Cause of Damage and Failures in Silo Structures

Silos are special structures subjected to many different unconventional loading conditions, which result in unusual failure modes. Failure of a silo can be devastating as it can result in loss of the container, contamination of the material it contains, loss of material, cleanup, replacement costs, environmental damage, and possible injury or loss of life. Silo damage and failures that occurred in different regions of the world are presented in the paper using illustrative photos. Also provided are a review and discussion of the common or spectacular silo failures due to explosion and bursting, asymmetrical loads created during filling or discharging, large and nonuniform soil pressure, corrosion of metal silos, deterioration of concrete silos due to silage acids, internal structural collapse, and thermal ratcheting. Silo damage and failures from several earthquakes are also presented.     

EFFECT OF ELECTRONIC IRRADIATION IN THE PRODUCTION OF NbSe2 NANOTUBES

In this work, we report the production of NbSe₂ (niobium diselenide) nanotubes formed by irradiating NbSe₂ with high doses of electron irradiation. The apparatus used for the irradiation was a 2 MeV Van de Graaff accelerator at the following conditions: voltage 1.3 MeV, current 5 μA, dose rate 25 kGy/min, and total dosage 1000 kGy. These conditions were maintained fixed while irradiation dosage was changed between 100, 250 and 500 Mrad. We observed enormous and very well defined nanotubes with a length of several nm and width of a few nm, which are hollow and capped at one end. As the level of irradiation is increased to 500 Mrad, onion-like structures were observed.     

WSe2 Nanotubes: Their Formation by Electron Irradiation

The discovery of multi-walled carbon nanotubes¹ and single-walled carbon nanotubes² has prompted numerous studies of the structure, properties^3,4, and potential applications^5,6of these materials. For example, nanotubes are expected to have a high strength-to-weight ratio⁶, which is advantageous in advanced composites to be used in high performance materials such as aircraft frames. The small dimensions of the tubes show promise for use as a gas absorption medium⁷, a field emitter for use in flat-panel displays⁸, and nanoscale electronic devices⁹.     

The Effect of B Addition on the Microstructural and Mechanical Properties of FeNiCoCrCu High Entropy Alloys

High-entropy alloys (HEAs) are a new class of alloys having equiatomic ratios of alloying elements in their composition. Boron is an important element that can increase the strength of steels and wear resistance of hard facing coatings with its high hardness compounds. The effect of boron (B) in FeNiCoCrCu-based HEAs has not been studied in detail to date. In the current study, the microstructural and mechanical properties of FeNiCoCrCuB_x HEAs with varying boron contents (x = 1, 2, 3, 4, 5 at. pct) were investigated using specimens prepared by two-stage processing (sintering and vacuum arc melting). Microstructural and structural studies were carried out using optical microscopy, scanning electron microscopy, electron probe microanalysis, X-ray diffraction, and differential scanning calorimetry. Vickers microhardness and three-point bending tests were also performed to observe the variations in mechanical properties. Results showed that the microstructures of HEAs are generally dendritic and contain two different FCC phases, i.e., Fe-Ni-Co-Cr-rich dendritic and Cu-rich interdendritic phases. The hardness values increased with increasing B content with a maximum hardness of 337 HV. According to three-point bending test results, the highest strength of about 1900 MPa and good ductility were obtained with HEA-3 (3 at. pct B).

     

Preparation of nanoclay incorporated PAN fibers by electrospinning technique and its application for oil and organic solvent absorption

In this work, polymer nanofibers (PAN/n-OMMT clay) were successfully produced by using an electrospinning process. The PAN/n-OMMT nanofibers were studied as an oil and solvent absorbent material due to their super hydrophobicity and super oleophilic properties. The generated composite nanofibers were found to have a very high oil and solvent absorption capacity in the case of 3% n-OMMT clay loading. It showed excellent absorption capacity up to 160 times its own weight for motor oil. The findings reported in this work might provide a fast and facile approach for the removal of oils and organic solvents on water surfaces.     

Investigation of the hydrogen production of a laser FUSION driver thorium breeder using various coolants

In this present work, hydrogen production and neutronic calculations of a Laser Inertial Confinement Fusion Fission Energy (LIFE) driven thorium breeder using various coolants have been investigated. In the neutronic calculations for fusion driver power of 500 MW_th has been examined with MCNP code. The 95 vol% Flibe or natural lithium 5 vol% TRISO coated ThC fuels have used in the neutronic calculations. Tritium breeding ratio (TBR) has been calculated as 1.08 and 1.19, respectively, for Flibe and natural lithium coolants. The energy multiplication values have been computed as 3.17 and 1.62, respectively, for these coolants. The burnup values with flibe and natural lithium have been obtained as 6 GWd/tM and 22 GWd/tM over 11 and 23 years, respectively. Also, the hydrogen production of a laser fusion driver thorium breeder using steam methane reforming (SMR), high temperature electrolysis (HTE) and sulfur-iodine (S–I) thermochemical water splitting processes have been performed. The highest hydrogen production values with flibe coolant of SMR method have been obtained as ~200 kg/s over 11 years.     

First-Principles Calculations of Structural,Electronic, Optical,and Thermoelectric Properties of LuNiBi and LuNiSb Half-Heusler

Journal of Superconductivity and Novel Magnetism - The structural, electronic, optical, and thermo-electric properties of LuNiBi and LuNiSb Half-Heusler have been studied using a full potential...     

Properties of spray-dried food flavours microencapsulated with two-layered membranes: Roles of interfacial interactions and water

Engineering the interface of oil-in-water emulsion droplets with biopolymers that modify its permeability could provide a novel technique to improve flavour retention in dry powders. The objective of this study was to determine if volatile compounds were more retained in dry emulsions stabilized by pea protein isolate (PPI)/pectin complex than that stabilized by PPI alone. The retention of ethyl esters during spray-drying increased with decreasing volatility of the encapsulated compound and ranged from 28% to 40%. The addition of pectin to feed emulsions was quite effective in markedly improving the retention of the three studied flavour compounds. In our previous work (Gharsallaoui et al., 2010), we showed that pectin was able to improve physical integrity of emulsion oil droplets during spray-drying. However, the pectin positive effect on both the droplet stability and the flavour retention at the time of spray-drying can also be explained by a protein molecular structure protective effect. Indeed, the obtained FTIR results showed that pectin was able to preserve the β-sheet secondary structure of pea protein when pea globulins/pectin complexes are heated. The study of the release characteristics of a flavour compound from dried powders showed that pectin addition did not affect the release profile mainly accomplished by the diffusion mechanism.     

Optimization of cutting parameters on drill bit temperature in drilling by Taguchi method

In this study, the optimization of the cutting parameters on drill bit temperature in drilling was performed. Al 7075 work piece and the uncoated and Firex® coated carbide drills in the experimental were used. The optimization of the cutting parameters was evaluated by Taguchi method. The control factors were considered as the cutting speed, feed rate and cutting tool. Taguchi method was used to determining the settings of cutting parameters. The L₁₈ orthogonal array was used in experimental planning. The most significant control factors affected on drill bit temperature measurements was obtained by using analysis of variance (ANOVA). Taguchi design method exhibit a good performance in the optimization of cutting parameters on drill bit temperature measurements. In addition, the empirical equations of drill bit temperatures were derived by using regression analysis. The obtained equations results compared with the drill bit temperature measurement results. The empirical equations results indicated a good agreement with experimental results.