Species richness and stand diversity in relation to site and succession of forests in Sarawak and Brunei (Borneo)

Site conditions in the Mixed Dipterocarp forests of Sarawak and Brunei are characterised by the absence of prolonged drought. This permits minor site differences to become ecologically fully effective. In the kerangas forests, drought conditions occur frequently and regularly. An extremely variable water regime and uniformity of chemical and physical soil conditions are typical of kerangas peat bogs and deltaic peatswamp forest sites. Consequently, fewer niches are available and the number of species is less on these sites than in Mixed Dipterocarp forest. Upland kerangas sites are intermediate in this respect. About 850 tree species (428 genera) are recorded from kerangas forests. It is estimated that the total number of tree species in all forest types in Sarawak and Brunei is between 2 500 and 3 000, and 2 800 and 3 300 respectively. The positions, shapes, and variation coefficients of the species-area lines are strongly influenced by conditions of soil and physiography. The diversity index of McINTOSH and the average information content indicate a high degree of diversity among trees of stands on sites with balanced water regime. Low values occur in late phases of peat development and on sites with frequent droughts or with alternating dry and waterlogged conditions. The differences are accentuated if the basal area is substituted for number of individuals in the index. The shape of the dominance-diversity curves according to WHITTAKER indicates that on favourable sites a great number of environmental factors determines the diversity of ecological niches. On less favourable sites, niche space appears to be restricted by environmental severity, and a tendency to dominance and reduced species diversity is evident. The values of an integrating index of diversity are related to soil-landform units which reflect ecological gradients primarily related to the water regime. The trend of the index values agrees with the trend of structural complexity expressed as estimated aerodynamic surface roughness. A synoptic assessment of the various indicators of diversity suggest the important role which environmental factors play in shaping ecological niche-spaces in the equatorial lowland forests

A methodology for collecting donning times of thermal protective immersion suits intended to be worn by passengers on vessels operating in cold environments

Adequate thermal protection for passengers travelling on-board vessels in cold climate regions, such as that provided by thermal protective immersion suits (TPIS), enhances passenger survivability in emergency situations, in particular those requiring the abandonment of the vessel. As emergency abandonment is a time critical process, it is essential to consider the time required to correctly don the TPIS. Testing standards, such as the International Maritime Organization guidelines, require that TPIS must be able to be donned within 2 minutes. Unfortunately, current practices quantifying donning times are questionable and so there is a limited evidence base that reliably quantifies donning times required by typical passengers. This paper presents a test procedure designed to reliably quantify the time required by test subjects to don the TPIS. Furthermore, the procedure assesses the donning correctness – a TPIS that is incorrectly donned is unlikely to offer appropriate thermal protection. The paper will also discuss the deficiencies in current practices to assess required donning time

A multi-scale crystal plasticity model for cyclic plasticity and low-cycle fatigue in a precipitate-strengthened steel at elevated temperature

peer-reviewedIn this paper, a multi-scale crystal plasticity model is presented for cyclic plasticity and low-cycle fatigue in a tempered martensite ferritic steel at elevated temperature. The model explicitly represents the geometry of grains, sub-grains and precipitates in the material, with strain gradient effects and kinematic hardening included in the crystal plasticity formulation. With the multiscale model, the cyclic behaviour at the sub-grain level is predicted with the effect of lath and precipitate sizes examined. A crystallographic, accumulated slip (strain) parameter, modulated by triaxiality, is implemented at the micro scale, to predict crack initiation in precipitate-strengthened laths. The predicted numbers of cycles to crack initiation agree well with experimental data. A strong dependence on the precipitate size is demonstrated, indicating a detrimental effect of coarsening of precipitates on fatigue at elevated temperature. (C) 2016 Elsevier Ltd. All rights reserved.ACCEPTEDpeer-reviewe

Structure and functions in the rain forest of the international Amazon-ecosystem-project: Preliminary communication about the classification of stands, variation of stand structure and precipitation characteristics

Die Klassifizierung mit Hilfe einer monothetischen Teilung von Gruppen, die jeweils vom Zentralbaum und seinen 10 nahesten Nachbarn gebildet werden, bis zu einer Stufe bei der eine weitere Teilung weniger als 3 % Informationsminderung bringt, hat Straten ergeben, die offenbar gleichzeitig standort- und phasenbedingte Variationen der floristischen und geometrischen Bestandesstruktur ausdrücken. Die Auswirkung des Standorts wiegt vor, wenn der Mindestdurchmesser und die Fläche groß sind, die der Phase, wenn beide relativ klein sind. Die ersten Ergebnisse einer orientierenden Auswertung deuten an, daß das Volumen des belaubten Kronendaches weniger variiert als die aerodynamische Oberflächenrauhigkeit, die Bestandesgrundfläche, das Baumvolumen, die Artenanzahl und die Artendiversität je Quadrat (10 x 10 m). Es ist möglich, daß dies ein bedeutendes Merkmal der Anpassung an die Bedingungen der durch einen kritischen Wasser- und Nährstoffhaushalt gekennzeichneten Standorte ist. Die Varianz der Artenzusammensetzung und der Struktur des Kronendaches ist eng gekoppelt mit Veränderungen des Strahlungshaushaltes, der Temperatur und Luftfeuchte im Bestandesinneren. Hingegen konnten Zusammenhänge mit den Bestandesniederschlagshöhen nicht nachgewiesen werden