Recently, the media has seemed to catch on the new invention—NFTs. NFT is a unique, non-interchangeable digital asset basked by blockchain ledger technology. Non fungible characteristic of these tokens or assets refers to the unique and non-replicable nature of this digital-crypto assets, compared to, for example a Bitcoin or a US$1 bill, where each unit of the asset is interchangeable and is the same.
Examples of NFTs range widely from digital art, domain names, games, and collectibles to are audio and video recordings. NFTs are created (i.e., minted) on a blockchain, such as Ethereum, which authenticates the ownership and the NFT asset (i.e., where it comes from, where it originates, and who is the owner).
In the physical world, a tangible example would be Mona Lisa’s painting by Leonardo Da Vinci. Although there are many replicas, there is one original Mona Lisa in the world, and this piece of art is unique, creative and indivisible.
Similarly, NFTs are creative works of art that, for the most part, do not allow for fractional ownership. Some NFTs can be very expensive, with a price tag of millions of dollars.
Some trace the origins of the NFTs back to 2012-2013 when colored, small denominations of bitcoins were created. These coins represent different assets with different uses, ranging from collectibles to access tokens. These colored coins were “unique and identifiable from regular bitcoin transactions. “
In 2014, Robert Dermody, Adam Krellenstein, and Evan Wagner founded a peer-to-peer financial platform, Counterparty, which was built on top of the bitcoin blockchain. In 2015 and onward, trading cards and memes became prevalent. Various video games popularized the creation of digital assets to be stored on blockchain technology; these included swords, shields, and even digital parcels of real estate. Crypto kitties became famous in 2017, launched by the Vancouver-based company Axion Zen.
In 2021, NFTs have gained more momentum and have started to permeate the mainstream economy in some unexpected ways. The NFTs are poised to create a brand-new aspect of the digital.
In fact, we are launching our own NFTs based on a series of paintings by a famous Sabah artist, Dato’ Sri Wilson Yong, who called himself the Borneo Art Creator.
British Malaya (then Malaysia) used to be the major producer of natural rubber, gutta percha and tin. These three commodities made British Malaya an important British colony in the late 19th century and the early 20th century.
Natural rubber industry is no longer important in Malaysia, as rubber has been replaced by oil palm as the most important industrial crop in the country since the 1970s. However the economic and social impacts of the natural rubber industry have been very significant for Malaysians during the period from late 19th century to 1970s.
In the next few articles, we will be covering various aspects of the natural rubber industry, from its development in British Malaya, the innovators of the rubber products and the decline of the rubber industry. Every pupil in Malaysia knew that the seeds of rubber trees originally were smuggled out of Brazil. Later they came to British Malaya.
The first of the article is how I membered about rubber trees and daily activities revolving around rubber.
Rubber trees and daily tapping of latex
An early clone of rubber tree used to be able to be productive after 5 to 7 years. The bark needs to be tapped to allow the bark to “bleed” a white latex. The white latex is collected in a cup made of porcelain. The work of a rubber tapper started early in the morning at about 6 am. My parents used to have a small holding of rubber trees about a few kilometres from our home in Beranang, Selangor, Malaysia, in the 1960s. They cycled to the rubber small holding about 6.00 am, with a sharp rubber tapping knife. First, using a headlight light for illumination, they removed a thin slice of the rubber bark which was enough for the rubber latex to “bleed” and to be collected in the attached cup. They would take about an hour to complete the tapping of rubber trees in the small holding. By 8.00 am, the cups would be filled with white rubber latex. Then, they emptied the cups containing rubber latex to a big pail.
The pails would be placed onto the bicycle and transported to a communal rubber rolling centre. Every village would have a communal rolling centre to process the rubber latex into rubber sheets.
At the communal rolling centre, a measured amount of formic acid would be added to the rubber latex which had been poured into a special rectangular steel container. After a while, the rubber latex would coagulate, separating water from rubber. The rubber was still soft and about 4 to 5 cm thick. The soft block of rubber would be passed through an iron roller to reduce the thickness of rubber block to about 1 cm. The remaining water in the rubber block would have been completely removed after going through several times of rolling. Finally, the thin rubber sheet was dried in the sun to remove the remaining water. The dried drubber sheet would turn slightly brown after several days under the sun. The rubber was now ready to be sold for cash.
The tapping of rubber trees and the conversion of rubber latex into rubber sheets would take from 6 am to about 12.00 noon, every day.
After resting for lunch, most villagers would go to the their small paddy field to prepare their rice fields or to harvest their paddy. The rice filed would become their supplementary income after rubber sheets. In every town in Malaysia, there would be rubber dealers who would buy the rubber sheets at “discounted prices” after quality checks.
As expected, rubber small holders and the villagers were poor, surviving from selling of rubber sheets. This was compounded by the fluctuations of prices of rubber sheets on the world market. At time of high rubber prices, they would purchase a new bicycle for the family or a having “a feast” with the first-harvest of rice from the paddy field.
Rubber plantation companies were wealthy
The rubber small holding sector was a not a significant segment of the rubber industry. Rubber estates or plantations were much bigger with substantial acreage. The rubber estates boomed in the early 1900s to 1930’s when the motor industry emerged in Europe, US and Japan, thanks to Mr Henry Ford. In the early 1900s investment syndicates based in London drew investors, both individuals and institutions, to invest in rubber estates in British Malaya. At the time, British administrators in British Malaya opened up a vast area of forest to be cleared to plant rubber. Established British companies in British Malaya also attracted investors to buy smaller rubber estates to be consolidated into larger estates.
If we were to travel by car in British Malaya in the 1930s, rubber estates with British names would be scattered throughout British Malaya. These rubber estates would be managed by British planters, with the help of locals. They employ mostly Indian rubber tappers brought in from India, who were paid low salaries.
The larger rubber estates would have their own golf courses and social clubs. My wife’s late mother described the lives of the British planters vividly. She was about ten and lived in Rantau, Negeri Sembilan, Malaysia, where her village was surrounded by one of largest rubber estates in British Malaya.
“ Every evening, about 6 pm, I saw many cars, driven by Malay drivers, cruising to the Club in the centre of the town. The “missuses” of the British planters wore nice dresses, which were different from those worn by the local women.”
There was the days when rubber was the economic pillar of the economy of British Malaya.
Everyone knew that the rubber sheets sold to local rubber dealers would be destined to Europe. Very few would know that the innovations that led to the use of natural rubber into industrial products, notably tyres, were created much earlier in the mid of the 19th century. Many of these innovators went bankrupt many times during the innovative pursuits.
The next article would cover these innovators, which had transformed British Malaya from a nation of mainly forests to a modern economy driven by rubber trees. As Malaysians now, we should salute these innovators, such as the Hancocks of Marlborough and Charles Goodyear.
Previously, we covered about Magawa, the landmine detector that was awarded a gold medal for heroism for clearing ordnance from the Cambodian countryside. Magawa has just died.
Magawa, a giant African pouched rat originally from Tanzania, helped clear mines from about 225,000 square metres of land – the equivalent of 42 football pitches – over the course of his career.
After detecting more than 100 landmines and other explosives, Magawa retired in June last year.
Magawa passed away “peacefully” this weekend at the age of eight, said the Belgian charity Apopo, which trained him.
“All of us at Apopo are feeling the loss of Magawa and we are grateful for the incredible work he’s done,” the group said.
Apopo said Magawa was in good health and spent most of last week playing with his usual enthusiasm.
But towards the weekend “he started to slow down, napping more and showing less interest in food in his last days”, the charity said.
Apopo trained Magawa to detect the chemical compounds in explosives by rewarding him with tasty treats – his favourites being bananas and peanuts.
He would alert deminers by scratching the earth after using “his amazing sense of smell”.
Magawa was able to cover an area the size of a tennis court in 30 minutes, something that would take four days using a conventional metal detector.
In September 2020, the rodent won the animal equivalent of Britain’s highest civilian honour for bravery because of his uncanny knack for uncovering landmines and unexploded ordnance.
Magawa was the first rat to receive a medal from British veterinary charity PDSA in the 77 years of the awards, joining an illustrious band of brave canines, felines – and even a pigeon.
Millions of landmines were laid in Cambodia during the country’s nearly three-decade civil war which ended in 1998, causing tens of thousands of casualties.
Three Cambodian deminers were killed on Monday by anti-tank landmines that exploded as they tried to remove them, just 20 minutes after a man burning vegetation on his farm was killed by war-era ordnance in the same village.
Five LED pioneers, comprising Isamu Akasaki, Shuji Nakamura, Nick Holanyak Jr, M. George Craford and Russel Dupuis, were awarded the 2021 Queen Elizabeth Prize for Engineering. They joined a list of distinguished individuals for their contribution to the engineering world and humanity. The five LED pioneers shared a prize of £1.0 million.
The Queen Elizabeth Prize for Engineering, also known as the QEPrize, is a global prize for engineering and innovation. The prize was launched in 2012. It is run by the Queen Elizabeth Prize for Engineering Foundation, which is a charitable company. The QEPrize receives donations from, large International companies.
The Queen Elizabeth Prize for Engineering is awarded for engineering-led advances that are judged to be of tangible and widespread benefit to the public. The foundation invites nominations from the public, engineering and science academies, universities, research organizations, and commercial organizations from anywhere in the world.
The judging panel works from the information provided in the nomination, comments from referees and any other information required in order to establish which nomination most fully meets the following prize criteria.
What s it that his person has done ( or up to five people have done) that is ground-breaking innovation in engineering?
In what way has this innovation been of global benefit to humanity?
Is there anyone else who might claim to have had a pivotal role in this development?
The winner (winners) of the QEPrize are announced every two years by the chairman of the QEPrize Foundation. To-date, nineteen individuals have been awarded the QEPrize, namely from US, Japan, France and UK.
(1), (2), and (3): Robert Kahn, Vinton Cerf and Louis Puzin for their contribution to the protocols that make up the fundamental architecture of the internet.
(4): Tim Berners-Lee for his contribution as the creator of the World Wide Web.
(5): Marc Andreessen for his contrition as the creator of the Mosaic web browser.
(6): Robert Langer for work in controlled-release large molecule drug delivery.
(7): George E. Smith for the invention of the charge-coupled device (CCD) principle.
(8): Michael Tompsett for the development of the CCD image sensor, including the invention of the imaging semiconductor circuit and the analogue-digital converter.
(9): Nobukazu Teranishi for the creation of the pinned photodiode (PPD).
(10): Eric Fossum for developing the CMOS image sensor.
(11): Bradford Parkinson for leading the development, design, and testing of key GPS components.
(12): James Spilker, Jr for developing the L-band GPS civil signal structure using CDMA.
(13): Hugo FrueHauf for his role in creating a highly accurate miniaturized atomic clock using a rubidium oscillator.
(14): Ricard Schwartz for leading the design and development of the highly robust, long-lasting Block I satellites.
(15): Nick Holonyak for developing the first (red) visible-light light emitting diode.
(16): Isamu Akasaki for the development of blue and white LED.
(17): M. George Crayford for developing the yellow LED and pioneering the development of AllnGaP LEDS using metal organic chemical vapor deposition (MOCVD).
(18): Shuji Nakamura for the development of blue and white LEDs
(19): Russel Dupuis for demonstrating that MOCVD could be applied to high-quality semiconductor thin films and devices to produce high performance LEDs.
We hope the QEPrize and Nobel prize would spur young scientists and engineers to develop innovations for humanity. We also hope that Malaysian scientists and engineers would be among the recipients of these QEPrize and Nobel prizes.
Future trends will influence the types of businesses that would emerge in the future. A report, NatWest Future Businesses report caught my attention this week. NatWest is a leading bank in the UK. I was one of its customers in the 1970s.
The NatWest Future Businesses report highlights and explores the business trends most likely to emerge in the UK in the next 10-15 years, included within it, are predictions from a panel of four leading futurists and consumer business experts.
From virtual reality travel agents to the evolution of the e-scooter-these expert forecasts provide a fascinating insight into the future businesses we could see, and the industries where new job opportunities may emerge. Environment and sustainability, healthcare and education are among the many categories that are set to benefit from new technologies such as artificial intelligence (AI) and robotics.
General trends Identified
There are several trends identified in the NatWest Future Businesses report.
One, we are operating in an age of high-frequency change where technology has taken the friction out of business. It is easier than ever to get started with all the digital tools at our fingertips giving us significant power and reach. That doesn’t mean that success is easy though: with great technological progress comes even greater market opportunity.
Over the next 15 years, we will likely see continued growth in the number of self-employed people, particularly freelancers. Their numbers have doubled since the turn of century and though the trend was disrupted by the pandemic, it will return to growth as the economy recovers.
Freelancers allow organizations to scale up and down much more rapidly. Businesses built as networks will be able to take advantage of this flexibility, and thus be able to plug in new technologies quickly-as and when they add value.
But alongside a highly adaptable model, companies that adhere to a set of core values and proven social conscience will most likely thrive.
Government’s green policies mean the energy and transport sectors are being encouraged to evolve; something set to continue as newer and renewably powered technologies emerge. This is already evident in the electric vehicle market where firms race against each other to provide future-proofed solutions, from fuel cells to lithium batteries.
And all this is against a backdrop of the AI and robotic revolution. Mundane tasks from turning on the lights to food shopping will be carried out by automations, in a trend that is increasingly evident. Drone could keep us safe, driverless vehicles could take us to works, virtual shop assistants could help us select the perfect outfits for us to wear, and farmers could use algorithms to decide which crops to feed.
However, there will still many roles that require human skills such as caring for patients, dealing with customers and crucially in education. In essence, the more advanced technology becomes, the more people will be forced to concentrate on being people. With this in mind, the economy is gradually shifting towards a care-focused model, dominated by emotion-led skills such as leadership, motivation and nurture.
Looking ahead, society will become more connected than ever. The digital world will blend with the real world, and the ability to communicate will no longer be restricted by poor WIFI or distance.
Overall, the future looks bright for small and middle-sized enterprises, especially those built as networks, which, whilst having relatively few full-time employees, will be able to compete with global giants. Increasingly consumers are seeking out companies that give back to society, offer a bespoke service and meet their individual needs.
The future businesses
Among the future businesses highlighted by the NatWest Future Businesses report include the following:
Agriculture: Precision farming, urban food farms, and livestock wearables.
Health and medicine: Smart skin clinics, AI doctors, 3D printed organ production, intelligent ambulances, mind-controlled exoskeletons and biosimulator businesses.
Energy: Microgrid managers
Media and entertainment: Haptic body suits, AI digital entertainment critics, and interactive TV.
The future businesses are interesting to explore. Algae farming and rental of robots and exoskeletons (light and compact) are my interests. An area of application is wearing exoskeletons to lift patients in hospitals and at home.
An LED, which stands for light-emitting diode, is a semiconductor diode that glows when a voltage is applied. Devices with LEDS are everywhere in our house: televisions, mobile phones, solar flood lights, torchlights, inhouse lighting, street lightings, and cars day- indicator lights. .
Many companies are producing LED lights, and there are ample choices to buy indoor lights, which previously were made by Philips and Osram using the older fluorescent lights. .
The working of an LED
In my MIT Sloan days, a well-known Professor of Innovation, James M. Utterback, brought to the class a collection of hairs (animal and human) that were used by Thomas Edison to develop his filament bulbs. Since then, filament bulbs have been used to light homes. Sadly, these filament bulbs would be largely substituted by LED lights of various shapes and sizes.
The workings of the LED bulb are vastly different from that of the older incandescent lightbulb. The incandescent light bulb works by running electricity through a filament that is inside the glass bulb. The filament heats up and glows, and that creates the light. However, it also creates a lot of heat. The incandescent light bulb loses about 98% of its energy-producing heat, making it quite inefficient.0datret light.
LED was built from a series of inventions
LEDs are part of a new family of lighting technologies called solid-state lighting; LEDs are cool to the touch. Instead of one lightbulb, in an LED lamp there are many small light-emitting diodes.
LEDs create light by electroluminescence in a semiconductor material. Electroluminance is a phenomenon of a material emitting light when electric current or an electric field is passed through it. This happens when electrons are sent through the materiel and fill electron holes. An electron hole exists where an atom lacks electrons (negatively charged) and therefore has a positive charge. Semiconductor materials like germanium or silicon can be “doped” to create and control the number of electron holes. Doping is the adding of other elements to the semiconductor material to change its properties. By doping a semiconductor, we can make two separate types of semiconductors in the same crystal. The boundary between the two types is called a p-n junction. The junction only allows current to pass through it one way. This is why they are used as diodes. LEDs are made using p-n junctions, As electrons pass through one crystal to the other they fill electron holes. They emit photons (light). This a complex process.
The pioneers of the LED
Currently the LED light is popular due to its efficiency and many believe it is a “new technology”. The LED, as we know it, has been around for over 50 years. The recent development of white LED is what has brought it into the public attention as a replacement for other white light sources.
The current state of the development of the LED was built on a series of innovations and their innovators. Many innovators have helped create the LED lights that are used today.
These innovators include:
Henry Joseph Round
Electro luminesce, the natural phenomenon upon which LED technology is built, was discovered in 1907 by a British radio research and assistant to Guglielmo Marconi, Henry Joseph Round, while experimenting with silicon carbide and a cat’s whisker.
During the 1920s, Russian radio researcher Oleg Vladimirovich was studying the phenomena of electroluminescence in diodes in radio sets. In 1927, he published a paper “Luminous Carborundum (silicon carbide) Detector and Detection with Crystals” detailing his research. While no practical LED was created at that time based on his work, his research did influence future inventors
Robert Biard and Gary Pittman
Years later in 1961, Robert Biard and Gary Pittman invented and patented an infrared LED for Texas Instruments. This was the first LED. However, since it was infrared, it was beyond the visible light spectrum. Human cannot see infrared light. Biard only accidentally invented a light-emitting diode while they were actually attempting to invent a laser diode.
In 1962, Nick Holonyack, a consulting engineer for General Electric, invented the first visible light LED. It was a red LED and Holonyack used gallium arsenide phosphide as a substrate for the diode. Holonyack has earned the honour of being called the “Father of light -emitting diode” for his contribution. .
He also holds 41 patents and his other inventions include the laser diode and the first light dimmer.
M. George Craford
In 1972, electrical engineer, M. George Craford, invented the first yellow-coloured LED for Monsanto using gallium arsenide phosphide in the diode. Craford also invented a red LED that was 10 times brighter than Holonyack’s.
Monsanto was the first company to mass-produce visible LEDs. In 1968. Monsanto produced red LEDs used as indicators. But it was not until the 1970s that LED became popular when n Fairchild Optoelectronics began producing low-cost LED devices for manufacturers.
Herbert Maruska and Waalden C. Rhines.
In 1986, Herbert Maruska and Walden C. Rhines from Stanford University, US, created a working blue LED using magnesium, and set all future standards.
Isamu Araski and Hiroshi Amano
In 1993, physicists Isamu Araski and Hiroshi Amano developed a high-quality gallium nitride for blue LEDs.
In 1979, Shuji Nakamura developed the world’s first bright blue LED using gallium nitride. It wouldn’t until the 1990s that the blue LED would become low cost for commercial production. These developments led to the development of white LEDs.
The Importance of white light LEDs
Blue LEDs have been developed based on gallium nitride and silicon carbide materials. Production of light in this shorter-wavelength, more energetic region of the visible spectrum, has long been elusive to designers of LEDs. High photon energies (light) typically increase the failure rate of semiconductor devices, and the low sensitivity of the human eye to blue light adds to the brightness requirement for a useful blue diode. One of the most important aspects of a blue LED is that it completes the red, green, and blue (RGB) primary color family to provide an additional mechanism of producing solid-state white light, through the mixing of these component colors.
The addition of bright blue-emitting LED to the earlier-developed red and green devices makes it possible to use three LEDs, tuned up to an appropriate output levels, to produce any color of the visible light spectrum, including white. Other possible approaches to producing white light, utilizing a single device, are based on phosphor or dye wavelength converters or semiconductor wavelength converters. The concept of white LED is particularly attractive for general illumination, due to the reliability of solid-state devices, and the potential for delivering very high luminous efficiency as compared to conventional incandescent and fluorescent sources.
The human eye perceives light as being white if the three types of photosensory cone cells, located in the retina, are attenuated in particular ratios. The three cone types exhibit response curves that peak in sensitivity at wavelength representing red, green and blue, and the combination of these response signals produces various color sensations in the brain. A wide variety of different color mixtures are capable of producing a similar perceived color, especially in the case of white, which may be realized through many combinations of two or more colors.
A chromaticity diagram is a graphical means of representing the results obtained from mixing colors. Monochromatic color appear on the periphery of the diagram, and a range of mixture representing white is located in the central region of the diagram. Light that is perceived as white can be generated by different mechanisms. A chromaticity diagram is shown in Table 1.
Table 1: LED chromaticity diagram
One method is to combine light of two complementary colors in the proper power ratio. The ratio that produces tristimulus response to the retina (causing perception of white) varies for different color combinations.
A selection of complementary wavelengths, along with the power ratio for each pair that produces the chromaticity coordinates of a standard illuminant is designated D(65) by the International Commission for Illumination (CIE, Commission Internationale de I’Eclairage).
Another means of generating white light is by combining the emission of three colors that will produce the perception of white light when they are combined in the proper power ratio. White light can also be produced by broadband emission from a substance that emits over a large region of the visible spectrum. This type of emission approximates sunlight, and is perceived as white. Additionally, broadband emission can be combined with emission at discrete spectral line to produce a perceived white, which may have particular desirable color characteristics that differ from these of white light produced by other techniques.
The combination of red, green, and blue diode chips into one discrete package, or in a lamp assembly housing a cluster of diodes, allows the generation of white light or any of 256 colors by utilizing circuitry that drives the three diodes independently. In applications requiring a full spectrum of colors from a single point source, this type of RGB diode format is the preferred technique.
Most white-light diodes employ a semiconductor chip emitting at a short wavelength (blue, violet or ultraviolet) and a wavelength converter, which absorbs light from the diode and undergoes secondary emission at a longer wavelength. Such diodes, therefore, emit light of two or more wavelengths, that when combined, appear as white. The quality and spectral characteristics of the combined emission vary with the different design variations that are possible. The most common wavelength converter materials are termed phosphors, which exhibit luminescence when they absorb energy from another radiation source. The typically utilized phosphors are composed of an inorganic host substance containing an optically active dopant. Yttrium aluminium garnet (YAG) is a common host material, and for diode applications, it is usually doped with one of the rare-earth elements or a rare-earth compound. Cerium is a common dopant element in YAG phosphors designed for white light emitting diodes.
The first commercially available white LED (fabricated and distributed by the Nichia Corporation) was based on a blue-light-emitting gallium-indium-nitride (GaInN) semiconductor device surrounded by a yellow phosphor. The phosphor is Ce-doped YAG, produced in powder form and suspended in the epoxy resin used to encapsulate the die. The phosphor-epoxy mixture fills the reflector cup that supports the die on the lead frame, and a portion of the blue emission from the chip is absorbed by the phosphor and reemitted at the longer phosphorescence wavelength. The combination of the yellow photo-excitation under blue illumination is ideal in that only one converter species is required. Complementary blue and yellow wavelengths combine through additive mixing to produce the desired white light. The resulting emission spectrum of the LED represents the combination of phosphor emission, with the blue emission that passes through the phosphor coating unabsorbed.
The relative contributions of the two emission bands can be modified to optimize the luminous efficiency of the LED, and the color characteristics of the total emission. These adjustments can be accomplished by changing the thickness of the phosphor-containing epoxy surrounding the die, or by varying the concentration of the phosphor suspended in the epoxy. The bluish white emission from the diode is synthesized, in effect, by additive color mixing, and its chromaticity characteristics are represented by a central location (0.25, 0.25) on the CIE chromaticity diagram ( Bluish White LED).
White light diodes can generate emission by another mechanism, utilizing broad-spectrum phosphors that are optically excited by ultraviolet radiation. In such devices, an ultraviolet-emitting diode is employed to transfer energy to the phosphor, and the entire visible emission is generated by the phosphor. Phosphors that emit at a broad range of wavelengths, producing white light, are readily available as the materials used in fluorescent light and cathode ray tube manufacture. Although fluorescent tubes derive their ultraviolet emission from a gas discharge process, the phosphor emission stage producing white light output is the same as in ultraviolet-pumped white diodes. The phosphors have well known color characteristics and diodes of this type have the advantage that they can be designed for applications requiring critical color rendering. A significant disadvantage of the ultraviolet-pumped diodes, however, is their lower luminous efficiency when compared to white diodes employing blue light for phosphor excitation. This results from the relatively high energy loss in the down-conversion of ultraviolet light to longer visible wavelengths.
Dyes are another suitable type of wavelength converter for white diode applications, and can be incorporated into the epoxy encapsulant or in transparent polymers. The commercially available dyes are generally organic compounds, which are chosen for a specific LED design by consideration of their absorption and emission spectra. The light generated by the diode must match the absorption profile of the converting dye, which in turn emits light at the desired longer wavelength. The quantum efficiencies of dyes can be near 100 percent, as in phosphor conversion, but they have the disadvantage of poorer long-term operational stability than phosphors. This is a serious drawback, as the molecular instability of the dyes causes them to lose optical activity after a finite number of absorptive transitions, and the resulting change in light emitting diode color will limit its lifetime.
White light LEDs based on semiconductor wavelength converters have been demonstrated that are similar in principle to the phosphor conversion types, but which employ a second semiconductor material that emits a different wavelength in response to the emission from the primary source wafer. These devices have been referred to as photon recycling semiconductors (or PRS-LEDs), and incorporate a blue-emitting LED die bonded to another die that responds to the blue light by emitting light of a complementary wavelength. The two wavelengths then combine to produce white. One possible structure for this type of device utilizes a GaInN diode as a current-injected active region coupled to an AlGaInP optically-excited active region. The blue light emitted by the primary source is partially absorbed by the secondary active region, and “recycled” as reemitted photons of lower energy. In order for the combined emission to produce white light, the intensity ratio of the two sources must have a specific value that can be calculated for the particular dichromatic components. The choice of materials and the thickness of the various layers in the structure can be modified to vary the color of the device output.
Because white light can be created by several different mechanisms, utilizing white LEDs in a particular application requires consideration of the suitability of the method employed to generate the light. Although the perceived color of light emitted by various techniques may be similar, its effect on color rendering, or the result of filtration of the light, for example, may be entirely different. White light created through broadband emission, through mixing of two complementary colors in a dichromatic source, or by mixing of three colors in a trichromatic source, can be located at different coordinates on the chromaticity diagram and have different color temperatures with respect to illuminants designated as standards by the CIE. It is important to realize, however, that even if different illuminants have identical chromaticity coordinates, they may still have substantially different color rendering properties, due to variations in details of each source’s output spectrum.
Two factors, referred to previously, are of primary importance in evaluating white light generated by LEDs: the luminous efficiency, and the color rendering capabilities. A property referred to as the color rendering index (CRI) is utilized in photometry to compare light sources, and is defined as the source’s color rendering ability with respect to that of a standard reference illumination source. It can be demonstrated that there exists a fundamental trade-off between luminous efficiency and color rendering ability of light-emitting devices. For an application such as signage, which utilize blocks of monochromatic light, the luminous efficiency is of primary importance, while the color rendering index is irrelevant. For general illumination, both factors must be optimized.
The spectral nature of the illumination emitted from a device has a profound influence on its color rendering ability. Although the highest possible luminous efficiency can be obtained by mixing two monochromatic complementary colors, such a dichromatic light source has a low color rendering index. In a practical sense, it is logical that if a red object is illuminated with a diode emitting white light created by combining only blue and yellow light, then the appearance of the red object will not be very pleasing. The same diode would be quite suitable for backlighting a clear or white panel, however. A broad-spectrum white light source that simulates the sun’s visible spectrum possesses the highest color rendering index, but does not have the luminous efficiency of a dichromatic emitter.
Phosphor-based LEDs, which either combine blue emission wavelengths with a longer-wavelength phosphorescence color, or create light solely from phosphor emission (as in ultraviolet-pumped LEDs), can be designed to have color rendering capabilities that are quite high. They have color character that is similar in many respects to that of fluorescent lamp tubes. The GaInN LEDs utilize blue emission from the semiconductor to excite phosphors, and are available in cool white, pale white, and incandescent white versions that incorporate different amounts of phosphor surrounding the chip. The cool white is the brightest, utilizing the least phosphor, and produces light with the most bluish color. The incandescent white version surrounds the blue-emitting chip with the most phosphor, has the dimmest output, and the yellowest (warmest) color. The pale white has brightness and color shade characteristics intermediate between the other two versions.
The availability of white LEDs has generated great interest in applying these devices to general lighting requirements. As lighting designers become familiar with the characteristics of the new devices, a number of misconceptions will have to be dispelled. One of these is that the light from a white LED can be used to illuminate a lens or filter of any color, and maintain the accuracy and saturation of the color.
In a number of the versions of white LED, there is no red component present in the white output, or there are other discontinuities in the spectrum. These LEDs cannot be used as general sources to backlight multicolored display panels or colored lenses, although they function well behind clear or white panels. If a blue-based GaInN white LED is employed behind a red lens, the light transmitted will be pink in color. Similarly, an orange lens or filter will appear yellow when illuminated with the same LED. Although the potential benefits in application of LEDs are tremendous, consideration of their unique characteristics is necessary in incorporating these devices into lighting schemes in place of more familiar conventional sources.
White LEDs are becoming popular sources of while lights. There were many inventors involved since the early 1900s to bring about this useful and practical white LEDs and its applications.
Let us salute those inventors who were from various nationalities.
Aspirin is an effective and inexpensive medicine that millions take daily to prevent heart attacks and strokes. Who could improve on that?
The inventor of aspirin
In ancient times, salicylate-containing plants such as willow were commonly used to relieve pain and fever. A salicylate is a salt or ester of salicylic acid . Salicylates are thought to protect the plant against insect damage and disease. Aspirin is a derivative of salicylic acid. It is known as acetylsalicylic acid.
In 1897, a German chemist, Dr. Felix Hoffman, working for the Bayer company, was able to modify salicylic acid to create acetylsalicylic acid, which was named aspirin. However, the company dismissed the market potential of aspirin on the ground that it had an “enfeebling” action on the heart. At that time, the company was more interested on the potential of another new drug-heroin, which was also synthesized by the company.
Subsequently, aspirin was found to be more tolerable to the stomach than salicylic acid, which led to the widespread use of aspirin for pain relief. Furthermore, Hoffman’s acetylation of salicylic acid also proved its ability to prevent cardiovascular events. Aspirin, was considered by many as a wonder drug.
One common adverse effect of aspirin is an upset stomach. More significant side effects include stomach ulcers, stomach bleeding and worsening asthma. Aspirin is not recommended in the last part of pregnancy.
Aspirin is one of the most widely used medications globally, with an estimated 40,000 MT (50 to 120 billion pills) consumed each year. It is on the World Health Organization’s List of Essential Medicines. It is available as a generic medication. In 2018, it was the 40th most commonly prescribed medication in the US, with more than 19 million prescriptions (wikepedia).
According to Bayer, the history of aspirin can be summarized in the following milestones.
In a Bayer laboratory in Wuppertal, Germany, Dr Felix Hoffman was the first to succeed in synthesizing a chemically pure and stable form of acetylsalicylic acid (ASA), which became the active ingredient of aspirin.
Aspirin was registered as a trademark. It was launched on the market in powder form. Bayer delivered the medicine to pharmacies in small 250-grams glass vials. 500 mg of the powder was then weighed out and dispensed to customers in small paper bags. One year later, Bayer launched the analgesic in the classic tablet form-one of the first medicines to be marketed in dosage form.
Aspirin became available without prescription and became a best-seller in the US.
Aspirin turned 50, and the following year, was the first time it featured in the Guinness Book of Records as the most frequently sold pain reliever in the world.
A box of aspirin flied to the moon aboard Apollo 11.
A study reported that aspirin could prevent ischemic stroke in appropriate patients. In the same year, the World Health Organization introduced its “Essential Drug List. Aspirin was included right from the start as an essential analgesic.
Acetylsalicylic acid, the active ingredient in aspirin, celebrated its centenary.
Aspirin took its place among such medical advances as the stethoscope and artificial heart when it was inducted into the Smithsonian Institution’s Museum of American History, US.
British researcher Professor Derek W. Gilroy elucidated the anti-inflammatory properties of aspirin.
Publication in the journal Headache by Lampl et al, which reaffirmed the effectiveness of aspirin as a first-time treatment of migraine or episodic tension type headache and found that pre-treatment headache did not predict potential success or failure of aspirin.
The active ingredient of new aspirin, acetylsalicylic acid, was used in the form of microparticles that were on average 10 per cent of size of particles found in previous aspirin tablets.
Microparticles were combined with sodium carbonate, which acted as a disintegrant and local buffer, helping new aspirin dissolved more quickly, entered the bloodstream faster, and relieved pain twice as fast as previous aspirin tablets.
Enter a “new aspirin”: Vazalore
A US-based company, PLx Pharma (www.plxpharma.com) is trying to do that. According to the Barron’s online on September 20th, 2021, there has been no innovation in the aspirin market in over 50 years. The company, based in Sparta, New Jersey, US, is seeing an opportunity to launch a new product, Vazalore, in some 30,000 retail drug stores in the US.
The aspirin market is a crowded field, where aspirin has been around since 1899. The company noted that Vazalore’s advantage is that it reduces aspirin’s tendency to irritate the stomach for people who use it regularly, a problem that can lead to ulcers. In addition, Vazalore has been shown to achieve better absorption than coated aspirin, according to studies by Harvard Medical School cardiologist Deepak Bhatt, who heads PLx Pharma scientific advisory board. PLx Pharma is facing the challenge of convincing existing users of aspirin to switch to Vazalore. Vazalore will cost US$25 a month versus a few dollars for coated aspirin. It is estimated that 43 million Americans take aspirin on their doctor’s advice, plus millions more to treat the symptoms of arthritis and other ailments. The company estimates that every new customer will be worth US$230 a year to PLx Pharma, so that it could realize US$100 million in annual revenue from each 1 pe cent of those 43 million people.
The Vazalore capsule holds a liquid formulation of aspirin bound up in lipid, which prevents the aspirin’s release until it passes through the stomach to the intestine. It was reported that PLx Pharma will apply its patented technology to ibuprofen and other drugs that give some users stomach problems.
We doubt users of aspirin will drop it anytime soon.