Tag Archives: copper

Copper can be an important ally against coronavirus — and most viruses, for that matter

A recent report published in the New England Journal of Medicine reminds us just how stunning copper’s antimicrobial properties can be. While the novel coronavirus survived for up to three days on plastic surfaces and two days on stainless steel, it was completely gone from copper surfaces after only four hours. This was hardly surprising. After all, we’ve known about copper’s disinfectant powers for millennia.

Copper’s properties make it an extremely attractive antimicrobial material.

There aren’t many folk remedies that have stood the test of time — and the test of science — but copper is one of them.

From ancient times to modern buildings

The Edwin Smith Papyrus, ascribed to an Egyptian doctor circa 1700 BC, shows that Egyptians considered copper as a tool to treat infections. In 1600 BC, Chinese doctors would sometimes use copper coins to treat heart and stomach pain, and around the same period, Phoenician warriors used shavings from their bronze swords to prevent wound infections. The use of copper as a disinfectant also propagated throughout history.

In many cultures, children used copper drinking vessels because it was known that children who drink from copper don’t get diarrhea as often.

Copper is biostatic, meaning most bacteria and viruses don’t grow on it. For this reason, it has been used to line parts of ships to protect against barnacles and mussels — initially in pure or alloy form, and then in copper-based paint. Copper alloys are also used in aquaculture for the same reason.

More recently, researchers have also studied copper and copper alloys and found that they can be used in a myriad of situations to kill germs, with the EPA approving the registrations of these copper alloys as “antimicrobial materials with public health benefits”.

The East Tower of the Royal Observatory, Edinburgh. Some parts are refurbished in 2010, while the other (green) ones are still the original 1894 copper. Image credits: Wiki Commons.

The properties are long-lasting, as well. When Southampton University Professor Bill Keevil analyzed the old railings at New York City’s Grand Central Terminal, they found that the copper worked just as fine as when it was installed 100 years ago.

The key to copper’s antimicrobial properties lies in its chemistry.

Why copper kills germs

Several heavy metals (including gold and silver) can be antimicrobial, but copper’s chemical structure gives it an extra edge.

Copper has a free electron in its outer orbital shell. This free electron makes the metal a good conductor aid also grants the metal a sort of ballistic defense system against germs. When a microbe lands on copper, it is bombarded by ions, much like a plane is hit by ballistic missiles. These “missiles” pierce the cellular membrane or viral coating, especially when the surface is dry. More importantly, the ions also destroy the DNA and RNA inside a bacteria or virus, preventing mutations that would create drug-resistant superbugs.

Gold and silver don’t have this property, which substantially reduces their antimicrobial properties. For instance, silver does not work as an antimicrobial surface when dry, there needs to be water for it to kill microbes.

It’s ironic that stainless steel is used a lot in making railings and handles because it is perceived as cleaner. Not only is this not the case, but stainless steel has numerous microscopic indentations and scratches which create a safe haven for bacteria and viruses. Copper railings and handles, which tend to cost just as much as stainless steel, maintain their antimicrobial properties even if they are tarnished or oxidized.

Can copper be used against COVID-19?

The fact that copper surfaces seem very potent at destroying the novel coronavirus fits with what we know of the metal so far. Coronaviruses in general are vulnerable to copper surfaces, and there is no apparent reason why SARS-CoV-2 would be an exception.

Plenty of coins throughout history were made out of copper — though not necessarily due to its antimicrobial properties. Image credits: Dan Dennis.

So while no formal study has yet been published on the effectiveness of copper against the novel coronavirus, there is plenty of science suggesting that copper can be an effective ally in this fight.

For instance, a 2015 study found that a closely-related human coronavirus – 229E – can remain infectious on common surface materials for several days, but is rapidly destroyed on copper. Viruses such as influenza, bacteria like E. coli, superbugs like MRSA, or even coronaviruses are handily destroyed by copper within hours. In hospitals, copper has been shown to substantially reduce infection rates for even the sturdiest of bugs, and there’s no reason to believe SARS-CoV-2 would be more resilient.

Researchers have also suggested mixing copper with textiles to produce drug-killing face masks. Phyllis Kuhn at the University of Massachusetts Amherst developed a mask that is made of 99.95% pure copper mesh that allows for “a miniscule amount of copper to be deposited in the nasopharyngeal (np) area, potentially killing viruses and stimulating an anti-inflammatory response without the use of drugs.”

So why don’t we use copper more often then?

Increasingly, research is showing that copper is self-sterilizing and has the potential to kill off a myriad of bacteria and viruses. But it hasn’t really taken off, even in hospitals.

In many parts of the world, copper used to be common in hospitals up until a few decades ago. Copper took off during the industrial revolution, but it slowly faded from interest in the 1970s and 1980s.

In 1983, medical researcher Phyllis J. Kuhn wrote a critique of the disappearance of copper in hospitals. During a training exercise in Pittsburg, she noted that many of the non-copper surfaces were dirty and covered in bacteria — while the toilets (which were fitted with copper plumbing) were pretty clean. The disappearance of copper continued over the following years.

Part of the reason for this might be that many people are not entirely aware of the antimicrobial properties of the metal — and how these properties carry on even after tarnishing. But perhaps even more importantly, the problem is cost.

Copper’s electric conductivity is also what makes it so effective at killing pathogens.

Copper isn’t necessarily more expensive than stainless steel or other similar alternatives. Copper alloys (or other solutions, like copper-based paint) can be comparable in price. But the problem is that for buildings such as hospitals or office buildings, hand-gel dispensers may be considered a cheaper option to get rid of pathogens — even though sanitizer doesn’t kill all the viruses and many people won’t end up using it at all.

But when you factor in the money that could be saved through the material’s antimicrobial properties, copper might end up being the cheaper material, at least in hospitals.

In the US, one in 31 hospital patients has at least one healthcare-associated infection, according to the Centers for Disease Control, costing as much as $50,000 per patient. But copper can reduce these infections by 58%, which could end up saving hospitals $1,176 a day.

Some places are picking up on this.

In the past few years, copper doorknobs and bed railings have been increasingly used by hospitals to reduce the transfer of disease. Meanwhile, copper plumbing can suppress Legionnaires’ disease. Some countries have embraced the metal even more, and copper alloy products are now being installed in healthcare facilities in the U.K., Ireland, Japan, Korea, France, Denmark, and Brazil. But the transition is still slow.

It’s hard to say whether copper could protect us from this pandemic, or the next. But it could be an important ally, and further research is certainly warranted in this direction. After all, if a simple material has the potential to destroy viruses, why not use it to our advantage?

Copper-lined hospital beds harbor up to 95% less bacteria, can help save patient lives

Lining hospital beds with copper could be a cheap and easy way to reduce healthcare-associated infections (HAIs), especially among the most vulnerable patients.

Image via Pixabay.

A new study led by Michael G. Schmidt, PhD, Professor of Microbiology and Immunology at the Medical University of South Carolina, Charleston, reports that copper hospital beds in the Intensive Care Unit (ICU) carry an average of 95% fewer bacteria than conventional beds. Better yet, this reduced bacterial population remained constant throughout the patients’ stay in hospital.

Copper solutions

“Hospital-acquired infections sicken approximately 2 million Americans annually, and kill nearly 100,000, numbers roughly equivalent to the number of deaths if a wide-bodied jet crashed every day,” said coauthor Michael G. Schmidt, PhD, Professor of Microbiology and Immunology, Medical University of South Carolina, Charleston. They are the eighth leading cause of death in the US.

Hospital beds are among the most contaminated surfaces in medical settings, the team explains. Although healthcare workers do clean and sanitize them, these efforts fall short — the beds are cleaned either not often enough, or not well enough to remove all pathogens, the team explains. And, while the antimicrobial properties of copper have been known for a long time now, patient beds that incorporate copper-lined surfaces aren’t commercially available.

In an effort to quantify the effectiveness of such beds — and potentially bring them to hospital settings around the world — the team performed an on-site experiment using five ICU beds, which see some of the heaviest patient use. The team compared the relative contamination levels of beds lined with copper rails, footboards, and bed controls to traditional hospital beds (which have plastic surfaces). All in all, they report that 90% of bacterial samples taken from plastic surfaces had bacteria concentrations that exceeded safe levels. Meanwhile, copper-lined surfaces “harbored significantly fewer bacteria throughout the patient stay than control beds,” they explain, “at levels below those considered to increase the likelihood of HAIs”. Furthermore, if daily and terminal cleaning regimes are respected, these beds don’t tarnish and don’t require additional cleaning or maintenance.

Copper-lined surfaces for hospital beds can help keep them hygienic for longer (provided they are cleaned regularly) and reduce the risk of HAIs spreading between patients. The use of copper-lined equipment can help improve patient outcomes, save lives, and reduce healthcare expenditures, the team concludes.

“Based on the positive results of previous trials, we worked to get a fully encapsulated copper bed produced,” said Dr. Schmidt. “We needed to convince manufacturers that the risk to undertake this effort was worthwhile.”

The paper “Self-Disinfecting Copper Beds Sustain Terminal Cleaning and Disinfection (TC&D) Effects Throughout Patient Care” has been published in the journal Applied and Environmental Microbiology.

Bronze axeheads.

The Vikings’ Bronze Age relied on imported metal, new study finds

The forefathers of Vikings build their axes with imported metal.

Bronze axeheads.

British-developed bronze flat-axe from Selchausdal, northwest Zealand. Scandinavia holds the largest proportion of British type axes outside the British Isles 2000–1700 BC.
Image credits Heide W. Nørgaard, Ernst Pernicka, Helle Vandkilde, 2019, PLOS One.

The geographic origins of the metals used in Scandinavian mixed-metal (bronze) artifacts can be traced back to Britain and continental Europe, a new study reports. Based on the findings, the authors from Aarhus University, Denmark, estimate that Scandinavia was “dependent” on imported tin and copper at the beginning of the Nordic Bronze Age.

Shipping Bronze

“4000 years ago, Britain and Central Europe supplied copper and tin to Denmark, which has no metal sources of its own,” the authors write. “Instead finished metal objects were imported and recast to fit local tastes. In this creative process at the onset of the rich Nordic Bronze Age mixing of the original sources took place. This conclusion is prompted by robust archaeological and geo-chemical data.”

The earliest signs of bronze-type alloys being used in Scandinavia (known as Nordic Bronze age) hail from around 2000-1700BC. Around this time, both tin and copper (which mix to make bronze) had rapidly, and drastically, increased in availability in the area. In a bid to understand where this metal came from, Heide W. Nørgaard from Aarhus University, Denmark, and colleagues performed isotope and trace-element analyses on 210 Bronze Age artifact samples (mostly axe heads) collected in Denmark. The majority of samples (141 counts) date between 2000–1700 BC and 50 samples from 1700–1600 BC.

The sample size represents around 50% of all known Danish metal objects from the early Nordic Bronze age, the team explains.

Trade was how the early Danes got their metal, the findings suggest. Robust trading networks were established to import raw metal and finished metal goods such as tools and weapons via two major routes: one leading down across the Baltic Sea towards the Únĕtice (a Bronze Age civilization in what is now eastern Germany and Bohemia), and another leading west to the British Isles.

These two sources made up a sizeable portion of the Scandinavian bronze ‘market’ at the time, the team explains. This is underscored by findings of particular isotopic signatures and the particular make-up of the alloys, which allowed the team to track their origins. Artifacts from between 2000–1700 BC are mainly made from high-impurity copper (fahlore type copper), except those imported from the British isles. Local production was based on the re-casting of foreign items, the team explains, as suggested by the presence of this British copper in axes of local styles. The team also reports finding lower lead contents in locally-crafted items than in imported ones, which suggests locals were mixing copper from different sources.

Later, around 1800–1700 BC, the team reports that a new and distinct type of copper with low impurity levels starts coming to the forefront. Copper from Slovakia was widely-used in Scandinavia during this time, with the Úntice people likely acting as middlemen facilitating the trade.

Metal recycling remained common in Scandinavia, with smiths here repeatedly re-casting imported objects into goods of local styles. The authors also found evidence of relatively pure copper sourced from the eastern Alps that would become dominant in Scandinavian smithing later in the Bronze Age.

The findings showcase how important trade was even for communities that we’d consider ‘primitive’. They also align with previous findings of copper trade networks dating from the time of Otzi the Iceman, stone-age Vietnam, and Ancient Babylon, showcasing how important this metal was at its time — and the efforts people were willing to go through to trade in it.

The paper “On the trail of Scandinavia’s early metallurgy: Provenance, transfer and mixing” has been published in the journal PLOS One.

Copper.

Copper-coated uniforms for medical staff could help shred bacteria in hospitals

Healthcare professionals might soon be bringing on the bling in the workplace, as UK and Chinese researchers designed copper-covered uniforms to help fight bacteria.

Copper.

Image via PxHere.

Materials scientists from the University of Manchester, working with counterparts from several universities in China, have created a ‘durable and washable, concrete-like’ material made from copper nanoparticles. They’ve also developed a method of bringing this composite to textiles such as cotton or polyester, a world first.

Coppering out

Bacterial infections are a major health issue in hospitals across the world. These tiny prokaryotes spread throughout healthcare facilities on surfaces and clothing, leading to losses both of life and of funds. The issue becomes worse still after you factor in the rise of drug resistance in most strains, which is rendering our once-almighty antibiotics more and more powerless. So we need to look for alternative ways of dealing with them, ones that do not rely on antibiotics.

One increasingly promising set of tools in our fight against disease are precious metals, such as gold and silver, which have excellent antibacterial and antimicrobial properties. However, deploying these on the surfaces and clothing mentioned earlier runs into some pretty obvious problems: first, gold and silver are really expensive — after all, they literally used to be money. Secondly, they don’t lend that well to making practical clothes, especially in a hospital setting.

Enter copper. Less expensive than gold or silver, copper is nevertheless still very good at killing pathogens, which solves problem one. However, up to now, we still didn’t have an adequate answer to issue number two — which is what the team addresses in this paper.

Using a process dubbed ‘Polymer Surface Grafting’, the researchers were successful in tying copper nanoparticles to cotton or polyester using a polymer brush. Cotton and polyester were chosen as a test bed as they’re the most widely used natural fiber and a typical man-made synthetic fabric, respectively.

The materials were brushed over with copper nanoparticles measuring between 1 and 100 nm, which is really small — one nm equals one-millionth of a mm. The metal particles formed a strong, stable chemical bond with the cloth, meaning the metal won’t flake off or be washed away.

“Now that our composite materials present excellent antibacterial properties and durability, it has huge potential for modern medical and healthcare applications,” says lead author Dr Xuqing Liu, from UoM’s School of Materials.

During lab tests, the copper-coated materials easily killed Staphylococcus aureus (S. aureus) and E. coli, two of the most common and infectious bacteria in hospitals, even after being washed 30 times.

The team says their results are very promising, and Dr. Liu adds that “some companies are already showing interest” in developing it further.

“We hope we can commercialise the advanced technology within a couple of years,” he adds. “We have now started to work on reducing cost and making the process even simpler.”

The paper “Durable and Washable Antibacterial Copper Nanoparticles Bridged by Surface Grafting Polymer Brushes on Cotton and Polymeric Materials” has been published in the Journal of Nanomaterials.

Glenfield Park site.

UK archaeologists unearth “nationally important” collection of Iron Age artifacts

University of Leicester archaeologists have recovered a collection of rare Iron Age metal artifacts from a site in Glenfield Park, Leicestershire, England. Among the objects are decorated cauldrons, a complete sword, and a brooch from the 3rd century BC.

Glenfield Park site.

Aerial shot of the Glenfield Park roundhouse.
Image credits: University of Leicester Archaeological Services.

The collection includes eleven cauldrons, several fine-crafted ring-headed dress pins, an involuted brooch and a cast copper-alloy ‘horn-cap’, likely a part of a ceremonial staff, archaeologists say. The objects were inhumed at the site in a series of events that took part over a considerable span of time, they add, resulting in multiple episodes of sediment deposition across the settlement.

“Glenfield Park is an exceptional archaeological site, with a fantastic array of finds that highlight this as one of the more important discoveries of recent years,” said Dr. John Thomas, director of the excavation and project officer from the University of Leicester Archaeological Services.

Dr. Thomas explains that human occupation in the area during the middle Iron Age (5th to 4th centuries BC) was “modest”, consisting of a small settlement with no walls on the south-facing slopes of the spur. Some time later, around the 4th to 3rd centuries BC according to current radiocarbon dating results, the site underwent major changes. Individual roadhouses were enclosed, “there was far more evidence for material culture”, and the inhabitants adopted rituals and rites that seem to involve “deliberate burial of a striking assemblage of metalwork.”

That metalwork is what truly sets the site apart, Dr. Thomas says. Not only is it found in much larger quantities than in other known comparable sites in the area, the items are also of much higher quality and the composition of the artifacts is also unique.

[ALSO READ: Huge treasure of medieval silver and gold unearthed at abbey in France

“The cauldron assemblage in particular makes this a nationally important discovery,” Dr. Thomas said. “They represent the most northerly discovery of such objects on mainland Britain and the only find of this type of cauldron in the East Midlands.”

The team reports that the cauldrons appear to have been placed in a large circular enclosure ditch that surrounded a building. It’s not known why yet, but it’s very likely that this was a deliberate choice, not an accident, the archaeologists add. The cauldrons had been placed either upright or inverted, after which the ditch was filled in. One hypothesis is that this burial was meant to mark an end to the activities carried out at this part of the site. Other cauldrons were found buried across the site, suggesting that these rituals were used to mark significant events over a long period of time as the settlement developed.

They are fashioned from several distinct parts — iron for the rims, upper bands, and the ring handles attached to them, copper alloy for the body. Size-wise, they range between 14.2 and 22 inches (36-56 cm) in diameter, with the summed-up capacity of all cauldrons around 550 liters. This volume is quite significant, and the team suspects that they may have been used to provide food for large groups of people, for example at gatherings held in the site for the area’s wider Iron Age community.

CT scans performed on the cauldrons show evidence of wear, tear, and repair, pointing to long-term and repeated use of the objects. The amount of care and effort that went into repairing them further reinforces the hypothesis that the cauldrons were special for the Iron Age community at Glenfield Park.

“Due to their large capacity it is thought that Iron Age cauldrons were reserved for special occasions and would have been important social objects, forming the centerpiece of major feasts, perhaps in association with large gatherings and events,” Dr. Thomas said.

“They are rarely found in large numbers and, with the exception of a discovery in Chiseldon, where 17 cauldrons were found in a pit, there have been few excavated examples in recent years.”

Dr. Thomas adds that cauldrons held a symbolic value in the area at the time, as evidenced by their frequent appearance in early-medieval Irish and Welsh literature.

The Iceman's Axe.

Otzi’s copper axe offers hints of ‘extensive trade networks’ in Italy 5,300 years ago

Isotope analysis of Otzi’s copper axe blade hints at a long-distance trade route between central and northern Italy in the early copper age.

The Iceman's Axe.

The Iceman’s Axe.
Image credits Gilberto Artioli et al., 2017.

Otzi’s mummified body was found back in 1991, flash-frozen in an Alpine glacier on Italy’s northern border with Austria. He’s estimated to have lived in the early copper age, around 3360-3105 BCE, not very far from the place where his remains were found.

So far, nothing too unexpected. But appearances were deceiving  — turns out that the copper used in Otzi’s axe came from a much more distant place than the man himself, unlike previously believed. A new paper led by University of Padua geoscientist Gilberto Artioli reports that the metal was sourced about 500 kilometers to the south, in today’s Southern Tuscany region of central Italy.

Follow the lead

While the blade is made of copper, it was manufactured in a time where metal working and refining were still in their infancy. As such, the blade contains noticeable levels of impurities in the form of lead, arsenic, silver, and a host of other elements.

Up to now, researchers assumed the metal was sourced from the known (and quite sizeable) copper deposits found less than 100 km from the site where the mummy was found. But by analyzing the lead isotopes (atoms of the same number of protons and electrons but a different number of neutrons) contained in the blade and comparing them with copper samples from present-day exploitations across Europe, Artioli’s team reports that the metal likely came from Southern Tuscany. Other elements in the chemical makeup also point to Southern Tuscany as the likeliest point of origin, they add.

Finding a bit of copper so far away from its point of extraction — especially considering the closer deposits, which people likely knew about by the time of Otzi — would suggest that complex trade networks existed by this time. After all, copper was very expensive and heavy, so transporting it over such a long distance meant the merchants had to be able to defend their wares and turn a nice profit at the end for it to be worth it.

Archaeological evidence does point to a flourishing copper extraction and production industry in central Italy when Ötzi was alive, the team says. They propose it was complemented by an extensive trade network which supplied the goods to the northern Alpine lands. This would make it one of the earliest organized trade networks in the area, established at the dawn of civilization, at a time when people still used stone for most tools.

Radiocarbon measurements on the axe’s wooden shaft indicate that the item was fabricated roughly 5,300 years ago. It’s not yet clear whether the copper was transported as a raw material or a finished product.

The paper “Long-distance connections in the Copper Age: New evidence from the Alpine Iceman’s copper axe” has been published in the journal PLOS one.

The original haute couture: archaeologists unearth fabrics from King Solomon’s time

Recent archaeological findings in the Timna region in Israel’s southern Arava Valley showcase the surprising variety and quality of the clothes worn some 3,000 years ago.

If there’s anything my girlfriend has thought me is that I don’t know anything about modern fashion. And she’s right, I’m the Jon Snow of haute couture. But since fashion is something that she can get really caught up in, I thought I’d start from the beginning and learn my way from there — and you can’t really get any earlier that ancient Israel.

Tel Aviv University’s Timna excavation team on-site, setting the earliest trends in fashion.
Image credits Central Timna Valley Project/TAU.

So, what would have been on the catwalk in the days of King Solomon? Recent archaeological findings by a team from Tel Aviv University might answer that question. They uncovered an extensive collections of fabrics in the country’s southern desert copper mines. This is the first discovery of the materials people wore some 3,000 years ago, Israel’s Foreign Ministry reports.

“No textiles have ever been found at excavation sites like Jerusalem, Megiddo and Hazor, so this provides a unique window into an entire aspect of life from which we’ve never had physical evidence before,” said lead archaeologist Erez Ben-Yosef in a statement Wednesday.

“We found fragments of textiles that originated from bags, clothing, tents, ropes and cords.”

Try to imagine an ancient Israeli getup, I’ll wait. Done? The first images to pop in your head are the ones from movies like Passion of the Christ, right? Where everyone is wearing a gray sack with a hole cut out for their head, looking miserable. And even the fancier clothes look like they’re weaved from something so rough it makes your eyes itchy.

And well, probably. But the rich, powerful and influential people of the time had a pretty impressive range of clothing to choose from. Varied materials, colors and models were available to them, the findings show.

A thick goat hair cord made using many threads twisted together for durability and strength.
Image credits Clara Amit/Israel Antiquities Authority.

The fabrics were found in Timna in the Arava Valley of southern Israel, an active mining area around the 10th century BC, during King Solomon’s reign. The colorful artifacts offer unique insight into the attires, but also the trade practices and economy of that period.

Many of the fabrics, including water-intensive linen cloths, were grown and woven far from the mine in which they were found. This hints at intense trade between the Timna region and Northern Israel of the Jordan Valley, with copper exports being used to pay for the daily goods that were required by the community to survive in Israel’s harsh deserts.

“We found linen, which was not produced locally,” said TAU masters student Vanessa Workman.

“It was most likely from the Jordan Valley or northern Israel. The majority of the fabrics were made of sheep’s wool, a cloth that is seldom found in this ancient period.”

Far from the undyed fabrics we’re used to associate with those times, archaeologists found fragments of a surprising variation in color, weaving patterns and ornamentation. One woolen fragment, for example, is dyed red and blue with strands of animal hair woven in to form decorative bands within the fabric.

“We found simply woven, elaborately decorated fabrics worn by the upper echelon of their stratified society,” Ben-Yosef adds.

“Luxury- grade fabric adorned the highly skilled, highly respected craftsmen managing the copper furnaces. They were responsible for smelting the copper, which was a very complicated process.”

Fine wool textile dyed red and blue. The black and orange colored bands are made with naturally-colored wool.
Image credits Clara Amit/Israel Antiquities Authority.

Turns out Hollywood isn’t the best source for accurate historical info (who would have guessed, right?). These fabrics adorned the higher-ups in the society, men with the skill to turn ore into precious copper. The mines themselves were worked by slaves, in harsh conditions and presumably, humbler attires.

“Miners in ancient Timna may have been slaves or prisoners; theirs was a simple task performed under difficult conditions,” Ben-Yosef concludes.

“But the act of smelting, of turning stone into metal, required an enormous amount of skill and organization. The smelter had to manage some 30 to 40 variables in order to produce the coveted copper ingots.”

The findings show the geopolitical and economical importance of the Edomites (the tribe living in this region and working the copper mines) during the time of King Solomon. Supplying a population with water, food and other goods in the middle of the desert raises difficulties even today, and must have been a Sisyphean task with the age’s technological levels.

“Copper was a source of great power, much as oil is today,” Ben-Yosef concludes.

“If a person had the exceptional knowledge to create copper, he was considered well-versed in an extremely sophisticated technology.”

The fabrics are just one part of the larger Central Timna Valley Project, an ongoing effort started in 2012 to explore the archaeological record of the southern Arava’s copper mining and smelting sites. Arid conditions in the area have helped organic materials such as fabric and leather survive.

How the Copper Age changed humanity

Since man first found he could sharpen a stick to defend himself, we’ve realized the importance of good quality tools in making our life easier and more bountiful. In our search for better and better tools and weapons, wood gave way to rocks tied to sticks, that were in turn replaced by chiseled pieces glued and fastened to hardy handles. Whole communities came to rely on those that could turn their hand to working stone, to people such as Otzi.

Otzi was the finest stone-shaper in the village; the tools he produced bit deep into soil, fell trees and boars alike with ease, and chased away many a pillaging group. They were the zenith of the day’s technology, underpinning every field of human activity, from agriculture to crafts, to battle. And today, grasping an axe that he himself chiseled, standing next to his fellow villagers, facing strange people from stranger lands, Otzi was prepared to defend his home once again. But as battle raged and stone splintered on the invader’s weird, reddish weapons and armor, realization crept over the defenders; stone was no longer king.

The age of copper had begun.

Copper bars
Image via images-of-metals

The red stone that won’t break

Copper is widely believed to be the second metal (after gold) that humans learned to shape and utilize. It was more easily encountered and obtained than other metals as it forms native element bodies throughout the crust, and archaeological consensus places its discovery at 9000 BC somewhere in the Middle East — though like agriculture, it was most likely discovered independently by several groups of people.

A lot softer than iron, with 3.0 on the Mohs scale compared to iron’s 4.5, and very malleable, the metal could easily be beaten into shape and if done at room temperature this would create more durable edges as the metal’s crystals aligned to the mechanical stress. Being easy (compared with other metals) to mine and process but more durable, malleable and less brittle than stone, copper started replacing it as the material of choice for tools, weapons and other objects. However, as limited people had knowledge of the metal or how to work it and as it was fairly expensive, stone remained the most used material throughout the copper age.

Still, this was little comfort to the peoples that were enslaved by more technologically advanced tribes and empires, in part due to lacking the adequate weapons to defend themselves, such as our hypothetical Otzi.

From finding to extracting

Elemental copper was the first source of the metal that humans used, for obvious reasons — it’s easy to find and doesn’t need much refining. If a big enough chunk was found, all you had to do was hammer it into whatever shape you needed.

Native copper. Image via wikimedia

Native copper.
Image via wikimedia

However, this is limited by the size and shape of the nuggets miners were able to find, and there wasn’t any way of making sure there weren’t impurities in the metal mass, that could ruin the final object’s properties. As copper deposits were exploited over time, such pieces of metal were increasingly hard to come by, so craftsmen started melting together smaller bits of copper into bars that they would then turn into finished products.

Most copper nuggets are found in this size.
Image via images-of-elements

Experimenting with melting the metal, smiths learned that they could treat copper to have different properties, depending on what they would use it for. If you took a copper bar, heat it up and let it cool down slowly (a process known as annealing), the metal’s crystalline structure would arrange in a more homogeneous structure and the copper was much softer and easier to shape, good for jewelry or coinage.

On the other hand, cold-processed copper had a more arranged crystalline structure, harder than the annealed metal. Tools and weapons were shaped this way, to make them more durable and allow them to keep a better edge.

Top: Annealed steel alloy, showing a heterogeneous, lamellar microstructure, consisting of phases richer in carbon next to phases richer in iron. Bottom: tempered steel, in which the carbon remains trapped within the crystals, creating internal stresses. While steel is an alloy, copper crystals behave similarly to heat treatment, with cold-shaped pieces showing the same internal stresses between crystals, helping them hold each other in place. Image via wikipedia

Top: Annealed steel alloy.
Bottom: tempered steel.
While steel is an alloy, copper crystals behave similarly to heat treatment, with cold-shaped pieces showing the same internal stresses between crystals, helping them hold each other in place.
Image via wikipedia

After deposits were depleted of most native copper bodies, smelting was employed to extract the metal from its ores. Early smelters were very primitive, so in these early days of metallurgy, only the most worthwhile material was processed. For example, some of the first recorded smelters were employed by the Sumerians, and they were no more than shallow pits in which ore was thrown over burning charcoal.

Exactly how they reached sufficiently high temperatures in the absence of bellows is still a matter of speculation — one theory holds that the smelters were covered with clay, leaving only an opening towards the prevailing wind to feed the fire. Hieroglyphs show that the Egyptians also had this problem, but solved it using a long tube to blow air into the furnace.

“I swear Amun, this job blows!”
Image via tf.uni-kiel

This is another major turning point in our history that copper brought about. Smelting involves much more than just melting the metal from the rock — it’s a delicate chemical process, requiring the use of a reducing agent to scrub the metal atoms of oxidizers (most often carbon in the form of charcoal that releases carbon monoxide as it burns, then pulls oxygen atoms from the ore, forming CO2) that usually bind to them, and flux is used to purify the melt.

Smelting was probably developed over a long period of time, with small improvements being added over time to the procedure. But without a metal useful enough to impose itself in human society, that could be found both in native and ore forms, smelting might have never been developed. And without smelting, other metals such as iron or aluminum would have never been discovered and used.

In the later part of the Copper age, as technology advanced, casting was employed on a wider and wider scale as a production method, especially for works of art such as statues or jewelry, for religious objects and some tools. This process required skilled craftsmen, as it is quite difficult to do with copper because of the formation of gas bubbles during the pouring of the metal and its shrinking when it cooled down.

The social impact

Ok so now we have a pretty good idea of how copper was extracted and processed in the beginning, but how exactly did the discovery of metal (especially one durable and abundant enough to rival stone) impact the lives of people?

In a time where virtually all labor was muscle-driven, having access to a material that can make your tools bend a bit instead of breaking — but that’s ok because you can totally hammer it back up — or make your sword shatter an enemy’s weapon was like playing life with cheat codes. This is why we tend to create chronologies (Stone age, Iron age, etc.) based on how widespread the use of some such material was in a certain region.

During the early stages of an age the use of the new metal was still infrequent, but became widespread during the middle stage and common in the final period, and the impact on societies should be viewed with this in mind.

One of the most distinctive societies of prehistoric Cyprus (the island from which the name of copper is derived) was the Erimi Culture. Mainly fishers and farmers throughout the Paleolithic, during the Copper Age the Erimi experienced a huge population increase, an explosion of arts and crafts but most importantly — the creation of social hierarchies.

People loved it; they used it for everything, from nails to pans to roof tiles, statues of gods or demons or pretty young ladies (hopefully) — if they could afford it. Villages grew in size and were fortified, with large houses and high-status goods denoting differences in wealth and position. Grain storage and food preparation became private rather than communal, as it was in the earlier villages.

Reconstruction of an Erimi house.
Image via wikipedia

With access to better tools, farmers — most of the population — were able to produce much more food than they required to feed themselves; those that had access to copper — few in number — would sell the tools, the weapons and miscellaneous metal goods that the community required, turning a sweet profit for themselves. Trade flourished both internally and with other peoples, and as the Erimi accumulated wealth, they had more and more time and resources to spend on arts, culture and science.

A typical copper ingot in the late Chalcolithic, meant for export.
Image via wikipedia

This trend keeps around the globe — as groups discovered copper and the means to extract it, they experienced (with some exceptions) huge demographic, economic, and cultural explosions, with social layers or hierarchies being cemented during this period.

Copper leads to bronze

Sometime in the late Chalcolithic, someone figured out that if you melt copper together with another metal such as arsenic, it becomes harder, more resilient and altogether better at everything people used copper for up to them. Exactly how this was discovered is still a matter of debate, but since copper ores are naturally contaminated with other metal, such as arsenic and tin, it’s likely it was discovered by chance during smelting.

No matter how the alloy came to be, it quickly started replacing copper wherever it was available, just as metal once replaced stone. Most artifacts retrieved from the Bronze age are made up of a type of copper alloy called brass, a mixture of copper and zinc, known for its bright gold-like appearance.

Brass bar.
Image via sino-cool

Although it lost its monopoly on human metal industry a long time ago, copper is still one of the most valuable and sought-after metals even today. Its resistance to corrosion, thermal and electrical conductivity, ductility and malleability make it irreplaceable in a wide range of industrial sectors, from plumbing to electronics.

Bars of bronze.
Image via atlantishome

It’s so valuable to us that up to the 20th century, Sweden was known to have a “copper backed currency” — a mine in Falun, known as the Great Copper Mountain, operated from the 10th century to 1992, produced two thirds of Europe’s copper demand in the 17th century and helped fund many of Sweden’s wars during that time.

But no matter how useful it is, or how profitable it is to trade, in my opinion the real value of copper is that it thought us how to shape metal. It freed us from the constrains of wood, bone, fibers, stone and gave us the means and knowledge to produce tools and technologies powerful enough to shape the world around us.

 

 

“Copper kills everything”: A Copper Bedrail Could Cut Back On Infections For Hospital Patients

As modern medicine can be quite paradoxical sometimes, checking into a hospital can actually boost your chances of an infection; and if you’re thinking that this only happens in poorer, underdeveloped countries – you’re wrong. No matter where you check in at a hospital, you are vulnerable to infections which have nothing to do with your original problem. Now, a team from Chile studying this issue believe they have found a solution for this problem: copper.

A copper bedrail can kill germs on contact.
Courtesy of CopperBioHealth

The World Health Organization estimates that “each year, hundreds of millions of patients around the world are affected” by healthcare-acquired infections. These are called healthcare-acquired infections, healthcare-associated infections or hospital-acquired infections. Most of them can be very dangerous, and there doesn’t seem to be a correlation between how well the hospital is equipped and how likely you are to get an infection. However, in developing countries, the rate of hospital infection seems to be higher.

The source of these infections can come as quite a surprise – Constanza Correa, a Chilean researcher and her team found that bed safety railings are major source of infections. They replaced the railings with copper ones, and the effect was immediate and visible.

“Bacteria, yeasts and viruses are rapidly killed on metallic copper surfaces, and the term “contact killing” has been coined for this process,” wrote the authors of an article on copper in Applied and Environmental Microbiology. That knowledge has been around a very long time. The journal article cites an Egyptian medical text, written around 2600-2000 B.C., that cites the use of copper to sterilize chest wounds and drinking water.

Indeed, this is called the “Oligodynamic effect” – many metals have a strong antimicrobial effect, being toxic not only for microbes, but also for algae, molds, spores, fungi, prokaryotic and eukaryotic microorganisms, even in relatively low concentrations. Most heavy metals exhibit this effect, but also silver, iron, and of course, copper. Silver and copper actually have the strongest antimicrobial effect.

Correa and her team hasn’t yet assessed the entire impact that bed railings can have, but a study of the effects of copper-alloy surfaces in U.S. hospitals’ intensive care units, published last year in Infection Control and Hospital Epidemiology, showed promising results: Their presence reduced the number of healthcare-acquired infections from 8.1 percent in regular rooms to 3.4 percent in the copper rooms. That’s a reduction of almost 60 percent.

“Healthcare-acquired infections are a huge problem. People come to the hospital with a sickness, and they get another one in the hospital. Then they have to stay longer and spend more money on treatment. Sometimes it can cause death. Eighty percent of these infections come from touching hospital surfaces. In the hospital room, the most contaminated surface is the bed rail. It’s the most manipulated by medical staff and patients. It’s in direct contact with the patient. That’s the most critical surface in the room”, Correa said in an interview published on NPR.

 

“Copper kills everything”, she says, so why not use it more in hospitals? There is a huge number of ways in which you can use it. You can have copper IV poles, feeding tables, night tables, even mattress covers (a copper additive).

“Copper kills everything. Why wouldn’t you use it? It has so much sense for people.”

Copper foam turns CO2 into useful chemicals

Brown University researchers reported the development of a copper foam which could turn CO2 into useful chemicals such as formic acid – a preservative and antibacterial agent in livestock feed.

Copper1

Copper is the only metal that can reduce CO2 to useful hydrocarbons. A foam of copper offers sponge-like pores and channels, providing more active sites for CO2 reactions than a simple surface. Credit: Palmore lab/Brown University

As CO2 emissions continue to grow, scientists are trying to find potential uses to it. The problem with carbon dioxide is that it is extremely stable, so breaking it and making useful industrial chemicals is no easy feat. The catalyst they made from copper foam has “vastly different properties” from catalysts made with smooth copper in reactions involving carbon dioxide:

“Copper has been studied for a long time as an electrocatalyst for CO2 reduction, and it’s the only metal shown to be able to reduce CO2 to useful hydrocarbons,” said Tayhas Palmore, professor of engineering and senior author of the new research. “There was some indication that if you roughen the surface of planar copper, it would create more active sites for reactions with CO2.”

Copper foam was virtually ignored until a few years ago, when it started receiving the attention it deserves. The foam is created by depositing copper on a surface in the presence of hydrogen and a strong electric current. Hydrogen creates bubbles and the copper is deposited in a sponge-like arrangement of varying sizes.

After the foam was created, researchers set out to experiment, and see which chemicals strongly react to it; lo and behold CO2 was one of the winners. Their experiments showed that the copper foam converted CO2 into formic acid much more efficiently than common copper. The reaction also produced small amounts of propylene, a useful hydrocarbon that’s never been reported before in reactions involving copper.

“The product distribution was unique and very different from what had been reported with planar electrodes, which was a surprise,” Palmore said. “We’ve identified another parameter to consider in the electroreduction of CO2. It’s not just the kind of metal that’s responsible for the direction this chemistry goes, but also the architecture of the catalyst.”

To me, it’s remarkable that a material so common and well studied as copper still yields surprises for us. But it’s clear that we still have much to learn about it.

“People have studied electrocatalysis with copper for a couple decades now,” she said. “It’s remarkable that we can still make alterations to it that affect what’s produced.”

Source: Brown University.

Scanning electron microscope images show typical carbon nanotube fibers created at Rice University and broken into two by high-current-induced Joule heating. Rice researchers broke the fibers in different conditions — air, argon, nitrogen and a vacuum — to see how well they handled high current. The fibers proved overall to be better at carrying electrical current than copper cables of the same mass. (Credit: Kono Lab/Rice University)

Carbon nanotube fiber can carry four times more charge than copper

Reliable, well supplied and with years and years of manufacturing experience behind it, copper is the most widespread material used for delivering electrical charge. Some applications warrant more efficient materials, though,  and researchers at Rice recently showed that carbon nanotubes spun into fiber can carry four times as much electrical charge than copper cables of the same mass.

Of course, carbon nanotubes taken individually can deliver 1,000 times more current than copper, but real-world applications require macroscopic conductors. Previous attempts at mustering carbon nanotubes for high power electrical charge failed, however Rice University researchers demonstrated that wet-spun carbon nanotube fiber is a good alternative.

Rice professors Junichiro Kono and Matteo Pasquali developed a strong and flexible cable even though at 20 microns wide, it’s thinner than a human hair. For benchmark purposes, the researchers analyzed the “current carrying capacity” (CCC), or ampacity, of the nanotube fiber against that of copper cables. Four mediums were chosen for this analysis: open air, in a vacuum and in nitrogen or argon environments.

Scanning electron microscope images show typical carbon nanotube fibers created at Rice University and broken into two by high-current-induced Joule heating. Rice researchers broke the fibers in different conditions — air, argon, nitrogen and a vacuum — to see how well they handled high current. The fibers proved overall to be better at carrying electrical current than copper cables of the same mass. (Credit: Kono Lab/Rice University)

Scanning electron microscope images show typical carbon nanotube fibers created at Rice University and broken into two by high-current-induced Joule heating. Rice researchers broke the fibers in different conditions — air, argon, nitrogen and a vacuum — to see how well they handled high current. The fibers proved overall to be better at carrying electrical current than copper cables of the same mass. (Credit: Kono Lab/Rice University)

The number one cause of electrical cable failure is overheating. When current passes through a conductor, it also produces heat because of the material’s resistivity. When temperatures exceed rated values, the cable gets too hot, breaks and, of course, can potentially become a fire hazard. Concerning the carbon nanotube fibers, those working in nitrogen atmosphere proved to have the best CCC, followed   by argon and open air, all of which were able to cool through convection. The same nanotube fibers in a vacuum could only cool by radiation and had the lowest CCC.

“The outcome is that these fibers have the highest CCC ever reported for any carbon-based fibers,” Kono said. “Copper still has better resistivity by an order of magnitude, but we have the advantage that carbon fiber is light. So if you divide the CCC by the mass, we win.”

Ever carried a copper or aluminium cable? That’s some heavy gear, but not because of the conducting material itself, but rather because both copper and aluminium don’t have a high tensile strength, a heavy steel-core reinforcement is needed to support the cable. In applications where weight is an important factor to consider, like aerial or spacial projects, carbon nanotube fiber could prove to be a better option, according to the Rice scientists.

Pasquali even suggested the thread-like fibers are light enough to deliver power to aerial vehicles. We’ve heard of wackier stuff work.

 “Suppose you want to power an unmanned aerial vehicle from the ground,” he mused. “You could make it like a kite, with power supplied by our fibers. I wish Ben Franklin were here to see that!”

Details were published in the journal Nanoscale. [story via Kurzeweil]

A novel technique cools electronic devices faster and cheaper

Researchers at  North Carolina State University have developed a new technique of cooling electronic devices which they claim and prove through their findings that it can lead to an increase of performance by improving the rate of heat exchange, while also lowering the cost of manufacturing. The scientists’ findings might lead to a new generation of more efficient heat sinks, as well as better cooling for devices that generate a lot of heat, such as lasers and power devices.

The technique is centered around what the researchers call a “heat spreader”, a copper-graphene composite, which is attached to the electronic device using an indium-graphene interface film. Together, the materials provide a much higher thermal conductivity than the conventional lonesome copper used ubiquitously for standard cooling of electronic devices. To be more precise, copper-graphene composite films with thickness greater than 200 microns showed an improvement in thermal conductivity over that of electrolytic copper from 380 W/m.K to 460 W/m.K at 300 K – more than 20%.

Besides the remarkable improvement in thermal conductivity, the researchers point out that the copper-graphene composite is also low-cost and easy to produce, using an electrochemical deposition process “Copper is expensive, so replacing some of the copper with graphene actually lowers the overall cost,” conclude the researchers.

Their findings have been published in the journal Metallurgical and Materials Transactions B.

source: NCSU

Rare Earth minerals to be mined from the seafloor

The next step in prospecting and mining has always been a subject of speculation and theories, ever since the days of Jules Verne. For decades, an idea that flourished more and more was to gather up potato-sized magnanese nodules, rich in nickel, cobalt and manganese, that are very valuable in large quantities. The problem is that pretty much all the time, they lie miles below the seafloor, which obviously poses some serious technical questions.

The classical idea of building giant vacuums to suck up the nodules never proved to be economically sustainable; however, it was recently discovered that these modules are have a high content of rare earth minerals, elements that have a high demand rate but have recently reached a production roadblock. China, which controls about 95% of the worldwide quantity had stopped seeling them, creating huge political and industrial alarms; they stopped the embargo a few weeks ago, but the hunt for other sources still continues – this could give the seabed miners quite a few reasons to smile and rub their hands.

“People are quite intrigued,” said James R. Hein, a geologist with the United State Geological Survey who specializes in seabed minerals. Depending on China’s behavior and the global reaction, he said, “rare earths may be the driving force in the near future.”

About a month ago, Dr. Hein and five colleagues from Germany presented a paper on harvesting the nodules for rare and valuable metals, and concluded that there really is something there.

“They really do add value,” Charles L. Morgan, chairman of the institute, said of the rare earths in an interview. The result, he added, is that the nodules have taken on a new luster. “People are starting to think, ‘Well, maybe these things aren’t so dumb after all.’ ”

Rare earths are quite interesting from a number of perspectives; most of them are not really rare at all, but they rarely gather up in large quantities; some of them are practically neglectable. For example, an isotope of Promethium has only 572 g in the entire Earth’s crust. Right now, they really aren’t extremely important, but things could change pretty quick, especially with the current unstable political situation.

“The global activity is tremendous,” said Dr. Hein of geological survey, referring to undersea exploration as well as processing assessments on land. “Right now, rare earths are not the driving force,” he said. “But for copper and nickel, the prices are there.”