Newly developed materials such as engineered nanomaterials are produced in increasing amounts and applied in a growing number of products. Once released to the environment, they can pose a hazard to ecosystems and human health. To assess potential risks, the exposure of the material to humans and the environment has to be determined. For many materials such as engineered nanomaterials, a quanti...

In this paper, we study the VoIP capacity of IEEE 802.11b (DCF), i.e., the maximum number of simultaneous voice calls that can take place in a WLAN cell. This capacity is highly dependent on the chosen codec and on the distance from the access point (AP) to the users. Thus several codecs are studied, namely G711, GSM-EFR, and G723.1. All users are assumed to be at a fixed distance from the AP. ...

A miniature methane sensor composed of a long ultra-low loss waveguide and a micro-ring resonator filter is proposed with high sensitivity and good selectivity. This sensor takes advantage of the evanescent field to implement methane concentration detection at a near infrared band (1650 nm). In the sensor, two waveguides, a strip waveguide and a slot waveguide, are specially designed and discus...

Accounting for natural differences in flow variability among rivers, and understanding the importance of this for the protection of freshwater biodiversity and maintenance of goods and services that rivers provide, is a great challenge for water managers and scientists. Nevertheless, despite considerable progress in understanding how flow variability sustains river ecosystems, there is a growin...

Models are often highly complex incorporating different processes, parameters, scenarios and subjects, and thereby producing different outcome endpoints. The first recommended model development step is the construction of a conceptual model, thereby specifying and defining the processes and relationships to be covered by the model. However, model results are also often highly complex, being fra...

Environmental turbulence is ubiquitous in natural habitats, but its effect on flying animals remains unknown because most flight studies are performed in still air or artificially smooth flow. Here we show that variability in external airflow limits maximum flight speed in wild orchid bees by causing severe instabilities. Bees flying in front of an outdoor, turbulent air jet become increasingly...

abstract given the importance of environmental cycles had led to allocation of water-right for water species and ecosystems which is known as environmental flow or in stream flow. from among the various methods for estimating environmental flow, building block approach is considered as a very powerful tool for estimating the water needs. in this paper, beside simplifying the building block appr...