Portions of this study have been previously published in the Journal of Radioanalytical and Nuclear Chemistry.3,13 A patent is pending for this method.

Caution: The process outlined here includes the use of radioactive material (e.g., Uranium Nitrate Hexahydrate) and several corrosive substances. Appropriate protective clothing and equipment should be used (including a lab coat, gloves, eye protection, and a fume hood) during sample preparation. In addition, laboratory areas used for this work should be monitored regularly for radioactive contamination.
Note: The chemical compounds needed are listed in Table 1. This formulation was developed by examining previously reported compositional data for trinitite.10 The mass fractions reported here were determined by averaging the mass fractions for several different trinitite samples.10 The &#34;missing&#34; mass (the fractions to not sum to unity) exists to allow for some flexibility when adding fuel, tamper, and other constituents. Our independent analysis of several trinitite samples suggests that quartz is the only mineral phase surviving in trinitite.5 Therefore, quartz is the only mineral included in our Standard Trinitite Formulation (STF). Although relic grains of other minerals have been reported in trinitite,11 these tend to be the exception, rather than the rule. In general, quartz is the only mineral found in the melt glass.10,12 Also, quartz sand is a common component of asphalt and concrete which will be important in the formation of urban nuclear melt glass.
<table fo:keep-together.within-page="1">
	<tbody>
		<tr height="41">
			<td colspan="2" height="41" style="height:42px;width:317px;">Averaged Trinitite Data</td>
			<td colspan="2" style="width:317px;">Standard Trinitite Formulation (STF)</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:159px;">Compound</td>
			<td style="width:159px;">Mass Fraction</td>
			<td style="width:159px;">Compound</td>
			<td style="width:159px;">Mass Fraction</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:159px;">SiO2</td>
			<td style="width:159px;">6.42x10-1</td>
			<td style="width:159px;">SiO2</td>
			<td style="width:159px;">6.42x10-1</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:159px;">Al2O3</td>
			<td style="width:159px;">1.43x10-1</td>
			<td style="width:159px;">Al2O3</td>
			<td style="width:159px;">1.43x10-1</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:159px;">CaO</td>
			<td style="width:159px;">9.64x10-2</td>
			<td style="width:159px;">CaO</td>
			<td style="width:159px;">9.64x10-2</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:159px;">FeO</td>
			<td style="width:159px;">1.97x10-2</td>
			<td style="width:159px;">FeO</td>
			<td style="width:159px;">1.97x10-2</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:159px;">MgO</td>
			<td style="width:159px;">1.15x10-2</td>
			<td style="width:159px;">MgO</td>
			<td style="width:159px;">1.15x10-2</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:159px;">Na2O</td>
			<td style="width:159px;">1.25x10-2</td>
			<td style="width:159px;">Na2O</td>
			<td style="width:159px;">1.25x10-2</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:159px;">K2O</td>
			<td style="width:159px;">5.13x10-2</td>
			<td style="width:159px;">KOH</td>
			<td style="width:159px;">6.12x10-2</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:159px;">MnO</td>
			<td style="width:159px;">5.05x10-4</td>
			<td style="width:159px;">MnO</td>
			<td style="width:159px;">5.05x10-4</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:159px;">TiO2</td>
			<td style="width:159px;">4.27x10-3</td>
			<td style="width:159px;">TiO2</td>
			<td style="width:159px;">4.27x10-3</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:159px;">Total</td>
			<td style="width:159px;">9.81x10-1</td>
			<td style="width:159px;">Total</td>
			<td style="width:159px;">9.91x10-1</td>
		</tr>
	</tbody>
</table>
Table 1. List of chemical compounds.
1. Preparation of the STF
Note: Equipment needed includes a microbalance, metal spatulas, a ceramic mortar and pestle, a chemical fume hood, latex gloves, a lab coat, and eye protection.
<ol>
	<li>Mixing of non-radioactive components
	<ol>
		<li>Acquire at least 65 g of quartz sand (SiO2), 15 g of Al2O3 powder, 10 g of CaO powder, 2 g of FeO powder, 2 g of MgO powder, 2 g of Na2O powder, 7 g of KOH pellets, 1 g of MnO powder and 1 g of TiO2 powder (compounds listed in Table 1).</li>
		<li>Use a microbalance and small spatula to precisely measure the mass fractions of each compound as listed in Table 1. For best results prepare 100 g of the non-radioactive precursor matrix at one time.</li>
		<li>Use a mortar and pestle to pulverize (to ~10-20 &#181;m size granules) and thoroughly mix the compounds, forming a homogenous powder mixture containing 64.2 g of SiO2, 14.2 g of Al2O3, 9.64 g of CaO, 1.97 g of FeO, 1.15 g of MgO, 1.25 g of Na2O. 6.12 g of KOH, 0.0505 g of MnO, and 0.427 g of TiO2.</li>
		<li>Agitate the mixture, using a ball mixer, shortly before the next step is taken.</li>
	</ol>
	</li>
	<li>Mixing of STF with Uranium Nitrate Hexahydrate (UNH)
	<ol>
		<li>Acquire at least 1 g of UNH.</li>
		<li>Inside a fume hood, pulverize a few UNH crystals (using a mortar and pestle) to form a fine powder of 1-2 &#181;m granules.</li>
		<li>Add 33.75 &#181;g of UNH per gram of the non-radioactive precursor matrix (this ratio is appropriate for simulating a simple weapon with a yield of 1 kiloton).13</li>
		<li>Thoroughly mix the powder mixture, including the UNH, using a mortar and pestle. Complete final mixing shortly before the melting step.</li>
	</ol>
	</li>
</ol>
2. Production of 1-gram Melt Glass Sample
Note: Equipment needed includes an HTF rated at 1,600 &#176;C or higher, high purity graphite crucibles, long stainless steel crucible tongs, heat resistant gloves, and eye protection. Heat resistant gloves and eye protection should be worn when introducing or removing samples from the furnace. Tinted safety goggles (or sun glasses) are useful as they reduce the glare from the furnace.
<ol>
	<li>Production of a non-radioactive sample
	<ol>
		<li>Fill a thick ceramic dish (such as a mortar) with ~100 g of pure quartz sand and maintain at RT near the location of the furnace where the samples will be melted.</li>
		<li>Preheat the HTF to 1,500 &#176;C.</li>
		<li>Carefully measure 1.00 g of the non-radioactive powder mixture and place the powder in a high purity graphite crucible.</li>
		<li>Carefully place the crucible in the heated HTF (using a long pair of steel crucible tongs) and melt the mixture for 30 min.</li>
		<li>Remove the sample (again using the tongs) and pour the molten sample into the mortar filled with sand.</li>
		<li>Allow the glass bead to cool for 1-2 min before handling.</li>
		<li>Polish the bead to remove residual sand (if necessary).</li>
	</ol>
	</li>
	<li>Production of a radioactive sample
	<ol>
		<li>Repeat steps 2.1.1 and 2.1.2 above.</li>
		<li>Carefully measure 1.00 gram of the radioactive powder mixture (including UNH) and place the powder in a high purity graphite crucible using a separate spatula and microbalance to avoid cross contamination.</li>
		<li>Repeat steps 2.1.4 - 2.1.6 above.</li>
		<li>Monitor the area around the furnace (using a hand-held radiation detector and/or swipe assays) to check for radioactive contamination.</li>
	</ol>
	</li>
</ol>
3. Sample Activation
Note: The equations that follow were derived assuming the use of weapons grade (enriched) uranium metal. The quantities of UNH or Uranium Oxide will need to be scaled according to the mass fraction of elemental uranium and the level of 235U enrichment.
<ol>
	<li>Activation of a Melt Glass Sample with Uranium Fue
	<ol>
		<li>Calculate the mass fraction of uranium metal required for the sample using the equation below13 (where mU represents the uranium mass fraction and Y represents the weapon yield): 
		<img alt="Equation 1" src="/files/ftp_upload/53473/53473eq1.jpg" /></li>
		<li>Optional: Calculate the mass fraction of tamper (e.g., natural uranium, lead, tungsten) using the equation below:13 
		<img alt="Equation 2" src="/files/ftp_upload/53473/53473eq2.jpg" /></li>
		<li>Calculate the target number of fissions in the sample using the following equation13 where Ms represents the mass of the sample in grams and Nf represents the number of fissions produced in the sample during irradiation: 
		<img alt="Equation 3" src="/files/ftp_upload/53473/53473eq3.jpg" /></li>
		<li>Calculate the required irradiation time using the equation below13 where m235 represents the 235U mass fraction (enrichment level) and tirr is the irradiation time in seconds: 
		<img alt="Equation 4" src="/files/ftp_upload/53473/53473eq4.jpg" /></li>
		<li>Irradiate the sample for tirr seconds at a thermal neutron flux of 4.0 x 1014 n/cm2/sec. For example, a 60 sec irradiation in Pneumatic Tube 1 (PT-1) at HFIR (with a thermal to resonance ratio of 35) will produce approximately 1.1 x 1011 fissions in a sample containing 870 &#181;g of UNH (equivalent to 410 &#181;g of natural uranium, or 3.0 &#181;g of 235U). This has been accomplished for one 0.433 g glass bead designed to simulate a melt glass sample produced by a weapon with a 0.1 kiloton yield. This sample has been thoroughly analyzed by Cook et al.14</li>
		<li>Follow applicable safety protocols for handling the radioactive sample post-irradiation.&#160;</li>
	</ol>
	</li>
	<li>Activation of a Melt Glass Sample with Plutonium Fuel (Planning Factors)
	<ol>
		<li>Calculate the mass fraction of plutonium metal required for the sample using the equation below13 where mPu represents the plutonium mass fraction and Y represents the weapon yield: 
		<img alt="Equation 5" src="/files/ftp_upload/53473/53473eq5.jpg" /></li>
		<li>Repeat Steps 3.1.2 and 3.1.3 above.</li>
		<li>Determine the irradiation time required to obtain the desired number of fissions in the melt glass sample. This time will depend on the composition and grade of the plutonium as well as the neutron energy spectrum.</li>
	</ol>
	</li>
</ol>
Note: Great care should be taken when dealing with plutonium and additional analysis will be required. As of this writing, only uranium has been used in the synthetic melt glass samples produced at UT and irradiated at HFIR.&#160;

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J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+synthetic+nuclear+melt+glass+for+forensic+analysis.">Development of synthetic nuclear melt glass for forensic analysis.</a> J Radioanal Nucl Chem. 304 (3), 1293-1301 (2015).</li><li>Fluegel, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+of+Glass+Liquidus+Temperatures+using+Disconnected+Peak+Functions.">Modeling of Glass Liquidus Temperatures using Disconnected Peak Functions.</a> , (2007).</li><li>Oldham, C. J., Molgaard, J. J., Auxier, J. D., Hall, H. 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This work was performed under grant number DE-NA0001983 from the Stewardship Science Academic Alliances (SSAA) Program of the National Nuclear Security Administration (NNSA).

Note regarding steps 1.2.2 and 1.2.3: The exact amount of UNH will vary depending on the scenario being simulated. The planning formulas developed by Giminaro et al. can be used to choose the appropriate mass of uranium for a given sample13 as discussed in the &#34;Sample Activation&#34; section of this paper. Also, Uranium Oxide (UO2 or U3O8) may be used in place of UNH, if available, and the mass fraction of 235U in the compound (whether UNH or Uranium Oxi...

Concerns over the potential malicious use of nuclear weapons by terrorists or rogue nations have highlighted the importance of nuclear forensics analysis for the purpose of attribution.1 Rapid post-detonation analysis techniques are desirable to shorten the attribution timeline as much as possible. The development and validation of such techniques requires realistic nuclear debris samples for testing. Nuclear testing no longer occurs in the United States and nuclear surface debris from the testing era is not readily available (with the exception of trinitite - the melt glass produced by the first nuclear test at the trinity site) and therefore realistic surrogate debris is needed. 
The primary goal of the method described here is the production of realistic surrogate nuclear debris similar to trinitite. Synthetic nuclear melt glass samples which are readily available to the academic community can be used to test existing analysis techniques and to develop new methods such as thermo-chromatography for rapid post-detonation analysis.2 With this goal in mind the current study is focused on producing samples which mimic trinitite but do not contain any sensitive weapon design information. The fuel and tamper components within these samples are completely generic and the comparison to trinitite is based on chemistry, morphology, and physical characteristics. The similarities between trinitite and the synthetic nuclear melt glass produced in this study have been previously discussed.3
The purpose of this article is to outline the details of the production process used at the University of Tennessee (UT). This production process was developed with two key parameters in mind: 1) the composition of material incorporated into nuclear melt glass, and 2) the melting temperature of the material. Methods exist for estimating the melting temperature of glass forming networks4 and these techniques have been employed here, along with additional experimentation to determine the optimal processing temperature for the trinitite matrix.5
Alternative methods for surrogate debris production have been published recently. The use of high power lasers has the advantage of creating sufficiently high temperatures to cause elemental fractionation within the target matrix.6 Porous chromatographic substrates have been used to produce small particles similar to fallout particles using condensed phase methods7. The latter method is most useful for producing particulate debris (nuclear fallout) and has been demonstrated with natural metals. The advantages of the method presented here are 1) simplicity, 2) reproducibility, and 3) scalability (sample sizes can range from tiny beads to large chunks of melt glass). Also, this method is expandable both in terms of production output and variety of explosive scenarios covered, and it has already been demonstrated using radioactive materials. A sample has been successfully activated at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Natural uranium compounds were added to the matrix prior to melting and fission products were produced in situ by neutron irradiation. 
Methods within the glass making industry and those employed for the purpose of radioactive waste immobilization8 have been consulted in the development of the method presented here. The unique effects of radiation in glasses are of inherent interest9 and will constitute an important area of study as this method is further developed. 
The method described below is appropriate for any application where a bulk melt glass sample is desired. These samples most closely resemble the material found near the epicenter of a nuclear explosion. Samples of various sizes can be produced, however, methods employing plasma torches or lasers will be more useful for simulating fine particulate debris. Also, commercial HTFs do not reach temperatures high enough to cause elemental fractionation for a wide range of elements. This method should be employed when physical and morphological characteristics are of primary importance.

<table><tbody><tr><td>High Temperature Furnace (HTF)</td><td>Carbolite</td><td>HTF 18</td><td>1,800 &amp;#176;C HTF used to melt samples</td></tr><tr><td>High Temperature Drop Furnace</td><td>CM Inc.</td><td>1706 BL</td><td>1,700 &amp;#176;C Drop Furnace used to melt samples</td></tr><tr><td>Graphite Crucibles</td><td>SCP Science</td><td>040-060-041</td><td>27 ml high purity graphite crucibles (10 pack)</td></tr><tr><td>Crucible Tongs</td><td>Grainger</td><td>5ZPV0</td><td>26 in., stainless steele tongs for handling crucibles</td></tr><tr><td>Heat Resistent Gloves</td><td>Grainger</td><td>8814-09</td><td>Gloves used to protect hands from heat during sample intro/removal</td></tr><tr><td>Mortar &amp;amp; Pestle</td><td>Fisherbrand</td><td>S337631</td><td>300 ml, Ceramic mortar and pestle for powdering and mixing</td></tr><tr><td>Micro Balance</td><td>Grainger</td><td>8NJG2</td><td>220 g Cap, high precision scale for measuring powder mass</td></tr><tr><td>Spatulas</td><td>Fisherbrand</td><td>14374</td><td>Metal spatulas for measure small quantities of powder</td></tr><tr><td>SiO&lt;sub&gt;2&lt;/sub&gt;</td><td>Sigma-Aldrich</td><td>274739-5KG</td><td>Quartz Sand&amp;nbsp; CAS Number: 14808-60-7</td></tr><tr><td>Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;</td><td>Sigma-Aldrich</td><td>11028-1KG</td><td>Aluminum Oxide Powder&amp;nbsp; CAS Number: 1344-28-1</td></tr><tr><td>CaO</td><td>Sigma-Aldrich</td><td>12047-2.5KG</td><td>Calcium Oxide Powder&amp;nbsp; CAS Number: 1305-78-8</td></tr><tr><td>FeO</td><td>Sigma-Aldrich</td><td>400866-25G</td><td>Iron Oxide Powder&amp;nbsp; CAS Number: 1345-25-1</td></tr><tr><td>MgO</td><td>Sigma-Aldrich</td><td>342793-250G</td><td>Magnesium Oxide Powder&amp;nbsp; CAS Number: 1309-48-4</td></tr><tr><td>Na&lt;sub&gt;2&lt;/sub&gt;O</td><td>Sigma-Aldrich</td><td>36712-25G</td><td>Sodium Oxide Powder&amp;nbsp; CAS Number: 1313-59-3</td></tr><tr><td>KOH</td><td>Sigma-Aldrich</td><td>278904-250G</td><td>Potasium Hydroxide Pellets&amp;nbsp; CAS Number: 12030-88-5</td></tr><tr><td>MnO</td><td>Sigma-Aldrich</td><td>377201-500G</td><td>Manganese Oxide Powder&amp;nbsp; CAS Number: 1344-43-0</td></tr><tr><td>TiO&lt;sub&gt;2&lt;/sub&gt;</td><td>Sigma-Aldrich</td><td>791326-5G</td><td>Titanium Oxide Beads&amp;nbsp; CAS Number: 12188-41-9</td></tr></tbody></table>

production of synthetic nuclear melt glass

Realistic surrogate nuclear debris is needed within the nuclear forensics community to test and validate post-detonation analysis techniques. Here we outline a novel process for producing bulk surface debris using a high temperature furnace. The material developed in this study is physically and chemically similar to trinitite (the melt glass produced by the first nuclear test). This synthetic nuclear melt glass is assumed to be similar to the vitrified material produced near the epicenter (ground zero) of any surface nuclear detonation in a desert environment. The process outlined here can be applied to produce other types of nuclear melt glass including that likely to be formed in an urban environment. This can be accomplished by simply modifying the precursor matrix to which this production process is applied. The melt glass produced in this study has been analyzed and compared to trinitite, revealing a comparable crystalline morphology, physical structure, void fraction, and chemical composition.

The non-radioactive samples produced in this study have been compared to trinitite and Figures 1-3 show that the physical properties and morphology are indeed similar. Figure 1 provides photographs that reveal the similarities in color and texture which are observed at the macroscopic level. Figure 2 shows Scanning Electron Microscope (SEM) Secondary Electron (SE) images which reveal similar features at the micron level. SEM analysis was performed using a SEM and SEM sof...

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Production of Synthetic Nuclear Melt Glass

A protocol for the production of synthetic nuclear melt glass, similar to trinitite, is presented.

Realistic surrogate nuclear debris is needed within the nuclear forensics community to test and validate post-detonation analysis techniques. Here we ...

production-of-synthetic-nuclear-melt-glass

Research

JoVE Journal

Engineering

9.4K Views.  United States Military Academy. A protocol for the production of synthetic nuclear melt glass, similar to trinitite, is presented.

Video: Production of Synthetic Nuclear Melt Glass

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic glasses (MGs). Despite their amorphous nature, the identification of hyperfine interactions unveils faint structural modifications. For this purpose, we have employed two techniques that utilize nuclear resonance among nuclear levels of a stable 57Fe isotope, namely M&#246;ssbauer spectrometry and nuclear forward scattering (NFS) of synchrotron radiation. The effects of heat treatment upon (Fe2.85Co1)77Mo8Cu1B14 MG are discussed using the results of ex situ and in situ experiments, respectively. As both methods are sensitive to hyperfine interactions, information on structural arrangement as well as on magnetic microstructure is readily available. M&#246;ssbauer spectrometry performed ex situ describes how the structural arrangement and magnetic microstructure appears at room temperature after the annealing under certain conditions (temperature, time), and thus this technique inspects steady states. On the other hand, NFS data are recorded in situ during dynamically changing temperature and NFS examines transient states. The use of both techniques provides complementary information. In general, they can be applied to any suitable system in which it is important to know its steady state but also transient states.

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Here, we present a protocol to describe ex situ and in situ investigations of structural transformations in metallic glasses. We employed nuclear-based analytical methods which inspect hyperfine interactions. We demonstrate the applicability of M&#246;ssbauer spectrometry and nuclear forward scattering of synchrotron radiation during temperature-driven experiments.

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic ...

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. Here, we introduce the molten-salt synthesis (MSS) method for making metal oxide nanomaterials. Advantages over other methods include its simplicity, greenness, reliability, scalability, and generalizability. Using pyrochlore lanthanum hafnium oxide (La2Hf2O7) as a representative, we describe the MSS protocol for the successful synthesis of complex metal oxide nanoparticles (NPs). Furthermore, this method has the unique ability to produce NPs with different material features by changing various synthesis parameters such as pH, temperature, duration, and post-annealing. By fine-tuning these parameters, we are able to synthesize highly uniform, non-agglomerated, and highly crystalline NPs. As a specific example, we vary the particle size of the La2Hf2O7&#160;NPs by changing the concentration of the ammonium hydroxide solution used in the MSS process, which allows us to further explore the effect of particle size on various properties. It is expected that the MSS method will become a more popular synthesis method for nanomaterials and more widely employed in the nanoscience and nanotechnology community in the upcoming years.

Here, we demonstrate a unique, relatively low-temperature, molten-salt synthesis method for preparing uniform complex metal oxide lanthanum hafnate nanoparticles.

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. ...

Chemistry

Optimized Sealing Process and Real-Time Monitoring of Glass-to-Metal Seal Structures

Residual stress is an essential factor to keeping the hermeticity and robustness of a glass-to-metal seal structure. The purpose of this report is to demonstrate a novel protocol to characterize and measure residual stress in a glass-to-metal seal structure without destroying the insulation and hermeticity of sealing materials. In this research, a femto-laser inscribed fiber Bragg grating sensor is used. The glass-to-metal seal structure that is measured consists of a metal shell, sealing glass, and Kovar conductor. To make the measurements worthwhile, the specific heat treatment of metal-to-glass seal (MTGS) structure is explored to obtain the model with best hermeticity. Then, the FBG sensor is embedded into the path of sealing glass and becomes well-fused with the glass as the temperature cools to RT. The Bragg wavelength of FBG shifts with the residual stress generated in sealing the glass. To calculate the residual stress, the relationship between Bragg wavelength shift and strain is applied, and the finite element method is also used to make the results reliable. The online monitoring experiments of residual stress in sealing glass are carried out at different loads, such as high temperature and high pressure, to broaden functions of this protocol in harsh environments.

Key procedures to optimize the sealing process and achieve real-time monitoring of the metal-to-glass seal (MTGS) structure are described in detail. The embedded fiber Bragg grating (FBG) sensor is designed to achieve online monitoring of temperature and high-level residual stress in the MTGS with simultaneous environmental pressure monitoring.

Residual stress is an essential factor to keeping the hermeticity and robustness of a glass-to-metal seal structure. The purpose of this report is to ...

Comparison of Two Different Synthesis Methods of Single Crystals of Superconducting Uranium Ditelluride

Single crystal specimens of the actinide compound uranium ditelluride, UTe2, are of great importance to the study and characterization of its dramatic unconventional superconductivity, believed to entail spin-triplet electron pairing. A variety in the superconducting properties of UTe2 reported in the literature indicates that discrepancies between synthesis methods yield crystals with different superconducting properties, including the absence of superconductivity entirely. This protocol describes a process to synthesize crystals that exhibit superconductivity via chemical vapor transport, which has consistently exhibited a superconducting critical temperature of 1.6 K and a double transition indicative of a multi-component order parameter. This is compared to a second protocol that is used to synthesize crystals via the molten metal flux growth technique, which produces samples that are not bulk superconductors. Differences in the crystal properties are revealed through a comparison of structural, chemical, and electronic property measurements, showing that the most dramatic disparity occurs in the low-temperature electrical resistance of the samples.

Here, we present a protocol to synthesize two types of UTe2 crystals: those exhibiting robust superconductivity, via chemical vapor transport synthesis, and those lacking superconductivity, via molten metal flux synthesis.

Single crystal specimens of the actinide compound uranium ditelluride, UTe2, are of great importance to the study and characterization of its dramatic ...

Hydrothermal Synthesis of Persistent Luminescent Nanoparticles

Synthesis of Persistent Luminescent Nanoparticles for Rewritable Displays and Illumination Applications

Persistent luminescent nanoparticles (PLNPs) possess the capabilities to maintain extended longevity and robust emission even after the excitation has ceased. PLNPs have been widely used across various domains, including information displays, data encryption, biological imaging, and artistic decoration with sustained and vivid luminosity, providing boundless possibilities for a variety of innovative technology and artistic projects. This protocol focuses on an experimental procedure for the hydrothermal synthesis of PLNPs. The successful synthesis of enduring luminescent nanomaterials with Mn2+ or Cr3+ serving as a luminescent center in Zn2GeO4: Mn (ZGO: Mn) or ZnGa2O4: Cr highlights the universality of this synthetic method. On the other hand, the optical properties of ZGO: Mn can be changed by adjusting the pH of precursor solutions, demonstrating the tunability of the protocol. When charged with ultraviolet (UV) at a wavelength of 365 nm for 3 min and then stopped, PLNPs exhibit the remarkable capacity to generate afterglow efficiently and consistently, which makes them ideal for making two-dimensional rewritable displays and three-dimensional transparent, luminous artworks. This protocol outlined in this paper provides a feasible method for the synthesis of persistent luminescent nanoparticles for further illumination and imaging applications, opening up novel prospects for the fields of science and art.

Author Spotlight: Advancing Bioimaging and Therapy with Functional Nanomaterials

A protocol is presented for the synthesis of persistent luminescent nanomaterials (PLNPs) and their potential applications in rewritable displays and artistic processing utilizing the afterglow effect under ultraviolet light (365 nm) irradiation.

Persistent luminescent nanoparticles (PLNPs) possess the capabilities to maintain extended longevity and robust emission even after the excitation has ...

Fluid-cell Raman Spectroscopy for operando Studies of Reaction and Transport Phenomena during Silicate Glass Corrosion

Fluid-cell Raman Spectroscopy (FCRS) enables the real-time and space-resolved (operando) study of reaction mechanisms, kinetics, and their mutual interactions with transport processes during silicate glass corrosion at the micrometer scale and at elevated temperatures. This manuscript provides a detailed protocol for setting up an FCRS experiment, exemplified by a corrosion experiment with a ternary Na borosilicate glass and a 0.5 M NaHCO3 solution at a temperature of 86 &#177; 1 &#176;C. The protocol involves (i) sample preparation, (ii) assembly of the fluid cell, and (iii) setting of Raman measurement parameters for collecting Raman spectra across the sample/solution interface in regular time intervals. The results from the experiment show the formation of a water-rich zone between a silica-based surface alteration layer (SAL) and the pristine glass, which is an intrinsic feature of an interface-coupled dissolution-precipitation model for the formation of a SAL during silicate glass corrosion. The ability to track the reaction and transport processes during the corrosion of silicate glasses and potentially of other transparent materials, spatially resolved and in real-time, represents a unique strength of this technique, overcoming the disadvantages of conventional analysis of multi-step quenching experiments. The corrosion of the top side of the glass sample represents a current issue, reducing spatial resolution at depth due to precipitation within the laser pathway. This is caused by a solution-filled gap between the sapphire window of the fluid cell lid and the top side of the monolith, which is difficult to avoid during the experimental setup. This must be taken into account when choosing the depth at which the measurement should be made. In a few cases, the formation of air bubbles was observed, which disrupted or even led to the termination of the experiment. However, this can be avoided by carefully setting up the experiment, which requires little practice.

Fluid-cell Raman Spectroscopy (FCRS) enables in operando observations of reaction and transport phenomena during the aqueous corrosion of silicate glasses at a microscopic level, at elevated temperatures, and in real-time. Without interrupting ongoing processes, FCRS provides information about reaction mechanisms, kinetics, and transport processes.

Fluid-cell Raman Spectroscopy (FCRS) enables the real-time and space-resolved (operando) study of reaction mechanisms, kinetics, and their mutual ...

Fabricating Optical-quality Glass Surfaces to Study Macrophage Fusion

Visualizing the formation of multinucleated giant cells (MGCs) from living specimens has been challenging due to the fact that most live imaging techniques require propagation of light through glass, but on glass macrophage fusion is a rare event. This protocol presents the fabrication of several optical-quality glass surfaces where adsorption of compounds containing long-chain hydrocarbons transforms glass into a fusogenic surface. First, preparation of clean glass surfaces as starting material for surface modification is described. Second, a method is provided for the adsorption of compounds containing long-chain hydrocarbons to convert non-fusogenic glass into a fusogenic substrate. Third, this protocol describes fabrication of surface micropatterns that promote a high degree of spatiotemporal control over MGC formation. Finally, fabricating glass bottom dishes is described. Examples of use of this in vitro cell system as a model to study macrophage fusion and MGC formation are shown.

This protocol describes the fabrication of optical-quality glass surfaces adsorbed with compounds containing long-chain hydrocarbons that can be used to monitor macrophage fusion of living specimens and enables super-resolution microscopy of fixed specimens.

Visualizing the formation of multinucleated giant cells (MGCs) from living specimens has been challenging due to the fact that most live imaging ...

Immunology and Infection

Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups

Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later.1,2 Their redox chemistry is even younger, just about ten years old, but despite this short history these deltahedral clusters ions E9n- (E = Si, Ge, Sn, Pb; n = 2, 3, 4) have already shown interesting and diverse reactivity and have been at the forefront of rapidly developing and exciting new chemistry.3-6 Notable milestones are the oxidative coupling of Ge94- clusters to oligomers and infinite chains,7-19 their metallation,14-16,20-25 capping by transition-metal organometallic fragments,26-34 insertion of a transition-metal atom at the center of the cluster which is sometimes combined with capping and oligomerization,35-47 addition of main-group organometallic fragments as exo-bonded substituents,48-50 and functionalization with various organic residues by reactions with organic halides and alkynes.51-58 
This latter development of attaching organic fragments directly to the clusters has opened up a new field, namely organo-Zintl chemistry, that is potentially fertile for further synthetic explorations, and it is the step-by-step procedure for the synthesis of germanium-divinyl clusters described herein. The initial steps outline the synthesis of an intermetallic precursor of K4Ge9 from which the Ge94- clusters are extracted later in solution. This involves fused-silica glass blowing, arc-welding of niobium containers, and handling of highly air-sensitive materials in a glove box. The air-sensitive K4Ge9 is then dissolved in ethylenediamine in the box and then alkenylated by a reaction with Me3SiC&equiv;CSiMe3. The reaction is followed by electrospray mass spectrometry while the resulting solution is used for obtaining single crystals containing the functionalized clusters [H2C=CH-Ge9-CH=CH2]2-. For this purpose the solution is centrifuged, filtered, and carefully layered with a toluene solution of 18-crown-6. Left undisturbed for a few days, the so-layered solutions produced orange crystalline blocks of [K(18-crown-6)]2[Ge9(HCCH2)2]&bull;en which were characterized by single-crystal X-ray diffraction. 
The process highlights standard reaction techniques, work-up, and analysis towards functionalized deltahedral Zintl clusters. It is hoped that it will help towards further development and understanding of these compounds in the community at large.

We present the high-temperature synthesis of intermetallic precursors K4Ge9, their dissolution in ethylenediamine to form Ge94- deltahedral Zintl ions, and the reaction of the clusters with alkynes to form organo-Zintl ions. The latter are characterized by electrospray mass spectrometry in solutions and by single-crystal X-ray diffraction in the solid state.

Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later.1,2 ...

Biology

Customizing a Cryolite Glass Prosthetic Eye

In Germany, Austria, and Switzerland, over 90% of ocularists still manufacture customized prostheses using cryolite glass from Thuringia. The present manuscript demonstrates this long-forgotten technique in detail. This manuscript shows some major advantages of manufacturing prosthetic eyes using cryolite glass in comparison to poly(methyl methacrylate) (PMMA). These advantages include a lighter weight of the prosthesis, higher levels of patient satisfaction, and only one appointment necessary for the customized manufacturing. Potential risk of breakage seems not to be a critical disadvantage for glass prosthetic eye wearers. However, in some patients, manufacturing a well-fitting prosthetic eye is not possible or reasonable due to anophthalmic socket complications such as post nucleation socket syndrome, scarred fornices, or an orbital implant exposure. This article gives ophthalmologists a better insight into ocularistic care in order to improve the essential interprofessional collaboration between ocularists and ophthalmologists.

This manuscript shows each step of customizing a cryolite glass prosthetic eye including some major advantages of the use of cryolite glass for manufacturing an eye prosthesis compared to poly(methyl methacrylate). In addition, this manuscript gives ophthalmologists better insight into the ocularistic care that could improve interprofessional collaboration.

In Germany, Austria, and Switzerland, over 90% of ocularists still manufacture customized prostheses using cryolite glass from Thuringia. The present ...

Medicine

Cleaning Glassware

Source: Vy M. Dong and Daniel Kim, Department of Chemistry, University of California, Irvine, CA
Organic synthesis is about transforming a readily available reagent into a more valuable product. Having clean glassware is crucial for the efficiency of this process. Dirty glassware can potentially affect the reaction and make isolation of the final product more challenging. Thus, a synthetic chemist must keep the glassware spotless. The methods described here will detail different glass cleaning techniques that are regularly used to remove organics, metals, grease, and salts.

Production of Synthetic Nuclear Melt Glass

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