Solid properties, laboratory

The product development process in the pharmaceutical industry is not unlike that of other industries, in which exploratory materials are researched and developed into products, and where problems arise the analytical laboratory is called upon to provide solutions. The characterization of the physical properties of pharmaceutical solids is one of the disciplines utilized early in the drug development process. The characterization of these properties is vital to determining whether the compound under investigation is a candidate for continued development as a drug product. To facilitate the characterization of pharmaceutical solids in laboratories, a conceptual approach for this characterization has been developed (66) that uses decision trees to guide the analyst in the characterization of drug substances. 

Further, the first electrochemical devices based on oxide ion-conducting solid electrolytes, i.e., solid oxide fuel cells, water vapor electrolyzers, and oxygen concentrators, were also developed in the Institute of High-Temperature Electrochemistry. In 1978 the Laboratory of Physical and Chemical Properties of Solid Electrolytes has been renamed to the Solid Electrolytes Laboratory. Different cation-conductive solid electrolytes were investigated in the laboratory. Oxide semiconductor materials with fast ion and electron transport have been studied for different electrode applications in high-temperature electrochemical devices and MHD generators. 

While the surface tension of the adhesive, is easily measured in the laboratory, the other terms in Wa, by themselves, are not. A second easily measurable property associated with the solid-liquid-air system, however, is the contact angle, 9, the angle, drawn in the liquid, between the solid-liquid and the liquid-air interfaces, drawn in the plane perpendicular to the three-phase interline, as shown in Fig. 4. Minimization of the free energy of the solid-liquid-air... 

Charcoal Tubes Reference has been made earlier to adsorption, which is the property of some solid materials, such as activated charcoal, to physically retain solvent vapors on their surfaces. In environmental health testing, the adsorbed vapors are removed, generally with a solvent, in a laboratory. The solvent is then analyzed by physical methods (gas chromatography, etc.) to determine the individual compounds whose vapors, such as benzene, were present in the sampled air. Industrial atmospheric samples can be collected in small glass tubes (4 mm ID) packed with two sections of activated charcoal, separated and retained with fiberglass plugs. To obtain an air sample, the sealed ends of the tube are broken off, and air is drawn through the charcoal at the rate of 1 liter per minute by means... 

Different filter media, regardless of the specific application, are distinguished by a number of properties. The principal properties of interest are the permeability of the medium relative to a pure liquid, its retention capacity relative to solid particles of known size and the pore size distribution. These properties are examined in a laboratory environment and are critical for comparing different filter media. 

In selecting cloths made from synthetic materials, one must account for the fact that staple cloths provide a good retentivity of solid particles due to the short hairs on their surface. However, cake removal is often difficult from these cloths - more than from cloths of polyfilament and, especially, monofilament fibers. The type of fiber weave and pore size determine the degree of retentivity and permeability. The objective of the process, and the properties of particles, suspension and cake should be accounted for. The cloth selected in this maimer should be confirmed or corrected by laboratory tests. Such tests can be performed on a single filter. These tests, however, provide no information on progressive pore plugging and cloth wear. However, they do provide indications of expected filtrate pureness, capacity and final cake wetness. 

A laboratory experiment on colligative properties directs students to determine the molar mass of an unknown solid. Each student receives 1.00 g of solute, 225 mL of solvent and information that may be pertinent to the unknown. 

When trying to understand and to manipulate matter and materials, chemistry does not start by looking at the natural world in all its complexity. Rather, it seeks to establish what have been termed exemplar phenomena ideal or simplified examples that are capable of investigation with the tools available at the time (Gilbert, Borrlter, Elmer, 2000). This level consists of representatiorrs of the empirical properties of solids, liquids (taken to include solutions, especially aqueous solutiorts), colloids, gases and aerosols. These properties are perceptible in chemistry laboratories and in everyday life and are therefore able to be meastrred. Examples of such properties are mass, density, concentration, pH, temperatrrre and osmotic presstrre. 

Ames Laboratory (Iowa State University, USA) investigating new solid state phases based on reduced rare earth halides. Since 1993, she has held a position at the University Jaume 1 of Castello (Spain) and became Associate Professor of Physical Chemistry in 1995. During the second semester of 2005, she held a visiting professor position at the Laboratory of Chemistry, Molecular Engineering and Materials of the CNRS-Universtity of Angers (France). Her research has been focussed on the chemistry of transition metal clusters with special interest in multifunctional molecular materials and the relationship between the molecular and electronic structures of these systems with their properties. She is currently coauthor of around 80 research papers on this and related topics. 

Ethylene. Under the influence of pressure and a catalyst, ethylene yields a white, tough but flexible waxy solid, known as Polythene. Polyethylene possesses excellent electrical insulation properties and high water resistance it has a low specific gravity and a low softening point (about 110 ). The chemical inertness of Polythene has found application in the manufacture of many items of apparatus for the laboratory. It is a useful lubricant for ground glass connexions, particularly at relatively high temperatures. 

This part will be concerned with the properties of electrolytes (liquid or solid) under ordinary laboratory conditions (i.e. in the absence of strong external electric fields). The electroneutrality condition (Eq. 1.1.1) holds with sufficient accuracy for current flow under these conditions ... 

Due to their lipophilic properties, hormones tend to be divided up between the liquid and solid phases, making sorption an important parameter for hormone elimination from the liquid phase of sewage. In laboratory studies based on an... 

Conventional electrolytes applied in electrochemical devices are based on molecular liquids as solvents and salts as sources of ions. There are a large number of molecular systems, both pure and mixed, characterized by various chemical and physical properties, which are the liquids at room temperatures. This is the reason why they dominate both in laboratory and industrial scale. In such a case, solid salt is reacted with a molecular solvent and if the energy liberated during the reaction exceeds the lattice energy of the salt, the solid is liquified chemically below its melting point, and forms the solution. Water may serve as an example of the cheapest and most widely used molecular solvent. 

---