Concrete of various type have been used extensively for the adequate shielding of the radiological equipment using X and gamma rays. In its basic form, concrete is composed of pieces of inert aggregate held together by hardened cement paste. Dierent concrete types with special cements have been prepared. The linear attenuation coecients of conventional concrete and concrete with supplementary mineral additives (barite and witherite) at dierent gamma energies (Co-60: 1.25 MeV, Cs-137: 0.662 MeV, Ir-192: 0.37 MeV) in narrow beam conditions have been measured. This paper includes some experimental data regarding the inuence of barite and witherite additives on photon attenuation coecients of concrete.
The priσciple τf critical eσergy PCE is a traσsdiscipliσary priσciple that may be used iσ all chapters τf scieσces fτr superpτsitiτσ aσd/τr cumulatiτσ τf differeσt exterσal actiτσs mechaσical, thermal, magσetic, electrical, chemical, etc. It may be used fτr lifetime evaluatiτσ τf eσgiσeeriσg structures, as well as fτr liviσg τrgaσisms, by takiσg iσtτ accτuσt the iσflueσces due tτ pτllutiτσ, due tτ iσterσal deteriτratiτσ, due tτ prelτadiσg τr residual stresses, etc. Iσ this paper, we explaiσ what PCE is, hτw it may be practically used aσd the iσterdepeσdeσces betweeσ the terms cτmprised iσ its geσeral relatiτσ. PCE was applied fτr sτlviσg prτblems τf superpτsitiτσ τf exterσal actiτσs aσd iσterσal deteriτratiτσs iσ the fτllτwiσg chapters τf scieσces mechaσical eσgiσeeriσg, thermτmechaσical-chemical lτadiσgs, multiple pτllutiτσ, medical field aσd viscτelasticity. It was cτmpared with syσergy theτry aσd with catastrτphe theτry.Keywords: Traσsdiscipliσarity, iσterdiscipliσarity, priσciple τf critical eσergy, superpτsi-tiτσ aσd cumulatiτσ τf lτad actiτσs, multiple pτllutiτσ, applicatiτσ iσ medical field, viscτus aσd elastic behaviτur, syσergy
Following the activities developed in a nuclear facility result gaseous and liquid radioactive effluents and radioactive solid waste. All these waste contain radioactive isotopes which are potentially pollutants for the environment. In the same time chemicals are, also, pollutants. According to the legislation, discharging of chemicals and radioactive liquid and gaseous effluents into the environment, should meet the requirements of the unrestricted discharge. However, what happens when several pollutants superpose: only chemical pollutants, or only radioactive pollutants, or chemical and radioactive pollutants? Such problems have been solved in this paper on the basis of the principle of critical energy.
It is analyzed: � the actions whose effects are different stresses that can load a body or the environment; � the superposition problem of two or several loads. On the basis of critical energy principle, a relationship is established, consisting of dimensionless values, for the evaluation the stress state with respect to a value defined as admissible state. The result can be applied to loads superposition in some cases, such as: � solid bodies; � environmental pollution with a single sort of pollutant; � environmental multiple pollution: chemical, radiations and magnetic.
Tritium bonded to electrophilic atoms like O, S, N or halogens can spontaneously exchange places with hydrogen from the water. These tritium species are exchanged even at a very low temperature and have the generic name`labile'. In this paper, a new facility for the removal and quantitative determination of labile tritium is shown. The working principle is as follows: tritium sources are brought in contact with protic solvent, leading to a spontaneous exchange of labile tritium, then the obtained tritiated solvent is extracted by distillation. The new facility was tested for removal eciency of labile tritium from labeled compounds and wastes with dierent compositions.
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