The electrochemical behavior of thallium was studied on glassy carbon electrodes in sulfate solutions. Cyclic voltammetry was used to study the kinetics of the electrode processes and to determine the nature of the limiting step of the cathodic reduction of thallium ions. According to the dependence of current on stirring rate and scan rate, this process is diffusion limited. Chronocoulometry showed that the electrodeposition can be performed with a current efficiency of up to 96% in the absence of oxygen.
This paper presents the results of a study of experiments on the sorption characteristics of phosphorus-containing ion exchangers Purolite MTS9580 (functional group ‒ derivatives of phosphonic acid) and Lewatit TP260 (functional group ‒ aminomethylphosphonic acid) on scandium. Using the method of low-temperature nitrogen adsorption, structural characteristics of selected ion exchangers Purolite MTS9580 and Lewatit TP260 respectively were measured. The specific surface of Purolite MTS9580 and Lewatit TP260 ion exchangers was measured as 5.1 and 4.5 m2/g, respectively. The obtained values indicate the presence of a macroporous structure in the ion exchangers. Experiments were carried out on the sorption of scandium and critical impurities in a static mode and dynamic mode while varying the acidity of the initial mother liquor of the sorption of uranium. Comparison of scandium sorption from pre-acidified uranium sorption mother liquor with Lewatit TP260 and Purolite MTS9580 ion exchangers showed an advantage for MTS9580 resin. The MTS9580 resin had an exchange capacity of 200 mg Sc/dm3 versus 59.7 mg Sc/dm3 for TP260. The dynamic exchange capacity of Purolite MTS9580 is much lower in relation to harmful impurities as Al, Fe, Ca, etc.
The article provides data on monthly monitoring of breast pathologies for lactating cows during 2019. Observations were made on a herd of cows of Holstein breed, the cows were kept free during all season. Cows were kept n premises with a workshop structure of industrial milk production. In this farm, milking of cows was carried out three times in milking rooms with the equipment of the company GEA Farm Technologies models “Yalinka” and “Parallel”.
The following six issues were addressed during the monthly monitoring:
determination of the dynamics of indicators characterizing the reproductive status of cows;
- finding out the effect of seasonality on the number of average monthly cow disease for mastitis during the year;
- tracking the degree of disease of cows with mastitis by months after calving lactation;
- determination of the degree of disease of cows with mastitis, depending on the number of their lactation in the farm;
- manifestation of the average monthly number of cow disease for clinical and subclinical mastitis;
- tracking the frequency of each of the four proportion of udders of lactating cows.
The data obtained are summarized in the relevant tables and discussed in the results section of the research, on which the main conclusions are drawn:
- manifestation of breast pathologies in cows varied by season.
The highest was in winter – 14.37%; slightly lower – in summer and autumn (respectively 12.16 and 10.32%); and the lowest (6.41%) – in spring months;
- the highest percentage of udders pathologies of lactating cows was noted in the first, fourth and fifth months of lactation (14.9, 13.7 and 11.43%, respectively);
- the highest percentage of mastitis was observed in young cows from the first to the third lactation (respectively 18.0; 26.4 and 20.7%);
- the clinical form of mastitis most often was observed in winter months (92.1%). In spring, its percentage decreased (up to 72.2%) and increased slightly in summer (up to 83.1%), while in autumn there was a significant reduction of this pathology to 49.9%;
- сonsideration of frequency of impression of each share of udder of cows, shows that the majority of pathologies (57.1%) were found on the posterior lobes.
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