In situ

Summary

In situ (ɪn_ˈsɪtjuː,_-ˈsaɪtjuː,-_ˈsiː-; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in many different contexts. For example, in fields such as physics, geology, chemistry, or biology, in situ may describe the way a measurement is taken, that is, in the same place the phenomenon is occurring without isolating it from other systems or altering the original conditions of the test. The opposite of in situ is ex situ. Aerospace In the aerospace industry, equipment on-board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may work but interference from nearby equipment may create unanticipated problems. Special test equipment is available for this in situ testing. It can also refer to repairs made to the aircraft structure or

Official source

https://en.wikipedia.org/wiki/In_situ

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications (100)

Related publications

Related people (22)

Related people

Related units (16)

Related units

Related concepts (22)

Related concepts

Related courses (43)

Related courses

Related lectures (65)

Related lectures

Related publications (100)

The kinetics of the ethanol dehydration under dynamic conditions - a reaction with stop-effect. In-situ surface and gas phase analysis

EPFL1998

Identifying contaminated sediment problems associated with urban stormwater discharges in lakes

Tom Hugo Antoine Benejam

Urban stormwater discharges during wet weather has always been a sensitive issue to deal with. By inducing combined sewer overflows, substantial impacts on receiving water are commonly feared. Aware of this problematic situation, the VSA already created the STORM guideline to cope with this issue in small rivers. However, such a guideline is still lacking for large rivers and lakes. This project is a first step towards this direction and tries to prospect the necessity of such instructions for lakes. For this purpose, the present master thesis studies the impact of urban stormwater discharged via the Flon river into the Vidy Bay of Lake Geneva, next to the city of Lausanne. A Sediment Quality Triad, meaning a combination of three assessment methods (chemistry, ecotoxicology and in situ benthic communities), was implemented to assess the impact of stormwater discharges on the sediments in this part of the lake. On a large sampling grid composed of 15 sites, heavy metals were measured and ostracod bioassays were performed with the sediment samples collected at these sites. Subsequently, on the five sites located in the central transect of this sampling grid, further experiments were led to understand the incidence of stormwater discharges on sediment quality while moving away from the Flon river’s effluent. In addition to heavy metals, PAHs and PCBs were measured at these sites. A battery of three extra ecotoxicological bioassays was also carried out. These tests were implemented with the following organisms: chironomids, macrophytes and nematodes. Finally, two kind of in situ communities were studied in these five sites: microbial communities in order to perform a pollution-induced community tolerance (PICT) and oligochaete communities in order to implement the oligochaete index of lake bioindication (IOBL). The implementation of these experiments showed that the contamination induced by urban stormwater discharges is limited to the proximity of the combined sewer overflow. A set of pollutants mainly composed of copper, zinc, PCBs and PAHs was identified within this contaminated area. Although no toxicity was observed on the sites affected by this contamination, in situ community studies revealed substantial shifts towards resistant species in both oligochaete and microbial community structures. Another contamination area, observed in remote sites and mainly composed of cobalt, chromium, iron, manganese and nickel, remains not well understood. The laboratory toxicity tests detected some toxicity in benthic invertebrates but the benthic communities studied in situ showed no apparent alteration. Modeling tools are required to get a better understanding of the source of this contamination.

2017

In this thesis, the magnetic and structural properties of layered epitaxial film systems and clusters are presented. A main achievement is the investigation of the direct correlation between magnetism and structural or morphological details of ultrathin films. For this purpose, the film structure has been accessed directly by means of surface science methods. The effect of structural changes on the magnetism were observed in-situ by magneto-optical techniques. First, epitaxial Fe films grown at low temperature (∼ 120K) on Cu(100) have been investigated. Such layers assume an fcc-crystal structure due to their interaction with the underlying Cu substrate. Within this work it is shown that the morphology of these films can be altered by annealing treatments. The thermally-induced morphological changes have direct consequences for domain wall propagation and result in increased coercivity and in modified surface anisotropy. Flat fcc-Fe layers on Cu(100) have been used as templates to form fcc-Fe/Cu/Fe trilayers with coupled perpendicular magnetization. Such systems might be of relevance for data storage applications. The perpendicular coupling is ascribed to the realignment of the magnetization of the bottom Fe layer within the stray field produced by the top Fe layer magnetization. The magnetic coupling has been investigated as a function of the thickness of the top and the bottom Fe layer as well as the Cu spacer thickness. It was found that the magneto-static interaction is a direct consequence of the fcc-structure of both Fe layers and the interface roughness. It is demonstrated that Fe films with fcc-structure and perpendicular magnetization can also be prepared on other fcc-templates, such as Pt substrates. Monatomic steps on the substrate surface are exploited to steer the growth of the film and with it the magnetism. Despite significant differences in the morphology and the atomic structure of Fe films on flat Pt(111) and stepped Pt(997), the critical thickness for the spin reorientation transition is similar on the two surfaces. However, the local atomic arrangement above three monolayer film thickness determines in-plane easy magnetization axis parallel to the step edges. For all layered systems investigated in this thesis, epitaxial strain is a the driving force which influences the film structure and triggers structural transitions. The strain dependence of the morphology and the magnetism was probed by a comparative study of Fe deposited on Pt substrates with and without a noble gas buffer layer. The formation of relaxed Fe clusters during Xe layer desorption is favored in the absence of the overlayer-substrate interaction. Striking differences in the magnetic anisotropy between the systems are attributed to magneto-elastic contributions. Measurements of the blocking temperature of the Fe clusters allow estimating the cluster size. All samples have been investigated under ultra high vacuum conditions. The study of the sample magnetic properties study was done by in-situ magneto-optical Kerr effect measurements and Kerr microscopy. Structural characterization was done by low energy electron diffraction and, in collaboration with other scientists, by scanning tunnelling microscopy.

EPFL2006

Identifying contaminated sediment problems associated with urban stormwater discharges in lakes

Tom Hugo Antoine Benejam

2017