Grabbing device

Lanyard. A lanyard is a short, flexible rope or strap that connects a safety belt to an anchor point or a grabbing device on a lifeline. Lanyards must be V2 in. nylon rope or... 

Grabbing Device A grabbing device connects a body belt or lanyard to a lifeline. Some grabbing devices move freely along a lifeline when there is no load, but when there is a sudden load or movement, they lock onto the line. Some fixed ladders have grabbing devices that lock quickly if a climber falls. 

When a 3-foot extension is not possible, you need to secure the side rails at the top to a rigid support and use a grab device. 

Belt Conveyors. Belt conveyors consist of an endless moving belt which carries materials within a supporting frame. The belt can be made from a variety of materials and may or may not be equipped with cleats or other grabbing devices. The belt may be supported by a solid-slider-type bed of wood or metal or by rollers. 

The devices used for sampling of solid samples (sludge, sediment, and soil) are usually grab samplers or corers. Box corers or multicorers can be employed if more detailed information on the spatial distribution of the analytes is needed. The samples are stored in the dark at 4 °C or more commonly at -20 °C, preferably in glass containers [53]. Very often, solid samples are also dried or lyophilized prior to storage. 

For on-site measurement from grab sampling, a compact optical device with disposable strips for BOD determination has been developed [36]. The system includes three pairs of light-emitting diodes and photodiodes, and the disposable strips are made of inexpensive, transparent polycarbonate plates, where Pseudomonas fluorescens is immobilized. Using the 2,6-dichlorophenol-indo-phenol sodium salt as chromophore, a linear relationship was observed between the bioluminescence of the exposed strip and the BOD value. 

Two questions, where to monitor or sample and how to obtain representative samples are both important. Surface water samples often are collected by automatic sampling devices controlled by a variety of sensors. The simplest method of collecting water is the grab technique, whereby a container is lowered into the water, rinsed, filled, and capped. Specialized samplers frequently are used to obtain water at greater depths. 

Evaluations of various soil and sediment samplers have been reported [56, 57]. The sediment shovel proved highly practical, but was limited because small particles tend to be lost when the shovel is lifted [56]. A cryogenic sediment sampler was less convenient to use, but allowed the collection of almost undisturbed samples. Houba described a different device for the automatic subsampling of soil, sediment and plant material for proficiency testing [57]. In another study, Thoms showed that freeze-sampling collects representative sediment samples, whereas grab-sampling introduces a bias into the textural composition of the 120 mesh fraction, due to washout and elutriation of the finer fractions [58]. 

Stabilized liquid membrane device (SLMD) A water-insoluble organic complexing mixture diffuses to the exterior surface of the sampler through a polymeric membrane Divalent metal ions Preconcentration, in situ sampling, determination of labile metal ions in grab samples Days to several weeks Extraction with acid 73... 

Portable sampling devices were categorised by Nielsen and Yeates (1985) as grab samplers, suction lift devices and positive displacement mechanisms. A brief review of each category is given below. 

Tab. 1 Samples of Havel and Spree river sediments. Sampling devices EB = Eckman-Birge-grab sampler NF = liquid nitrogen deep freeze method.

Four sediment samples were taken in 1998 and 1999 from three locations at the Teltow Canal in Berlin, as indicated in Fig. 1. In addition to the surface sediment samples T1 and T3 taken by means of a 4L Ekman-Birge grab sampler a short sediment core T2 was obtained by using a tube coring device. The sediment core was subdivided into an upper part T2a (0-3 cm) and a lower part T2b (3-10 cm), that represents an older accumulation time between 1980 and 1990. 

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