Let me remind you that Europe features the most diverse, rich and numerous cultural heritage around the world. 609 million tourists visited the “old continent” by 2015 (29 million in 2014) according to the World Tourism Organization, and, although it is somewhat pretentious, it is suggested that 37% of these tourists are cultural tourists, a figure that grows by 15% each year. This “curious specie” wanders around the cities getting the urgent need to visit the built heritage and being actively involved in cultural events.
I agree on speaking about cultural heritage as a touristic resource is disappointing when heritage is properly identified as integrator item and a completely intangible social identifier, but also certainly is an economic resource and just making cash its sustainability is ensured. This is the way to fix and create thousands of jobs, which in turn reinforce the character of social backbone that heritage is by itself, even allowing to improve the citizens’ quality of life.
Because of this the public sector comes boosting the creation of more and more cultural attractions with the built heritage as backdrop. Cultural tourism is perceived as the main source for funding heritage preservation: tourists generate the resources needed for maintenance and restoration. Let’s see if this is really so in the coming years, since the Richards report, ensures there is a much higher offer than real demand right now.
Making sure the protection and the preservation of our built heritage is, today, more urgent than ever. Not only as “prey” of cultural tourism, and not only as a brand of territory (including citizens), but because of their vulnerability to pollution, climate change and socio-economic pressures. We all get sick from time to time and we know it is always better to prevent than cure. The same happens to the built heritage: it is as much desirable as important to have automated systems that continuously tell us how the built heritage is, preventing “ills” just before they are such as expensive as irreparable. It is somewhat comparable to doctor’s auscultation, but what do we need listening to? In the technical jargon we say “monitoring” and many types of sensors are used to, but three aspects are mainly registered:
The temperature and relative humidity. Both are always linked (in fact they are inverse). Any kind of heritage building has greater or lesser water content in the air at a given temperature, having a decisive influence on the physical-chemical stability of the materials they are made of. Inadequate conditions of temperature and humidity produce deformation and rupture; rust and corrosion; as well as bio-deterioration (emergence of organisms).
Natural and artificial lighting. the Sun, or electric sources are electromagnetic radiation mainly covering the ultraviolet (UV), visible (VIS) and infrared (IR) ranges. Together they cause photo-degradation (discoloration) and temperature increases, especially in the case of organic materials (paintings, textiles, books and documents).
Pollutants. The air composition and quality are altered by compounds that mostly come from the use of fossil fuels (road traffic, heating of buildings and industrial activities). These compounds are able to make chemical reactions that affect the materials causing corrosion; spots and coatings; and also bio-deterioration.
These parameters will be particularly broken in subsequent posts.
In any case, the role of technological centres as CARTIF is decisive to take step forward in the technical developments required so that monitoring can be done affordably and fully compatible with the aesthetics and functionality of the building. Relevant international projects on this regard where CARTIF is playing a major role are:
After Italy and recently China, Spain is the country that holds the largest number of human heritage sites. We are also a first order world tourist destination, with a yearly increasing cultural component. Playing at home, Castilla y León accounts for 60% of the Spanish heritage… Do we take the fingers out?
What is the use of 3D digitalization of infraestructures? Inspecting coatings, detecting cracks, inventorying and sensorization of tunnels and other structures. In the following video, we explain you what we do in CARTIF:
David Olmedo and José Llamas, researchers of CARTIF.
With global positioning systems, a phenomenon similar to what happened with mobile phones has occurred: in a few years we have gone from non-existence to consider it essential. The truth is that, in fact, geolocation is one of those technologies that has led to the development of many applications and in many areas is not conceived to work without the use of commonly called GPS.
These types of positioning systems are based on receiving the signal from three or more satellites and using trilateration: position is obtained in absolute coordinates (usually WGS84) by determining the distance to each satellite.
Global positioning systems based on satellites have their origin in the US system TRANSIT in the 60s. With this system you could get fix the position once an hour (at best) with an accuracy of about 400 meters. This system was followed by the Timation system and in 1973 the Navstar project began (both from USA). The first satellite of this project was launched in February 1978 and full operational capability was declared in April 1995. This Navstar-GPS system is the origin of the GPS generic name we usually apply to all global navigation systems. In 1982 the former Soviet Union launched the first satellite of a similar system called GLONASS that became operational in 1996. Meanwhile, the People’s Republic of China in 2000 launched the first satellite of BeiDou navigation system, which is scheduled to be fully operational in 2020. Finally, in 2003, it began the development of the positioning system of theEuropean Union called Galileo, with a first launch in 2011. Currently there are 12 satellites in active (and 2 in tests) and the simultaneous launching of four more is scheduled on 17 November 2016. This way, 18 satellites will be in orbit and initial service of Galileo positioning system could begin in late 2016. It is expected to be fully operational in 2020. It must be said that there are also other systems, complementary to those already mentioned, in India and Japan in a local range.
As you can see, the global positioning systems are fully extended and are widely used both military and commercial level (transport of people and goods, precision agriculture, surveying, environmental studies, rescue operations …) and on a personal level (almost everyone has a mobile phone with GPS available, although their battery always run out at the worst moment).
Regarding the precision obtained with current geolocation equipment, it is about a few meters (and even better with the Galileo system) and can reach centimetre accuracy using multifrequency devices and applying differential corrections.
One of the problems of these systems is that not work properly indoors since the satellite signal cannot be received well inside buildings (although there are highly sensitive equipment that reduce this problem and other devices called pseudolites, acting simulating the GPS signal indoors). And of course it’s not enough to know our exact position outdoors but now comes the need to also be located inside large buildings and infrastructure (airports, office buildings, shopping centres, …).
So indoor positioning systems (IPS) have appeared allowing location inside enclosed spaces. Unlike global positioning systems, in this case there are many different technologies that are usually not compatible with each other making it difficult to dissemination and adoption by the general public. There are already very reliable and accurate solutions in enterprise environments but these developments are specific and not easily transposable to a generic use of locating people indoors. In this type of professional context, CARTIF has done several projects indoor positioning for autonomous movement of goods and service robotics. There is not a standard indoor positioning system but there are many technologies competing for a prominent place.
The technologies used can be differentiated on the need or not of a communications infrastructure. Those who no need existing infrastructure are often based on the use of commonly available sensors in a smartphone: variations in the magnetic field inside the building that are detected by the magnetometer, measuring the movements by using accelerometers or identifying certain feature elements (such as QR codes) using the camera. In all these cases the accuracy achieved is not very high but may be useful in certain applications as simple guidance in a large building.
Indoor positioning systems using communications infrastructure exploit almost all available technologies of this kind for the location: WiFi, Bluetooth, RFID, infrared, NFC, ZigBee, Ultra Wideband, visible light, phone masts (2G / 3G / 4G), ultrasound, …
With these systems, the position is usually determined by triangulation, calculating the distance to the fixed reference devices (using the intensity of the received signal, coded signals or by direct measurement of this distance). Thus you can reach greater precision than in the three previous cases. There are also new developments that combine several of the above technologies in order to improve the accuracy and availability of positioning.
Although, as has been said there is no standard, the use of systems based on Bluetooth low energy are spreading (BLE nodes). Examples of such systems are the Eddystone (from Google) and iBeacons (Apple).
Logically, as in the case of outdoor positioning the corresponding environment map is required to allow navigation. There are other systems, called SLAM, which generate environment maps (which may be known or not) as they move, widely used in robots and autonomous vehicles. A recent example is the Tango project (from Google once again) that generates 3D models of the environment just using mobile devices (smartphones or tablets).
As we have seen, we are closer to be located anywhere, which can be very useful but also can make us overly dependent on these systems while the usual privacy issues concerning positioning systems are increased. So although thanks to these advances the sense of orientation is less necessary, we must always keep common sense.
The Sustainable Public Procurement Initiative (SPPI) is nowadays the key policy instrument to promote sustainable development and move towards a green economy that fosters the development of products and services maximizing social and environmental benefits. EU public procurement directives oblige contracting authorities to base tendering decisions on the most economically advantageous tender (MEAT) principle, focusing on life-cycle costs and environmentally and socially sustainable products. Member States should generally promote the whole life-cycle cost analysis as standard practice in long-term investment.
Transport infrastructure investments have a positive impact on economic growth, creates wealth and jobs, but it has to be done in a way maximises these positive impacts and minimises negative impact on the environment. Specifically, rail transport causes 0.2% of global emissions in EU27. Infrastructure supposes 28% of these emissions, half of them caused during construction. This shows the high environmental impact of these activities.
According to the IODC post “Fighting climate change: the ultimate data challenge”, data are most powerful when they are available as open data and scientists are using data not only to monitor climate change but to help provide solutions, combining data science with climate science.
In line with these ideas an initiative, partially supported by LIFE+ Programme of the European Commission, combines life cycle assessment (LCA) techniques with intelligent data analysis, in order to improve sustainability of railway infrastructure construction processes as a whole, considering environmental, economic and social aspects. The goal is to reduce carbon and water footprints of railway infrastructure construction projects from their earliest stages, i.e. design and planning processes.
On a recent keynote speech, Martina Werner, member of the European Parliament and the ITRE Committee on Industry, Research and Energy, argues that many manufacturers concentrate on competing mainly on the basis of the mere purchase price. A thorough implementation of the procurement directives and particularly the MEAT principle gives suppliers a competitive advantage. Numerous factors now can be taken into account during the procurement procedure. This includes the reliability of the supply chain, services, maintenance costs, environmental factors and criteria of corporate social responsibility.
Based on environmental and social impact of most relevant tasks, an Open Access tool provides selected specific footprint values and environmental & social indicators as open data to the community, promoting the incorporation of environmental criteria on construction projects. This tool is available online, with all the information regarding LCA and Social LCA (SLCA) and it is intended for spreading the word on sustainable development and paving the way for the use of this or similar tools by public bodies or bidders.
Everybody knows what a thermographic camera is. Movies as “Predator”, the formula 1 broadcast, etc. have helped people to know this technology. CARTIF has been using it, during last years, in construction and infrastructure inspection.
My intention is not to tell you again, what everyone already knows, but talking about some myths and misconceptions that people have regarding its use.
Thermography is based on that any object with a temperature above zero kelvins emits infrared radiation, which is not visible to the human eye. This radiation depends on the object temperature, thus knowing the said radiation; it is possible to obtain the temperature.
A thermographic camera not only acquires this radiation (emitted radiation), but also the reflected and the transmitted radiation. Moreover, there are other parameters beyond the object temperature involved, so the temperature determination is not easy.
Thermographic camera have software which is able to calculate the object temperature in a transparent way to the user. If the operator relies too much on the said software and he doesn’t know well what he is doing, then issues might appear. A non-experienced operator may make some mistakes. In this post, we would like to clarify some misconceptions about thermography that general public has:
1. Thermal imaging cameras can see below the surface of a target. FALSE. The camera only sees the surface of a target and calculates the temperature
2. All types of materials can be easily measured with thermal imaging cameras. FALSE. The temperature information is given in the emitted radiation, but the imager also “sees” the reflected and transmitted components. Most materials are opaque to infrared, so we can usually ignore the transmitted energy. However, many materials (with low emissivity) reflect infrared radiation, thus these materials are difficult to be measured using a thermal camera.
3. Thermal imaging cameras should never be used in the daylight. FALSE. Infrared thermal imaging cameras do not detect visible light. They are only sensitive to infrared radiation, but it is easier to control reflected radiation at night, so it is advisable doing thermal inspection during that period of time.
4. Knowing the emissivity of the inspected object is not necessary. FALSE. This is the most important factor the camera must know to correctly calculate the temperature.
2. Detection of tiny motors in pro cyclist bikes Femke Van den Driessche, one of the favorites at the Under-23 Women’s World Championships in Belgium, was found to be racing with a mechanical motor this past January by the UCI. This is known as the first mechanical doping in cycling history.
3. Orthopaedic diagnosis Researchers at UPM confirm the usefulness of infrared thermography (IRT) for detection and early diagnosis of orthopaedic injuries.
A research group of Thermography Unit from the Faculty of Sciences for Physical Activity and Sport (INEF) at Universidad Politécnica de Madrid (UPM) in collaboration with CEMTRO has carried out a study to establish the capacity of infrared thermography (IRT) to discriminate injuries and to evaluate its applicability in emergency trauma scenarios.
Results show that this technology is a great support tool to correctly identify the presence or absence of injuries in a particular body part.
4. Pest control Some tests have concluded that it is possible to use thermography in order to pest detection, due to the correlation between the presence of insects and humidity. Furthermore, some anomalies detected on thermal images might be caused by some insects such as termites.
5. Breast cancer prevention using thermography This method is based on detect temperature changes in thermal images. Cancer creates blood vessels when it starts to develop. This process, which is known as angiogenesis, produces heat, so a thermal camera could detect this heat long before cancer can develop.
Despite the title, this blog is not about ballroom dances, but about something related to movement and how to guide your dance partner.
Have you ever felt how a footbridge sways when you walk over it or how a stadium stand vibrates under your feet when you are jumping and cheering up your favorite football team? If not, I highly recommend you to see these videos: Millenium Bridge London, Commerzbank-Arena Frankfurt or Volga Bridge Volgograd.
Why do these structures sway if they are building with strong and rigid materials like concrete or steel? In general, all structures vibrate in response to external excitation like people, vehicles or wind gust, but some structures sway more perceptible than others.
Structures perform more or less amplitude oscillations depending on their stiffness, mass and damping parameters. As a rule of thumb, the more slender, the more sensitive to develop noticeable rocking motions and even ones annoying and dangerous for people.
The best way to understand these concepts is by testing. If you are at home, I encourage you to go to the kitchen and take some spaghetti noodles and strawberries. Also you can use small balls made with a putty-like modelling material like plasticine® instead of the fruit. Now, hold tightly one end of a noddle and pierce a strawberry/plasticine® ball in the opposite end. Then, make small back and forth movement with your hand.
Changing the frequency of the movement you realize that the noddle performs big oscillationsand even is broken at a particular rate. This frequency is called resonance frequency and is defined by the noddle flexibility or “stiffness” and the strawberry/plasticine® weight or “mass”. If now you try with two noodles instead of one and later you use a heavier or lighter strawberry, you will perceive how the resonance frequency changes, being lower as long as you have lower stiffness and/or bigger mass.
With regard to damping, this property is related to the material used and basically it opposes to the movement. In other words, the more damping, the lower oscillations will be developed at the resonance frequency and the vibration will stop sooner once the excitation is ceased. This can be checked using a steel wire instead of the spaghetti. You notice the spaghetti damping is higher however it is more fragile than steel.
Coming back to structures, these ones are designed and built using different materials and geometries. Therefore they have different mass, stiffness and damping values and consequently different resonance frequencies. What would happen if one of the footbridge resonance frequencies was closed or the same to the people pacing rate crossing over it? As we saw in the experiment, the footbridge would sway perceptibly with lower or bigger oscillations depending on the damping. With a very low damping value, the oscillations performed would be so big that the structure must be closed to be modified. This was what happened three days after the London Millenium Bridge opening day.
Basically, there are two solutions to avoid noticeable vibrations in a structure. The first one would be modifying its resonance frequency changing its stiffness and/or mass. The second one would be based on adding damping to the structures. The first solution is in general expensive and would modify the final structure design becoming less slender what usually dislike the structure designer/architect. The second solution would be more affordable and unnoticeable. It would consist on adding damping devices along the structure in order to increase the structure global damping. Some examples of these devices are oil dampers and viscoelastic dampers. To work properly, these devices need to link two points of the structure with relative movement.
Other damping systems in what CARTIF has been working for years are the “Tuned Mass Dampers” or TMD. These systems consist on a mass attached to the structure by means of coil springs or metallic cables (pendulum TMD) and passive damping devices like oil dampers and neodymium magnets or active ones like magnetorheological dampers.
These systems only need to be attached to one point of the structure, being generally the one with the biggest oscillations. Its functioning principle is based on kinetic/inertial energy transference between the structure and the TMD. An example of these systems is the one recently installed in the second world tallest building, the Shanghai Tower, where a 1000 tons pendulum TMD drastically reduces the skyscraper oscillations in response to wind loads.
Summarizing, in spite of the fact that structures sway, it is always possible to “guide” them to gentle movements by means of damping system such as Tuned Mass Dampers.
