the atmosphere. As a result of the removal of vegetation, the accumulation of CO₂will increase since there are no green plants to absorb CO₂and produce food for everyone. Production of CH₄ also contributes to the greenhouse effect. This can occur via hot springs, garbage dumps and production of biogas.

With industrial and scientific development, we are unable to stop the use of fossil fuel. the finding of an environmental friendly alternative energy source is time consuming and also it needs a lot of money and knowledge. Therefore what we can possibly do is to reduce the CO₂emission while searching for an Eco friendly alternative energy source. We should also reduce the deforestation as much as possible. By reducing the CO₂concentration of the earth’s atmosphere, we can thus reduce the greenhouse effect. By employing the above mechanisms we can surely find solutions to global warming. The total elimination or at least a considerable reduction of the global warming will undoubtedly make earth a better place for living.

Climatic Changes

2011-05-21T18:53:00.002+05:30

Climate basically includes changes in temperature, humidity, atmospheric pressure, wind, precipitation of that place from a long period of time, whereas weather is the present condition of these elements. And we all know that climate is changing from place to place, since climate is affected by the latitude, terrain, altitude and the nearby water bodies. Therefore, we can say that climate is a prediction made by observing the weather of a place for a long period of time; these predictions of climate, are very important to human life because the distribution of natural resources like forest/ vegetation depends on the climatic factors. Therefore, even a slight change in the climate can influence human life at a greater degree.

Climatic changes are long term changes in the statistical distribution of weather patterns over period of time that range from decades to millions of years. The United Nations framework conversion on climatic changes defines climatic changes as “A change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods”. Climatic changes occur mainly due to the human behaviors that destroy the environment. Other than that, variation of solar radiation, deviation in the earth orbit, mountain building and continental drift contribute to the present undesirable climatic changes like extreme weather conditions.

As I mentioned, the most undesirable climatic changes are due to the human behaviors that cause major environmental issues, such like emission of CO₂ from fossil fuel combustion which lead to global warming. When the average temperature of the earth’s nearby surface air and ocean is increasing causing a high annual temperature and other climatic changes such like change in precipitation due to the high evaporation of surface water.

Not only human behavior cause climatic changes. Uncontrollable factors like variation of solar radiation cause changes in climate by affecting the global warming via cycle sunspot activity. Another factor is the orbital variation. Seasonal distribution of earth is mainly due to the rotation of the earth in current orbit, a slight change of the earth’s orbit can induce a large change in sunlight that reach earth surface and cause seasonal changes on earth. Variation of earth’s orbit can be due to

1. Change in tilt angle of earth’s axis of rotation

2. Precession of earth axis

3. Combination of above phenomena.

Other than these uncontrollable factors, volcanism which causes a cooling by partially blocking the solar radiation that receive by earth surface, plate tectonics (Building mountains, Continental drift) and ocean variations also cause climatic changes where position of continent affect the geometry of the ocean and thereby influences the patterns of ocean circulation which helps to transfer heat around the world.

Even though we got interested in climatic changes recently, changes in climate are not a new thing for earth, since they occur throughout the history of earth. Early scientists thought that climate changes occur slowly and that they cannot be seen during human life time. They thought that outside forces, ranging from human activities cannot make a permanent change in the atmosphere, since earth atmosphere is so vast and it would automatically drift back to normal state. With the increasing population, human influence on environment is so high and rapid so that changes have no more time to drift back to the normal state. Therefore, climatic changes are rapid and can be seen in naked eye. And these changes are not like early climatic changes; they are harmful for human life. Whereas these rapid changes in climate can incur health problems like water bone diseases due to undesirable precipitation causing floods. And it would introduce climatic sensitive vector bone diseases like “Dengue” (commonly found in Sri Lanka). And climate stress and the shifting of animal population would create conditions for the spread of certain infections, diseases from animal to human. Not only in health care,

modern unfavorable climatic changes have an impact on the world economy, like the undesirable changes like heavy precipitation, long term droughts. Tornadoes, cyclones destroy agriculture lands and living places thus creating problems that take much time to recover.

http://en.wikipedia.org/wiki/Climate_change

http://www.aip.org/history/climate/rapid.htm

http://www.who.int/globalchange/climate/summary/en/

FABRIC SOFTENERS/FABRIC CONDITIONERS

2011-04-13T21:12:00.005+05:30

Fabric softeners or Fabric conditioners are liquid product that used while laundering to make cloths soft and eliminate static cling. Fabric softeners or conditioners are introduce in early 20^thcentury in cotton industry since dye which use to colour the fibers make them feel harsh. Therefore cotton softeners were introduce to improve the quality of the cotton. With the rapid development in Industrial Chemistry more effective fabric softeners make their way in to commercial market.

When fabric softener is introduce in to the washing cycle, Fabric softener tends to deliver a variety of attributes to the cloth. Such as superior softness, Improve iron glide, Reduce the winker formation during wash cycle, Improve winker removal after washing, Better colour retention and enhance the stain protection.

With the increasing use of Fabric softeners/conditioners Scientist tends to manufacture environmental friendly, aesthetically pleasing, cost effective and safe fabric conditioners. In early 20^th century Fabric softener mainly Cotton softener manufactures use water emulsion of soap and Olive oil, Corn oil or Tallow oil. Major disadvantage of these early softener was they are not capable with the detergents therefore they should add after the detergents are removed from the rinse cycle. Not with the detergent. To overcome this problem, Scientists introduce dryer sheets in 1970s. Which can be added in the dryer instead of the washer rinse cycle. But the efficiency of dryer sheet is less than that of liquid fabric softeners. So Scientist involve more in manufacturing and developing liquid fabric softeners. They developed new liquid Fabric softeners based on quaternary Ammonium salts. In here Scientists use Ammonium salts with one or two long alkyl chains, a typical compound being dipalmitoylethyl hydroxyethylmonium methosulfate. Other cationic compounds can be derived from imidazolium substituted amine salts, or quaternary alkoxy Ammonium salts. One of the most common compounds of the early formulations was dihydrogenated tallow dimethyl ammonium chloride (DHTDMAC).

And there are anionic fabric softeners are manufactured by industrialists such as salts of monoesters and diesters of phosphoric acid and the fatty alcohols. These are often used together with the conventional cationic softeners. Even though these are effective softeners they also have disadvantageous. To overcome this Scientists invented a new type of Fabric softener which is Silicon based fluid called polydimethylsiloxane (PDMS) which has an ability to lubricate fibers to give improve softness and ease ironing. These Silicon derivatives not like quaternary ammonium salts they substantive to fabric and can dramatically improve its feel.

Almost all the Fabric softeners are hydrophobic due to the conditioning ingredients used. Therefore emulsifiers should use in order to avoid the separation of Fabric softener in to two layers. Fabric softener manufactures use 3 types of emulsifiers in the process of fabric softeners. They are

· Micro-emulsions

Creates oil particles that are so small that light will pass around them. And silicone particles are so tiny that they will actually penetrate into the fibers

· Macro-emulsions

The emulsifier molecules surround the hydrophobic oil or silicone droplets and allow them to be dispersed in water. And only deposit on the fiber's surface

· Emulsion polymers

Create dispersions that look similar to a macro-emulsion. This system does not use true emulsifiers to suspend and dissolve the oil phase. Instead, emulsion polymers create a stabilized web of molecules that suspend the tiny silicone droplets like fish caught in a net.

Other than these emulsifiers fragrance and colours are added to make softeners more pleasing to consume. And Other compounds are included to provide additional functions; acids or bases for maintaining the optimal pH for adsorption to the fabric, electrolytes, carriers

Manufacturing Fabric softeners involves several steps. For that we use mixing tanks that constructed from high grade stainless steel to prevent attack from the corrosive agents in the formula. The tank is typically equipped with a jacketed shell that allows steam and cold water to be circulated, so the temperature of the batch can be easily controlled. In addition the tank is fitted with a propeller type mixer that is driven by a large electric motor. This kind of mixing blade provides the high shear that is needed to properly disperse the ingredients.

And we can have our own Fabric softeners which are home made. In order to have homemade fabric softener we use hair conditioner and vinegar.

· In a seal able container combine 2 cups hair conditioner, 3 cups vinegar, and 6 cups water.

· Mix all ingredients together.

· Store in air tight container.

Of cause Fabric softeners make cloths feel better. But use of Fabric softeners cause problems to people with sensitive skin. These problems due to the ingredients that used in the manufacturing process. most of the time these allergies due to the fragrance used in Fabric softeners. And another problem that comes with Fabric softeners is they cannot easily remove from the cloths. For that washing it with vinegar can help. Other than that Borax also can use. And also Fabric softeners contain some amount of toxins such as

· Benzyl acetate

· Benzyl alcohol

· Chloroform

· Ethanol

· Ethyl Acetate

CHRONIC KIDNEY DISEASE IN SRI LANKA

2011-03-20T02:41:00.005+05:30

Chronic kidney disease is a major health problem in Sri Lanka since in last 8-10 years. CKDu or chronic kidney disease of unknown aetiology is characteristic from other kidney disease by its slow progressive asymptomatic development. This disease start at a younger age group and it is common among people who engaged in agriculture typically around age 40-60 years

In chronic kidney disease kidney dose not usually fail at once instead it slowly stepwise fail to perform it tasks chronic kidney disease involves 5 stages. Therefore stage 5 chronic kidney disease is also referred to as kidney failure, end-stage kidney disease, or end-stage renal disease, wherein there is total or near-total loss of kidney function. There is dangerous accumulation of water, waste, and toxic substances, and most individuals in this stage of kidney disease need dialysis or transplantation to stay alive.

Table 1. Stages of Chronic Kidney Disease

Stage	Description	GFR* mL/min/1.73m²
1	Slight kidney damage with normal or increased filtration	More than 90
2	Mild decrease in kidney function	60-89
3	Moderate decrease in kidney function	30-59
4	Severe decrease in kidney function	15-29
5	Kidney failure	Less than 15 (or dialysis)

"GFR level," or glomerular filtration rate, is a measure of how well your kidneys are cleaning your blood. Your doctor can calculate your GFR, based on a formula.

As I mention early CKDu is common among people who involve in agriculture. Geographically it is distributed in North central region ( North central province, part of North weston and part of Uva province) like Medawachchiya, Padaviya, Dehiaththakandiya.

Since CKDu is a major helth problem in Sri Lanka, Sri Lankan government try to identify the prevalence and main determinant of the chronic kidney disease. In this process researches and local authorities are mainly consider about

• Case Control study

• Cohort study

• Renal biopsy study (tissue and data collection)

• Environmental study group for case control phase of the study

• Environmental study group for analysis of water for case

• control study

• Post mortem study group (collection of organs and data)

• Human tissue (post mortem), urine and blood analysis study

• Chronic Kidney Disease registry and Geographical Mapping study

• Study group for analysis of animal tissues study

• Nutrition and Sociology Study

Even though several studies have been conducted main reason for CKDu is not yet verified by any research group that are involve in CKDu researches. But there are some acceptable explanations and theories associated with CKDu

01. Excessive quantities of naturally found fluoride in the ground water which can harm the kidney.

02. Excessive use of fertilizers, Insecticides, and weedicides.

03. The use of aluminum utensils made out of low quality cheap Aluminum to store water and to prepare food. The fluoride content found in the groundwater reacts with the Aluminum creating Toxic compounds (ALF x)

04. Entry of Toxic element such as Cadmium via food chain

05. Excessive consumption of poor quality illegal liquor.

Other than these explanations mycotoxins, use of herbal/ ayurvedic medicine, smoking and history of snakebite are some other factors to be considered. A combination of two or more of above factors possibly a synergistic effect. Or chemical substance form by combining agrochemical derivatives and naturally found Fluoride could also be responsible.

Reference:-

www.whosrilanka.org

http://www.emedicinehealth.com

http://www.hopkinsmedicine.org