Erosion caused by external factors such as wind, rain, sunlight and temperature changes is considerable in raw materials used
to build pre-hispanic monuments. However, there does exist an internal destruction factor even stronger: the humidity coming
from the soil, which goes up by capillarity, depositing soluble salts on the walls surface. Therefore, one way to find some
figure related to the specific capillarity or porosity shown by each raw material, is to obtain small prism-shaped pieces
cut out from the large debris fallen down spontaneously from ancient walls due to internal humidity. Once these small samples
are placed in contact with a 22Na labeled solution during a given time, at the same geometrical conditions, dried overnight, conditioned either in test tubes
or wrapped into polyethylene and detected in a well type 3″×3″ scintillation detector, the counts accumulated per time and
weight units are a measure of the relative porosity shown by each material. In order to pull down this porosity, the samples
are impregnated with a gelatin solution (50 g/l) at 60–80 °C plus food preservatives such as potassium sorbate (2.5%) and
sodium benzoate (2.5%). When gelatin begins to be formed 3 hours later and the samples look humid and brilliant, they are
impregnated with formaldehyde solution (38%), and their absorption rate is dramatically reduced overnight (75–100%), which
can be proven when samples are tested by making use of the 22Na labeled solution. This technique has been applied at real scale in some pre-hispanic monuments. Ancient raw materials seems
to be much more compact and well preserved during one limited period of time (10 to 13 months). Treatment is unnoticeable
and reversible, and it may be applied periodically.
Today’s nuclear curricula have the purpose to fulfil labor requirements of the nuclear market, both power and applications,
as well as keeping up the academic level required for research and development in nuclear sciences. This work analyses the
power and applications markets and the situation of nuclear education in several countries, including Mexico, as well as collective
efforts promoted by the International Atomic Energy Agency (IAEA) and other organizations. Conclusions are obtained about
the status and trends in nuclear education, emphasizing the role of the academic and users sectors to fit the future demand
and the availability of skilled personnel.
During the past two decades, Thermally Stimulated Creep Recovery (TSCR) has been used successfully to study molecular mobility in polymers. The main feature of this technique is its quite good sensitiveness: the sample undergoes a shear stress, so that the subsequent strain is linear in a range larger than in elongation or compression experiments. Furthermore, the low equivalent frequency of TSCR permits the resolution of normally overlapping peaks.
Guadiana River Chalcolithic middle basin (Badajoz, Spain) pottery was
in many cases decorated with bone, which suffers a hydroxyapatite to β
tri-calcium phosphate transformation while firing. The evolution of physico-chemical
characteristics of bone decorations and experimentally heated fossil bone
as a function of temperature through 1) major XRD planes, and 2) OH librational
mode at 630 cm–1 in the FTIR spectra let
us establish a correlation between the physico-chemical features and firing
temperature, allowing the estimate of firing temperatures for bone decorated
pottery. What is a reliable criterion to differentiate over potters behavior
and skill during the pottery production.
This paper shows the result of soil-plant relation in samples from Cuban sugar canes of different soil types and cane varieties, using INAA from a thermal reactor. The behavior of minor and trace elements in sugar cane leaves is unifor and independent of sugar cane variety of type of soil. The soil-plant relation shows four principal groups of micro elements, according to their absorption by the plant.
This paper provides the profiling on the ‘relative absorptive capacity of knowledge’ research to provide insights of the field based on data collected from the ISI Web of science database during the years 2001–2010. The analysis is established in three phases, namely, the general publication, the subject area, and the topic profiling. The study obtains patterns, characteristics, and attributes at country, institutions, journals, author, and core reference levels. It shows the increase of the research activity in the field, based on the publication productivity during the years mentioned. Most of these publications are classified in the subject areas of business and economics, engineering, and operations research and management science. We highlight the nascent interest of the computer science subject area as a way to operationalize the different studies conducted. We found a lack of contribution from African and Latin–American countries despite the importance of the field for them. Our results are useful in terms of science strategy, science and technology policy, research agendas, research alliances, and research networks according to the special interest of specific actors at the individual, institutional, and national levels.
After the Chernobyl accident in 1986, Mexico imported from an European country 28,000 tons of contaminated powder milk with
the fission product 137Cs. When the contamination was detected, the alarm among the authorities and population spread out very quickly and of course
the product was retired at once from the foodstuff market. Nevertheless, the public panic grew up in such a manner, that even
the way to manage and to dispose safely this material, considered highly dangerous, was largely discussed. Now, about two
decades ago from this event, a study has been performed to compare the level of radioactivity due to both radioisotopes present
in one saved sample: the artificial contaminant 137Cs, beside the natural, all around present 40K, in order to evaluate in a more realistic way how risky was the management, possible consumption, and final disposition
of this nourishment. This paper considers results obtained within an uncertainty degree equal to ±5%, and set up conclusions
by comparing artificial and natural radioactivity present in that contaminated powder milk.