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Hach Company manufactures and distributes analytical instruments and reagents used to test the quality of water and other liquid solutions. Manufactured and distributed worldwide, Hach systems are designed to simplify analysis by offering on-line instrumentation, portable laboratory equipment, prepared reagents, easy-to-follow methods, and technical support.
The conjugate gradient method can also be used to solve unconstrained optimization problems such as energy minimization. It is commonly attributed to Magnus Hestenes and Eduard Stiefel, [1] [2] who programmed it on the Z4, [3] and extensively researched it. [4] [5] The biconjugate gradient method provides a generalization to non-symmetric matrices.
An example of back titration, the Volhard method, named after Jacob Volhard, involves the addition of excess silver nitrate to the analyte; the silver chloride is filtered, and the remaining silver nitrate is titrated against ammonium thiocyanate, [1] with ferric ammonium sulfate as an indicator which forms blood-red [Fe(OH 2) 5 (SCN)] 2+ at the end point:
In this method, a pulsed UV laser is focused on the sample and creates a plume of ablated material, which can be swept into the plasma. This allows geochemists to spatially map the isotope composition in cross-sections of rock samples, a tool which is lost if the rock is digested and introduced as a liquid sample.
McFarland standards. No. 0.5, 1 and 2. In microbiology, McFarland standards are used as a reference to adjust the turbidity of bacterial suspensions so that the number of bacteria will be within a given range to standardize microbial testing.
Agar dilution is one of two methods (along with broth dilution) used by researchers to determine the minimum inhibitory concentration (MIC) of antibiotics. It is the dilution method most frequently used to test the effectiveness of new antibiotics when a few antibiotics are tested against a large panel of different bacteria.
An illustration of Newton's method. In numerical analysis, the Newton–Raphson method, also known simply as Newton's method, named after Isaac Newton and Joseph Raphson, is a root-finding algorithm which produces successively better approximations to the roots (or zeroes) of a real-valued function.
The MIL-STD-883 standard establishes uniform methods, controls, and procedures for testing microelectronic devices suitable for use within military and aerospace electronic systems including basic environmental tests to determine resistance to deleterious effects of natural elements and conditions surrounding military and space operations; mechanical and electrical tests; workmanship and ...