Durable past - sustainable future

The section Heritage & Architecture of the Faculty of Architecture at Delft University of Technology deals with the built environment in terms of conservation, refurbishment and re-use. Reflecting the department philosophy, this book focuses on the durability and sustainability of existing buildings (heritage in a broad sense, from historic buildings to listed monuments), considered in terms of material and building techniques, form and function, and part of the wider context of sites and cities. At the basis stands the Heritage triangle: Design – Cultural value – Technology. &nbsp

Beoordeling van de staat van conservering van een Midden-Neolithische vuursteenmijn in Valkenburg aan de Geul

Upper Cretaceous Maastricht limestone (locally denominated as ‘mergel’) outcrops in the provinces of Dutch and Belgian Limburg. The Upper Cretaceous in the Netherlands consists of the geological Maastricht Formation and the upper part of the Gulpen Formation. Limestone from the Maastricht Formation represents one of the few native Dutch types of natural stone used for building and construction. Locally, limestone from both formations contains considerable amounts of flint. This flint was mined in Neolithic times, both from the Lanaye limestone in the Gulpen Formation and the Emael Limestone in the Maastricht Formation. Flint from the South Limburg province was used for tools in a major part of north-west Europe. Around the village of Valkenburg aan de Geul, flint was mined from the Emael limestone. The originally subsurface mine, which had become exposed due to excavation of the valley slope in the past, was discovered in the 1990s. In the current study, the state of conservation of a Middle Neolithic flint mine situated at Plenkertweg in Valkenburg aan de Geul is assessed, eight years after the site was discovered. The assessment is based on determination of hydric behaviour and petrographic investigation of Maastricht limestone from the outcrop, and analysis of moisture conditions of the outcrop itself.Upper Cretaceous Maastricht limestone (locally denominated as ‘mergel’) outcrops in the provinces of Dutch and Belgian Limburg. The Upper Cretaceous in the Netherlands consists of the geological Maastricht Formation and the upper part of the Gulpen Formation. Limestone from the Maastricht Formation represents one of the few native Dutch types of natural stone used for building and construction. Locally, limestone from both formations contains considerable amounts of flint. This flint was mined in Neolithic times, both from the Lanaye limestone in the Gulpen Formation and the Emael Limestone in the Maastricht Formation. Flint from the South Limburg province was used for tools in a major part of north-west Europe. Around the village of Valkenburg aan de Geul, flint was mined from the Emael limestone. The originally subsurface mine, which had become exposed due to excavation of the valley slope in the past, was discovered in the 1990s. In the current study, the state of conservation of a Middle Neolithic flint mine situated at Plenkertweg in Valkenburg aan de Geul is assessed, eight years after the site was discovered. The assessment is based on determination of hydric behaviour and petrographic investigation of Maastricht limestone from the outcrop, and analysis of moisture conditions of the outcrop itself

Restorative glass: reversible, discreet restoration using structural glass components

The application of structural glass as the principal material in restoration and conservation practices is a distinguishable, yet discreet approach. The transparency of glass allows the simultaneous perception of the monument at both its original and present condition, preserving its historical and aesthetical integrity. Concurrently, the material’s unique mechanical properties enable the structural consolidation of the monument. As a proof of concept, the restoration of Lichtenberg Castle is proposed. Solid cast glass units are suggested to complete the missing parts, in respect to the existing construction technique and aesthetics of the original masonry. Aiming for a reversible system, the glass units are interlocking, ensuring the overall stability without necessitating permanent, adhesive connections. This results in an elegant and reversible intervention

Restorative glass: reversible, discreet restoration using structural glass components

The application of structural glass as the principal material in restoration and conservation practices is a distinguishable, yet discreet approach. The transparency of glass allows the simultaneous perception of the monument at both its original and present condition, preserving its historical and aesthetical integrity. Concurrently, the material’s unique mechanical properties enable the structural consolidation of the monument. As a proof of concept, the restoration of Lichtenberg Castle is proposed. Solid cast glass units are suggested to complete the missing parts, in respect to the existing construction technique and aesthetics of the original masonry. Aiming for a reversible system, the glass units are interlocking, ensuring the overall stability without necessitating permanent, adhesive connections. This results in an elegant and reversible intervention

Characterization and damage of brick masonry

Series : Building pathology and rehabilitation, ISSN 2194-9832, vol. 2Clay brick is among the oldest used masonry materials. Given the technological evolutions since the industrial revolutions, old brick are much dif-ferent from todays’ bricks. This chapter provides a review on the chemical, physi-cal and mechanical properties of mortar, brick and masonry. In addition, a discus-sion on the possible causes of damage and the usage of expert systems in building diagnostics is also given

DURABILITY OF LIME BASED RENDERS: A REVIEW OF SOME DEGRADATION MECHANISMS AND ASSESSMENT TEST METHODS

Lime based mortars used for the repair and renovation of old lime renders have important functions in historic buildings, such as the protection of the masonry and aesthetics of the surfaces. Hence, they have a significant contribution to the durability of the walls, which often are structural elements. Cracking and loss of adherence are two of the most severe defects for renders, as they drastically affect their functional capacity. Cracking is related to shrinkage, elastic characteristics, and kinetics of the gain of strength as well as to water transport properties of the render. Most of these aspects are governed by the porous structure of the mortar, which is a function of the composition of the mix and application issues. Loss of adherence is related to the compatibility of the render with the substrate, concerning mechanical, thermal and hygric aspects. Loss of cohesion, due to leakage of the binder, freeze-thaw, salts crystallization or other causes, results in significant damage, difficult to repair. The appearance of stains either by pollutants deposition or by biocolonization is also a concern related to durability of renders. In the present paper the degradation mechanisms leading to cracking, loss of adhesion or cohesion and stains formation are analysed based on literature, and a review of assessment test methods are carried out. Finally, the need for test improvement in this area is highlighted.authorsversionpublishe

Sorted B cell transcriptomes point towards actively regulated B cell responses during ongoing chronic hepatitis B infections

The natural course of chronic hepatitis B virus (HBV) infections follows distinct clinical disease phases, char-acterized by fluctuating levels of serum HBV DNA and ALT. The immune cells and their features that govern these clinical disease transitions remain unknown. In the current study, we performed RNA sequencing on pu-rified B cells from blood (n = 42) and liver (n = 10) of healthy controls and chronic HBV patients. We found distinct gene expression profiles between healthy controls and chronic HBV patients, as evidenced by 190 differentially expressed genes (DEG), but also between the clinical phenotypes of a chronic HBV infection (17?110 DEG between each phase). Numerous immune pathways, including the B cell receptor pathway were upregulated in liver B cells when compared to peripheral B cells. Further investigation of the detected DEG suggested an activation of B cells during HBeAg seroconversion and an active regulation of B cell signalling in the liver

Moving forward with backwards compatibility: Translating wrist accelerometer data

Purpose: To provide a means for calibrating raw acceleration data from wrist-worn accelerometers in relation to past estimates of children’s moderate-to-vigorous physical activity (MVPA) from a range of cut-points applied to hip-worn ActiGraph data. Methods: This is a secondary analysis of three studies with concurrent 7-day accelerometer wear at the wrist (GENEActiv) and hip (ActiGraph) in 238 children aged 9-12 years. The time spent above acceleration (ENMO) thresholds of 100, 150, 200, 250, 300, 350 and 400 mg from wrist acceleration data (<5 s epoch) was calculated for comparison to MVPA estimated from widely used children’s hip-worn ActiGraph MVPA cut-points (Freedson/Trost 1100 counts per minute (cpm); Pate 1680 cpm; Evenson 2296 cpm; Puyau 3200 cpm) with epochs of <5, 15 and 60 s. Results: The optimal ENMO thresholds for alignment with MVPA estimates from ActiGraph cut-points determined from 70% of the sample and cross-validated with the remaining 30% were: Freedson/Trost = ENMO 150+ mg, irrespective of ActiGraph epoch (ICC>0.65); Pate = ENMO 200+ mg, irrespective of ActiGraph epoch (ICC>0.67); Evenson = ENMO 250+ mg for 0.69) and ENMO 300+ mg for 60 s epochs (ICC=0.73); Puyau = ENMO 300+ mg for <5 s epochs (ICC=0.73), ENMO 350+ mg for 15 s epochs (ICC=0.73), ENMO 400+ mg for 60 s epochs (ICC=0.65). Agreement was robust with cross-validation ICCs=0.62-0.71 and means within ?7.8?±4.9% of MVPA estimates from ActiGraph cut-points, except Puyau 60 s epochs (ICC=0.42). Conclusion: Incremental ENMO thresholds enable children’s acceleration data measured at the wrist to be simply and directly compared, at a group level, to past estimates of MVPA from hip-worn ActiGraphs across a range of cut-points

Glossaire illustré sur les formes d’altération de la pierre

The ICOMOS International Scientific Committee for Stone (ISCS) is providing a forum for the interchange of experience, ideas, and knowledge in the field of stone conservation. ISCS aims at facilitating the publication, dissemination and presentation of state of the art reviews on pre-identified issues. Simplification and demystification of scientific information for practitioners are also part of the main goals of the group. In studies on stone deterioration and conservation, terminological confusions lead to major communication problems between scientists, conservators and practitioners. In this context, it is of primary importance to set up a common language; if degradation patterns can be shown, named and described, then they can be recognised and compared with similar ones in a more accurate way in further investigations. The ISCS glossary constitutes an important tool for scientific discussions on decay phenomena and processes. It is also an excellent basis for tutorials on stone deterioration. It is based on the careful examination of pre-existing glossaries of English terms. It does not aim at replacing these glossaries, often set up originally in a language other than English, and for most of them done to a high standard. As President of ICOMOS I would like to congratulate the International Scientific Committee for Stone and its President Véronique Verges-Belmin for the results of years of research presented in this publication. Stone conservation is a crucial topic in monument conservation and many of our National Committees all over the world hope for advice and help from the specialists familiar with traditional and modern methods of conservation. The Illustrated Glossary on Stone Deterioration Patterns offers a wide range of suggestions and practical advice. Probably, after the English-French version becomes available the Glossary will also be translated into other languages. In view of the accelerating decay of our stone monuments worldwide this is an exemplary contribution which will promote the international cooperation so important in this field.peer-reviewe