Wärme‐ und Feuchtetransport in Holzbauelementen unter freier Bewitterung

Es wurden vergleichende Untersuchungen des Wärme‐ und Feuchtetransportes in unterschiedlichen Holzbaukonstruktionen unter freier Bewitterung durchgeführt. Insgesamt wurden fünf Konstruktionen an Versuchsbauten auf dem Gelände der ETH Zürich getestet. Neben einer verdübelten Massivholzkonstruktion wurden zwei Ständerkonstruktionen und zwei weitere Vollholzkonstruktionen untersucht. Aus den gewonnenen Daten wurden dynamische Parameter der Gebäudehüllen ermittelt. Zusätzlich wurden Messungen an drei realen Bauten (zwei verdübelte Massivholzkonstruktionen, eine Ständerkonstruktion) durchgeführt. Die gemessenen Daten der Versuchsbauten wurden mit den Daten der Messungen an realen Bauten verglichen. Die Ergebnisse zeigen unter anderem, dass die Vollholzkonstruktionen sehr ausgewogene, hygrothermische Eigenschaften aufweisen. Heat and moisture transfer in wood‐based constructions under natural weathering. In this project comparative measurements of heat and moisture transfer in wood‐based constructions were carried out under natural weathering conditions at the campus of ETH Zurich. Altogether, five different constructions designed as small test buildings were investigated. In the first observation, the solid wood construction connected with wooden dowels — without any further binders is compared to two conventional wood frame constructions with one and two insulation layers. In the second observation, the mentioned solid wood construction is compared to one log construction and one solid wood construction with slotted wood elements. From the data, the dynamic parameters of the heat and moisture transfer of these building envelopes were determined. Additionally, the heat and moisture data of three real used buildings (two solid wood constructions with wooden dowels and one conventional wood frame construction) were measured. These data were compared with the data measured on the small test buildings. The results, inter alia, are showing that the solid wood constructions achieve a good balance in hygrothermal properties.     

Total organic halogens (TOX) analysis in ether solutions

A new procedure to determine TOX (total organic halogens) recovered in ether extracts was developed as a modification of the EPA standard method for TOX analysis in aqueous solutions. A volume of sample was injected directly into the carbon in the pyrolysis furnace sample boat. Good recoveries (80–100%) were found for all the model compound solutions, except for the n-chloroalkanes. In this case, the molecules are long chain aliphatics and were not easily pyrolysed in the furnace. A linear correlation was found between the percentage recovery of these aliphatic compounds and the number of carbons in the molecule. The precision of the method was found to be 2–3% for TOX in the 10³–10⁵ ng injected range.     

Leaching patterns from wood of different tree species and environmental implications related to wood storage areas

Batch tests were carried out with sawdust obtained from oak (Quercus robur), maple (Acer platanoides), pine (Pinus sylvestris), beech (Fagus sylvatica) and wood chips from oak and pine. Leaching of organic compounds expressed as dissolved organic carbon (DOC) in mg/kg of dry mass took place during the first 24 h. The following additional variables were analysed: pH, conductivity, colour, phenols, tannins and lignin, and biochemical oxygen demand (BOD₇). When leachates obtained with oak wood chips and pine wood chips were compared, no significant difference was observed. However, in batch tests with sawdust, DOC released by oak (90 000 mg/kg) was significantly higher (P = 0.0001) than DOC released by pine (30 000 mg/kg). The results suggest that particle size is not the only variable affecting the leaching of organic compounds from wood. Regarding BOD, colour [platinum‐cobalt (Pt‐Co)], phenols, tannins and lignin, the leaching patterns differed among species, and oak was the species with the highest released values.     

Embedding built environments in social–ecological systems: resilience-based design principles

Globalization, the process by which local settlements and ecosystems are becoming linked in a global network, presents policy scientists and planners with difficult design challenges. Coping with either natural or built environments in isolation is extremely challenging in its own right (e.g. built environments at different scales: a single building, a collection of buildings, a neighbourhood or a city are in themselves very complex). In the Anthropocene era, where human activities shape the planetary system in which built and natural environments are becoming more tightly linked across scales, these complex systems need to be considered as elements in a global network, i.e. as a coupled social–ecological system (SES) at the global scale. In the context of this spiralling complexity, multi-scale and multilevel processes become more important and design/management problems become extraordinarily difficult. Preliminary ideas are explored for how research on this multilevel design problem might proceed. Specifically, based on combining insights from a collection of theories and models based on resilience and robustness concepts, the basic elements of a new approach are presented that recognizes the importance of self-organizing processes at multiple scales and emphasizes the use of feedbacks to link these processes across scales.     

Natural radioactivity in various surface waters in stanbul, Turkey

Gross-α and gross-β, activities of eight well and five tap water samples taken in stanbul were determined. Ra²²⁶, Rn²²², Pb²¹⁴, Bi²¹⁴, K⁴⁰, Cs¹³⁷ activity concentrations in four lake, four sea water, one snow and one rain water samples were also analyzed in order to determine their radioactivity. The results obtained showed that, in general, natural activities in drinking water samples did not exceed WHO and ITS guidelines. In sea and lake water, four samples were over WHO and TSI guidelines. Concentrations ranging from 0.007 to 0.04 Bq l⁻¹ and from 0.02 to 0.1 Bq l⁻¹ were observed for drinking water and the gross-α and gross-β activities, respectively. For all samples the gross-β activities were higher than the corresponding gross-α activities. In order to evaluate the annual effective dose equilavent of ingestion of these waters, a conservative dosimetric calculation was carried out using dose conversion factor suggested by the ICRP. An average annual effective dose equivalent of 0.84 μSv y⁻¹ for Ra²²⁶ was calculated.     

Ermittlung des Wasserdampfdiffusionswiderstandes von Baustoffen in Abhängigkeit von der Baustofftemperatur

Determination of the water vapour diffusion permeability of building materials in dependency on the temperature. Investigations concerning the correlation between the water vapour diffusion permeability (μ ‐value) and the temperature were done at two wood based panels (MDF and OSB), an external thermal insulation compound system, a plaster system and an EPS‐insulation. The investigations were made by analogy to the measurement method described in ISO 12572 but at the chosen temperature levels from –10, –5, 0, 10 up to 50 °C. Based on the measured results, it can be concluded, that the μ ‐value is influenced by the temperature.     

Indoor carbon monoxide and PM2.5 concentrations by cooking fuels in Pakistan

Abstract Abstract In developing countries biomass combustion is a frequently used source of domestic energy and may cause indoor air pollution. Carbon monoxide (CO) and particulate matter with an aerodynamic diameter of 2.5 μm or less (PM_2.5) were measured in kitchens using wood or natural gas (NG) in a semi‐rural community in Pakistan. Daytime CO and PM_2.5 levels were measured for eight continuous hours in 51 wood and 44 NG users from December 2005 to April 2006. The laser photometer PM_2.5 (Dustrak, TSI) was calibrated for field conditions and PM_2.5 measurements were reduced by a factor of 2.77. CO was measured by an electrochemical monitor (Model T15v, Langan). The arithmetic mean for daytime CO concentration was 29.4 ppm in wood users; significantly higher than 7.5 ppm in NG users (P < 0.001). The arithmetic mean for daytime PM_2.5 concentrations was 2.74 mg/m³ in wood users; significantly higher than 0.38 mg/m³ in NG users (P < 0.001). Higher peak levels of CO and PM_2.5 were also observed in wood users. Time spent in the kitchen during fuel burning was significantly related to increasing CO and PM_2.5 concentrations in wood users. These findings suggest that cooking with wood fuel may lead to hazardous concentrations of CO and PM_2.5.     

Natural radioactivity in various surface waters in stanbul, Turkey

Gross-α and gross-β, activities of eight well and five tap water samples taken in stanbul were determined. Ra²²⁶, Rn²²², Pb²¹⁴, Bi²¹⁴, K⁴⁰, Cs¹³⁷ activity concentrations in four lake, four sea water, one snow and one rain water samples were also analyzed in order to determine their radioactivity. The results obtained showed that, in general, natural activities in drinking water samples did not exceed WHO and ITS guidelines. In sea and lake water, four samples were over WHO and TSI guidelines. Concentrations ranging from 0.007 to 0.04 Bq l⁻¹ and from 0.02 to 0.1 Bq l⁻¹ were observed for drinking water and the gross-α and gross-β activities, respectively. For all samples the gross-β activities were higher than the corresponding gross-α activities. In order to evaluate the annual effective dose equilavent of ingestion of these waters, a conservative dosimetric calculation was carried out using dose conversion factor suggested by the ICRP. An average annual effective dose equivalent of 0.84 μSv y⁻¹ for Ra²²⁶ was calculated.     

A participatory approach to conservation in the Calakmul Biosphere Reserve, Campeche, Mexico

Since the advent of integrated conservation and development programs, participatory approaches have been used to engage local people in protected area management and conservation action. While participatory approaches provide local people a role in telling their own story and enable them to contribute to conservation and development processes, it is unclear how much consideration local people's opinions receive within the framework of a participatory process that exists to meet the specific goals and objectives of conservation programs. This paper evaluates the strengths and weaknesses of the participatory approach used in an applied research program conducted in three ejido communities in the Calakmul Biosphere Reserve on the Yucatan Peninsula of Mexico. The research program used community mapping, historical matrices, institutional diagramming, seasonal calendars, semi-structured interviewing and other community-level reflection techniques to assess the complex interrelationships among population growth, migration, tenure regimes, and land-use practices in rural communities bordering the reserve. The program also sought to build local capacity and support for land-use planning and conservation programs. While the paper acknowledges the critical benefits of local participation it also questions the compatibility of this approach with conservation programs administered by conservation organizations as they are currently structured.     

Investigation of flow properties in natural streams using the entropy concept

This paper examines the discharge and velocity distributions in natural open channel flows using the entropy theory. Flow measurements were carried out at four different cross‐sections in central Turkey. The mean and maximum velocities at these stations exhibited a linear distribution and the entropy parameter was calculated to be M=1.31. Using this value, discharges for all flow conditions were calculated as a function of the measured maximum velocities (u_max). It was observed that the u_max/H and z_max/H ratios remained relatively constant when 0.2≤y/T≤0.8, especially for the wider channels. Using these constant values for each station, u_max and z_max could be determined solely as a function of the water depth H. Although the calculated velocities were higher than those measured at some verticals, the entropy‐based approach presents an attractive alternative to the traditional flow‐measurement techniques for the determination of flow properties because of its simplicity and quick application.     

Trees and wood: working with natural river processes

A history of land clearance and riparian tree and wood management has resulted in limited riparian woodland and wood along British rivers. However, river management approaches are now being promoted that ‘work with natural processes’ to reduce flood risk through measures intended to restore, protect and emulate the natural function of catchments, rivers, estuaries and coasts. Wood has started to be reintroduced into river channels during river restoration and natural flood management activities, but this needs to be undertaken using appropriate quantities, locations and designs that mimic natural tree‐wood features. This paper reviews the knowledge that is needed to support wood reintroduction activities including (i) the characteristics of the riparian tree species and wood that are present; (ii) the importance of river size relative to that of trees and wood pieces; and (iii) the way trees, wood and geomorphic processes interact across rivers and floodplains of different energy and style.     

A trapezoidal Fourier p-element for membrane vibrations

A trapezoidal Fourier p-element for the analysis of membrane transverse vibrations is investigated. Trigonometric functions are used as shape functions instead of polynomials to avoid ill-conditioning problems. The element matrices are analytically integrated in closed form. With the enrichment degrees of freedom in Fourier series, the accuracy of natural frequencies obtained is increased in a stable manner. One element can predict many modes accurately. Since a triangle can be divided into three trapezoidal elements, the range of application is wider than the previously derived rectangular Fourier p-element. The natural modes of a square membrane consisting of two trapezoidal elements are computed as test cases and convergence is very fast with an increasing number of trigonometric terms. Comparison of natural modes calculated by the trapezoidal Fourier p-element and the conventional finite elements is carried out. The results show that the trapezoidal Fourier p-element produces higher accurate natural frequencies than the conventional finite elements with the same number of degrees of freedom.     

Effect of wood dust type on mechanical properties,wear behavior,biodegradability, and resistance to natural weathering of wood-plastic composites

The present work reports the inclusion of different proportions of Mango/Sheesham/Mahogany/Babool dust to polypropylene for improving mechanical, wear behavior and biodegradability of wood-plastic composite (WPC). The wood dust (10%, 15%, 20% by weight) was mixed with polypropylene granules and WPCs were prepared using an injection molding technique. The mechanical, wear, and morphological characterizations of fabricated WPCs were carried out using standard ASTM methods, pin on disk apparatus, and scanning electron microscopy (SEM), respectively. Further, the biodegradability and resistance to natural weathering of WPCs were evaluated following ASTM D5338-11 and ASTM D1435-99, respectively. The WPCs consisting of Babool and Sheesham dust were having superior mechanical properties whereas the WPCs consisting of Mango and Mahogany were more wear resistant. It was found that increasing wood powder proportion results in higher Young’s modulus, lesser wear rate, and decreased stress at break. The WPCs made of Sheesham dust were least biodegradable. It was noticed that the biodegradability corresponds with resistance to natural weathering; more biodegradable WPCs were having the lesser resistance to natural weathering.     

Selection of the optimal alternative: rehabilitation of a regional drainage channel in Bangladesh

Due to the dynamic inter-relationship between human society and water resources, decision-making is a tricky task in water management sectors. In this study, multi-criteria analysis has been used as a decision support tool for the selection of a sustainable option in a regional channel improvement in Bangladesh. The Malnichara channel flows across the north-eastern divisional city of the country, and is responsible for storm water conveyance to the downstream Surma River. The channel was observed to be at risk due to anthropogenic activities such as encroachment, sewage and solid waste disposal and the filling up of natural depression basins. Using the multi-criteria analysis, three alternatives for channel improvement (sodding natural channel, lined natural channel and concrete box culvert) were evaluated with respect to ten indicators, grouped into four sustainability criteria (technical, economic, environmental and social). Sodding natural channel was found to be the optimal alternative, though the selection was sensitive to social criteria. Such a straightforward tool can efficiently be used to ensure sustainability of the channel through stakeholders' involvement in decision-making.     

Fourier p-elements for curved beam vibrations

Several Fourier p-elements for in-plane vibration of thin and thick curved beams are presented. Fourier trigonometric functions are used as enriching functions to avoid the ill-conditioning problems associated with high order polynomials. The element matrices are analytically integrated in closed form. With the additional Fourier degrees of freedom, the accuracy of the computed natural frequencies is greatly improved. Furthermore, the elements with enriching shape functions can avoid membrane and shear locking. The vibration of a thin ring, whose exact solutions are available, is analyzed by the present elements. The present elements can compute accurately high natural modes as the higher mode shapes synchronize with the Fourier functions nicely. The free vibration analysis of a number of hinged circular arches with various subtended angles and the tapered cantilever arches having uniform and non-uniform cross-section is carried out as numerical examples. The condition numbers for polynomial p-elements and Fourier p-elements are compared to show the superior numerical stability of the method.     

自然语言处理技术在建筑使用后评价中的应用

为拓展建筑使用后评价（POE）方法的研究思路，弥补过去人工分析文本评价信息在效率方面的局限，通过对自然语言处理技术最新研究成果的介绍，指出其可为建筑POE 提供的技术支持。利用现有自然语言处理工具对小学儿童的自由报告式环境评价性文本进行建筑POE 案例研究。结合案例，指出词性分词、关键词词云、情感分析及评论观点抽取等技术在建筑POE 应用中的研究方式与步骤，并初步探讨自然语言处理技术在建筑POE 中的局限性和应用前景。     

Impact of urbanization on the quality of water in a natural reservoir: a case study with the Deepor Beel in Guwahati city,India

The Deepor Beel is a natural, freshwater wetland in the south-west corner of Guwahati, India. The Beel harbours a large number of migratory aquatic birds, especially in winter, and is a Ramsar site since 2002. The wetland provides livelihood to the people of the surrounding villages through collection and sale of fish, nymphaea nuts and flower, ornamental fish, orchids, medicinal plants, etc. The water quality of the Beel is threatened by excessive fishing, hunting of water birds, pollution from pesticides and fertilizers and infestation by water hyacinth. The present work reports on the water quality of the wetland by continuous monitoring from February to July, covering the dry, temperate period and the wet, hot and humid period. Sampling was carried out at 10 sites for physical and aggregate properties, metallic and nonmetallic constituents, organic contaminants and microbiological parameters.     

Europäische Ansätze für Energieeffizienz‐Monitoring auf der Basis von Energieausweis‐Daten

Das DATAMINE‐Projekt wurde angesichts des Bedarfs nach konkreten Daten über den tatsächlichen energetischen Zustand des europäischen Gebäudebestands und die bestehenden Potentiale zur Energieeinsparung und CO2‐Emissionsminderung ins Leben gerufen. Diese Daten sollen längerfristig helfen, das politische Instrumentenbündel (ordnungsrechtliche, steuerliche, Förder‐Maßnahmen, Informationsvermittlung) so zu gestalten, dass es wirkungsvoll und kosteneffizient ist. Entsprechend dem DATAMINE‐Konzept basieren die Informationen auf Energieausweisen, die gemäß EU‐Gebäuderichtlinie ausgestellt werden, sobald ein Gebäude gebaut, verkauft oder vermietet wird. Im Rahmen des DATAMINE‐Projekts wurden in zwölf Ländern Feldversuche mit größeren Gebäudedaten‐Sammlungen durchgeführt, jeder mit unterschiedlichen Analysezielen. Dabei nutzte jedes Land die gleiche Datenstruktur für die Sammlung seiner Energieausweis‐Daten, die im Vorfeld gemeinsam entwickelt worden war. Diese lässt sich auf die verschiedenen Zertifizierungssysteme anwenden, die die europäischen Länder auf Grund der Unterschiede in Informationsbedürfnissen, Gebäudearten und Klima entwickelt haben. Rund 19.000 Datensätze wurden im gemeinsamen DATAMINE‐Format gesammelt. In einem Ländervergleich konnten verschiedene Energieeffizienz‐Indikatoren gegenübergestellt werden. Das Ergebnis der Analysen ergibt einen genaueren Einblick in den aktuellen Stand der energetischen Modernisierung spezifischer Gebäudegruppen in den beteiligten Ländern. Schließlich wurden Schlussfolgerungen in Bezug auf die Entwicklung von Monitoringsystemen in jedem Land und auf EU‐Ebene gezogen. European attempt at energy performance monitoring based on data collections and certification schemes. The launch of the DATAMINE project has been driven by the need for concrete data on the actual energy performance of the European building stock as well as the potential energy savings and CO₂ reductions. In the longer term data can help develop tailored, cost‐efficient complementary measures to energy performance legislation, such as soft loans and tax incentives. DATAMINE aims to construct a knowledge base using the information on the energy performance certificates issued when buildings are constructed, sold or rented. In the framework of DATAMINE test projects were carried out on large samples of buildings in 12 countries, each with individual monitoring targets. In each country the same data structure was used for data collection which had been developed at the forefront. Full allowance is made for the Europe‐wide differences in certification schemes, since each country has a scheme tailored to its specific needs, building stock and climate. Around 19,000 datasets have been collected in the common DATAMINE format. Cross‐country analysis of the collected data was performed comparing different energy performance indicators. The result of the evaluation activities gives a clearer insight into the current state of refurbishment of specific building subsets in each country. Finally conclusions were drawn regarding the development of monitoring systems in each country and on EU level.     

Model scale tunnel tests with water spray

A model scale study (1:23) was carried out in order to improve the basic understanding of water spray systems in longitudinal tunnel flow. The water spray system consisted of commercially available axial-flow hollow cone nozzles. Tests with both a deluge system made of 12 nozzles placed directly above the fire source and a water curtain system consisting of four nozzles placed either downstream or upstream of the fire source were carried out. A wood crib was used to simulate the fire source, which was designed to correspond to a HGV (heavy goods vehicle) fire load in large scale. A second wood crib was used as a target pile and was placed downstream the ignited wood crib. The parameters varied were the water flow rate and water pressure, the longitudinal ventilation rate and the arrangement of the nozzle system. Possible fire spread between wood cribs, with a free distance corresponding to 15 m in large scale, was investigated.     

Modeling pyrolysis of wet wood under external heat flux

Experiments on the thermal decomposition of wet wood in air were carried out in this work. The samples (typically 100×100 mm exposed surface, 15 mm thick) of several species with moisture content from 5% to 30% were subjected to a uniform heat flux 20–70 kW m⁻². A one-dimensional pyrolysis model is proposed to examine the influence of heat flux, species and moisture content on the process of thermal decomposition of wet wood. Temperature profiles at different points and solid conversion are calculated and compared with experimental data. There is good agreement between the experimental and calculated results.