Topics Covered
- Magnetoresisance
- Uttaramerur inscription
- Voice samples for investgation
- Facts for Prelims – Aspirational Toilet Scheme, Coco Islands, Bailey Bridge
1 . Magnetoresistance
Context: Researchers in the UK, led by Nobel laureate Andre Geim, have discovered another property of graphene – a single-atom-thick layer of carbon atoms bonded in a honeycomb pattern – that further distinguishes this ‘wonder’ material.
What is magnetoresistance? –
- Giant magnetoresistance (GMR) is a quantum mechanical magnetoresistance effect observed in multilayers composed of alternating ferromagnetic and non-magnetic conductive layers. GMR is the result of the electrical resistance of a conductor being affected by magnetic fields in adjacent mater.
- The overall resistance is relatively low for parallel alignment and relatively high for antiparallel alignment.
- Uses– It is used in hard disk drives and magneto resistive RAM in computers, biosensors, automotive sensors, microelectromechanical systems, and medical imagers.
- GMR-based devices are particularly used to sense magnetic fields.
What did the study find?
- A study conducted by Dr. Geim & co. found that graphene displays an anomalous Giant Magnetoresistance (GMR) at room temperature.
- The magnetoresistance observed in the graphene-based device was “almost 100-times higher than that observed in other known semimetals in this magnetic field range,”
- The effect is due to the way electrons in the conductor scatter off electrons in the ferromagnets depending on the orientation of the latter’s spin, which is affected by the direction of the magnetic field.
- Conventional GMR devices are cooled to low temperatures to suppress the kinetic energy of their constituent particles, keeping them from deflecting the electrons moving past them. In graphene, the researchers found this suppression unnecessary.
- The study found that graphene based GMR device can’t replace existing devices because the latter have other properties that the former doesn’t.
What is Graphene?
- Graphene is a single layer (monolayer) of carbon atoms, tightly bound in a hexagonal honeycomb lattice.
- It is an allotrope of carbon in the form of a plane of sp2-bonded atoms with a molecular bond length of 0.142 nanometres.
- This material is part of one of the most abundant substances in nature, graphite (graphite can be found, for example, in the mines of our pencils). One millimetre of graphite contains three million layers of graphene.
What are the Properties of Graphene?
The most outstanding properties of graphene are:
- High thermal conductivity
- High electrical conductivity
- High elasticity and flexibility
- High hardness
- High resistance. Graphene is approximately 200 times stronger than steel, similar to diamond resistance, but much lighter.
- Ionizing radiation is not affected
- Able to generate electricity by exposure to sunlight
- Transparent material
- High density which doesn’t let Helium atoms pass, but it does allow the passage of water, which evaporates at the same speed as if it were in an open container.
- Antibacterial effect- Bacteria are not able to grow in it.
- Low Joule effect, heating when conducting electrons.
- Low electricity consumption compared to other compounds
What are the applications of Graphene?
- In the field of electronics, graphene is used, for example, in the manufacture of microchips, transistors, development of conductive inks that allow the circuits printing.
- Graphene can enhance the use of renewable energy, such as solar energy. By introducing this material into the solar panels it will be possible to increase its efficiency and produce more energy.
- In the automotive sector, the use of graphene in batteries will increase its autonomy and reduce charging times, thus improving the performance of electric cars.
- Graphene has a lot of promise for additional applications: anti-corrosion coatings and paints, efficient and precise sensors, faster and efficient electronics, flexible displays, efficient solar panels, faster DNA sequencing, drug delivery, and more.
- Graphene is an exciting material that is getting a lot of attention – especially since the 2010 Nobel prize in physics went to Andre Geim and Konstantin Novoselov, who first isolated Graphene in 2004
2 . Uttaramerur Inscription
Context: Prime Minister Narendra Modi referred to the Uttaramerur inscription in Kanchipuram, Tamil Nadu, while discussing India’s democratic history.
Where is Uttaramerur?
- Uttaramerur lies in present-day Kanchipuram district, approximately 90 km southeast of Chennai. It is known for its historic temples built during Pallava and Chola rule.
- While Uttaramerur has multiple inscriptions spanning centuries, the most famous one – being referred to by the Prime Minister– is from the reign of Parantaka I (907-953 AD). These provide a detailed description about the village’s self-governance and have been cited by historians and political leaders alike as evidence of India’s history of democratic functioning.
- The famous inscription from Parantaka I’s reign is found on the walls of the Vaikunda Perumal Temple.
What does the inscription say?
- The inscription gives details of the functioning of the local sabha, i.e. the village assembly. A sabha was an assembly exclusively of brahmans and had specialised committees tasked with different things. The Uttaramerur inscription details how members were selected, the required qualifications, their roles and responsibilities, and even the circumstances in which they could be removed.
Appointing representatives to the Sabha
- Describing how the sabha shall be constituted, the inscription says, “There will be 30 wards. Everyone living in these 30 wards would assemble and select one representative for the village assembly.”
- It describes the qualifications for such a representative must be. These include ownership of a certain amount of land, having a house, being between the age of 35 and 70 and “knowing mantras and Brahmanas” (from the Vedic corpus).
- An exception can be made on land ownership if the person has learnt at least “one Veda and four Bhashyas”. One must also be “well-versed in business” and “virtuous”.
- The inscription then lists a number of factors which disqualify someone and their family (all the relations are systematically listed) from consideration.
- These include, “not having submitted accounts” while previously serving in a committee, committing any of the first four of the five ‘great sins’ (killing a brahman, drinking alcohol, theft and adultery), being associated with outcastes, and eating ‘forbidden’ dishes.
- All those eligible and willing would write their names on palm leaf tickets following which, the representative would be chosen on the basis of an elaborate draw of lots, conducted by priests in the inner hall of the building where the assembly meets.
Detailing responsibilities
- The inscription describes a number of important committees within the sabha with their own distinct functions. These include, the garden committee, the tank committee, the annual committee (an executive committee which required prior experience and knowledge to be a part of), the committee for supervision of justice (for supervising appointments and wrong doing), the gold committee (in charge of all the gold in the village temple) and the five-fold committee (its role is unclear in the inscription).
- These committee assignments would last for 360 days after which the members would have to retire.
- Anyone in the committee who was implicated in any wrongdoing, such as forgery or having ridden an donkey (i.e. being punished for a crime), was removed instantly. Also, the inscription emphasises upon the keeping of accounts – any discrepancy can also disqualify members of the sabha.
Is this an example of a democracy?
While the Uttaramerur inscription gives details of local self-governance, on closer inspection, it is far from a truly democratic system.
- Not only does it restrict sabha membership to a tiny subsection of land-owning brahmans, it also does not have true elections. Rather, it chooses members from the eligible pool of candidates through a draw of lots.
- That being said, this does not mean that this inscription should not be cited as a precedent for democratic functioning. The idea of a democracy, as understood today, is a fairly recent phenomenon. The United States, often hailed as the epitome of a liberal democracy, only gave universal adult franchise to its population in 1965.
- What the Uttaramerur inscription details is a system of local self-government, outside the direct authority of the king. Furthermore, for all intents and purposes, the inscription is like a constitution – it describes both the responsibilities of members of the sabha as well as the limitations to the authority of these members. If the rule of law (rather than rule by personal diktat) is an essential component of a democracy, the Uttaramerur inscription describes a system of local self-government
About Paranthaka Chola I
- Parantaka I (reigned 907–c. 953), known as the destroyer of Madurai (the capital city of the Pandyas), defeated Sinhalese invaders and united the lands of the Cholas and the Pandyas between 926 and 942. Coming to terms with the Rastrakutas, he took Nellore from them in about 940, but Rastrakutas king, Krishna III, seized Tondaimandalam.
3 . Voice samples for investigation
Context: The Congress leader Jagdish Tytler appeared before the Central Bureau of Investigation (CBI) to submit samples of his voice in connection with his alleged role in three murders in Delhi’s Pul Bangash area by a mob during the 1984 anti-Sikh riots. The CBI said it had fresh evidence in the case, for which Tytler’s voice had to be corroborated with a particular speech he made 39 years ago.
How is a voice sample taken?
- “A voice sample is generally taken in an echo-proof room for a controlled and noise-free environment and a voice recorder is used…the person is asked to speak a specific clue word from a statement already part of the evidence”.
- An investigating agency generally moves court, seeking permission to collect a person’s voice sample in connection with a case. Such forensic analysis is used to corroborate other aspects of the case.
- The frequency of a person’s voice remains the same for several years unless there is a medical condition in the voice chord or tract.
- A spectral analysis of the audio speech is undertaken where the pitch, energy and frequency of the voice are kept as the base to study and match the original audio sample.
- Forensic officials use international phonetic alphabets while recording a voice sample and ask the subject to pronounce only a small part of the original statement so that both vowels and consonants in the spoken bit can be alternatively analysed.
Methods of Voice sampling
- “There are two methods of comparison, you either get an anonymous voice sample and check it with a suspect list of five persons, or you know who the speaker is and corroborate both the voices”.
- A semi-automatic spectrographic method of voice sampling is used in Indian forensic labs while some countries use the automatic method where a likelihood ratio of the voice samples is developed, which increases accuracy.
- The spectrographic method for speaker recognition makes use of an instrument that converts the speech signal into a visual display.
- While the results of the voice sample either turn out to be positive or negative and the final report is submitted by the forensic lab to the investigating agency. Inaccuracies mainly arise when the person’s voice is altered due to the effect of medicines, or if the person is suffering from a cold.
How does a matching voice sample help the police’s case in court?
- A matching voice helps confirm the evidence already collected by the investigating agency. Depending on the evidence, an investigating officer directs the forensic expert to extract a particular sample which will help their case in court. The credibility of the sample depends on the technique used by the expert and how the court analyses it for proving a person’s culpability.”
When was it first used?
- The US Federal Bureau of Investigation (FBI) had first used the technique of voice identification analysis, also known as spectrographic at the time, as early as in the 1950s, but the procedure gained legitimacy in a 1962 study by Lawrence Kersta, a researcher working with a 1940s-model Bell Laboratory sound spectrograph.
What were the past cases in India where voice samples were collected?
- A special NDPS court had in February this year allowed a plea moved by the Narcotics Control Bureau (NCB), seeking collection of voice samples among 33 accused in a drugs case it was investigating after the death of actor Sushant Singh Rajput. NCB had claimed that it needed to verify certain voice calls that had emerged among the accused.
- Last year, the voice sample of Aftab Poonawala, accused of killing his live-in-partner and chopping her body into several pieces, was taken at CFSL after a local court allowed a police plea in light of an audio recording surfacing of the couple purportedly fighting.
- The Mumbai Police collected the voice samples of Aniksha Jaisinghani, daughter of alleged cricket bookie Anil Jaisinghani, accused of allegedly trying to blackmail and bribe Maharashtra Deputy Chief Minister Devendra Fadnavis’ wife, Amruta Fadnavis.
What is the legality behind collecting voice samples?
- In a 2013 case, the Supreme Court considered whether compelling an accused to give his voice sample in the course of an investigation would be violative of the fundamental right against self-incrimination or the right to privacy.
- India’s Criminal procedure laws do not contain a specific provision for testing voice samples because it is a relatively new technological tool. Collection of semen, hair samples for DNA analysis or taking general body measurements is routine and has specific provisions under law but for collection of voice samples, the police have to move court or seek consent of the accused.
- Section 53 (1) of the Code of Criminal Procedure allows examination of accused by a medical practitioner at the request of a police officer. The word examination in this provision includes “the examination of blood, blood stains, semen, swabs in case of sexual offences, sputum and sweat, hair samples and fingernail clippings by the use of modern and scientific techniques including DNA profiling and such other tests which the registered medical practitioner thinks necessary in a particular case.”
- While delivering a split verdict in the 2013 case, the SC acknowledged that there is no specific law for collection of voice samples. The case was subsequently heard by a 3-judge bench in which the SC said that the fundamental rights of the accused will not be violated by collecting a voice sample for investigation.
- The Court held that fundamental right to privacy cannot be construed as absolute and must bow down to compelling public interest.
- In a ruling on March 30, 2022, the Punjab and Haryana High Court observed that “voice samples in a sense resemble fingerprints and handwriting, each person has a distinctive voice with characteristic features dictated by vocal cavities and articulates. The samples are collected after having permission in accordance with the law. The sample taken itself would not be an evidence, rather they are for comparing the evidence already collected.
4 . Facts for prelims
Aspirational Toilet Scheme
- The aspirational toilets scheme was launched in September 2022 as part of the Swachh Bharat Mission (SBM) 2.0, with an aim to help make cities open defecation free.
- A link aspiration of this second phase of the mission would be that every Indian city should have at least an ODF++ certification. The essence of this certification is that every Indian city in the next five years, i.e., by 2026 must have functional community and public toilets.
- The Centre is planning to make a quarter of public restrooms in cities that will have high-end features like luxurious bath cubicles, touchless flushing, breast-feeding rooms, and automatic sanitary napkin incinerators, and will be visible on Google Maps as ‘Aspirational Toilets’.
- According to the report, the Centre has sent a directive to states that they need to make sure that henceforth 25 per cent of public toilet seats added in any city or urban unit are ‘aspirational toilets’.
- Aspirational Toilet Scheme will focus on include well-known cities as well as tourism and religious hotspots. High-traffic areas, including well-known marketplaces, railway stations, interstate bus depots, and national highways, would be allotted priority in such hotspots.
- The goal is to make sure that these public restrooms are present in locations where people are likely to spend longer than three to four hours at a time.
- The bathrooms must be free of stains and graffiti, have low-height toilets and sinks for kids, be surrounded by well-kept patches of green, have readily available hand dryers, paper napkins and have vending machines for sanitary napkins.
- According to the report, the government is also planning to have libraries, cafes, and shopping complexes attached to these restrooms in order to raise funds for their maintenance and upkeep.
- In order to make these restrooms self-sustaining, the government is also contemplating one of the economic models where these toilets will be attached to other public services like restaurants, shopping centres, libraries, movie theatres, or even chemist stores.
Coco Islands
- Coco Islands are a small group of islands in the north-eastern Bay of Bengal. They are part of the Yangon Region of Myanmar.
- The islands are located 414 km (257 mi) south of the city of Yangon.
- Coco Island group consists of five islands: four on Great Coco Reef and one on the Little Coco Reef.
- To the north of this island group lies Preparis Island, belonging to Myanmar. To the south lies the Landfall Island, belonging to India.
- Geographically, they are a part of the Andaman and Nicobar Islands archipelago, most of which belongs to India. They are separated from Landfall Island, the northernmost island in the Indian part of the archipelago, by the 20 kilometres (12 mi) wide Coco Channel.
Bailey Bridge
- A Bailey bridge is a factory-made truss bridge. It was made in small sections that could be easily moved and put together on site. It was developed by the British during World War II for military use.
- A Bailey bridge did not need special tools or heavy equipment to put into place. The bridges were strong enough to carry tanks. Bailey bridges continue to be used in building projects and to provide temporary crossings for people and vehicles.
- It was designed by a British engineer, Donald Bailey. The British army tested different bridge designs in 1941–1942, including a suspension bridge and a stepped arch bridge. The flat truss bridge was the most successful.
- A Bailey bridge between the Suru River and Dras River in Ladakh, India is the highest bridge in the world at an altitude of 5,602 meters (18,379 ft) above sea level. It was built in 1982 by the Indian Army