In a previous post the social and economic importance of heritage conservation were already described. Also we promised that on successive posts we will go into more detail describing the three main aspects that need to be monitored to ensure such conservation. Refreshing your memory, they were:
Relative humidity and temperature.
Lighting (natural and artificial).
Contaminants.
As promised is debt, in this post we will focus on the first point (be patient, we will talk about others further on), which makes us to face the heritage “bad boys”. Relative humidity and temperature are very damaging in the effects they can cause on the materials of which historic buildings are made of. Taking advantage of Physics, relative humidity is a very useful indicator of the water content in the air (vapour), and, on the other hand, temperature indicates the level of kinetic energy (movement) of the molecules of the air.
Both parameters vary according to the local meteorological conditions, the human actions and the conservation state of the historical buildings. This means that the atmosphere surrounding the historical buildings consist of a greater or lesser amount of water vapour at a certain temperature, definitely influencing the physical & chemical stability of the materials of which they are built on, or even of which the objects inside are composed.
In this sense, it is not negligible the effect caused by people, not only by our increasingly demanding comfort requirements, but by the number of visitors. We can influence the relative humidity and the temperature in such a way that inadequate values are reached. The effects of people are added to those of the local climate (more or less wet or warm), to the assets by itself (watertightness and ventilation capacity), to the derivatives of the proximity of heat sources (heating, sunny glass surfaces, old artificial lighting systems), the proximity of cold sources (external walls or air conditioning systems), as well as sources of humidity (leaks and floods).
The main factor to be controlled because the risk of direct deterioration that could originate is just humidity. The amount of water vapour in the air results in dimensional changes such as the well-known expansion and contraction of wood, making fractures and cracks when strong fluctuations happen. In addition, extreme relative humidity values cause softening or drying of organic materials such as adhesives and binders. But it also affects the stability of inorganic materials, such as metals, accelerating the corrosion processes, especially in the presence of salts. In poorly ventilation and dirty conditions, high values of relative humidity will cause the proliferation of living organisms causing biodeterioration (from microorganisms to rodents … Disgusting!). Even health problems as shown in the image.
Conversely, the temperature accelerates the chemical reactions and favours the biological activity. It contributes to the softening of waxes and adhesives and the loss of adhesion between different materials, such as enamels.
Perhaps reading all this causes some discomfort (and even itching …). But, what can we do to prevent these adverse effects? The answer is as simple as reasonable: just avoiding too high or too low levels of temperature and relative humidity, ensuring the highest possible stability
Following the indications of the IPCE (Spanish Cultural Heritage Institute, dependent on the Ministry of Culture), which establishes the National Preventive Conservation Plan (PNCP), the evaluation of risks derived from the microclimatic factors of which we are talking about, three aspects must be monitored:
Extreme levels of relative humidity and air temperature.
The magnitude and speed of fluctuations in relative humidity and air temperature.
The proximity of sources of humidity and heating or cooling emission sources.
A wide range of sensors is available on the market to monitor temperature and humidity, either continuously or timely (see image). Indeed, it is necessary to know how to properly treat, interpret and integrate the data they provide.
What is not so frequent is using alternative methods to evaluate the effects of moisture on the materials of the built heritage. Even before these appear and the remedy is worse than the disease. CARTIF is a pioneer in the use of laser scanners to make this assessment. A recent article published in the prestigious international journal Studies in Conservation, together with the developments carried out for the European research project INCEPTION show that while 3D documenting a historical building, the level of humidity present in a known type of material could be registered in parallel. A trustworthy 2×1 to take into account in the minimum conservation expenditure times we live in. The cloister of the Cathedral of Ciudad Rodrigo (Salamanca, Spain) has been the choice for on-site validations.
An important example that gives account of the scope of applied research in cultural heritage by a technology centre within a sector where it still takes more than expected that not so new technologies to be of daily use.
As you know, drones are becoming more and more used nowadays. The main reason is the decrease in its price. Therefore, taking aerial images using drones is more competitive than using other devices, such as planes, helicopters or satellites. This also allows ad-hoc measurement campaigns to be carried out, instead of using images from a data base, so the use of more detailed images are made possible.
But, what is aerial photography and how does it work? Aerial photography is not only the process of taking photographs from the air, but also the treatment of these images. There are many variables involved in an aerial acquisition, which must be considered to ensure that the data is useful enough to obtain the desired results.
The main advantage of aerial images is the ability to see elements of the landscape, which are very difficult to see from the ground level.
Aerial photographs are taken in two basic forms, oblique or vertical, and both have different uses and applications.
Oblique: These images are usually taken at an angle, typically 45 degrees, but they can be whatever angle that gives the best view of the photographed area. The oblique image is primarily used in archaeology to take a wider context of the supervised zone and the area around it, and also to give depth. Nearly always they are taken at a much lower elevation than when are taken in vertical and its application is fairly limited as they often only work for a specific purpose. These images are taken from small fixed aircrafts, such as drones, and are perfectly suited for monitoring erosion of features and monuments over time.
Vertical: Taking a zenithal photograph over a landscape is the more usual form of aerial photograph. It is a plan view, so there is no perspective to distort the image. This also means that it is difficult to read the features of the photographed area, such as changes in height.
Applications of Aerial Photography
In Archaeology: Aerial photography is ideal for locating lost monuments, especially those that are not visible at ground level, those that are under the soil and cannot be seen on a field walk and those that can only be seen under certain conditions.
In Agriculture: Crop field reports and statistic can be delivered for farmers using multispectral image data from special devices, such as thermal cameras. CARTIF has a lot of experience using this type of devices in some R&D projects (more info).
In Climate Change studies: It’s possible to detect rivers which are drying up, the reduction of inland lakes, forests that are dying, etc. Researchers keep vital records in changes over seasons and years to track local effects of climate change and risks to local ecosystems. Localised aerial photographs are fundamental for that purpose.
In Other Earth Sciences: They can also be used to study the process of natural changes, such as variations in soil and geology over time as well as changes to the underlying ground that leads to disasters such as landslides.
Energy and Infrastructure: Mitigate business risks, accelerate pipeline planning, learn about surface composition, and predict environmental impact using the data from aerial images.
Engineering and Construction: From construction site selection and evaluation to the assessment of existing structures, this technology facilitates every step of the project.
Defense and Intelligence: Defense agencies, military contractors, and law enforcement are continually faced with new challenges. Aerial images provide an unrivalled advantage when planning strategic and tactical operations, carrying out combat missions, and developing simulations.
Disaster Response: When timeliness counts, image data provide crucial insight for disaster response efforts and insurance operations. CARTIF is involved in a project which uses this type of technology in order to accomplish these goals.
Urban development: High resolution Aerial Images has gained popularity among Planners, Developers and Engineers for small scale mapping for most urban and land development applications. Information from Aerial Photos when combined with GIS (Geographic Information System) mapping is amongst others, used for analysis, strategic planning and evaluation in urban planning. CARTIF has been working in a research line related to this topic for many years.
Computer-aided engineering tools (CAE) are more pervasive nowadays, and finite element analysis is having more impact than at any other time. In the past, CAE abilities have been used in specific fields with highly trained engineer teams and large computing facilities. For example, in the aeronautical industry the objective is, among others, to design more efficient airliners and the automotive industry must produce safer cars in case of accident.
Currently there are not field of science or engineering that has not been affected, and in some cases transformed, by computer simulation. Almost most manufacturing companies, regardless of the industry, can take advance of CAE abilities to simulate their process and improve their performance.
Sport industry show off this fact, for example, SPEEDO produced swimsuits including compressing effects for changing, in certain way, the shape of the swimmer’s body. Using this idea, SPEDOO designed suit able to achieve drag reductions in more than 15 per cent. In the JJ.OO. of Beijing, 94% of the medals were won by swimmers dressed with SPEDOO swimsuits (Michael Phelps, Mireia Belmonte …) and 23 out of 25 Olympic records where beaten using this technology (according to data from FINA).
For an airliner or for an Olympic swimmer the engineering problem is essentially the same. There is a shape moving through a fluid and the drag must be minimized. That is, advanced engineering aerodynamic concepts also works in the textile industry. This example clearly defines the current situation of CAE abilities, where high technology is used to solve what we could define as trifling problems.
According to Lesa Roe, NASA Langley Research Center director, “Modeling and simulation is older than NASA”. Since the first models of digital calculators, computing machines evolved step by step and around year 2000 some experts believed that engineering simulation programmes had reached its peak due to the big improvement in abilities for the limited supply of high-level engineers.
However, the more powerful computers and the friendly integrated analysis environments have allowed companies to take advantage of the enormous potential of simulation programmes to make accurate predictions about natural phenomena, providing compelling evidence that we are really gaining in our understanding of how the products, processes and services can be optimized. Therefore, the almost endless engineering simulation techniques provide big growth opportunities, based on the current needs and the challenges that this poses.
As the saying goes, “Necessity is the mother of invention” CARTIFbelieves and works in endless possibilities to help customers develop better products and processes. I would like to stress in a particular application: the estimation of the static and buckling behaviour of very thin walled containers for food packaging.
Through simulation programmes we are able to detect weak points and design failures prior to manufacture, with consequent savings in time, material and money. Note that the containers are manufactured by plastic injection machines using expensive cast moulds. During the analysis are taken into account parameters such as constitutive material properties (PET, HDPS, aluminium …), thickness, type of liquid or granular product to be content, etc. that define the containers and allows us to predict its performance, resulting in deformation curves under load, loads of collapse, tensions and stretching under certain loads which it may be subjected to circumstances of the production process, storage and transport conditions, including temperature, pressure and impact effects among others.
Beside theses services, being aware that “data is the new currency”, CARTIF is also working on structural health monitoring in civil structures. The aim of this work is predict when maintenance will be needed or what the expected behaviour of structure should be if the real system begins to deviate from the digital models’ behaviour. This idea can be reviewed in my previous post ‘When structures age’.
Public initiatives like ‘Connected Industry 4.0’ are developing measures that allow the industrial fabric to benefit from the intensive use of ICT in all areas of its activity. These initiatives are linked to the term Industry 4.0, which refers to the challenge of carrying out the 4th Industrial Revolution through the transformation of industrial sector by the enabling technologies incorporation: 3D printing, robotization, sensors and embedded systems, augmented reality, artificial vision, predictive maintenance, cybersecurity, traceability, big data, etc.
Construction sector, as the industrial one, is immersed in a deep metamorphosis before the irruption of these new technologies. The economic crisis has been very intense in this market. As a strategy for its recovery, it must its particular revolution, taking full advantage of the opportunities offered by enabling technologies. For this reason, the ‘Construction 4.0’ concept appears as a necessity to digitize the construction through the incorporation of enabling technologies adapted to their particularities.
In this sector, it is the first time that a revolution is built ‘a priori’, which gives us the opportunity both to companies and to research centres to participate actively in the future.
In CARTIF, we work along this line by means of some projects that apply these technologies. In the case of the BIM (Building Information Modeling), which proposes to manage the complete cycle of the project through a digital 3D model, we develop improvements to include all the actor of the value chain.
With reference to 3D printing, a methodology that allows the construction of objects layer by layer, obtaining singular pieces or with complex geometries, CARTIF applies technologies to the direct printing on vertical surfaces for the rehabilitation of facades.
If we talk about robotization, besides the fact that making specific robots to certain tasks, adapt existing machines increasing their autonomy and safety of operators. In this line, we collaborate to develop monitoring and navigation technologies for the automatic guidance of machinery and to detect risks situations between machinery and operators.
With all these innovations, the future of construction is promising, if and when this research would be considered as an essential basis for its growth.
Latin America and Caribbean (LAC) is the developing region with the highest urbanization rate in the world. Its urban population has grown from 41% in 1950 to 80% in 2010 while the economic activity is focused on urban centers (60% – 70% of regional GDP). However, despite their capacity to generate richness, almost 70% of people that lives in these cities are doing so in poverty conditions. Furthermore, if we also consider the environment impact of these cities at the same time of their high vulnerability to climate changes, natural disasters and financial constraints, we are forced to think about the sustainability of their urban development.
The theory about traditional development postulates that the industrialization triggers to a gap between urban and rural productivity, reflecting in addition salaries differences between the two areas, and promoting thus rural-urban migration. At the same time, this theory justifies that welfare indicators are better for urban residents than rural ones, because they have more coverage in public services and higher incomes. However, this theory is not useful to demonstrate the development pattern of LAC countries, more in fact when they have levels of urbanization substantially higher than other regions of the world. Urban population growth in LAC necessarily does not let to their inhabitants better living conditions.
Therefore the cities, even more LAC ones, are based on complex and interdependent systems that have defined a sustainability new concept. This new approach goes beyond environmental issues because include cultural, political, institutional, social and economic variables. Thus, it is necessary to develop methodologies that study cities as a holistic, complex and multisector system that will allow us a qualitative and quantitative understanding of the problems of urban development and management in the region.
Smart City concept is born from this challenge and we, in CARTIF, understand it as a new city model based on three basic concepts: life quality, sustainability and innovation. This city model use to involve information and communication technologies (ICTs), but mainly the definition of sustainable and cohesive territorial models with environmental, social, economic, territorial and administrative objectives. As a result, smart cities and resource efficient cities are achieved, diminishing costs and saving energy, improving the services provided and the quality of life, and decreasing the environmental footprint. The final objective of these smart cities is not to show off their advanced systems and innovations, instead of this they must provide to their citizens a better quality of life, and in a future, anticipate their needs solving any problem that could arise.
In this sense, CARTIF has been working for years to allow the transformation of “traditional cities” into “smart and sustainable cities” in Europe and, more recently in LAC.
Our model seeks an efficient and integral urban regeneration that achieves social, economic and environmental objectives coming from the specific priorities of each city, integrating innovative technological solutions in the different urban scenarios, with a large citizen engagement, stablishing the foundations of a business ecosystem to facilitate the deployment of pilot projects and their subsequent upscaling and replication.
We hope to see examples of this new model of city in many LAC cities in the following years. Meanwhile, CARTIF has involved the city of Medellín (Colombia) in a project funded by European Research and Innovation Program H2020, which seeks new strategies to renaturing cities through nature-based solutions. Thanks to this, Medellín will have the collaboration of experts to identify, in a first approach, the economic, social and regulatory barriers that impede this kind of integral projects in the city.
To a large extent, when driving on the road, our safety depends on the state of the pavement. Real-time information provided by embedded sensors can help us to take action before deterioration (risk) occurs. What can we do to power these autonomous sensors? Piezoelectric devices vs. wireless power transmission?
The fundamental objective of road pavement is to provide users with a quality service that meets their mobility needs during the lifetime for which it is designed. A situation of deterioration generates a greater risk of an accident, more driving discomfort, fuel consumption, vehicle deterioration, harmful emissions to the atmosphere…
In May 2016, the Spanish Road Association (AEC) published the report “Study on Conservation Investment Needs” to review the state of the Spanish road network. The report notes that the state of maintenance of roads continues to worsen. If this trend continues, before 2020 it will be necessary to rebuild a good part of the network.
I agree with the experts that the conservation of our roads cannot be left to chance: nor to depend on crisis situations that force the budget to be reduced or to wait for irreversible situations.
In these circumstances, it is necessary to continue developing new technologies and methodologies that support the management of infrastructures and that allow conserving and rehabilitating our road network at the lowest economic and environmental cost.
Instrumentation with sensors embedded in the pavement
Traffic and environment/weather conditions, aggravated by climate change problems, significantly affect the pave roads deterioration.
The number of axles, the load per axis, the vehicles speed…, affect the structural behavior of the pavement. Solar radiation, rainfall, thermal gradients, ice-melt cycles, melting salts used against ice or the spillage of oils and fuels, among other factors, have a significant impact on pavement life and fatigue.
Preventive maintenance is necessary based on information on the state of the pavement and aimed to prevent the occurrence of this deterioration or to correct it quickly through repair and maintenance.
Visual inspection and periodic auscultation are commonly used to assess the condition of a pavement. A dynamic alternative is the instrumentation with sensors embedded in the pavement. With continuous monitoring it is intended that those who make decisions can know, in real time, the status of the pavement.
Experiences such as those of the CENIT OASIS project, in which we collaborate with OHL Concesiones and GEOCISA, endorse this alternative, not without difficulties such as that the sensors overcome the aggressive conditions during the spread and the compaction, or feed the sensors along the lifetime of an asphalt pavement that is normally between 20 and 30 years.
In this second aspect, since wired power is not always available or to overcome the problems of wiring flexibility, a significant technological challenge is to embed autonomous sensors in the pavement with non-wired power supply and wireless communication. How to provide energy to the sensors without cables and during the lifetime of the pavement?
Piezoelectric devices vs. wireless power transmission?
Opposite to batteries power supply, which have a limited energy, requires a periodic replacement or recharge, the sensors can be powered with energy captured from the road itself, for example by means of piezoelectric devices.
At the end of the 19th century, Pierre and his brother Jacques Curie discover the piezoelectric effect, a phenomenon that occurs in certain crystals that when subjected to pressure or mechanical movement, electrical energy is generated. On the road, part of the vehicle’s energy is converted into vertical deformation of the pavement that can be transformed into electrical energy by piezoelectric devices. The amount of energy generated depends on the number of vehicles passing.
In the CIEN REPARA 2.0 project we have choosed another method, investigating, in collaboration with Sacyr Construcción, Acciona Infraestructuras, Repsol, Fractalia, CHM, Censo, Solid Forest and Inzamac, the recharge of the autonomous sensors batteries by mean of wireless power transmission.
Also at the end of the 19th century, Nikola Tesla proposed what is known as “Tesla effect”, variations in magnetic flux have the ability to transmit electricity at a distance without needing solid support or some kind of wire. On the road, the batteries of the sensors will be recharged periodically, according to their power needs (mainly defined by the data transmission). Energy transfer has a limited range.
Actually, the efficiency of both technologies is a critical point.
Curie vs. Tesla? Indeed, confronting these technologies (using “versus” with the meaning of “against”) is not a lucky expression. Both technologies open up a world of opportunities for new applications. Are they also complementary? Which is your opinion?
