Steel needles

Penetrability is the depth, expressed in tenths of a millimeter, a standard steel needle penetrates into a bitumen sample at 25°C. The needle carries a weight of 100 g and the test is applied for five seconds. The corresponding test method is relatively difficult to carry out and is defined in France by the standard NF T 66-004, and in the USA by the method ASTM D 583. Penetration is related to the viscosity. 

In the Irvine-Park falling needle viscometer (FNV) (194), the moving body is a needle. A small-diameter glass or stainless steel needle falls vertically in a fluid. The viscous properties and density of the fluid are derived from the velocity of the needle. The technique is simple and useflil for measuring low (down to lO " ) shear viscosities. The FNV-100 is a manual instmment designed for the measurement of transparent Newtonian and non-Newtonian... 

Micrometer syringe pipettes are fitted with a micrometer head which operates the plunger of the syringe, and when fitted with a stainless steel needle tip can be used for the dropwise addition of liquid the volume added is recorded by the micrometer. 

The hydrophilic Au SR (RSH = GSH, h-GSH, (PG)SH, (SA)SH) clusters were ionized by the ESI method [15,16,18,23,24] (Figures 2 and 3c). The details of the ESI source are depicted in Figure 3c, together with typical pressures of the chambers under operation. A 50%(v/v) water-methanol solution of the fractionated Au SR cluster with a typical concentration of 0.5mg/mL was electro-sprayed into the ambient atmosphere through the stainless steel needle of a syringe biased at ca. — 3kV. The solution was delivered by a syringe pump (SP310I, World Precision... 

FIGURE 4. Electrochemical reactor composed of a 2 cm3 capacity filter funnel and (A) stainless steel wire, (B, G) stainless steel needles for N2 entry and exit ports, (C) rubber septum, (D) lead foil cathode, (F) fine porosity glass filter, (H) plug of silicone glue and (I) silver wire anode. (Taken from Reference 176.)... 

For the more vigorous reactions, a twin-cell calorimeter was devised (188). It consisted of two nickel cylinders connected by a stainless steel needle valve and tubing and held rigidly to a metal top-plate. The cylinders and connections were immersed in a wide-necked Dewar vessel containing carbon tetrachloride which would react mildly with any BrF3 that escaped. Bromine trifluoride contained in one cylinder was transferred to the solid contained in the other cylinder by opening the valve and applying controlled suction. All measurements were made externally on probes in the carbon tetrachloride. 

Optical fibres, each made of two different types of glass, pass through the eye of a steel needle. 

The reason a heavy object floats on water is because in order to sink, it must overcome the surface forces. This clearly shows that, at any liquid surface, there exists a tension (surface tension) that needs to be broken when any contact is made between the liquid surface and the material (here the steel needle). A liquid can form three types of interfaces ... 

The most widely used method is that of Vicat in which a blunt steel needle (area of point 1 mm ) is applied vertically to the surface of a test piece (about 1 cm and 3-4 mm thick) under a load of 49 N. The oven temperature is then raised at 50 °C/h and the temperature determined at which the needle has simk 1 mm into the test piece this is taken as the softening point (Vicat temperature). 

In order to determine which expls are capable of ignition by an electrostatic discharge of an energy amounted to 100000 ergs, or less it. is necessary to subject each prospective expl to the following energy requirement test . For this a layer of the expl is spread in thickness of 0.010 inch on a steel plate and is separated by a a short gap from a steel needle. This needle is so arranged that it can be thrown into a closed circuit with a condenser of known capacity, on... 

Ass a stainless steel cannula was not available, the checkers made a minori modification in the operation without any trouble. They transferred fthe supernatant pentane and the solution of the sodium enolate using a Luer-lock hypodermic syringe with a stainless steel needle, prefluslbed with nitrogen, and the apparatus was swept with nitrogen during this operation. 

The sample to be analyzed is introduced to the ESI source by means of a flow stream from an HPLC instrument. The sample flows through a stainless-steel needle and then, sprays out in the form of a mist whose droplets hold peptide ions and mobile phase of HPLC. Peptide ions are separated from the mobile phase and subsequently, transferred into a mass analyzer either by a heated capillary or a curtain of nitrogen gas. Desolvation process can be carried out by a vacuum system. 

SPME uses a polymer-coated fused-silica fiber, typically 1 cm 100 m, that is fastened into the end of a fine stainless steel tube contained in a syringelike device and protected by an outer stainless steel needle. In use, the plunger of the device is depressed to expose the fiber to the sample matrix so that the organic compounds to be sorbed onto the fiber. The plunger is retracted at the end of the sampling time, and then it is depressed again to expose the fiber to a desorption interface for analysis typically by GC or LC. In a recent variation of this technique, the so-called in-tube SPME, the polymer is not coated on a fiber but on the inside of a fused-silica capillary before analysis by LC. 

Picatinny Test No. 2. The apparatus consists of a fixed gap electrode which. uses steel needles. The discharge circuit is similar to that of the Picatinny Test No 1, using the gap length of 0.005 inch set with a feeler gauge. In nearly very respect, this test is inferior to the test No 1. It has been used for distinguishing primaries from hoosters (Ref 35, p 27)... 

Microliter syringes, such as that in Figure 2-13, come in sizes from 1 to 500 p.L and have an accuracy and precision near 1%. When using a syringe, take up and discard several volumes of liquid to wash the glass walls and to remove air bubbles from the barrel. The steel needle is attacked by strong acid and will contaminate strongly acidic solutions with iron. 

Figure 24-24 Syringe for solid-phase microexfraction. The fused silica fiber is withdrawn inside the steel needle after sample collection and when the syringe is used to pierce a septum.

Plastic containers must be washed before use. Table 28-1 shows that manganese in blood serum samples increased by a factor of 7 when stored in unwashed polyethylene containers prior to analysis. In the most demanding trace analysis of lead at 1 pg/g in polar ice cores, it was observed that polyethylene containers contributed a measurable flux of 1 fg of lead per cm2 per day even after they had been soaked in acid for 7 months.4 Steel needles are an avoidable source of metal contamination in biochemical analysis. 

Gas supply for the eductor is vided by piping located external I above each compartment The gasfc, drawn from the vapor space through stainless steel needle valve to eductor. 

Break-seals (Fig. 9.31) are commonly used on sealed reaction and storage tubes because this type of seal allows recovery of volatile materials. The type illustrated in Fig. 9.31a may be opened in an apparatus which contains an off-center arm which may be rotated to break the small tube (Fig. 9.32a). Among the many variants of this design of tube opener, one by Mahler and Velmey is constructed from a /4-in. stainless-steel needle valve which is drilled out to receive the break-seal so that the valve stem may be screwed down on the small tube (Fig. 9.32b).59 The break-seal and vacuum system are connected to this... 

In 1959 Strehlow and Becker developed a pressure-jump apparatus that enclosed a conductivity cell containing the reaction solution, and a reference cell under xylene in an autoclave. The reaction and reference solutions were pressurized to about 6.1 MPa with compressed air. By the blow of a steel needle, a thin metal disk used to close the autoclave was punctured and the pressure was released within about 60 s. 

We have found the use of reusable stainless steel needles to be optimal as it is our experience that these are sharper and the needed length can be obtained. 

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