scholarly journals A Powdered Simulant of Triacetone Triperoxide (TATP) for Safe Testing of X-ray Transmission Screening Equipment

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1473
Author(s):  
Mitja Vahčič ◽  
David Anderson ◽  
John Seghers ◽  
Hanne Leys ◽  
Miguel Ruiz Oses ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Bulk Density ◽  
Explosives Detection ◽  
Civil Aviation ◽  
Coverage Factor ◽  
Triacetone Triperoxide ◽  
X Ray ◽  
Detection Systems ◽  
Safety Considerations ◽  
Screening Equipment

Explosives detection systems (EDS) based on X-ray are used at airports to screen baggage for the presence of explosives. Once EDS are installed in airports, however, it can be challenging to test the EDS equipment and verify that it continues to perform at the highest level, because of the impracticality of introducing bulk explosives into civil aviation airports. The problem is particularly acute for sensitive homemade explosives, such as triacetone triperoxide (TATP). This paper describes our work to develop a safe, accurate and stable simulant for TATP for EDS based on X-ray transmission. Bulk quantities of TATP were synthesised and characterised especially for this project, and we describe the unique challenges and safety considerations of collecting this data. Our calculations show that the expanded measurement uncertainty with a coverage factor of k = 2 is 5.7% for bulk density and 1.0% for Zeff at 24 months.

scholarly journals Development of Inert, Polymer-Bonded Simulants for Explosives Detection Systems Based on Transmission X-ray

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4330 ◽  
Author(s):  
Mitja Vahčič ◽  
David Anderson ◽  
Miguel Ruiz Osés ◽  
Grzegorz Rarata ◽  
Gabriela Diaconu
Keyword(s):  
United States ◽  
Effective Atomic Number ◽  
The United States ◽  
Explosives Detection ◽  
Civil Aviation ◽  
X Ray ◽  
Detection Systems ◽  
Wide Range ◽  
Fit For Purpose ◽  
Inert Polymer

Explosives detection systems (EDS) based on X-ray are used at airports to screen baggage for the presence of explosives. In Europe and the United States, EDS equipment is tested extensively by specialist test centres prior to approval for operational use in airports. Once EDS are installed in airports, however, it can be challenging to test the EDS equipment and verify that it continues to perform at the highest level, because of the impracticality of introducing bulk explosives into civil aviation airports. We have developed inert, non-toxic polymer-bonded simulants and validated them against real explosives using EDS equipment. The accuracy of our simulants is within 1% of the target bulk density, and within 2% of the target effective atomic number, and the materials have a stability of at least 4 years, with an uncertainty of 0.5%. The simulants generate alarms in almost 100% of cases on a wide range of commercial EDS models, and we consider the simulants fit for purpose for use during testing of EDS equipment at airports.

scholarly journals Sintering behaviour and microwave dielectric properties of MgO-2B2O3-xwt%BaCu(B2O5)-ywt%H3BO3 ceramics

2021 ◽  
Author(s):  
Haiquan Wang ◽  
Shixuan Li ◽  
Kangguo Wang ◽  
Xiuli Chen ◽  
Huanfu Zhou
Keyword(s):  
Dielectric Properties ◽  
Bulk Density ◽  
Single Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
X Ray Diffraction ◽  
Microwave Dielectrics ◽  
X Ray ◽  
Microwave Dielectric ◽  
Sintering Behaviour

AbstractThis study investigates the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 series ceramics synthesised by solid-state reaction. According to the X-ray diffraction and microstructural analyses, the as-prepared MgO-2B2O3 ceramics possess a single-phase structure with a rod-like morphology. The effects of different quantities of H3BO3 and BaCu(B2O5) (BCB) on the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 ceramics were investigated. Accordingly, the optimal sintering temperature was obtained by adding 30 wt% H3BO3 and 8 wt% BCB. We also reduced the sintering temperature to 825 °C. Furthermore, the addition of 40 wt% H3BO3 and 4 wt% BCB increased the quality factor, permittivity, and temperature coefficient of resonance frequency of MgO-2B2O3 to 44,306 GHz (at 15 GHz), 5.1, and −32 ppm/°C, respectively. These properties make MgO-2B2O3 a viable low-temperature co-fired ceramic with broad applications in microwave dielectrics.

Preparation and Microstructure of Pressureless Sintered Si2ON2-SiC Ceramic

2011 ◽  
Vol 335-336 ◽  
pp. 699-703
Author(s):  
Hui Hui Tan ◽  
Zhu Xing Tang ◽  
Xia Zhao ◽  
He Zhang
Keyword(s):  
Bulk Density ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Nitriding Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effect Of Additives ◽  
Sic Ceramic ◽  
Sintering Method ◽  
Scanning Electron

This paper introduces Si2ON2-SiC ceramic fabricated by pressureless sintering method and studies the effect of additives, nitriding temperatures on bulk density, porosity, phase composition and microstructure. It is discovered that additives MgO, CeO2 can increase the densities of Si2ON2-SiC ceramic apparently, and MgO additive has a better effect than CeO2. Nitriding temperature also is an important factor. The bulk density of the specimen with MgO additive reaches maximum at 1.91 g/cm3 when sintered at 1450 °C, and the bulk density of specimen with CeO2 additive is 1.86 g/cm3 at the same condition while the bulk density of the specimen without additive is only 1.75 g/cSuperscript textm3. The X-ray diffraction and scanning electron microscopy of the specimens show that the amount of Si2ON2 increase with the sintering temperature increase. But when the temperature is higher than 1500 °C the Si2ON2 grains will decompose into Si3N4, and Si2ON2 will vanish at 1550 °C

Use of an air brush to spray dry samples for X-ray powder diffraction

Clay Minerals ◽  
1999 ◽  
Vol 34 (1) ◽  
pp. 127-135 ◽  
Author(s):  
S. Hillier
Keyword(s):  
Bulk Density ◽  
Powder Diffraction ◽  
Marked Improvement ◽  
Smooth Surface ◽  
Preferred Orientation ◽  
Spray Drier ◽  
Spray Dry ◽  
X Ray ◽  
Spray Gun ◽  
Spray Dried

AbstractThe construction and operation of a spray drier is described where the spray is produced using an air brush, essentially a miniature spray gun. The spray-dried products consist of spheres 50–60 µm in diameter and typical product recoveries are 80%, a marked improvement over simple two-nozzle systems. The spray-dried samples are easy to load into XRD powder holders and present a smooth surface and relatively constant bulk density to the X-ray beam. Problems of preferred orientation are effectively eliminated and the resulting X-ray powder patterns are completely reproducible by different operators.

A multi-energy X-ray backscatter system for explosives detection

2013 ◽  
Vol 8 (04) ◽  
pp. P04003-P04003 ◽  
Author(s):  
C Paulus ◽  
J Tabary ◽  
N Billon Pierron ◽  
J -M Dinten ◽  
E Fabiani ◽  
...  
Keyword(s):  
Explosives Detection ◽  
X Ray

X-ray diffraction for explosives detection

2022 ◽  
pp. 315-338
Author(s):  
Joel A. Greenberg ◽  
Joshua Carpenter
Keyword(s):  
Explosives Detection ◽  
X Ray Diffraction ◽  
X Ray

The Influences of Addition of MgCO3 on the Properties of the Magnesia Prepared Using Magnesite

2018 ◽  
Vol 281 ◽  
pp. 230-235
Author(s):  
Wang Nian Zhang ◽  
Li Wang ◽  
Ni Deng
Keyword(s):  
Grain Size ◽  
Bulk Density ◽  
Raw Materials ◽  
Apparent Porosity ◽  
X Ray Diffraction ◽  
Linear Change ◽  
Change Rate ◽  
X Ray ◽  
Before And After ◽  
Calcination Method

Micropowder MgCO3 was added into magnesite as raw materials to prepare magnesia using a two-step calcination method. The sample magnesite was characterized use X-ray diffraction (XRD) and scanning electron microscopy (SEM). Experimental results showed that the sample insulated at 1600° C for 3 hours before and after sintering presented a linear change rate of 15.6 % in the case of without adding micropowder MgCO3, the prepared magnesia had a bulk density of 2.31 g/cm3 and apparent porosity of 32.8 %, while MgO grain size was 3.11 μm. In the case of adding 8 % micropowder MgCO3, the sample magnesite before and after sintering showed a linear change rate of 17.9 %. The bulk density, apparent porosity of prepared magnesia were 2.46 g/cm3 and 28.1 % respectively, while the grain size of MgO was 5.15 mm.

scholarly journals Effect of Sintering Temperature on Property of Low-Density Ceramic Proppant Adding Coal Gangue

2019 ◽  
Vol 26 (1) ◽  
pp. 94-98
Author(s):  
Jianying HAO ◽  
Huilan HAO ◽  
Yunfeng GAO ◽  
Xianjun LI ◽  
Mei QIN ◽  
...  
Keyword(s):  
Solid Waste ◽  
Bulk Density ◽  
Apparent Density ◽  
Sintering Temperature ◽  
Coal Gangue ◽  
Low Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sintering Method ◽  
Waste Coal

Calcined flint clay (45.6 wt.% Al2O3) and solid waste coal gangue were used to prepare low-density ceramic proppant by solid state sintering method. The density and breakage ratio of the ceramic proppant were systematically investigated as a function of sintering temperature. The morphology and phase composition of the ceramic proppant were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the ceramic proppant is composed of rod-like mullite and granular cristobalite. Bulk density and apparent density of the proppant first rise and then slightly decrease with increasing the sintering temperature, while breakage ratios under 35 MPa and 52 MPa pressure gradually decrease and then increase. As the sintering temperature increases up to 1400 °C, the ceramic proppant shows denser microstructure. The proppant sintered at 1400 °C have the best performance with 1.27 g/cm3 of bulk density, 2.79 g/cm3 of apparent density, 3.27 % of breakage ratio under 35 MPa closed pressure and 8.36 % of breakage ratio under 52 MPa closed pressure, which conform to the requirement of low-density ceramic proppant. The addition of solid waste can greatly reduce the preparation cost of the ceramic proppant.

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