star shaped polymers: a model for the conformation and its concentration dependence

a model giving the conformation of a star shaped polymer is proposed by taking into account the radial variation of the monomer concentration $phi$ (r). for an isolated star when increasing r (at the center of the star r $equals$ 0), the variation of $phi$ (r) is first given by a constant value (r $less than$ f**1**/**2 l) then has a (r/1..

behavior of cellulose graft copolymer towards persulphate oxidation - 3. poly(acrylonitrile) graft copolymers

in the reported experiments, cotton cellulose was graft copolymerized with poly(acrylonitrile) to different levels. the copolymers so obtained together with the nongrafted cellulose were oxidized at different ph's (4-10) and temperatures (50-70 $degree$ c) with potassium persulfate. the oxidation reaction was studied with respect to oxyge..

characterization of cotton-polystyrene graft copolymers

characterization of cotton-polystyrene graft copolymers prepared by ceric ion initiation is reported. various techniques studied include moisture sorption, solubility in cupriethylenediamine (ced), infrared spectra, differential thermal analysis (dta), electron micrographs and x-ray diffractograms, which point to the existence of true gra..

change in the chemical composition of the wax during the oxidation of peat

it is known that the bitumens of coals take an active part in the oxidation process. in the action of oxidizing agents on peat, oxidation of the resinous and asphaltenic compounds takes place, as a result of which a bleached wax is extracted. the present investigation was devoted to the influence of the depth of oxidation of peat with nit..

effects of molasses, summer emulsifiable oil concentrate, crude cotton seed oil, and glycerin on the residual life of sulprofos on cotton

the paper reports on a study to find a readily available and economical material that will increase the residual life and hence, efficacy, of a short-lived organophosphate by at least 24 h. the four spray additives chosen were molasses, summer emulsifiable oil concentrate, crude cotton seed oil, and glycerin. these were mixed with sulprof..

itt 1240 digital exchange architecture

the distributed control architecture of the itt 1240 digital exchange has been designed to improve exchange flexibility, utilize advanced component technology, and overcome the limitations of central control systems. conceptually simple, it consists of a number of autonomous terminal modules - each with its own microprocessor - connected ..

nowe technologie plytek drukowanych. $left bracket$ new technologies in the manufacture of printed circuit boards $right bracket$

results of studies in poland towards developing new production methods are reported. a new plating technique, using operating baths, is discussed. features of additive methods, as well as semiadditive methods, are described, along with a lamination technique for rigid-flexible printed boards. in polish

rechnerkonzept mit einchip-computer-praktische anwendung $left bracket$ computer concept with single-chip computer - practical application $right bracket$

a compact computer based on the use of one single-chip module type 8048 is reported. this computer is particularly useful for control and measurement applications. the computer can be extended by the addition of a p/c board. some practical aspects are pointed out. 2 refs. in german

cad-entwurf von leiterplatten steigert produktivitaet. $left bracket$ computer aided design of printed circuit boards increases productivity $right bracket$

a cost analysis is presented of a given p/c board. a comparison is made of the economic efficiency of manual and computer-aided design (cad) methods. it is pointed out that the use of cad over a period of four years results in considerable savings of money. depreciation aspects are also considered. 1 ref. in german

measurement of the magnetic birefringence in oxygen and nitrogen gases

the cotton-mouton constant for oxygen and nitrogen was measured at room temperature and pressure using a laser with $lambda$ $equals$ 514. 5 nm. 9 refs