Friday, 16 August 2013

Is Economics More Like History Than Physics?

Is economics like physics, or more like history? Steven Pinker says, “No sane thinker would try to explain World War I in the language of physics.” Yet some economists aim close to such craziness.
Pinker says the ”mindset of science” eliminates errors by “open debate, peer review, and double-blind methods,” and especially, experimentation. But experiments require repetition and control over all relevant variables. We can experiment on individual behavior, but not with history or macroeconomics.

Isaiah Berlin pointed out that “because” is used differently in science and history. In science, it means reliably causal. In history, it means a looser, narrative kind of causation, a useful explanation of the complex web of factors affecting a particular situation. Since Plato many have privileged universal timeless truths. But history’s truths are typically particular and time bound, describing changes through time.

Pinker’s science needs types and theories. It assumes that phenomena “may be explained by principles that are more general than the phenomena themselves.” But Berlin noted that knowledge can be nomothetic or idiographic. “Nomothetic” means fit for law-like generalizations, having reliably repeatable regularities. “Idiographic” means much the same as the Hebrew word “da’at”: knowledge gained through direct relationship with the particular (not via theories or types). ()

Physics is fortunate to enjoy a kind of closedness that human life lacks. Nothing in physics chooses. And nothing it studies innovates. History and economics study things that can change how they act and react. So the methods of the inanimate sciences face extra challenges when used on people. Even statistics and probability can’t always help. Previously measured distributions can be upset by the spread of behavioral changes, making social systems less predictable.

Jerome Kagan notes that “19th century economists, mimicking the physics of the era…adopted the mathematics that physicists used to describe” inanimate equilibria. Many economists still use such methods. And macroeconomists try to model events essentially as complex as world wars, using (insanely by Pinker’s standards) the language of physics.

The Oxford English Dictionary says “science” originally just meant knowledge. In the Middle Ages, the seven liberal arts (grammar, logic, rhetoric, arithmetic, music, geometry, astronomy) were also called the “seven liberal sciences.” Shakespeare used science in that sense: “Cunning in Musicke, and the Mathematickes, To instruct…in those sciences.”

We risk blinding ourselves with science, in its now narrower highly reliable form. It is dazzling. But it also has limits. Its tools don’t fit all situations. Economics, especially the macro kind, has history-like aspects. Its narratives might be woven with data, but not everything that counts can be counted. It must deal with different kinds of change that (to paraphrase Shakespeare) were never dreamt of in our physics. Perhaps this limits economics to moderately reliable maxims.

Crowdfunding Campaign Bids to Launch Tiny Interplanetary Probe

A mini-satellite, no bigger than a loaf of bread, could push itself out of Earth’s orbit as soon as next year if a crowdfunding campaign to support development of a diminutive propulsion system succeeds. If such small spacecraft can be made to operate far from Earth, they could one day make inexpensive expeditions to asteroids, Mars, and beyond.




Interplanetary spacecraft are typically bigger than a car, cost hundreds of millions to billions of dollars, and take many years to develop and launch. In recent years researchers have been pondering how to send small satellites, called CubeSats, which have been launched into Earth orbit over the past decade, mainly by university teams, farther afield.

Researchers at the University of Michigan have a design for a propulsion system they believe is ready to send a CubeSat on an expedition into deep space. Their campaign on the fundraising site Kickstarter asks for $200,000 to pay for development needed to make a test launch next year.

Since July 4, more than 800 people have pledged over $32,000 to the CubeSat Ambipolar Thruster project. That’s well short of the final goal, but the campaign seems likely to succeed thanks to interest from some deep-pocketed donors. “We’ve already had a couple of people contact us and tell us they just want to fund the whole thing,” says team leader Benjamin Longmier. The Michigan researchers have also applied for grants from U.S. government agencies.

The satellite could launch in a year, says Longmier, and embark on an interplanetary trip after being tested in low-Earth orbit. It is not clear how long it would survive, but on the Kickstarter page, the team jokes that 100 million years from now, the little probe could be found and displayed in a museum in the Alpha Centauri system.

No CubeSat has left Earth orbit before, but the Michigan team believes its propulsion system solves a key barrier to cheaper interplanetary exploration. CubeSats are made from one or more 10-centimeter-wide instrument boxes, and hitch rides to orbit with larger, more expensive spacecraft. That limits the kinds of propulsion systems that can be installed onto a CubeSat. Common systems that use explosive chemicals or highly pressurized gases to produce thrust would pose too much risk to a CubeSat’s pricier launch mates. Nearly all of the 100 or so CubeSats launched to date have had no propulsion system at all.

The Michigan system would pose no danger to the launch it was hitchhiking with because it would use a non-explosive propellant such as iodine or water stored in an unpressurized container.

To propel the satellite, a heater would vaporize the propellant, sending neutral atoms of gas into a small chamber. A radio antenna around that chamber would energize the gas, causing collisions that would knock electrons off the gas atoms to create a plasma. A ring-shaped permanent magnet would then accelerate these charged particles out a nozzle to thrust the CubeSat in the opposite direction.

The Michigan team says its system could fit inside one 10-centimeter-wide module of a three-unit CubeSat, and propel it at speeds of up to 10 kilometers per second. That would be enough to push the satellite at least a million kilometers from Earth, out of the planet’s gravitational grip.

Paulo Lozano, director of the space propulsion lab at MIT, says he has some doubts about the project. The plasma will need to be extremely dense to provide ions for thrust, he says, and high-density plasmas tend to damage anything they contact. “If they are able to do it, that’s great,” says Lozano, who is developing another electric propulsion system that uses ions in salty liquids, rather than plasmas, to generate thrust.

Longmier responds that the magnet that directs the spew of ions out of the thruster will also prevent most plasma from contacting the walls of its chamber, buying enough time for a CubeSat to escape Earth’s orbit. “It looks like we can process up to about 10 to 20 kilograms of propellant with our little thruster,” says Longmier, and simulations suggest less than three kilograms are needed to send a CubeSat beyond Earth. Erosion, he says, seems to be a “nonissue.”

Other spacecraft components—such as power and communication systems—still need to be developed for CubeSats to do much when they’re far from Earth. But in a few more years, they could be sent to study asteroids or to look for signs of life on distant icy moons, the team writes on its Kickstarter page. Because of their size, the petite probes may be able to take only a single type of measurement at each location rather than carry multiple instruments like a traditional craft, but Lozano says they have one big advantage over larger missions: “They are very inexpensive.”

Device Could Spot Seizures by Reading Brainwaves through the Ear

Neuroscientists often use electroencephalography (EEG) as an inexpensive way to record electrical signals in the brain. Though it would be useful to run these recordings for long periods of time, that usually isn’t practical: EEG recording traditionally involves attaching many electrodes and cables to a patient’s scalp.
Now engineers at Imperial College in London have developed an EEG device that can be worn inside the ear, like a hearing aid. They say the device will allow scientists to record EEGs for several days at a time; this would allow doctors to monitor patients who have regularly recurring problems like seizures or microsleep.
“The ideal is to have a very stable recording system, and recordings which are repeatable,” explains co-creator Danilo Mandic. “It’s not interfering with your normal life, because there are acoustic vents so people can hear. After a while, they forget they’re having an EEG.”
By nestling the EEG inside the ear, the engineers avoid a lot of signal noise usually introduced by body movement. They can also ensure that the electrodes are always placed in exactly the same spot, which, they say, will make repeated readings more reliable.


Since the device attaches to just one area, it can record only from the temporal region. This limits its potential applications to events that involve local activity. Tzzy-Ping Jung, co-director of the University of California, San Diego’s Center for Advanced Neurological Engineering, says that this does not mean the device will not be valuable.
“Different modalities will have different applications. I would not rule out the usefulness of any modalities,” says Jung. “I think it’s a very good idea with very promising results.”

Tuesday, 5 February 2013

Analytical instruments


Importance Of Analytical Instruments
Analytical instruments  a large class of instruments used to analyze materials and to establish the composition.e.g  spectrophotometers, mass spectrometers, gas chromatographs, potentiometric titrators, ion analyzers, polarographs, coulometer, x-ray spectro-meters, Karl Fischer titrators, atomic absorption spectrometers, fluorimeters and many, many others
Importance analytical instruments are very important because them the world would not have been such as it is now. Many chemical and physical processes are kept count of by using analytical instruments.It was due to the use of these instruments in field of science which opened door way to new world and new prospective. Due to use of instruments such as spectrometer we have gained better under standing of atomic and molecular structure so many vital roles have been played by analytical instruments in the field of science research.
With the help of different chromatographic techniques, the analyst is separated from molecules in a mixture for isolation. These instruments are designed for the benefit of lab technicians, so that they can measure the density of gases in a lab. This practice is carried out to maintain the cleanliness in the premises, so that the patients may not come across any breathing difficulties.
Hospital-to detect blood or alcohol levels in a patient’s blood stream
Law Enforcement – to compare a sample found at  a crime scene to samples from suspects
Environmental Agency – determine the level of  pollutants in the water supply
Manufacturing Plant – to purify a chemical needed to make a product

Industry  In industry analytical instruments are used widely to monitor the chemical and physical processes and to keep quality under control
Agriculture Analytical instruments are important part of research associated with agriculture. These are used to check soil fertility and then the data obtained is further used for the recommendation process to recommend what kind of crop will best suite this kind of soil
DairyAnalytical instruments such are widely used and important part of dairy industry
·        Instruments such as bactocount are used to count bacteria in milk which insures that milk is safe to drink
·         These are used to count number of somatic cells in sample of milk
Pharmaceuticals In medicine making different analytical instruments are used it won’t be wrong to say that medicine industry would not exist without these instruments
·         Quality analysis of medicine to see whether it is up to proportion or not
·         In research and development of new medicines
·         In extraction of desired chemicals from the natural sources
Biotechnology   The use of mass spectrometry in the biotechnology field has increased such that the technique is essential in the development, manufacture, and control of protein therapeutics. The combination of mass spectrometry and chromatography (LC-MS) has proven to be particularly effective. Peptide maps (digested pieces of proteins separated by RP-HPLC) are now monitored by mass spectrometry to determine protein degradations such as oxidation and post-translational modifications like glycosylation (sugar content).
Petroleum industry  The petroleum products used in vehicles are the chemical composition of many compounds. They can make be pure by determining the components both by traditional X-ray fluorescence (XRF) and by total reflection (TXRF) and also by fractional distillations, where it is necessary to verify the presence of micro-traces of pollutants in pure products..
·         It is important to determine the presence of metals during the production of fuels or lubricating oils. This may be made through X-ray fluorescence techniques (XRF) or through optical emission spectrometers (ROTROIL).
·         Few ppm sulphur content in fuels is determinate through X-ray fluorescence (XRF). In chemical and petrochemical plant-engineering field the quality check of materials employed to build the facilities is extremely important. The elementary analysis or PMI of metal materials such as valves, pipes, reactors, is made through optical emission spectrometry (OES) and portable X-ray fluorescence (XRF)
                  

GPS


GLOBAL POSITIONING SYSTEM
Global Positioning System is a navigational system involving  satellites  and computers
Working: Each GPS satellite transmits data that indicates its location and the current time. All GPS satellites synchronize operations so that these repeating signals are transmitted at the same instant. The signals, moving at the speed of light, arrive at a GPS receiver at slightly different times because some satellites are farther away than others. The distance to the GPS satellites can be determined by estimating the amount of time it takes for their signals to reach the receiver. When the receiver estimates the distance to at least four GPS satellites, it can calculate its position in three dimensions.
APPLICATIONS
saves lives: GPS saves lives by preventing transportation accidents, aiding search and rescue efforts, and speeding the delivery of emergency services and disaster relief.
 critical component of any successful rescue operation is time. Knowing the precise location of landmarks, streets, buildings, emergency service resources, and disaster relief sites reduces that time -- and saves lives. This information is critical to disaster relief teams and public safety personnel in order to protect life and reduce property loss. The Global Positioning System (GPS) serves as a facilitating technology in addressing these needs.

Mapping and Surveying: GPS applications in natural resource management include inventory and mapping of soils, vegetation types, threatened and endangered species, lake and stream boundaries and wildlife habitat. GPS has been used to aid in damage assessment after natural disasters such as fires, floods and earthquakes. GPS has also been used to map archaeological sites and for infrastructure (streets, highways and utilities) mapping, management, and planning for future growth. Engineers use GPS for surveying when building roads, bridges and other structures.

Military use: For marine operations, including search and rescue  GPS provides the fastest and most accurate method for mariners to navigate, measure speed, and determine location. This enables increased levels of safety and efficiency for mariners worldwide.
GPS  remains critical to U.S. national security, and its applications are integrated into virtually every facet of U.S. military operations. Nearly all new military assets -- from vehicles to munitions -- come equipped with GPS.

Alexa rank


ALEXA RANK

Alexa Rank is a relative measurement on how popular a web site among the Internet community. Alexa is relative because it depends on the data of Alexa Toolbar users. And also Alexa Toolbar is only for Internet Explore which means it doesn’t count growing group firefox fans or any other browser users. But there are over 10 million Alexa Toolbar users who make it a recognized measurement
·        The traffic rank is based on three months of aggregated historical traffic data from millions of Alexa Toolbar users and data obtained from other, diverse traffic data sources, and is a combined measure of page views and users (reach). As a first step, Alexa computes the reach and number of page views for all sites on the Web on a daily basis. The main Alexa traffic rank is based on a value derived from these two quantities averaged over time (so that the rank of a site reflects both the number of users who visit that site as well as the number of pages on the site viewed by those users). The three-month change is determined by comparing the site's current rank with its rank from three months ago. 
·        Reach measures the number of users. Reach is typically expressed as the percentage of all Internet users who visit a given site. So, for example, if a site like yahoo.com has a reach of 28%, this means that of all global Internet users measured by Alexa, 28% of them visit yahoo.com. Alexa's one-week and three-month average reach are measures of daily reach, averaged over the specified time period. The three-month change is determined by comparing a site's current reach with its values from three months ago.
·        Page views measure the number of pages viewed by site visitors.  The page views per user numbers are the average numbers of unique pages viewed per user per day by the visitors to the site.
·        The Trend graph shows you the site's daily traffic rank, charted over time. The daily traffic rank reflects the traffic to the site based on data for a single day. In contrast, the main traffic rank shown in the Alexa Toolbar and elsewhere in the service is calculated from three months of aggregate traffic data.
·        The movers and shakers list is based on changes in average reach (numbers of users). For each site on the net.they compute the average weekly reach and compare it with the average reach during previous weeks. The more significant the change, the higher the site will be on the list
·        They then normalize the data on demographic distribution of site visitors. Geographical distribution as such to represent those who do not use Alexa toolbar
Alexa rank
·        Google.com.pk                   138 alexa rank
·        Dawn news                         4017 alexa rank
·        Olx.com.pk                   1627  alexa rank   
·        Ilmkidunya.com.pk      12197 alexa rank
·        Rozee.pk                       4090   alexa rank        

Chemistry

CHEMISTRY II CHM 201
A chemical Engg. course introduced in 3rd semester usually
OBJECTIVES
Chemistry and Chemical Engineering remain critical professions today. Chemistry is essential to the modern society we live in. The chemicals, from which all manner of consumer products are manufactured, are produced in processes developed from the fundamental principles of chemistry. This course provides a key to the process development of consumer products, industrial materials, medicines and foodstuffs. This provides a basic understanding of the most common chemical processes being exploited in chemical industries with a special emphasis on kinetics and thermodynamics of the processes. It is expected to develop among students a sound understanding of physio-chemical principles of chemical industries. The course aims at learning and applying knowledge of organic chemistry for unit processes in organic synthesis. It also introduces students of chemical engineering about the fundamental concepts of biochemistry essential for the relevant biochemical industries.
OUTLINE
Functional groups, Inter conversion of functional groups (FGIs), Reactions mechanism. Unit Process; Thermodynamics, Kinetics, and the mechanism, of sulfonation; nitration; hydrogenation; amination; halogenation, oxidation, polymerization.
Introduction to Bio-chemistry, carbohydrates, proteins, lipids, Enzymes and their types, Mode of action of Enzyme, Factors influencing enzyme activity.
RECOMMENDED BOOKS
link 1
http://www.4shared.com/office/MlNArIOm/Organic_Chemistry_-_3rd_Editio.html

link2