Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

CONTENTS importance

Alkenes and chlorinated alkenes 10-100 Chlorine content important, AOP support oxidation... [Pg.26]

Percival, H. J., Parfitt, R. L., and Scott, N. A. (2000). Factors controlling soil carbon levels in New Zealand grasslands Is clay content important Soil Sci. Soc. Am. J. 64,1623-1630. [Pg.104]

Key points are provided for each case and are intended both as a short summary of the essential points and as a focus for revision. They can be used to preview or review the case content. Important points should then be easier to remember in the future, especially when, by association, you can recall them in an appropriate clinical context. [Pg.337]

Sulfur is present in a variety of forms, in its elementary form, as a bound molecule, but also in an oxidized state. High sulfur contents import certain acidity to industrial carbon blacks. Nitrogen, when present, is usually included in the graphite grid. One thing to bear in mind is that sulfur and nitrogen content are contingent primarily on feedstock type and quality. [Pg.179]

The determination of the elemental composition of a petroleum cut is of prime importance because it provides a quick means of finding out the quality of a given cut or determining the efficiency of a refining process. In fact, the quality of a cut generally increases with the H/C ratio and in all cases, with a decrease in hetero-element (nitrogen, sulfur, and metals) content. [Pg.27]

With respect to fuels utilized as heating fuels for industrial furnaces, or as motor fuels for large diesel engines such as those in ships or power generation sets, the characteristics of primary importance are viscosity, sulfur content and the content of extremely heavy materials (asphaltenes) whose combustion can cause high emissions of particulates which are incompatible with antipollution legislation. [Pg.178]

With regards to the overall balance of combustion, the chemical structure of the motor or heating fuel, e.g., the number of carbon atoms in tbe chain and the nature of the bonding, does not play a direct role the only important item is the overall composition, that is, the contents of carbon, hydrogen, and — eventually— oxygen in the case of alcohols or ethers added to the fuel. [Pg.179]

The 3D inspection system has a number of measuring and report utilities that enables the user to easily find, analyse and report possible indications in the test object. As an example, a moveable 2D projection view plane can be moved along e.g, the welding geometry dynamically updating the content of the 2D projection view window. Indications can be measured using any referenee co-ordinate system and the results and screen dumps can automatically be dumped in report files suited for later import into a word processing application. [Pg.872]

A8, which leads to D, = 1/(2A8). The factor of two arises because a minimum of two data points per period are needed to sample a sinusoidal wavefonn. Naturally, the broadband light source will detennine the actual content of the spectrum, but it is important that the step size be small enough to acconunodate the highest frequency components of the source, otherwise they... [Pg.1167]

The development of neutron diffraction by C G Shull and coworkers [30] led to the detennination of the existence, previously only a hypothesis, of antiferromagnetism and ferrimagnetism. More recently neutron diffraction, because of its sensitivity to light elements in the presence of heavy ones, played a cmcial role in demonstrating the importance of oxygen content m high-temperature superconductors. [Pg.1382]

Biological infonnation is also concerned witli tire analysis of biological messages and tlieir import. The fundamental premise of tire protein-folding problem section C2.14.2.2 is tliat tire full tliree-dimensional arrangement of tire protein molecule can be predicted, given only tire amino acid sequence, together witli tire solvent composition, temperature and pressure. One test of tire validity of tliis premise is to compare tire infonnation content of tire sequence witli tire infonnation contained in tire stmcture [169]. The fonner can be obtained from Shannon s fonnula ... [Pg.2844]

The JCAMP-DX file format is split into the sections CORE and NOTES with the intention of keeping less important data separated from the essential content. The CORE itself contains CORE HEADER and CORE DATA. NOTES are just between HEADER and DATA (see Figure 4-4 for an example). [Pg.210]

Publications of this kind are described as non-original. They are abstracting services and handbooks that catch the primary literature, condense the important contents, and make this information available (searchable). Secondary literature is not evaluated and is provided in both printable and electronic forms. Examples are Gmelin, Beilstein, Citations Chemisches Zentralblatt, Chemical Abstracts, or Science Citation Index handbooks include Houben-Weyl, and Landolt Bomstein. [Pg.239]

Now roll up the Carius tube (while still in a vertical position) in a strip of ordinary thick drying paper, and then place it in the heavy iron protector tube if the Carius tube is too short and tends to disappear within the iron tube, a short section of old glass tubing should first be placed in the iron tube so that the capillary of the Carius tube just projects. The function of the paper is to protect the Carius tubing from being scratched, and also (more important) to prevent the local overheating which would otherwise occur at places where the Carius tube is in direct contact with the iron tube. The sealed tube, throughout its manipulation, should be left as nearly vertical as possible, so that the contents do not leave the rounded end. [Pg.420]

The steam-distillation is continued for 5 minutes after steam can first be seen entering the condenser the ideal rate of distillation is about 4 -5 ml. of distillate per minute, but this is not critical and may be varied within reasonable limits. The receiver J is then lowered from the lip K of the condenser and the steam-distillation continued for a further two minutes, thus ensuring that no traces of liquid containing ammonia are left on the inside of the condenser. At the end of this time any liquid on the lip K is rinsed with distilled water into J, which is then ready for titration. It is important that the receiver and its contents are kept cold during the distillation and it is advisable to interpose a piece of asbestos board or other screen so that it is not exposed to the heat from the burner under the steam generator. [Pg.496]

An important application of the critical solution temperature is to the determination of the water content in such substances as methyl and ethyl alcohols. Here the system is usually the alcohol and a hydro carbon, such as -hexane or dicyclohexyl the water is, of course, insoluble in the hydrocarbon. Thus, the methyl alcohol - cyclohexane system has a C.S.T. of 45 -5° and even 0 01 per cent, of water produces a rise of 0-15° in the C.S.T. The experimental details are given below. [Pg.20]

In recent years, concentrated phosphoric acids, which may contain as much as 70% to 75% P2O5 content, have become of great importance to agriculture and farm production. World-wide demand for fertilizers has caused record phosphate production. Phosphates are used in the production of special glasses, such as those used for sodium lamps. [Pg.37]

All of this careful addition is to keep the reaction from starting before the bomb is sealed. It is also important to note that the chemist must scale up or scale down the amount of reactants so that the total amount of all the ingredients consumes no less than 90 of the volume space of her particular pipe bomb. Too much head space with its atmospheric air will lower the yield. The bomb is heated in an oil bath or oven at 105-115°C for 18-24 hours and the contents are then distilled with the 1,3 benzodioxole coming over at about 170-175°C with no vacuum, Alternatively, the chemist can only distill off the methanol, wash with dilute NaOH solution and extract with ether, etc. [Pg.216]

CD ROM set includes 8 important and stan dard mechanisms that can be used directly from the CD or im ported into your own lec ture presentation Digital Content Manager—... [Pg.1335]

Supercritical CO2 is used to extract fat from candy bars. Samples are placed in an extraction vessel and its weight determined before and after extraction. The %w/w fat content is determined by difference. The volume of CO2 needed to effect a complete extraction is determined experimentally. Variations in results for different samples illustrate the importance of sampling. [Pg.226]

At first glance, the contents of Chap. 9 read like a catchall for unrelated topics. In it we examine the intrinsic viscosity of polymer solutions, the diffusion coefficient, the sedimentation coefficient, sedimentation equilibrium, and gel permeation chromatography. While all of these techniques can be related in one way or another to the molecular weight of the polymer, the more fundamental unifying principle which connects these topics is their common dependence on the spatial extension of the molecules. The radius of gyration is the parameter of interest in this context, and the intrinsic viscosity in particular can be interpreted to give a value for this important quantity. The experimental techniques discussed in Chap. 9 have been used extensively in the study of biopolymers. [Pg.496]

What makes the latter items particularly important is the fact that the charge and electrolyte content of an unknown polymer may not be known hence it is important to design an osmotic pressure experiment correctly for such a system. It is often easier to add swamping amounts of electrolyte than to totally eliminate all traces of electrolyte. Under the former conditions a true molecular weight is obtained. Trouble arises only when the experimenter is indifferent toward indifferent electrolyte this sort of carelessness can be the source of much confusion. [Pg.574]

The words basic concepts" in the title define what I mean by fundamental." This is the primary emphasis in this presentation. Practical applications of polymers are cited frequently—after all, it is these applications that make polymers such an important class of chemicals—but in overall content, the stress is on fundamental principles. Foundational" might be another way to describe this. I have not attempted to cover all aspects of polymer science, but the topics that have been discussed lay the foundstion—built on the bedrock of organic and physical chemistry—from which virtually all aspects of the subject are developed. There is an enormous literature in polymer science this book is intended to bridge the gap between the typical undergraduate background in polymers—which frequently amounts to little more than occasional relevant" examples in other courses—and the professional literature on the subject. [Pg.726]

Hard red winter (HRW) is an important bread wheat that accounts for more than 40% of the United States wheat crop and wheat exports. This fall-seeded wheat is produced in the Great Plains, which extend from the Mississippi River west to the Rocky Mountains, and from the Dakotas and Montana south to Texas. Significant quantities are also produced in California. HRW has moderately high protein content, usually averaging 11—12%, and good milling and baking characteristics. [Pg.354]

Acid content calculated as tartaric acid is about 6—7 g/L for best flavor and stabiUty. It is higher for tart low Brix musts and less important for sweet high Brix musts. High acid levels coiacide with a higher level of the second acid of grapes, malic acid. [Pg.373]

A measurement of particle moisture content will normally be taken at the exit of the dryer. This allows the process operators to make such adjustments as may be needed to maintain moisture within the desired range. Various instmments are used, none of which are entirely satisfactory, and periodic hand samples are used in some mills. Considering the importance of moisture sensing and control at the dryers, it is unfortunate that a truly efficient, consistent, and accurate sensing system is not yet available to the industry. The primary reasons for the difficulty of measuring moisture at the dryer exit are the extreme and adverse conditions of heat, dust, and moisture present at this location. [Pg.391]


See other pages where CONTENTS importance is mentioned: [Pg.148]    [Pg.244]    [Pg.268]    [Pg.123]    [Pg.599]    [Pg.391]    [Pg.494]    [Pg.148]    [Pg.244]    [Pg.268]    [Pg.123]    [Pg.599]    [Pg.391]    [Pg.494]    [Pg.30]    [Pg.2527]    [Pg.2845]    [Pg.116]    [Pg.116]    [Pg.138]    [Pg.243]    [Pg.327]    [Pg.475]    [Pg.354]    [Pg.355]    [Pg.365]    [Pg.369]    [Pg.393]    [Pg.143]   
See also in sourсe #XX -- [ Pg.97 , Pg.236 , Pg.268 ]




SEARCH



© 2024 chempedia.info