scholarly journals Investigation of the Structural Changes and Catalytic Properties of FeNi Nanostructures as a Result of Exposure to Gamma Radiation

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 254
Author(s):  
Daryn B. Borgekov ◽  
Maxim V. Zdorovets ◽  
Dmitriy I. Shlimas ◽  
Artem L. Kozlovskiy

The paper presents the results of changes in the structural characteristics, and the degree of texturing of FeNi nanostructures close in composition to permalloy compounds as a result of directed modification by gamma radiation with an energy of 1.35 MeV and doses from 100 to 500 kGy. The choices of energy and radiation doses were due to the need to modify the structural properties, which consisted of annealing the point defects that occurred during the synthesis along the entire length of the nanotubes. The initial FeNi nanostructures were polycrystalline nanotubes of anisotropic crystallite orientation, obtained by electrochemical deposition. The study found that exposure to gamma rays led to fewer defects in the structure, and reorientation of crystallites, and at doses above 300 kGy, the presence of one selected texture direction (111) in the structure. During tests of the corrosion resistance of synthesized and modified nanostructures in a PBS solution at various temperatures, it was found that exposure to gamma rays led to a significant decrease in the rate of degradation of nanotubes and an increase in the potential life of up to 20 days. It was established that at the first stage of testing, the degradation of nanostructures is accompanied by the formation of oxide inclusions, which subsequently lead to the formation of pitting corrosion and subsequent partial or complete destruction of the nanostructures. It is shown that gamma radiation is promising not only for targeted modification of nanostructures and increasing resistance to degradation, but also for increasing the rate of catalytic reactions of the PNA-PPD type.

1999 ◽  
Vol 41 (6) ◽  
pp. 371-374 ◽  
Author(s):  
Elaine Barros da Costa CARVALHO ◽  
Ana Maria Mendonça de Albuquerque MELO ◽  
Mauricy Alves da MOTTA

The variation of resistance to 60Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose) to increasing doses of gamma radiation. Doses of 10, 20, 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell 60Co irradiator, were applied to the test groups and two groups control (non-irradiated) of snails - isolated and colony - were kept apart. After have been exposed, the snails were drew back to the aquaria where they were maintained before. The survival was estimated on a daily score of the alive animals in each group-dose, starting after the irradiation exposure day. As a result, the survival self-fertilization forms (DL50/30 = 218.2 Gy) was found greater than in cross-fecundation forms. These data point to a low radio-resistance on the cross-fertilization forms - the sexual reproductive form - which is most found in nature. The lower radio-resistance of the cross-fertilization forms suggests the presence of some sex-linked hormonal factor related to this phenomenon.


2012 ◽  
Vol 11 (7) ◽  
pp. 1355-1360
Author(s):  
Clement Ionescu ◽  
Liana Simona Sbirna ◽  
Monica Daniela Mateescu ◽  
Clementina Sabina Moldovan ◽  
Sebastian Sbirna

2013 ◽  
Vol 443 (1-3) ◽  
pp. 417-423 ◽  
Author(s):  
E. Ordóñez-Regil ◽  
A. Contreras-Ramírez ◽  
S.M. Fernández-Valverde ◽  
P.R. González-Martínez ◽  
H. Carrasco-Ábrego

2014 ◽  
Vol 77 (10) ◽  
pp. 1768-1772 ◽  
Author(s):  
ANA CAROLINA B. REZENDE ◽  
MARIA CRYSTINA IGARASHI ◽  
MARIA TERESA DESTRO ◽  
BERNADETTE D. G. M. FRANCO ◽  
MARIZA LANDGRAF

This study evaluated the effects of irradiation on the reduction of Shiga toxin–producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10-values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.


2013 ◽  
Vol 58 (4) ◽  
pp. 1331-1336 ◽  
Author(s):  
J. Berdowski ◽  
S. Berdowska ◽  
F. Aubry

Abstract The purpose of this paper was to investigate the physical and mechanical properties of compressed expanded graphite (CEG) and their porous derivatives after impregnation, polymerization; and carbonization by the use of acoustic emission method (AE). The mechanical and structural characteristics of compressed expanded graphite and their three groups of porous composites after each technological process are presented and discussed. The measurements of acoustic emission parameters in these materials were carried out at wide range of frequency of the waves (0.1÷2.5 MHz). The changes of two of parameters: - AE pulses counts rate and spectrum distribution of AE waves - are presented in this paper. The analysis of the respective parameters AE also gives possibility to determine the micro- and macro structural changes of materials at different levels of technological processes. Applications of these materials as catalysts with high specific surface make them very interesting subject of study. Also compressed expanded graphite composite membranes prepared from furfuryl alcohol polymers are promising for gas separation.


2019 ◽  
Vol 11 (3) ◽  
pp. 471-488 ◽  
Author(s):  
Liu Shouying

Purpose The purpose of this paper is to analyze the structure and changes of China’s land system. To achieve this aim, the paper is divided into four parts. The first part gives a brief introduction to the structural characteristics of the Chinese land institutional arrangements; the second part analyzes the reform process of the land system in the past 40 years and its path of change; the third part engages the discussion about the historic contribution made by the land institutional change to rapid economic growth and structural changes; and the final part is conclusion and some policy implications. Design/methodology/approach After 40 years of reforms and opening up, China has not only created a growth miracle unparalleled for any major country in human history, but also transformed itself from a rural to an urban society. Behind this great transformation is a systemic reform in land institutions. Rural land institutions went from collectively owned to household responsibility system, thereby protecting farmers’ land rights. This process resulted in long-term sustainable growth in China’s agriculture, a massive rural-urban migration and a historical agricultural transformation. The conversion of agricultural land to non-agricultural uses and the introduction of market mechanisms made land a policy tool in driving high economic growth, industrialization and urbanization. Findings Research shows that the role of land and its relationship with the economy will inevitably change as China’s economy enters a new stage of medium-to-high speed growth. With economic restructuring, low-cost industrial land will be less effective. Urbanization is also shifting from rapid expansion to endogenous growth so that returns on land capitalization will decrease and risks will increase. Therefore, China must abandon land-dependent growth model through deepening land reforms and adapt a new pattern of economic development. Originality/value This paper gives a brief introduction to the structural characteristics of the Chinese land institutional arrangements, analyzes the reform process of the land system in the past 40 years and its path of change, and evaluates the historic contribution made by the land institutional change to rapid economic growth and structural changes.


1964 ◽  
Vol 44 (2) ◽  
pp. 188-194 ◽  
Author(s):  
H. B. Heeney ◽  
W. M. Rutherford ◽  
K. F. MacQueen

The effects of gamma radiation doses of 110,000, 220,000, and 330,000 rad on the storage life and quality of two varieties of strawberries stored at 40°, 55°, and 70° F were studied. Results indicated that a dose of 330,000 rad prevented fungal development of the Redcoat variety stored for 26 days at 40° F. The fungal-free period was sharply reduced at lower radiation doses or at higher storage temperatures. Under the conditions of this trial there was no apparent effect of radiation on appearance or texture of fruit.In organoleptic tests in the first two weeks of storage observers were not able to differentiate between radiation treatments. There was some preference for treated berries as the storage period increased. After 20 days the flavor of the fruit deteriorated very rapidly and it soon became commercially unacceptable.


2013 ◽  
Vol 35 (2) ◽  
pp. 277-283
Author(s):  
A. Wosińska

Studies were undertaken on the effect of different doses of gamma radiation on survival rate of plants (germinated from irradiated seeds) for 5 China aster varieties specified at florescence time. During their growth under field conditions (from planting time to blooming) lethal effect of the radiation occurred in plants of all varieties and its level depended on dose and variety. Effect of 3 kR and 6 kR doses differed depending on variety and was not always harmful, but following irradiation with doses exceeding 6 kR a considerable decrease in survival rate was observed. Radioresistance of studied varieties - measured both: by LD<sub>50</sub> and LD<sub>l00</sub> - differed; depending on variety, LD<sub>50 </sub>and LD<sub>l00</sub> values fluctuated: from 6 to 9 kR and 12 to 15 kR respectively.


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