(+5 rating, 7 votes)
Loading ... Loading ...

PHYSICS: NUCLEAR PHYSICS

Nuclear Fission

  • Nuclear fission is a reaction in which the nucleus of an atom splits into smaller parts
  • Nuclear fission can either release energy or absorb energy: for nuclei lighter than iron fission absorbs energy, while for nuclei heavier than iron it releases energy
  • Energy released can be in the form of electromagnetic radiation or kinetic energy
  • The amount of free energy contained in nuclear fuel is about a million times that contained in a similar mass of chemical fuel (like petrol)
  • The atom bomb or fission bomb is based on nuclear fission
  • Example: fission of Uranium-235 to give Barium, Krypton and neutrons

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

Nuclear Fusion

  • Nuclear fusion is the process by which multiple nuclei join together to form a heavier nucleus
  • Nuclear fusion can result in either the release or absorption of energy: for nuclei lighter than iron fusion releases energy, while for nuclei heavier than iron it absorbs energy
  • Nuclear fusion is the source of energy of stars.
  • Nuclear fusion is responsible for the production of all but the lightest elements in the universe. This process is called nucleosynthesis
  • Controlled nuclear fusion can result in a thermonuclear explosion – the concept behind the hydrogen bomb
  • The energy density of nuclear fusion is much greater than that of nuclear fission
  • Only direct conversion of mass into energy (collision of matter and anti matter) is more energetic than nuclear fusion
  • Example: fusion of hydrogen nuclei to form helium

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

PIONEERS OF NUCLEAR PHYSICS RESEARCH
Scientist

Nationality

Discovery

Recognition

J J Thomson

Britain

Electron (1897)

Nobel in Physics (1906)

Henri Becquerel

Belgium

Radioactivity (1896)

Nobel in Physics (1903)

Ernest Rutherford

New Zealand

Structure of atom (1907)

Nobel in Chemistry (1908)

He is regarded as the father of nuclear physics

Franco Rasetti

Italy/USA

Nuclear spin (1929)

James Chadwick

Britain

Neutron (1932)

Nobel in Physics (1935)

Enrico Fermi

Italy/USA

Nuclear chain reaction (1942)

Neutron irradiation

Nobel in Physics (1938)

Hideki Yukawa

Japan

Strong nuclear force (1935)

Nobel in Physics (1949)

Hans Bethe

Germany/USA

Nuclear fusion (1939)

Nobel in Physics (1967)

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

APPLICATIONS OF NUCLEAR PHYSICS

Application

Developed by

Working principle

Use

Nuclear power

Enrico Fermi (Italy, 1934)

Nuclear fission

Power generation

Nuclear weapons

Enrico Fermi (Italy, 1934)

Edward Teller (USA, 1952)

Nuclear fission

Nuclear fusion

Weapons

Radioactive pharmaceuticals

Sam Seidlin (USA, 1946)

Radioactive decay

Cancer, endocrine tumours, bone treatment

Medical imaging

David Kuhl, Roy Edwards (USA, 1950s)

Nuclear magnetic resonance (for MRI)

Positron emission (for PET)

MRI: Musculosketal, cardiovascular, brain, cancer imaging

PET: cancer, brain diseases imaging

Radiocarbon dating

Willard Libby (USA, 1949)

Radioactive decay of carbon-14

Archaeology

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

IMPORTANT NUCLEAR RESEARCH FACILITIES

Nuclear research facilities in the world

Facility

Location

Established

Famous for

Brookhaven National Lab

New York

1947

Until 2008 world’s largest heavy-ion collider

European Organization for Nuclear Research (CERN)

Geneva

1954

World’s largest particle physics lab

Birthplace of the World Wide Web

Large Hadron Collider (LHC)

Fermilab

Chicago

1967

Tevatron – world’s second largest particle accelerator

ISIS

Oxfordshire (England)

1985

Neutron research

Joint Institute for Nuclear Research

Dubna, Russia

1956

Collaboration of 18 nations including former Soviet states, China, Cuba

Lawrence Berkeley National Lab

California

1931

Discovery of multiple elements including astatine, and plutonium

Lawrence Livermore National Lab

California

1952

Los Alamos National Lab

New Mexico, USA

1943

The Manhattan Project

National Superconducting Cyclotron lab

Michigan

1963

Rare isotope research

Oak Ridge National Lab

Tennessee

1943

World’s fastest supercomputer – Jaguar

Sudbury Neutrino Lab

Ontario

1999

Located 2 km underground

Studies solar neutrinos

TRIUMF (Tri University Meson Facility)

Vancouver

1974

World’s largest cyclotron

Yongbyon Nuclear Scientific Research Centre

Yongbyon, North Korea

1980

North Korea’s main nuclear facility

Sandia National Lab

New Mexico, USA

1948

Z Machine (largest X-ray generator in the world)

Institute of Nuclear Medicine, Oncology and Radiotherapy (INOR)

Abbottabad, NWFP (Pakistan)

Pakistan Institute of Nuclear Science and Technology (PINSTECH)

Islamabad

1965

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

Nuclear research facilities in India

Facility

Location

Established

Famous for

Bhabha Atomic Research Centre

Bombay

1954

India’s primary nuclear research centre

India’s first reactor Apsara

Variable Energy Cyclotron Centre (VECC)

Calcutta

1977

First cyclotron in India

Institute for Plasma Research (IPR)

Gandhinagar

1982

Plasma physics

Indira Gandhi Centre for Atomic Research (IGCAR)

Kalpakkam

1971

Fast breeder test reactor (FBTR)

KAMINI (Kalapakkam Mini) light water reactor

Built the reactor for Advanced Technology Vessel (ATV)

Saha Institute for Nuclear Physics

Calcutta

1949

Tata Institute for Fundamental Research (TIFR)

Bombay

1945

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

CHEMISTRY: POLYMERS

Overview

  • A polymer is a large molecule consisting of repeating structural units
  • The repeating units are usually connected by covalent chemical bonds
  • Polymers can be of two types
    • Natural polymers: shellac, amber, rubber, proteins etc
    • Synthetic polymers: nylon, polyethylene, neoprene, synthetic rubber etc
  • Synthetic polymers are commonly referred to as plastics
  • The first plastic based on a synthetic polymer to be created was Bakelite, by Leo Baekeland(Belgium/USA) in 1906
  • Vulcanization of rubber was invented by Charles Goodyear (USA) in 1839. Vulcanization is the process of making rubber more durable by addition of sulphur
  • The first plastic to be created was Parkesine (aka celluloid) invented by Alexander Parkes (England) in 1855

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

Synthesis of polymers

  • The synthesis of polymers – both natural and synthetic – involves the step called polymerization
  • Polymerization is the process of combining many small molecules (monomers) into a covalently bonded chain (polymer)
  • Synthetic polymers are created using of two techniques
    • Step growth polymerization: chains of monomers are combined directly
    • Chain growth polymerization: monomers are added to the chain one at a time
  • Natural polymers are usually created by enzyme-mediated processes, such as the synthesis of proteins from amino acids using DNA and RNA

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

Categories of polymers

  • Organic polymers are polymers that are based on the element carbon. Eg: polyethylene, cellulose etc
  • Inorganic polymers are polymers that are not based on carbon. Eg: silicone, which uses silicon and oxygen
  • Copolymer is one that is derived from two or more monomeric units. Eg: ABS plastic
  • Fluoropolymers are polymers based on fluorocarbons. They have high resistance to solvents, acids and bases. Eg: teflon

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

TYPES OF BIOPOLYMERS

DNA as a biopolymer

DNA as a biopolymer

  1. Structural proteins
    1. Structural proteins are proteins that provide structural support to tissues
    2. They are usually used to construct connective tissues, tendons, bone matrix, muscle fibre
    3. Examples include collagen, keratin, elastin
  2. Functional proteins
    1. Proteins that perform a chemical function in organisms
    2. Usually used for initiate or sustain chemical reactions
    3. Examples include hormones, enzymes
  3. Structural polysaccharides
    1. They are carbohydrates that provide structural support to cells and tissues
    2. Examples include cellulose, chitin
  4. Storage polysaccharides
    1. Carbohydrates that are used for storing energy
    2. Eg: starch, glycogen
  5. Nucleic acids
    1. Nucleic acids are macromolecules composed of chains of nucleotides
    2. Nucleic acids are universal in living beings, as they are found in all plant and animal cells
    3. Eg: DNA, RNA

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

TYPES OF SYNTHETIC POLYMERS
  1. Thermoplastics
    1. Thermoplastics are plastics that turn into liquids upon heating
    2. Also known as thermosoftening plastic
    3. Thermoplastics can be remelted and remoulded
    4. Eg: polyethylene, Teflon, nylon
    5. Recyclable bottles (such as Coke/Pepsi) are made from thermoplastics
  2. Thermosetting plastics
    1. Thermosettings plastics are plastics that do not turn into liquid upon heating
    2. Thermosetting plastics, once cured, cannot be remoulded
    3. They are stronger, more suitable for high-temperature applications, but cannot be easily recycled
    4. Eg: vulcanized rubber, bakelite, Kevlar
  3. Elastomers
    1. Elastomers are polymers that are elastic
    2. Elastomers are relatively soft and deformable
    3. Eg: natural rubber, synthetic polyisoprene

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

IMPORTANT NATURAL POLYMERS AND THEIR APPLICATIONS
Polymer

Application

Notes

Collagen

Connective tissue

Gelatine (food)

Most abundant protein in mammals

Keratin

Hair, nails, claw etc

Enzymes

Catalysis

Hormones

Cell signalling

Cellulose

Cell wall of plants

Cardboard, paper

Most common organic compound on Earth

Chitin

Cell wall of fungi, insects

Starch

Energy storage in plants

Most important carbohydrate in human diet

Glycogen

Energy storage in animals

DNA

Genetic information

RNA

Protein synthesis

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

IMPORTANT SYNTHETIC POLYMERS AND THEIR APPLICATIONS
Polymer

Developed by

Constituent elements

Application

Notes

Parkesine

Alexander Parkes (Britain, 1855)

Cellulose

Plastic moulding

First man-made polymer

Bakelite

Leo Baekeland (USA, 1906)

Phenol and formaldehyde

Radios, telephones, clocks

First polymer made completely synthetically

Polyvinylchloride (PVC)

Henri Regnault (France, 1835)

Vinyl groups and chlorine

Construction material

Third most widely used plastic

Styrofoam

Ray McIntre (USA, 1941)

Phenyl group

Thermal insulation

Brand name for polystyrene

Nylon

Wallace Carothers (USA, 1935)

Amides

Fabric, toothbrush, rope etc

Family of polyamides

First commercially successful synthetic polymer

Synthetic rubber

Fritz Hoffman (Germany, 1909)

Isoprene

Tyres, textile printing, rocket fuel

Vulcanized rubber

Charles Goodyear (USA, 1839)

Rubber, sulphur

Tyres

Vulcanized rubber is much stronger than natural rubber

Polypropylene

Karl Rehn and Guilio Natta (Italy, 1954)

Propene

Textiles, stationary, automotive components

Second most widely used synthetic polymer

Polyethylene

Hans von Pechmann (Germany, 1898)

Ethylene

Packaging (shopping bags)

Most widely used synthetic polymer

Teflon

Roy Plunkett (USA, 1938)

Ethylene

Cookware, construction, lubricant

Brand name for polytetrafluoroehtylene (PTFE)

Very low friction, non-reactive

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

DEGRADATION OF POLYMERS

Ozone cracking in natural rubber tubing

Ozone cracking in natural rubber tubing

  • Degradation of polymers can be desirable as well undesirable: desirable when looking for biological degradation, undesirable when faced with loss of strength, colour etc
  • Polymer degradation usually occurs due to hydrolysis of covalent bonds connecting the polymer chain
  • Polymer degradation can happen because of heat, light, chemicals and galvanic action
  • Ozone cracking is the cracking effect of ozone on rubber products such as tyres, seals, fuel lines etc. Usually prevented by adding antiozonants to the rubber before vulcanization
  • Chlorine can cause degradation of plastic as well, especially plumbing
  • Resin Identification Code is the system of labelling plastic bottles on the basis of their constituent polymers. This Code helps in the sorting and recycling of plastic bottles
  • Degradation of plastics can take hundreds to thousands of years

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

Biodegradable plastics

  • Biodegradable plastics are plastics than can break down upon exposure to sunlight (especially UV), water, bacteria etc
  • Biopol is a biodegradable polymer synthesized by genetically engineered bacteria
  • Ecoflex is a fully biodegradable synthetic polymer for food packaging

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

Bioplastics

  • They are organic plastics derived from renewable biomass sources such as vegetable oil, corn, starch etc

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

Oxy-biodegradable plastics

  • Plastics to which a small amount of metals salts have been added
  • As long as the plastic has access to oxygen the metal salts speed up process of degradation
  • Degradation process is shortened from hundreds of years to months

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

BIOLOGY: GENETIC DISORDERS

About genetic disorders

Huntington's disease is inherited in the autosomal dominant fashion

Huntington's disease is inherited in the autosomal dominant fashion

  • Genetic disorders are disorders that are passed on from generation to generation
  • They are caused by abnormalities in genes or chromosomes
  • Some genetic disorders may also be influenced by non-genetic environmental factors. Eg: cancer
  • Most genetic disorders are relatively rare and only affect one person in thousands or millions
  • To recollect, males have XY chromosome pairs while females have XX pairs

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

Single Gene Disorders

  • Single gene disorders result from the mutation of a single gene
  • They can be passed onto subsequent generations in multiple ways
  • Single gene disorders include sickle cell disease, cystic fibrosis Huntington disease

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

Multiple gene disorders

  • Multiple gene disorders result from mutation on multiple genes in combination with environmental factors
  • They do not have a clear pattern of inheritance, which makes it difficult to assess risk of inheriting a particular disease
  • Examples include heart disease, diabetes, hypertension, obesity, autism

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

TYPES OF SINGLE GENE GENETIC DISORDERS
  1. Autosomal dominant

    Sickle cell disease is inherited in the autosomal recessive pattern

    Sickle cell disease is inherited in the autosomal recessive pattern

    1. Only one mutated copy of the gene is necessary for inheritance of the mutation
    2. Each affected person usually has one affected parent
    3. There is a 50% chance that the child will inherit the mutated gene
    4. Autosomal dominant disorders usually have low penetrance i.e. although only one mutated copy is needed, only a small portion of those who inherit that mutation will develop the disorder
    5. Eg: Huntington’s disease, Marfan syndrome
  2. Autosomal recessive
    1. Two copies of the gene must be mutated for a person to be affected
    2. An affected person usually has unaffected parents who each have one mutated gene
    3. There is a 25% chance that the child will inherit the mutated gene
    4. Eg: Cystic fibrosis, sickle cell disease, Tay-Sachs disease, dry earwax, Niemann-Pick disease
  3. X-linked dominant
    1. X-linked dominant disorders are caused by mutations on the X chromosome
    2. Males and females are both affected by such disorders. However, males are affected more severely
    3. For a man with a X-linked dominant disorder, his sons will all be unaffected (since they receive their father’s Y chromosome) while his daughters will all be affected (since they receive his X chromosome)
    4. A woman with a X-linked dominant disorder has a 50% chance of passing it on to progeny
    5. Eg: Hypophosphatemic rickets, Rett syndrome, Aicardi syndrome
  4. X-linked recessive

    X-linked recessive with a carrier mother

    X-linked recessive with a carrier mother

    1. Caused by mutations on the X-chromosome
    2. Males are affected more frequently than females
    3. The sons of a man affected by a X-linked recessive disorder will not be affected, while his daughters will carry one copy of the mutated gene
    4. The sons of a woman affected by a X-linked recessive disorder will have have a 50% chance of being affected by the disorder, while the daughters of the woman have a 50% chance of becoming carriers of the disorder
    5. Eg: colour blindness, muscular dystrophy, hemophilia A
  5. Y-linked disorders
    1. Caused by mutations on the Y chromosome
    2. Y chromosomes are present only in males
    3. The sons of a man with Y-linked disorders will inherit his Y chromosome and will always be affected while the daughters will inherit his X chromosome and will never be affected
    4. Eg: male infertility
  6. Mitochondrial disorders
    1. These disorders are caused by mutations in the mitochondrial DNA
    2. Only mothers can pass on mitochondrial disorders to children, since only egg cells (from the mother) contribute mitochondria to the developing embryo
    3. Eg: Leber’s Heriditary Optic Neuropathy

Keywords: India, ias, upsc, civil service, study material, general studies, general science, free

PREVIOUS WEEK: OPTICS, FERTILIZERS, GENETICS
~~~~~~~~
NEXT WEEK: PARTICLE PHYSICS, CERAMICS, GENETIC ENGINEERING

Bookmark and Share

One Response to “General Science #6 | Study Material :: General Studies | IAS Help”

  1. [...] PREVIOUS WEEK: OPTICS, FERTILIZERS, GENETICS ~~~~~~~~ NEXT WEEK: PARTICLE PHYSICS, CERAMICS, GENETIC ENGINEERING [...]

Leave a Reply

You must be logged in to post a comment.