Friday, 27 June 2025

Wesleyan University

Wesleyan University is in Middletown Connecticut. Its values include boldness, rigor and practical idealism. Wilbur Fisk was its first President in 1831. Its name comes from John Wesley the founder of Methodism. Its initial focus was on the liberal arts.

Tuesday, 3 June 2025

Kharif Crops

Kharif crops are also known as monsoon or autumn crops. 

"Kharif" means autumn in Arabic, and "autumn" is when the crops are harvested (sowing happens in the monsoon). Monsoon happens around June to November in India, depending on the area. The crops are generally harvested from the third week of September to October.

Rice is the major Kharif crop of India.

Tuesday, 27 May 2025

POPS and POPOS

POPS are privately owned public spaces, and POPOS are privately owned public open spaces. They are prevalent in London, New York and San Francisco

Friday, 25 April 2025

Engine Oil Dilution

Engine oil dilution is also known as "crankcase dilution" is a common occurrence in combustion engines and causes wear on the engine. Fuel and exhaust gases migrate to where oil is used.  It is a process that happens slowly.  The oil serves as a less effective lubricant and therefore wear inside the engine increases, as there is more friction between moving parts. 

The AdBlue Injector

The AdBlue system uses an injector to spray the calculated amount of DEF into the system.  The injector is prone to clogging and failure, which can lead to dashboard warning lights and even limp mode. If the electronics are working fine, the injector can be cleaned with an ultrasonic bath.

Diesel Basics - AdBlue and SCRs

Diesel cars emit mono-nitrous-oxide gases (NOx) which contribute to smog and acid rain, and, together with sunlight, the generation of tropospheric ozone (which can irritate the respiratory system).  

Modern diesel engines are equipped with SCR systems (SCR = Selective Catalytic Reduction) featuring an AdBlue system to clean up emissions, reducing harmful nitrous oxides into diatomic nitrogen and water.  

This process is aided by a catalyst.  Catalysts tend to be oxides (for example of vanadium, molybdenum and tungsten). Porous ceramic materials are used as supports e.g. titanium oxide.

AdBlue is the brand name for a Diesel Exhaust Fluid. This combination of demi water (demineralized water) and urea is added to the exhaust gases to clean up NOx.

This multistage cleaning process operates as follows:
1. Exhaust fumes created
2. Fumes passed thru DPF taking out soot particles (cause particulate pollution)
3. NOx sensor measures the mono-nitrous-oxides (NOx)
4. Based on NOx reading, AdBlue control unit determines amount of fluid needed to clean up NOx
5. Fumes enter catalyst, injector sprays DEF cleaning up NOx from fumes
6. Another NOx sensor measures post catalyst NOx. Remainder of NOx, with nitrogen and water, leaves the exhaust pipe.

This process is required by emissions standards such as Euro 6. It does not stop the generation of the generation of pollutants but rather is an aftertreatment system to post process the pollutants into less harmful chemical products.

What is DPF Forced Regeneration?

DPF forced regeneration burns off soot and other particles accumulated in the diesel particulate filter. It is used when the DPF reaches a certain level of particulate matter usually 40%. A diesel engine used mainly for short journeys can create the need for DPF forced regeneration if soot (created due to incomplete diesel combustion) doesn't get burned off. This can also reduce fuel efficiency. 

What are turbo boost controllers?

Boost controllers regulate the boost pressure created by your turbocharger (this pressure is used to push more air into your engine, creating more power). Too much pressure, though, can damage your engine and this is where the boost controller comes in. It ensure a same amount of air is forced into the engine to amp up its performance.

Tuesday, 22 April 2025

Bangla Sahib

Bangla Sahib is a gurdwara in Delhi associated with Guru Har Krishan Ji, eight guru of the Sikhs, and the youngest guru in Sikhism (hence also known as Bal Guru), appointed by Guru Har Rai before his death. The site was originally the location of a bungalow of Raja Jai Singh. 

It is said Guru Har Krishan died by contracting smallpox while successfully healing his followers. He had the shortest reign of any Guru lasting just under two years and six months.

Bangla Sahib gurdwara has an inscription "Sri Har Krishan Dhiaeai Jis Dithai Sabh Dukh Jaee".

Monday, 21 April 2025

Maruti Nandan

An epithet for Hanuman, meaning "son of the wind". Maruti refers to Vayu, god of the wind. Nandan means "delighting" and can also mean "son". Hanuman is also referred to as "Pavan Putr" which has the same meaning.

India Gate

India Gate is a war memorial in New Delhi located near the Rajpath. It is a memorial to the 74,187 soldiers of the Indian army who died in the First World War.

Revisiting Ferlinghetti

Lawrence Ferlinghetti is an eminently quotable American poet whose signature spirit is eminently critical of politicians and the status quo. This can be felt in his poem "I am waiting".

"I am waiting

for the American Eagle

to really spread his wings"

He served in the US Navy and saw the aftermath of the atomic bomb dropped on Nagasaki. He told the New York Times "In Plato’s republic, poets were considered subversive, a danger to the republic… I kind of relish that role". He was interested in freedom and revolutionary movements.

Monday, 27 January 2025

Azimuthal Quantum Number

Azimuthal quantum number is a quantity that is being increasingly talked about in chemistry.  The concept comes from quantum mechanics, and is a number assigned to an atomic orbital - a function that describes the wave like behaviour of an electron in an atom. Certain classes of elements in the periodic table such as transition metals are classified by their azimuthal quantum number.