Sources alpha

Beta-glucanase, beta-glucanase (different source), alpha-amylase and bacillolysin... 

Domestic water source Alpha particle activity... 

Alpha-linolenic acid (18 3n-3) is an 18-carbon fatty acid with three double bonds at carbons 9, 12, and 15. It is an essential n-3 fatty acid that is a required nutrient for human beings and can be obtained through diets including both plant and animal sources. Alpha-linolenic acid can be converted by elongases and desaturases to other beneficial n-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosa-hexaenoic acid (DHA), which are implicated in normal brain development, normal vision, and a decreased risk of heart disease. Novel dietary sources of n-3 fatty acids are desired for those who do not consume adequate amounts of fish or fish-based food products rich in long-chain n-3 fatty acids. This section summarized fruit, spice, and herb seed oils rich in a-linolenic acid (18 3n-3). These include black raspberry, red raspberry, boysenberry, marionberry, blueberry, cranberry, sea buckthorn, basil, and hemp seed oils. 

Because almost all alpha radiation is stopped within the solid source and its container, giving up its energy, polonium has attracted attention for uses as a lightweight heat source for thermoelectric power in space satellites. 

Gr. aktis, aktinos, beam or ray). Discovered by Andre Debierne in 1899 and independently by F. Giesel in 1902. Occurs naturally in association with uranium minerals. Actinium-227, a decay product of uranium-235, is a beta emitter with a 21.6-year half-life. Its principal decay products are thorium-227 (18.5-day half-life), radium-223 (11.4-day half-life), and a number of short-lived products including radon, bismuth, polonium, and lead isotopes. In equilibrium with its decay products, it is a powerful source of alpha rays. Actinium metal has been prepared by the reduction of actinium fluoride with lithium vapor at about 1100 to 1300-degrees G. The chemical behavior of actinium is similar to that of the rare earths, particularly lanthanum. Purified actinium comes into equilibrium with its decay products at the end of 185 days, and then decays according to its 21.6-year half-life. It is about 150 times as active as radium, making it of value in the production of neutrons. 

Linear alpha-olefins are the source of the largest volume of ahphatic amine oxides. The olefin reacts with hydrogen bromide in the presence of peroxide catalyst, to yield primary alkyl bromide, which then reacts with dimethylamine to yield the corresponding alkyl dimethyl amine. Fatty alcohols and fatty acids are also used to produce amine oxides (Fig. 1). 

Historically, these sulfonates have been difficult to produce in good quaUty and to formulate into laundry powders because of thermal and hydrolytic stabihty problems. Used basically as an anionic, oleochemically sourced replacement for LAS, FAE sulfonate benefits include good detergency at low concentration, low environmental load, and good supply of high quaUty material (71). To avoid possible thermal stabihty problems, these sulfonates have found apphcation in Hquid products. They are used in at least one U.S. dishwashing Hquid, and the cocoyl derivative, Alpha-Step MC48, is marketed by Stepan Chemical Company. 

Cross-linked PVP can also be obtained by cross-linking the preformed polymer chemically (with persulfates, hydrazine, or peroxides) or with actinic radiation (63). This approach requires a source of free radicals capable of hydrogen abstraction from one or another of the labile hydrogens attached alpha to the pyrrohdone carbonyl or lactam nitrogen. The subsequently formed PVP radical can combine with another such radical to form a cross-link or undergo side reactions such as scission or cyclization (64,65), thus ... 

Radioactivity in environmental waters can originate from both natural and artificial sources. The natural or background radioactivity usuaUy amounts to <100 mBq/L. The development of the nuclear power industry as weU as other industrial and medical uses of radioisotopes (qv) necessitates the deterrnination of gross alpha and beta activity of some water samples. These measurements are relatively inexpensive and are useful for screening samples. The gross alpha or beta activity of an acidified sample is deterrnined after an appropriate volume is evaporated to near dryness, transferred to a flat sample-mounting dish, and evaporated to dryness in an oven at 103—105°C. The amount of original sample taken depends on the amount of residue needed to provide measurable alpha or beta activity. 

Alpha counting is done with an internal proportional counter or a scintiUation counter. Beta counting is carried out with an internal or external proportional gas-flow chamber or an end-window Geiger-MueUer tube. The operating principles and descriptions of various counting instmments are available, as are techniques for determining various radioelements in aqueous solution (20,44). A laboratory manual of radiochemical procedures has been compiled for analysis of specific radionucHdes in drinking water (45). Detector efficiency should be deterrnined with commercially available sources of known activity. 

The carbon—carbon double bond is the distinguishing feature of the butylenes and as such, controls their chemistry. This bond is formed by sp orbitals (a sigma bond and a weaker pi bond). The two carbon atoms plus the four atoms ia the alpha positions therefore He ia a plane. The pi bond which ties over the plane of the atoms acts as a source of electrons ia addition reactions at the double bond. The carbon—carbon bond, acting as a substitute, affects the reactivity of the carbon atoms at the alpha positions through the formation of the aHyUc resonance stmcture. This stmcture can stabilize both positive and... 

R wPrior to World War II, CN was produced mainly from cotton linters because of their higher degree of purity (alpha cellulose >98%). The high purity linters allowed a higher yield and better quaUty product compared to those obtained from less pure wood pulps or other cellulose sources. The development of highly purified chemical-grade wood pulps has allowed this material to be used in the same manner as are linters. 

There are two main sources of Rn to the ocean (1) the decay of sediment-bound "Ra and (2) decay of dissolved "Ra in a water column. Radon can enter the sediment porewater through alpha recoil during decay events. Since radon is chemically inert, it readily diffuses from bottom sediments into overlying waters. The diffusion of radon from sediments to the water column gives rise to the disequilibrium (excess Rn) observed in near-bottom waters. Radon is also continuously being produced in the water column through the decay of dissolved or particulate "Ra. 

Alternatively cellulose is produced from wood via wood pulp. A number of processes are used in which the overall effect is the removal of the bulk of the non-cellulosic matter. The most widely used are the sulphite process, which uses a solution of calcium bisulphite and sulphur dioxide, the soda process using sodium hydroxide and the sulphate process using a solution of sodium hydroxide and sodium sulphide. (The term sulphate process is used since sodium sulphate is the source of the sulphide.) For chemical purposes the sulphite process is most commonly used. As normally prepared these pulps contain about 88-90% alpha-cellulose but this may be increased by alkaline purification and bleaching. 

Source of narrow beam of fast-moving alpha particles... 

Plutonium-239 is used as the energy source for heart pacemakers and space probes. It decays by alpha emission. 

Los Alamos is processing a wide variety of residues, including Pu-Be neutron sources, polystyrene-Pu02-U02 blocks, incinerator ash, Pu-U alloys and oxides, Pu-Zr alloys and oxides, Pu-Np alloys and oxides, Pu-Th alloys and oxides, etc. Processes have been developed for these scrap items (see Figure 2), but we need to know more about Pu-Np separations Pu-Th separations oxalate precipitations for both plus 3 and plus 4 valences valence stabilization dissolution methods for high-fired impure oxides in-line alpha monitors to measure extremely low concentrations of Pu and Am in HNO3 solutions and solubility of various mixtures of Pu02 and UO2 under a variety of conditions. 

All reactor-produced plutonium contains a mixture of several plutonium isotopes. The continuous decay of 241pu (14.8 year half-life) is the source of 241/. jhis isotope decays by alpha emission with the simultaneous emission of 60 kilovolt gamma rays in 80% abundance. In order to minimize personnel exposure, this element is removed from the metal prior to fabrication. 

In the normal runs one irradiates the total volume over the leak. Provisions are also made for placing a collimating slit between the leak and the alpha source. The collimating slit was cut in a turret of 6-mm. diameter which screwed onto a leak-carrying cone provided with threads. The slit was elevated over the plane of the leak by unwinding the turret a certain number of revolutions. 

However, some of the conditions in the alpha ion source do differ significantly from those in conventional ion-molecule sources. The most important difference is caused by the absence of an electric field and the mode of sampling. Positive and negative particles are carried out by mass flow. Therefore it is necessary to understand the reaction and sampling conditions at least qualitatively. For this reason we are devoting this section to a description of the conditions and a discussion of some experiments which were done specifically to obtain a better understanding of the sample prehistory. 

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