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Notre Dame’s fire gives scientists a look at the cathedral’s origins

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The
“forest” of Notre Dame was one of Olivier de Châlus’ favorite places. That
dense lattice of timbers under the building’s lead roof epitomized the medieval
construction techniques that the engineer has spent years analyzing.

“There
was a very special wood smell, very strong, coming from the Middle Age,” de
Châlus says. “And it was very, very calm — impressive, compared to the very
noisy life inside the cathedral.” As one of the few visitors allowed in the
forest, de Châlus had the rare privilege of hearing the creaking noises emitted
by the timeworn wood and peering at numbers scrawled on the timbers by
long-gone carpenters.

That beloved forest is now gutted, lost in an April 15, 2019 blaze that destroyed the cathedral’s roof and spire and damaged parts of the masonry. De Châlus, who works for the global engineering firm Arcadis, is finishing a Ph.D. on the construction of the cathedral.

There’s
little documentation of the building process, which began in 1163 and continued
for about 200 years. De Châlus has devoted himself to teasing out the unwritten
rules of construction — how builders decided the size of columns or the height
of flying buttresses, for example. He notes that builders lifted 100-kilogram
stones more than 60 meters off the ground without the benefits of modern
technology. Exactly how this was accomplished has been lost to time, he says.

Olivier de Châlus studies Notre Dame construction techniques.E. Conover

“Notre Dame is my life, my whole life,” says de Châlus, who spent four years supervising the guides that show tourists around the cathedral. So, after the fire, he quickly joined an international effort organized by French scientists to use their expertise to help rebuild the cathedral and learn more about the iconic building. He is now the spokesperson for the group, Association des Scientifiques au Service de la Restauration de Notre Dame de Paris — the Association of Scientists in Service of the Restoration of Notre Dame of Paris.

The
fire has opened up access to parts of the building that could not be studied
when the structure was intact. Scientists have come together with plans to
research the history of the cathedral, as well as the fire’s environmental
impact on the surrounding city. Some will even explore what the cathedral’s
aged materials can reveal about climate change.

Getting organized

As
the flames died out, Paris despaired at the damage to one of its most treasured
historic structures. But “there’s much more to lose than what was lost
already,” says archaeologist Maxime L’Héritier of Université Paris 8. If the
materials that fell from the top of the cathedral — stone, wood, iron, lead — are
not studied, he says, the opportunity lost is “even worse than what the fire
has caused.”

The
day after the fire, L’Héritier and art historian Arnaud Ybert of the Université
de Bretagne Occidentale in Quimper, France, formed the association of
scientists. Today, more than 200 scientists are part of the group, including
geologists, archaeologists and engineers. The association aims to coordinate
work among experts in various specialties, share knowledge and advocate for
scientific study of the cathedral.

L’Héritier, who studies ancient metals, wants to know more about how iron was used in the structure, including its integration in the stone walls and the carpentry that held up the roof. While renovations in the 19th century added iron to the structure, the researchers will be searching for medieval iron placed during the original construction.

Notre Dame researchers
Researchers Lise Leroux, Aurélia Azéma and Maxime L’Héritier (left to right) are working on understanding the stone and metal within Notre Dame.E. Conover

Radiocarbon
dating is commonly used to sort out the age of materials, but for that, the
materials must contain some carbon. Luckily, medieval iron-production
techniques introduced small traces of carbon, which, when alloyed with iron,
make steel. Carbon dating those steel bits could demonstrate whether the metal
is original, L’Héritier says.

And
the iron, medieval or not, could act “like a thermometer,” revealing how hot
the fire got, says Philippe Dillmann, an archaeometallurgist at the Centre
National de la Recherche Scientifique, or CNRS. As temperatures rose inside the
fire, the corrosion on the iron — essentially rust — would have transformed
from typical rust into more unusual compounds. Analyzing that corrosion could
indicate how much heat was inflicted on the building, and so could help
scientists understand how much that heat weakened the limestone that makes up
the bulk of the cathedral’s structure.

Dillmann
is co-leader of a second effort to organize researchers to study Notre Dame,
spearheaded by CNRS. The CNRS team will also plan scientific meetings and
compile research.

Both
groups are still in the planning stages because the cathedral is still
contaminated with the toxic dust released when the lead roof burned. Most
scientists do not yet have access to the building, and all the materials within
must be sorted and cataloged before researchers can get their hands on them.

Inside the cathedral

A third group of scientists is already on the scene assisting with the building’s cleanup and restoration. Researchers from the French Ministry of Culture’s Laboratoire de Recherche des Monuments Historiques, or LRMH, develop scientific techniques for restoring monuments throughout France.

The
laboratory, located in Champs-sur-Marne near Paris, employs 23 scientists “for
all the materials and for all the monuments in France,” says LRMH’s Lise
Leroux. “We are very busy.” Even more so after the fire.

A
geologist and expert in the conservation of stone, Leroux is helping to
determine which of Notre Dame’s limestone blocks can stay in place or be
reused, and which must be replaced with new stones. “The monument is very
degraded,” she says. As the fire raged that night, the intense heat and the
deluge of water from firefighting efforts caused cracking and other damage in
the stones nearest the flames. And when the church’s spire collapsed, the
impact punched gaping holes in the limestone ceiling.

Notre Dame netting
Falling debris punched holes in the cathedral’s vaulted ceiling. Scientists are assisting with efforts to determine which of the remaining stones are damaged and need to be replaced.Brian Katz and Mylène Pardoen/CNRS

Finding
stones to replace damaged or destroyed ones will demand great care. Placing
stones of different compositions next to one another — for example, distinct
types of limestone quarried from different parts of the world — can cause water
or pollutants to accumulate in one stone more than another, weakening the
structure.

Even
before the fire, “the monument was very, very dirty,” says LRMH metals expert
and chemist Aurélia Azéma. Now, LRMH researchers are devising and testing
techniques for removing lead, which was strewn throughout the cathedral when
the roof burned. Metal, stone, paint and other materials require tailored
methods to extract the lead without causing damage.

A fire’s fingerprints

Problems
with lead extend beyond the cathedral walls. During the fire, extremely high
temperatures caused the lead to aerosolize into small particles that billowed
into the air and fell as dust nearby. That gave geochemist Sophie Ayrault, who
studies toxic metals, a new project.

Ayrault, of the Laboratoire des Sciences du Climat et de l’Environnement in Gif-sur-Yvette, France, previously searched for metals in the sediments of the Seine, the river that runs through Paris. Analysis of sediment cores from the river’s floodplain reveals how contamination has varied over the last 100 years.

To
pinpoint the origins of the lead she detects, Ayrault measures the relative
concentrations of its isotopes — different versions of the element with varying
numbers of neutrons in the nucleus. The ratios are a fingerprint that can be
used to trace the contamination’s source.

Notre Dame fire cleanup
After the fire, lead contamination near the cathedral mandated cleanup efforts (above). Researchers are measuring the isotopes of lead in samples taken from the Seine and other spots around Paris to tell which contamination came from the fire and which came before.Francois Mori/AP Photo

For example, in a paper published in 2012 in Chemosphere, Ayrault and colleagues reported that the signature of leaded gasoline was detectable in older Seine sediments, but faded away in sediments deposited after leaded gasoline was phased out in the mid-1980s.

Before
Notre Dame went up in flames, Ayrault had hoped to search the Seine’s sediments
for runoff from Notre Dame’s roof — which, when intact, contained as much as
460 metric tons of lead, she says. But Ayrault hadn’t yet procured the roof
samples she needed to discern its fingerprint. Now, to understand the fire’s
impact, determining that signature has become more important.

After
the fire, tests in parks and schools near the cathedral found lead levels high
enough to endanger children. But it’s not clear if all of that lead was a
result of the fire, or if some contamination predated it. To resolve that
question, Ayrault aims to collect samples of melted lead and dust from the
fire, as well as remaining intact parts of the roof. Then she’ll search for
signs of that lead in future tests around the city.

Into the woodwork

The
charred remnants of de Châlus’ beloved forest can also tell a story.

The oak trees that became the roof’s wooden frame grew during a hot spell in Europe known as the Medieval Warm Period, which lasted from the 11th century to the early 14th century (SN: 8/17/19, p. 6). Studying that wood could reveal details about that natural warming — such as how often droughts occurred — and may lead to a better understanding of what to expect from modern-day climate change, says Alexa Dufraisse of CNRS.

Dufraisse
plans to analyze tree rings within the burnt timber. The width of the rings and
the amounts of various isotopes found within the wood reveal the conditions
under which the tree grew. That could include how wet or dry the climate was
and the approximate geographic location of the forest.

Notre Dame supports
The “forest” of Notre Dame held up the cathedral’s roof and spire. It was destroyed in the fire, but researchers hope to study the charred remains of the medieval oak beams to learn about climate change.F. Epaud

She
and colleagues also hope to learn how builders chose the trees and whether the
forests were managed in some way. “This is a study that … could never have been
conducted without the destruction of the structure by fire,” says Dufraisse, a
dendroanthracologist, a scientist who studies tree rings within charred wood.

Other researchers are investigating less-tangible aspects of the cathedral, like its acoustics and its sociological significance. Anthropologists plan to interview people affected by the fire, including tour guides and musicians who’ve performed in the cathedral, to understand the psychological toll of the fire. “We all remember what we were doing when it was burning,” says molecular archaeologist Martine Regert of CNRS, who leads the CNRS group alongside Dillmann.

Regert compares the Notre Dame disaster to the 2018 fire in Brazil’s National Museum in Rio de Janeiro, in which millions of artifacts and preserved specimens were lost or damaged (SN Online: 9/7/18). In the Rio fire, “for me, we lost more” in terms of the scientific value, she says. Yet, emotionally, “I was probably more upset by Notre Dame.”

The
cathedral holds an outsize place in the hearts of Parisians and people around
the world. If another cathedral had burned, says de Châlus, there would have
been less interest. Determining how to rebuild requires understanding our
relationship with it, too, he says.

Subject
to bouts of emotion himself, de Châlus says he cried when he first entered the
cathedral after the fire. He felt an unfamiliar wind at his back, sweeping into
the church and up through the holes where parts of the ceiling had collapsed.
He says of Notre Dame: “It was much more than a church … much more than a study
subject for me.”



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Apple may be forced to ditch Lightning charge cable amid new EU rules

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On September 7th Apple will release the highly anticipated iPhone 7. Design changes to the new model are suggested to affect the 3,5mm headphone jack, to be replaced with the proprietary Lightning jack.

NurPhoto

The European Union (EU) is revamping plans that could force smartphone makers, such as Apple, to share the same charging method.

European policymakers want to make life easier for consumers as well as to reduce electronic waste across the 28-country region. As a result, they are looking at introducing a single universal charging cable. This would be particularly relevant for Apple given its different charging options.

“We are drowning in an ocean of electronic waste,” Roza Thun und Hohenstein, a European lawmaker said at the European Parliament Monday. “We cannot continue this way,” she added.

Old chargers generate more than 51 000 metric tons of electronic waste per year, according to the European Parliament. Lawmakers want one single charger that fits phones, tables, e-books and any other portable device. Apple’s Lightning connector cable, which is used to charge and sync different devices, would therefore be at risk.

However, Apple believes that the EU’s plan would hurt innovation.

“Regulations that would drive conformity across the type of connector built into all smartphones freeze innovation rather than encourage it. Such proposals are bad for the environment and unnecessarily disruptive for customers,” Apple said in a feedback form issued to the European institutions last year.

Apple, of its own choice, has already stopped using Lightning on the 2019 version of the iPad, moving to the USB-C port used on MacBooks. USB-C and micro-USB are also used on Android devices.

“This has been a long-term objective of the industry,” Dexter Thillien, a senior industry analyst at Fitch Solutions, told CNBC Friday. “Most Android devices already use the same charging system (USB-C and micro-USB), so it would impact Apple more than anybody else.”

However, Thillien also noted that Apple is already using USB for some iPads, “so it wouldn’t be completely new for them, and would only apply to future models.”

The EU pushed for a single charging mechanism back in 2014. At the time, the European Commission – the EU’s executive arm, tried to encourage smartphone makers to develop a solution among themselves. However, the voluntary scheme did not achieve what European policymakers wanted and they are now looking at putting it into law.

“It is never too late for industry to come up with a suitable proposal, but we now must consider the legislative approach,” a Commission source told CNBC via email.

The future is wireless

Smartphone developers, including Apple and Samsung, have presented devices that are charged wirelessly. Though the technology is still at its early stages, analysts believe this is the future.

“As tech wants to prove it’s becoming greener, (implementing a common charger system is) a move they might make without too much opposition. And obviously the future is wireless charging, so no need for cables,” Thillien told CNBC.

Apple shares are up by more than 100% over the last 12 months.



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New policy on Science, Technology & Innovation being framed by Centre

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The government is working on a new National Science, Technology and Innovation Policy, to replace the existing policy framed in 2013, which will be forward-looking and have both a vision document as well as an action plan on the fundamental research required in crucial areas such as space, health, atomic physics and bio-technology, a senior official has said.

The Department of Science & Technology is steering the exercise and will soon initiate stakeholder interaction on what the new policy should include, said Principal Scientific Adviser to the Prime Minister K Vijay Raghavan in an interaction with journalists.

Nothing wrong with the existing policy

“There is nothing wrong with the existing policy. But it was made keeping in mind a snapshot of what the world was then (in 2013),” Vijay Raghavan said, adding that the older policy focussed more on what the problem areas were than on what was to be done.

There was no strict timeline at the moment for completing the exercise of drafting the new policy, but the stakeholder consultation process, which will be at four levels, would kick-off soon, he said.

The Principal Scientific Advisor pointed out that private investment in India in R&D was still very low and a suitable environment needed to be created to induce entities to invest. “One way to increase R&D spend in the country is to make it attractive for companies to invest,” he said.

Restoring the 200 per cent income tax deduction for in-house R&D spend, which was reduced to 150 per cent from April 1 2017, could be one way to encourage investment in the area. This has been a demand of the industry for a long time, Vijay Raghavan said.

Of the total R&D investments made in the country, 70 per cent is made directly by the government while 30 per cent of the investment comes from the industry. As much as 90 per cent of the industry investment is also made by the public sector units with private sector accounting for just 10 per cent (of 30 per cent), he added.

Consultation process

Sharing details of the consultation process for framing the new Science, Technology and Innovation policy, the Principal Scientific Adviser said that in the first level of consultations, the scientific community and industry representatives would talk to citizens of the country to find out what kind of scientific break-through and innovation were they looking for. This would help narrow down the field of new research for scientific development and innovation.

At the second level, the Centre would talk to State governments to discuss how both could work together to make a policy that would help them develop world-class products.

The third level of stakeholder consultations will be with various Ministries and Departments such as Railways, Shipping and Water Resources to find out what science and technology advantage would they need in their respective areas.

The fourth level of interaction would be horizontal, focussing on basic research needed in fundamental areas such as condensed matter physics, solid state physics, material research, etc. “We have to see where are we in these areas and what more needs to be done,” Vijay Raghavan said.





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Google owner Alphabet becomes trillion-dollar company | Technology

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Google’s owner Alphabet has become a trillion-dollar company for the first time, making it only the fourth US firm to reach the bumper valuation.

Alphabet’s value, based on the price of its Wall Street-listed shares, passed $1tn in the final minutes of trading on Thursday night, with shares closing at a record high of $1,450.16 each.

It marks a stellar rise for Alphabet, which floated as Google for $85 per share in 2004. After its initial public offering, the Silicon Valley firm was worth $23bn.

It has followed its tech rivals Microsoft, Apple and Amazon over the $1tn mark, amid a long rally in so-called Faang stocks.

Google’s value has steadily surged as it has tightened its grip on the search market, boosted its advertising revenues from web searches and YouTube, created and grown its Android mobile operating system, and launched a series of smart-tech products including Google Home and Google Assistant.

Alphabet may be headed for fresh milestones, with some analysts predicting it could hit the $2tn mark. Christopher Rossbach, the CIO of the private investment firm J Stern & Co, believes Alphabet’s share price will continue to climb.

“As Alphabet joins Apple, Microsoft and (from time to time) Amazon among tech companies that have reached this level, it marks just the start for the company. It still has significant further room to grow, both in its core online advertising business as it innovates in advertising monetisation and formats and in its cloud computing business,” Rossbach said.

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“It is also disrupting new multitrillion-dollar markets, for example, healthcare, with this technology. Its sizeable investments give Alphabet a sustainable competitive advantage as it applies this technology across its business.”

“Alphabet can be a $2tn company in the near future and is a compelling opportunity for long-term investors.”

However, the tech sector is also facing calls for stronger privacy and antitrust regulation. Earlier this month Google was accused of “losing its way” by its former head of international relations, who says it prioritises profits over human rights.

Alphabet is now the third most valuable US company, behind Apple at $1.4tn and Microsoft at $1.27tn, with Amazon currently worth $931bn.



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