X-STREMEApplied Sciences

From Ebola to Ariane Rocketsa

Manufacturer’s perspective(a Multi-skilled Engineering

Jobbing Shop)

STEM

STEM SubjectsScience; Technology; Engineering; Maths are often taught as separate subjects in an educational environment.In the world of manufacturing they are inter-dependent and are crucial to the creation of viable, efficient and cost effective solutions to the problems facing humankind.

Why this title?It is difficult to think of two more diverse areas of specialist activity which both require the expertise of people with some degree of knowledge of STEM subjects. Never-the-less they demand equal levels of original thought and creativity based on scientific principles.

Problem solving in the field

The recent outbreak of Ebola virus on the African continent has made people more aware of the problems associated with bio-hazards. In particular the risk to humans from either contacting contaminated body fluids or breathing airborne contaminants which can have fatal consequences. How do STEM skills lead to the solution of these problems?

Bio-hazardsProblem; how do you keep people safe from exposure to bio-hazard material and chemicals when it is necessary for them to work in close proximity to highly infectious patients or while processing samples in the quest for a cure?The answer lies in isolation and containment but how?

Identify the problemBacteria typically measure 1000 nanometres

Viruses typically measure 40 nanometres

By coincidence, the maximum size particle that can be absorbed through skin pores is approximately 40 nanometres

Why not just use filters?Filters are percentage devices which means that they are not 100% efficient in removing everything that is present in the air. Also organisms can live in a filter, create colonies and migrate through the media.

So how efficient are filters?

Both HEPA and ULPA filters are constructed using a continuous paper media with aluminium or plastic separators and are typically between 6 and 12 inches thick.

FilterType Efficiency E (%)H10 85 @ 0.3µH11 95 @ 0.3µH12 95.5 @ 0.3µH13 99.95 @ 0.3µH14 99.995 @ 0.3µU15 99.9995 @ mppsU16 99.99995 @ mppsU17 99.999995 @ mpps(MPPS = Most Penetrating Particle Size) 0.1 to 0.2 micron

A typical virus is about O.04 micron.

HEPA & ULPA filtration

The dynamics of particle capture

HEPA = High-Efficiency Particulate Arrestance

Impaction, where larger particles are forced to embed in one of the fibres directly.Interception, where particles following a line of flow adhere to a fibre.Diffusion, an enhancing mechanism that is a result of the collision with gas molecules by the smallest particles, especially those below 0.1 µm (micron).

ULPA = Ultra Low Particulate Arrestance

Particle Sizes

Brownian* MovementBrownian motion or pedesis (from Greek: πήδησις /pɛ̌ːdɛːsis/ "leaping") is the random motion of particles suspended in a fluid (a liquid or a gas) resulting from their collision with the quick atoms or molecules in the gas or liquid.* Brownian motion or movement is named after Robert Brown, a Scottish botanist who first made this observation.

Terminal velocities of particles

Feet per minute I nches per hour5000 17501000 790500 555100 59.250 50000 14.810 10000 0.5925 5000 0.1481 1000 0.007 5

0.5 500 0.002 1.40.1 100 0.00007 0.050.04 40 0.000028 0

smaller 0 0

Maximum rate of fallDiameter in NanometersDiameter in Microns

Quarantine & IsolationUp until 1992 Glasgow’s Ruchill Hospital had a High Security Infectious Disease Unit capable of treating Viral Haemorrhagic Fevers such as Lassa and Ebola

Filtered air supply Suits

Because a filter is a percentage device it follows that more contaminants will pass through as the air flow increases. This table shows typical personnel factors at NTP. It is easy to see why working in a ventilated suit in Africa was limited to one hour at a time.

Heat (Kw) Moisture Emission Particle BreathingMEASURE OF EXERTION Emission (grams water) Emission @ 0.3 Requirements M3/HourAt Rest 0.1273 90.7184 100,000 0.51Light Work 0.1910 181.4368 1,000,000 0.99Movement at 3 MPH 0.3183 317.5144 5,000,000 2.12Movement at 4 MPH 0.4456 430.9124 10,000,000 2.55

Problem solving in the Laboratory

How do you keep people safe from exposure to bio-hazard material and chemicals while at the same time protecting the bio-hazard material and chemicals from ambient contamination?

Bio-hazards & MedicinesFume cupboards offer limited protection to people and no protection to the material being worked on. Dual protection needs an Isolator or a Glove box.

Isolators & Gloveboxes

Safe Change Filters

Safe Change Filter System

A typical 600 x 600 x 300 HEPA or ULPA weighs about 18 kilograms

Changing a filter involves the complicated procedure shown above. This has been going on for nearly 50 years and is anything but safe. A better system is desperately required

Hospital, Nuclear, Pharmaceutical and other

IsolatorsIsolators are used to contain a substance that is harmful to people or to the environment.They are also used to contain a substance that must be kept free from external ambient contamination.In some circumstances the requirement is to meet both of the above criteria although the safety of people is always the first priority.

Specialist Pharmaceutical & Hospital Containment Isolators

Manufacturing small batches of cytotoxic drugs commercially can be time consuming and very expensive. Mobile cabinets can work in a cleanroom and then be removed for cleaning and re-validation.

Bio-hazards in the newsProblem:How do you transfer a sterile or contaminated product from one containment area to another containment area without the risk of either cross contamination or endangering personnel?Solution:Use a specially engineered transfer hatch where not only does the hatch seal itself to the isolator but the two doors seal their contaminated faces to each other during transfer into the isolator.

La Calhène pass thro’ hatchLa Calhène (the dirty sandwich)

patented pass thro’ transfer hatch

STEM KnowledgeScience to understand the nature and behaviour of sub-micron particles and contaminantsTechnology to devise suitable methods to capture the contaminants and contain the isolated environmentEngineering to find the most efficient, and practical materials for the design and construction Mathematics to calculate the challenge to, and the function of the containment

Skills to devise hatch• Science to analyse the problem• Technology to create a solution• Engineering to find the most

efficient, fool proof and practical method of connecting and dis-connecting the hatch

• Mathematics to calculate tolerance rates and elastomer compression and friction factors for the double door seals

Something completely differentGyros - The Segway Scooter shown opposite, uses between five and seven solid state gyros

Ariane Rocket

Ariane RocketQuestion: How do you steer a rocket?Answer: With a Ring Laser Gyroscope Inertial Guidance SystemThe core component is a glass block with precision cut internal channels which can be used to focus a laser beam and which will not be affected by major changes in temperature.

Ring Laser Gyroscope

Marconi Space and

Defence Systems

Marconi Space and Defence Systems

Problem:Manufacture a glass block with precision cut internal channels that can house a laser which is generated in a helium/neon gas mixture by the application of a voltage. The finished channels must be free of swarf, cuttings and polished to a very high standardSolution:Use chemical machining.

Chemical MachiningZerodur, a proprietary glass which has low thermal expansion properties meets the specification.A block is mounted in a customised jig that allows pipe fittings to be connected to the channels for irrigation

Setting up the processHydrofluoric Acid (HF) is used to etch the glass channels. After etching they are rinsed with Deionised (DI) waterA customised computer programme allows the process parameters to be prototyped and recorded for routine production

The production machineThe production operator then uses a mousepad and two air switches to control the process An emergency shut down button is also provided

Skills needed to solve problem

• Science to analyse the problem• Technology to create a solution• Engineering to find the most

economical and safe method of manufacture

• Mathematics to calculate tolerance rates and programme a reproducible logic etch sequence

PostscriptWhat are the chances of making another similar machine? Would you imagine extremely poor?In fact the company’s web page generated another enquiry which resulted in a second customised machine being designed and built for Daewoo Industries in South Korea

Daewoo IndustriesThe machine shown during construction was for processing a square block to be used in jet aircraft.

Daewoo IndustriesSquare ring laser system

STEM KnowledgeScience - Chemistry and Physics for the understanding of the lasers and gyrosTechnology - is applied to the methods of manufacturing a solution.Engineering - to design and construct a practical safe and efficient production machine Mathematics - to create the process algorithms and logic sequences which will lead to simplified manufacturing

X-STREMEApplied Sciences