Heavy metal contamination of natural rivers and wastewaters is a problem for both the environment and human society. The accumulation and adsorption of heavy metals could happen with several organic and inorganic matters, but the most used adsorbents are (biological and chemical) organic compounds. This review article presents the basics of heavy metal adsorption on several organic surfaces. There are many organic matters, which seem to be useful as agents for heavy metal adsorption. All of the cited authors and articles present the adsorption kinetics by the most used isotherm models (such as Langmuir and Freundlich isotherms). By comparing several research results presented by a pre-selected assortment of papers, we would like to give an overview of the microbiological, organic chemical, and other surface adsorption possibilities. We draw conclusions for two new adsorption fields (adsorption with biosorbent and artificial materials). We present an optional possibility to study adsorption kinetics, efficiency and regeneration methods to successfully conclude the heavy metal treatment process, and we make some recommendations about the efficient water usage calculations using the water allowance coefficient (WAC) indicator.
Expanding the integrand, the general term is ßi 02 cos (kix -ht + 0i) cos (k 2 x -l 2 t + 0 2 ) cos Μ χ in which ki and k 2 may be the same or different. F ue = 0 unless ki ± k 2 ± M = 0 in which case F M caß 1 ß 2 cos[(l l ±l 2 )t + 0] The sign of l 2 is the same as that of k 2 which makes h ± fc 2 ± Af = 0Likewise, if F Me is the coefficient of the M 'th space order sine term in the expansion of F, FusOiß^iSinKh ±l 2 )t + 0] Thus F M α ft & cos ]Mx-(h ± Z 2 ) ί + 0] For M = 1, ΐ. β., with two fields differing by two poles there is a force simulating a mechanically unbalanced rotor revolving with speed h -l 2 tending to displace the rotor or stator as a whole. For M = 2, i. e., with two fields differing by four poles there are forces balanced across any diameter, rotating with speed y% (h -l 2 ) tending to distort the rotor and stator into a rotating ellipse. Also a single two-pole field produces the same kind of force rotating at speed I. Carrying out the sug gested mathematical deduction in detail shows that in this case the proportionality constant is one-half that in the case of two fields with unlike numbers of poles. Similarly, with two fields differing by any number of poles or a single field of half that number of poles the rotating forces tend to deform the stator and rotor into a rotating polygon of like number of sides. Forces are proportional to the product of the absolute values of the offending fields.When the vibration is produced by a single field the noise frequency is twice the frequency of the field. When the force is produced by two fields their frequen cies or direction of rotation must be different to cause noise producing vibrations. With two fields revolving in the same direction the noise frequency is the differ ence in frequencies of the two fields. If the fields re volve in opposite directions l 2 is inherently negative and the noise frequency is the sum of that of the two fields. Since most fields are either exactly or nearly funda mental frequency the most common noise frequency is exactly or nearly double applied line frequency.Synopsis.-The long distance telephone office serves to provide a concentration point for intercity telephone communication from a group of local exchanges, and its size will depend largely upon the number of stations served by the local offices.The Chicago toll office, which serves 1,200,000 stations, recently has been replaced largely with new equipment. This equipment, together with correlated improvements in handling toll service at Chicago, is described in this paper.The work of the toll operator in handling toll calls with the new equipment is compared with the former method.It is this change in operating practise which constitutes a major improvement in long distance service. The paper also includes d description of the toll lines entering Chicago, with their equipment arrangements including telephone repeaters, the power plants required to operate this equipment and that associated with the switchboards.The addendum describes the purpose of the auxilia...
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