Underwater welding.

Константин Константинович Хренов or in english Konstantin Konstantinovich Khrenov was a russian electrical engineer who was born in Borovsk, Russia in 1984.

Konstantin Konstantinovich Khrenov

 He is credited with the invention of underwater welding known as hyperbaric welding which is used on ships oil rigs and also pipelines, this is done by putting a flux on the weld at which  the electrodes burn the flux.  For its use in World war II  he was accredited the award of Stalin State prize in 1946.  He finished his schooling in electrochemistry in Saint Petersburg State Electrotechnical University. Khrenov spent most of his career creating inventions for welding techniques the science behind welding under water a nitrogen or argon bubble is blown.  Some welding techniques only require electrodes.  In his research he understood that the biggest hurdle was because of the sporadic bubbles that flowed under water.  

Wet welding.

Welding circuit.

 In this type of welding the the positive section of the electrode goes positive DC,  there is a quick deterioration of the flux. AC cannot be used because it can travel too easily in water.  The power needs to be around 300 or 400 amps.  Ground must be connected to the ship in order for the electrodes too flow.  A knife switch must be used for safety reasons.

The electrodes must be waterproofed so that the water cannot come into contact with the metal parts.  If the water makes any contact with the metal than it will destroy the ark as the voltage will yield to the metallic conductor.

Underwater wet welding.

Dry welding.

Dry hyperbaric welding  can be preformed at higher pressure the chamber filled with the gas mixture sealed around the structure. Most types of hyperbaric welding suffers as pressure increases. Dry water has been limited to less than 400m.

After the first successful wet weld due too the fact that metal was in such demand in Russia.

3D Printed Implants Save The Lives Of 3 Babies

In my earlier blogs I talked about how 3D printing is saving people lives and making things cheaper, the endless applications of 3D printing never cease to astound. The absolutely marvellous manufacturing technology is being used to produce houses, prosthetic beaks, robotic arms, rocket parts, blood vessels, food, exoskeletons - you name it. Now surprisingly it helped to save 3 babies in the U.S from life threatening condition.  

The infants suffered from a terminal disease known as Tracheobronchomalacia. This is a rare condition in which weakness of the walls of the windpipe causes the airway to narrow or collapse. Therefore it causes breathing problems, many patients experience a harsh collection of other side effects for example heat attacks or the inability to absorb food properly. 

Many children outgrow the condition by the age of two or three after newly developed tissue has reinforced the floppy airways but many children die before they have a chance to become strong enough. This was unfortunately outcome for the 3 young boys who had spent extended periods in intensive care.

 

Back in 2012 the first patient was Kaiba Gionfriddo, senior study author Glenn Green and biomedical engineering professor Scott Holister used 3D printing to create tailored stents for each individual patient as shown above in the picture. These were designed from the CT scan which provided details of the exact size and shape of their trachea. Then those hollow stents were stitched by surgeons on the outside of the trachea so that the weak airway remains open.

 

The implants were designed to be flexible enough to allow movement. The material they used was a cheap and harmless plastic called Polycaprolactone that's slowly breaks down over 3 or 4 years upon exposure to bodily fluids which is then absorbed by the body.  

 

Thankfully the surgery was a success in all 3 boys and has significantly improvement in their lives. The children are now 17 months and 3 years old they no longer have life-threatening airway disease and could go home.

 

“We were pleased to find that all of our cases so far have proven to improve these patients’ lives,” Green said in a statement. “The potential of 3D-printed medical devices to improve outcomes for patients is clear, but we need more data to implement this procedure in medical practice.”

 

 

http://www.iflscience.com/health-and-medicine/how-3d-printing-transformed-lives-3-babies-life-threatening-diseases

By Ayesha Javaid.