Preparation and Thermal/Fast Neutron Shielding Properties of Novel Boron Containing Ore Composites

2013 ◽  
Vol 743-744 ◽  
pp. 613-622 ◽  
Author(s):  
Zhe Fu Li ◽  
Xiang Xin Xue ◽  
Pei Ning Duan ◽  
Ang Tian ◽  
Shu Xian Li ◽  
...  
Keyword(s):  
Fast Neutron ◽  
Cross Section ◽  
Atomic Number ◽  
Absorbed Dose ◽  
Neutron Shielding ◽  
Factors Affecting ◽  
Average Atomic Number ◽  
Shielding Properties ◽  
Relationship Of ◽  
The Relationship

Four novel boron containing ores/epoxy composites were prepared by using nature ludwigite green ore (NLGO), artificial ores including boron containing iron ore concentrate (BCIOC), boron rich slag (BRS) and boron mud (BM) as neutron absorbers, which were obtained by dressing from NLGO, blast furnace separation from BCIOC and borax production, respectively. The microstructure of the composites was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Shielding properties of the composites against thermal and Cf-252 fast neutron were measured. Factors affecting the shielding properties were investigated. Energy deposition, absorbed dose and half value layers of the composites against neutron penetration were simulated by Monte Carlo method, and a simulated function was obtained. The results showed that the composites were compact and the particles of ores were homogeneous. Ascending boron mole numbers per unit volume (nB) in the composites can obviously enhance the macroscopic absorbing cross section (Σthermal) and improve the shielding properties for thermal neutron. The relationship of Σthermal and nB follows the equation of Σthermal=0.218+450.490nB. And the relationship of average atomic number (Z) of boron containing ores composites and the macroscopic removal cross section for fast neutron follows the equation of Σremoval=0.042exp (-Z/5.70)+0.032. Enhancement of the shielding abilities against Cf-252 fast neutron can be achieved by using the composites with low average atomic number.

Development of SiO2 based doped with LiF, Cr2O3, CoO4 and B2O3 glasses for gamma and fast neutron shielding

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Bünyamin Aygün ◽  
Erdem Şakar ◽  
Abdulhalik Karabulut ◽  
Bünyamin Alım ◽  
Mohammed I. Sayyed ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Fast Neutron ◽  
Cross Sections ◽  
Gamma Ray ◽  
Absorbed Dose ◽  
Neutron Shielding ◽  
Shielding Properties ◽  
Effective Neutron ◽  
Simulation Codes

AbstractIn this study, the fast neutron and gamma-ray absorption capacities of the new glasses have been investigated, which are obtained by doping CoO,CdWO4,Bi2O3, Cr2O3, ZnO, LiF,B2O3 and PbO compounds to SiO2 based glasses. GEANT4 and FLUKA Monte Carlo simulation codes have been used in the planning of the samples. The glasses were produced using a well-known melt-quenching technique. The effective neutron removal cross-sections, mean free paths, half-value layer, and transmission numbers of the fabricated glasses have been calculated through both GEANT4 and FLUKA Monte Carlo simulation codes. Experimental neutron absorbed dose measurements have been carried out. It was found that GS4 glass has the best neutron protection capacity among the produced glasses. In addition to neutron shielding properties, the gamma-ray attenuation capacities, were calculated using newly developed Phy-X/PSD software. The gamma-ray shielding properties of GS1 and GS2 are found to be equivalent to Pb-based glass.

Optimization Analysis of the Wedge Block Surface of NYD Contact Backstop

2013 ◽  
Vol 433-435 ◽  
pp. 2277-2281
Author(s):  
Quan Wei Wang ◽  
Ming Hui Wang ◽  
Dong Li ◽  
Dian Mao Wan ◽  
Rong Meng
Keyword(s):  
Cross Section ◽  
Design Parameters ◽  
Optimization Analysis ◽  
Archimedes Spiral ◽  
The Cross ◽  
Section Curve ◽  
Relationship Of ◽  
The Relationship

By analyzing the relationship of the design parameters of NYD contact backstop, the cross-section curve of the wedge block has been discussed as Archimedes spiral, logarithm spiral and arc. Each curve is designed optimally using MATLAB optimization toolbox. The merits and drawbacks of each curve are discussed.

scholarly journals 86 Factors affecting beef calf vigor at birth: Dam peripartum body condition score, calving season, and calf size

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 3-3
Author(s):  
Lindsey G Wichman ◽  
Colby A Redifer ◽  
Natalie B Duncan ◽  
Craig A Payne ◽  
Allison M Meyer
Keyword(s):  
Mixed Model ◽  
Body Condition Score ◽  
Negative Relationship ◽  
Beef Cows ◽  
Abdominal Girth ◽  
Factors Affecting ◽  
Condition Score ◽  
Calving Season ◽  
Relationship Of ◽  
The Relationship

Abstract To determine effects of cow BCS and calving season on calf vigor and size and the relationship of calf size with vigor, 310 multiparous and primiparous beef cows (age: 4.6 ± 2.2 yr; BW: 663 ± 86 kg; BCS: 5.3 ± 0.6) from 3 spring (2015, 2016, 2017) and 4 fall (2015, 2017, 2018, 2019) calving seasons were observed during parturition. Time to stand (n = 191) was determined as minutes from birth to standing successfully for 5 sec. Within 24 h, calf BW (n = 187) and size [shoulder to tailhead length (STL), heart girth (HG), and abdominal girth (AG; n = 154)] were recorded. Data were analyzed using a mixed model containing effects of calving season (spring and fall), BCS category (< 5, =5, ≥6), and their interaction. Correlations were determined between time to stand and calf measurements separately for spring (n = 79) versus fall (n = 111). Cows with BCS < 5 gave birth to lighter (P = 0.02) calves that tended to have a faster (P ≤ 0.13) time to stand than =5 and ≥6. Calves from cows with BCS ≥6 tended to have greater (P ≤ 0.09) STL than =5 and < 5. Calves from cows with BCS < 5 had smaller (P = 0.13) HG than =5. Fall-born calves tended to have smaller (P ≤ 0.06) BW, HG, and AG than spring-born calves. Within fall calves, there tended to be a positive relationship (r = 0.16; P = 0.09) between time to stand and calf BW. Despite this, spring calves had a negative relationship (r = -0.26; P = 0.02) between time to stand and calf BW. In conclusion, cow BCS and calving season affect calf size and may affect calf vigor. These data suggest that calving season may dictate the relationship between calf vigor and size.

scholarly journals A STUDY OF FACTORS AFFECTING THE FLUIDITY OF CEMENT

2019 ◽  
pp. 8-16
Author(s):  
Л. Шахова ◽  
L. Shakhova ◽  
Е. Черноситова ◽  
E. Chernositova ◽  
Л. Щелокова ◽  
...  
Keyword(s):  
Labor Costs ◽  
Factors Affecting ◽  
Correlation And Regression Analysis ◽  
Cement Powder ◽  
Production Factors ◽  
Variable Factor ◽  
Cement Binder ◽  
Cement Grinding ◽  
Relationship Of ◽  
The Relationship

The fluidity of cement powder has a significant impact on the duration and labor costs in the process of transportation and shipment of cement. This determines the relevance of the task of finding mechanisms to control this parameter. During the production process, the fluidity of the cement powder is formed depending on the properties of the initial cement charge, the requirements for the thinness of the grinding to the finished product, the hardware design and the conditions of the process. In turn, the fluidity of cement affects the grinding process and the productivity of the mill. The rheological characteristics of the cement binder change over time depending on the physical properties of the material, environmental conditions and the equipment used for its storage. The reasons for the deterioration of the flow of cement powder is still not fully studied. The article is devoted to the study of the main factors affecting the fluidity of cement. The results of the statistical analysis of cement fluidity depending on the thinness of cement grinding (on the residue on the sieve №008 and the specific surface area by Blaine method) humidity, bulk weight and weight in the most compacted state. In addition, the relationship of production factors and cement fluidity is considered. Correlation and regression analysis shows that the fluidity is affected by a variable factor, which is not yet quantified.

The Relationship of Previous Breastfeeding Experiences and Factors Affecting Breastfeeding Rates: A Follow-Up Study

2020 ◽  
Vol 15 (12) ◽  
pp. 789-797
Author(s):  
Jun-Yan Li ◽  
Yi Huang ◽  
Hao-Qi Liu ◽  
Jing Xu ◽  
Lu Li ◽  
...  
Keyword(s):  
Factors Affecting ◽  
Follow Up Study ◽  
Breastfeeding Rates ◽  
Relationship Of ◽  
The Relationship

scholarly journals Issues of wind mode visualization and pedestrian comfort assessment when designing residential buildings on sloping territories in the Arctic zone

2019 ◽  
Vol 64 ◽  
pp. 03013 ◽  
Author(s):  
Ilya V. Dunichkin ◽  
Emanuele Naboni ◽  
Anna E. Korobeinikova ◽  
Olga I. Poddaeva
Keyword(s):  
Urban Areas ◽  
Residential Buildings ◽  
The Arctic ◽  
Wind Regime ◽  
Local Climate ◽  
Factors Affecting ◽  
Aerodynamic Roughness ◽  
The Stability ◽  
Relationship Of ◽  
The Relationship

Subject of research: visualization of the wind regime of residential buildings on the slope area in the Arctic. Goals: the purpose of the study is to identify the problems of visualization of the wind regime on the slopes and the analysis of patterns of airflow around the sloping territories, affecting the comfort of pedestrians. Materials and methods: airflow patterns of slope areas with different characteristics and comfort assessment for humans are analyzed in the course of work. Geotechnical methods are presented in solving the problems of wind erosion and the stability of hillsides and complex terrain within the city limits. Results: The importance and novelty of the research in studying the relationship of slope geometry and environmental quality, as a decrease in comfort inevitably leads to a decrease in the development of nearby urban areas in settlements on the coast of the Arctic Ocean, problems with climate and local climate, as well as a decrease in the quality of life of people. The article considers the relationship of plastic relief with the aeration regime of the territory, the dependence of aerodynamic roughness on their height, features of aeration of the slope and hilly terrain, factors affecting the direction and speed of the wind and methods for studying the aeration regime of slope areas. Findings: The possibilities of applying existing approaches to research and visualization for slope areas are demonstrated. The direction of development of the technique for visualization of slope areas has been determined.

Chondrilla juncea L. in Australia. I. Some factors affecting flowering

1966 ◽  
Vol 17 (4) ◽  
pp. 457 ◽  
Author(s):  
EG Cuthbertson
Keyword(s):  
Dark Period ◽  
Critical Factor ◽  
Photoperiodic Response ◽  
Day Length ◽  
Floral Initiation ◽  
Factors Affecting ◽  
Two Stages ◽  
Relationship Of ◽  
The Relationship ◽  
Chondrilla Juncea

The interaction between day length and vernalization, and the influence of growth temperature on flowering, in Chondrilla juncea L. (skeleton weed) have been studied. Bolting and floral initiation in unvernalized plants were suppressed in a 9-hr photoperiod. Increasing the photoperiod beyond 12 hr resulted in progressively earlier bolting and floral initiation, the critical day length being slightly less than 12 hr. Interrupting a 16-hr dark period by 1 hr of low-intensity light near its centre caused some plants to flower. Prior vernalization further accelerated bolting and flowering and reduced the dependence on day length. Vernalization, however, was not an obligate requirement. Post-bolting development was favoured by high temperatures. It was concluded that flowering in skeleton weed occurred in two stages. The first or photo-inductive phase was controlled by at least two partial processes. These were vernalization and a photoperiodic response in which the length of the dark period was the critical factor. The relationship of the flowering processes to the distribution of skeleton weed in Australia is discussed briefly.

The relationship of skin follicle development to growth rate in sheep.

1955 ◽  
Vol 6 (2) ◽  
pp. 308 ◽  
Author(s):  
PG Schinckel
Keyword(s):  
Growth Rate ◽  
Birth Weight ◽  
Growth Conditions ◽  
Considerable Importance ◽  
Follicle Development ◽  
Factors Affecting ◽  
Relationship Of ◽  
The Relationship

Observations are reported on factors affecting the ratio of secondary to primary follicles (SJP) in a flock of Merino sheep.It was found that all follicles were initiated prior to birth but that the number which finally came to maturity (production of fibre) was significantly affected by birth weight and growth from birth to 1 month. Growth at later ages appeared to be unimportant. There was a significant correlation (r = +0.29) between birth weight and log potential S/P at birth. This is interpreted to indicate that while pre-natal growth conditions affect the number of follicles initiated, other factors are also of considerable importance. It is concluded that the larger animals at birth also have a greater total number of primary follicles than smaller animals. It is further concluded that this difference in total primary follicles results primarily from differences in size a t the 90th day of pre-natal life rather than from differences in density a t that time.

A Sacrificial Method for Fabricating Microchannel Accelerated by Galvanic Corrosion

2005 ◽  
Author(s):  
Hongjun Zeng ◽  
Alan Feinerman ◽  
Zhiliang Wan
Keyword(s):  
Cross Section ◽  
Etch Rate ◽  
Galvanic Corrosion ◽  
Channel Width ◽  
Etching Time ◽  
Sem Images ◽  
Sacrificial Material ◽  
Relationship Of ◽  
The Relationship

A metal sacrificial method has been investigated for creation of microchannels by galvanic corrosion in a metal multilayer. To achieve the fastest sacrificial metal combination, different metals and the corresponding etchants are chosen. Channels from 50 μm to 1 μm wide, 0.2 μm high, and 1500 μm long, as well as the channel array is fabricated, using Cr/Cu galvanic metal couple as sacrificial material. The relationship between the etching front vs. the etching time, and the relationship of the etch rate vs. channel width is measured and compared with the etching performance of the single metal. The measurement shows there is approximately 10 times faster etching in the galvanic coupled metals than that in the single metal. SEM images of the channels and channel array made by this method are presented. This method is compatible with the conventional VLSI process, and has the potential for fabricating microchannels with submicron or even nanometer cross section.

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