The maximum spreading of drops impacting on smooth and rough surfaces is measured from low to high impact velocity for liquids with different surface tensions and viscosities. We demonstrate that dynamic wetting plays an important role in the spreading at low velocity, characterized by the dynamic contact angle at maximum spreading. In the energy balance, we account for the dynamic wettability by introducing the capillary energy at zero impact velocity, which relates to the spreading ratio at zero impact velocity. Correcting the measured spreading ratio by the spreading ratio at zero velocity, we find a correct scaling behaviour for low and high impact velocity and, by interpolation between the two, we find a universal scaling curve. The influence of the liquid as well as the nature and roughness of the surface are taken into account properly by rescaling with the spreading ratio at zero velocity, which, as demonstrated, is equivalent to accounting for the dynamic contact angle.

Universal rescaling of drop impact on smooth and rough surfaces

Rainwater runoff from building facades: A review

Geomicrobially induced deterioration of stone monuments and buildings contributes to a considerable loss of world cultural heritage, especially when exposed to a changing climate or environment. The active biodeterioration processes typically involve biochemical activities and cooperation among functional microorganisms in epilithic biofilms, which assimilate mineral nutrients and metabolize anthropogenic pollutants through biogeochemical cycles. Development of any effective mitigation strategies requires the comprehensive understanding of such processes. We focus on how microbes contribute to the biodeterioration processes through their activities and biogeochemical cycles of elements, discuss biochemical mechanisms involved and provide innovative strategies for sustainable conservation of stone monuments and buildings. Biodeterioration of stone monuments and buildings can lead to a loss of world cultural heritage. This Review discusses the role of microbes in the deterioration processes, the biochemical mechanisms involved and possible strategies for sustainable conservation of stone monuments and buildings.

Microbial deterioration and sustainable conservation of stone monuments and buildings

https://wires.onlinelibrary.wiley.com/doi/pdf/10.1002/wcc.710

Climate change impacts on cultural heritage: A literature review

An integrated Terrestrial Laser Scanner (TLS), Deviation Analysis (DA) and Finite Element (FE) approach for health assessment of historical structures. A minaret case study

Assessment of wind-driven rain impact, related surface erosion and surface strength reduction of historic building materials

https://researchrepository.ucd.ie/bitstream/10197/3397/1/open%20repository%20version.pdf

Manufacturing, assembly, and testing of scaled, historic masonry for one-gravity, pseudo-static, soil-structure experiments

Increasingly historic masonry buildings are subjected to higher levels of traffic and rail vibrations due to urbanization and population growth. Deterioration and destabilisation of these buildings may result, especially if they were previously damaged (e.g. earthquakes or settlement problems). To better understand building response, vibration measurements were conducted on the Little Hagia Sophia Mosque, located adjacent to Istanbul’s Sirkeci-Halkali railway line. Transport-induced vibrations were recorded at several points on the ground and building. Attenuation characteristics in the ground and amplification features on the building were examined. Peak particle velocities often exceeded previously established thresholds for human perception and in some cases for structural damage. These are evaluated with respect to the building’s condition.

/pdf/investigation-of-the-rail-induced-vibrations-on-a-masonry-3lsq5v95d6.pdf

Investigation of the Rail-Induced Vibrations on a Masonry Historical Building

Worldwide urbanization has caused heritage buildings to be in ever-closer proximity to heavily travelled roadways and railways. As an example of this, the minaret of Little Hagia Sophia was analyzed due to its historic prominence and close proximity to heavy rail traffic. A vibration measurement program was performed on and around the minaret. After material properties were determined, three-dimensional numerical model of the minaret was constructed and validated based on frequency analyses of measured vibrations and modal analysis. Self-weight analysis and linear time-history analyses were applied to the model using ground motions measured at the minaret’s base. The results showed that stresses reached 32% of material strength and, critically, measured peak particle velocities of vibrations at times approached previously established damage thresholds. Therefore, construction and operation of traffic lines adjacent to heritage buildings in city centers should be analyzed carefully to prevent unint...

Transmission of Traffic-induced Vibrations on and around the Minaret of Little Hagia Sophia

Monumental tombs reflect various social, cultural, architectural, religious, economic, and engineering features of a community. However, environmental weathering, natural disasters, poor maintenance, vandalism, and misuse unfortunately pose serious threats to these cultural assets. Historic monuments are often exposed to the highest risk due to their vulnerability. The Ottoman-style Nisanci Hamza Pasa tomb located in Karacaahmet Cemetery, Istanbul, the largest and oldest public cemetery in Turkey, is a case in point. The tomb consisting of six granite columns and a brick dome supported by six arches was constructed in 1605. Cracks, material loss, and decay as a result of adverse environmental effects and past earthquakes are evident. Therefore, this paper analyses the overall value of the tomb with respect to its historical, communal, evidential, and aesthetic aspects. Using the finite element approach and data on the tomb's material properties, a structural analysis under the self-weight and a time history analysis based on the earthquake ground motion data recorded in Duzce, Turkey, in November 1999 were conducted to encourage the conservation of this tomb and similar cultural heritage assets all over the world. The damage observed in the structure is congruent with the analysis results.

/pdf/value-and-vulnerability-assessment-of-a-historic-tomb-for-4c3b5feh4g.pdf

Aykut Erkal

Papers

Assessment of wind-driven rain impact, related surface erosion and surface strength reduction of historic building materials

Manufacturing, assembly, and testing of scaled, historic masonry for one-gravity, pseudo-static, soil-structure experiments

Investigation of the Rail-Induced Vibrations on a Masonry Historical Building

Transmission of Traffic-induced Vibrations on and around the Minaret of Little Hagia Sophia

Value and vulnerability assessment of a historic tomb for conservation.