Lifetime of Imidazolium Salts at Elevated Temperatures

Solar Energy ◽  
2004 ◽  
Author(s):  
Daniel M. Blake ◽  
Luc Moens ◽  
Daniel Rudnicki ◽  
Heidi Pilath
Keyword(s):  
Power Systems ◽  
Elevated Temperatures ◽  
Initial Study ◽  
Slow Heating ◽  
Gravimetric Analysis ◽  
Imidazolium Salts ◽  
Heating Rates ◽  
Rough Approximation ◽  
Solar Plant ◽  
The University

This report summarizes progress to date on the thermal stability of imidazolium salts being considered for application as heat transfer and thermal storage fluids in solar parabolic trough power systems. Imidazolium salts are a subset of the general class of molten salts. They are termed ionic liquids because many have freezing points at or below room temperature. This class of salts was selected for initial study because there were many examples that were reported to be stable at high temperatures. These reports were usually based on the results of standard thermal gravimetric analysis (TGA) methods. Work by our subcontractor at the University of Alabama and at NREL showed that slow heating rates or when the temperature is held constant for long times resulted in decomposition temperatures that are much lower than found with the usual TGA methods. We have used a TGA technique that allows calculation of the rates of thermal decomposition as a function of temperature. The results lead us to the conclusion that the imidazolium salts known to be the most thermally stable would not have useful lifetimes above about 200°C. At present this determination is based on the rough approximation that the fluid in a solar trough system experiences a constant, high temperature. Better estimates of the useful lifetime will require a system model that takes into account the time at temperature distribution of a fluid moving through the different components in a solar plant.

Study on the residual performance of RC beams exposed to processed temperatures and fire

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sachin Vijaya Kumar ◽  
N. Suresh
Keyword(s):  
Failure Modes ◽  
Elevated Temperatures ◽  
Slow Heating ◽  
Maximum Temperature ◽  
Rc Beams ◽  
Heating Rates ◽  
Fast Heating ◽  
Content Type ◽  
Temperature Increment ◽  
Residual Performance

PurposeThe Reinforced Concrete(RC) elements are known to perform well during exposure to elevated temperatures. Hence, RC elements are widely used to resist the extreme heat developing from accidental fires and other industrial processes. In both of the scenarios, the RC element is exposed to elevated temperatures. However, the primary differences between the fire and processed temperatures are the rate of temperature increase, mode of exposure and exposure durations. In order to determine the effect of two heating modalities, RC beams were exposed to processed temperatures with slow heating rates and fire with fast heating rates.Design/methodology/approachIn the present study, RC beam specimens were exposed to 200 °C, to 800 °C temperature at 200 °C intervals for 2 h' duration by adopting two heating modes; Fire and processed temperatures. An electrical furnace with low-temperature increment and a fire furnace with standard time-temperature increment is adapted to expose the RC elements to elevated temperatures.FindingsIt is observed from test results that, the reduction in load-carrying capacity, first crack load, and thermal crack widths of RC beams exposed to 200 °C, and 600 °C temperature at fire is significantly high from the RC beams exposed to the processed temperature having the same maximum temperature. As the exposure temperature increases to 800 °C, the performance of RC beams at all heating modes becomes approximately equal.Originality/valueIn this work, residual performance, and failure modes of RC beams exposed to elevated temperatures were achieved through two different heating modes are presented.

FOAM TEMPERATURES DURING VAT PASTEURIZATION OF MILK PRODUCTS

1971 ◽  
Vol 34 (3) ◽  
pp. 133-139
Author(s):  
R. W. Dickerson ◽  
R. B. Read
Keyword(s):  
Milk Fat ◽  
Liquid Surface ◽  
Liquid Product ◽  
Ice Cream ◽  
Microbial Pathogens ◽  
Slow Heating ◽  
Milk Product ◽  
Heating Rates ◽  
Holding Period ◽  
Foam Thickness

Heating rates of foam during vat pasteurization were investigated to determine whether shorter holding times and higher processing temperatures would be feasible from a public health standpoint. A rake of 19 thermocouples, spaced 0.5 inch apart, was installed vertically in a 300-gal vat pasteurizer and the rake was adjusted to measure the temperature of the heated airspace, foam, and liquid product. With 200 gal of ice cream mix (16% milk fat), an 11-inch foam was generated on the liquid surface. The minimum temperature in the ice cream mix foam was below pasteurization temperature for 27 min of the 30-min holding period despite satisfactory temperatures as indicated by the product and airspace thermometers. When a 7-inch foam was generated above 218 gal of chocolate milk, the minimum foam temperature was below pasteurization temperature for the first 14 min of the holding period. Attempts to generate foams on milk were unsuccessful. Because of the slow heating rates of milk-product foams, holding times shorter than 30 min cannot ensure the inactivation of microbial pathogens in the foam, and, consequently, they are not recommended. Some foams should be held longer than 30 min to ensure pasteurization, and additional holding time needed may be computed from known values of foam thickness, airspace temperature , and heating rate of the liquid.

High-Temperature Dielectric Materials for Electrical Energy Storage

2018 ◽  
Vol 48 (1) ◽  
pp. 219-243 ◽  
Author(s):  
Qi Li ◽  
Fang-Zhou Yao ◽  
Yang Liu ◽  
Guangzu Zhang ◽  
Hong Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Power Systems ◽  
Oil And Gas ◽  
Elevated Temperatures ◽  
Temperature Stability ◽  
Electrical Energy ◽  
Dielectric Materials ◽  
Future Research ◽  
Capacitive Energy Storage

The demand for high-temperature dielectric materials arises from numerous emerging applications such as electric vehicles, wind generators, solar converters, aerospace power conditioning, and downhole oil and gas explorations, in which the power systems and electronic devices have to operate at elevated temperatures. This article presents an overview of recent progress in the field of nanostructured dielectric materials targeted for high-temperature capacitive energy storage applications. Polymers, polymer nanocomposites, and bulk ceramics and thin films are the focus of the materials reviewed. Both commercial products and the latest research results are covered. While general design considerations are briefly discussed, emphasis is placed on material specifications oriented toward the intended high-temperature applications, such as dielectric properties, temperature stability, energy density, and charge-discharge efficiency. The advantages and shortcomings of the existing dielectric materials are identified. Challenges along with future research opportunities are highlighted at the end of this review.

Automated Approaches Determine Solids Content in Drilling and Completions Fluids

2021 ◽  
Vol 73 (11) ◽  
pp. 51-52
Author(s):  
Chris Carpenter
Keyword(s):  
Elevated Temperatures ◽  
Drilling Fluid ◽  
Technical Conference ◽  
Drilling Fluids ◽  
Test Results ◽  
University Of Texas ◽  
Safety Issues ◽  
Recommended Practices ◽  
Solids Content ◽  
The University

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 201368, “Automated Solids-Content Determination in Drilling and Completions Fluids,” by Sercan Gul, SPE, Ali Karimi Vajargah, and Eric van Oort, SPE, The University of Texas at Austin, et al., prepared for the 2020 SPE Annual Technical Conference and Exhibition, originally scheduled to be held in Denver, 5–7 October. The paper has not been peer reviewed. Monitoring of low- and high-gravity-solids (LGS and HGS) content and maintaining these at ideal levels is essential for optimal drilling fluid performance, efficient hole cleaning and equivalent-circulating-density management, and prevention of failures of surface and downhole equipment during drilling. LGS and HGS monitoring in the field is currently accomplished using the API retort-kit measurement, which has certain drawbacks and is difficult to automate. In the complete paper, two new approaches are investigated to automate the LGS and HGS content measurements of drilling fluids, which potentially can replace the retort test. Introduction The conventional way to characterize LGS and HGS in the field is by using a retort-kit measurement specified in API Recommended Practices 13B-1 and 13B-2. The longevity of these tests is testament to the effectiveness of the API standards and the tests themselves in providing useful and practical field guidance. Despite their evident success, however, various downsides exist in current solids-content-testing methods. Retort-kit measurements present the following issues: - Difficulty in obtaining accurate and repeatable test results - Safety issues associated with laboratory testing at elevated temperatures (over 930°F) - Interpretive bias issues associated with test results, including the potential for deliberate manipulation of these results - Difficulty in automating the retort test for improved efficiency and safety The authors’ opinion is that automating antiquated API test protocols is not a useful practice. They write that a clean-slate approach would be better, in which a determination is made whether solids-content information can be provided in a novel and meaningful way using methods that deviate from standard API recommended practices. In the complete paper, the authors investigate a machine-learning (ML) and data-analytics method for this purpose in combination with a novel inline X-ray fluorescence (XRF) measurement method.

scholarly journals Role of Copper Oxide on Epoxy Coatings with New Intumescent Polymer-Based Fire Retardant

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5978
Author(s):  
Riyazuddin ◽  
Samrin Bano ◽  
Fohad Mabood Husain ◽  
Jamal Akhter Siddique ◽  
Khadijah H. Alharbi ◽  
...  
Keyword(s):  
Copper Oxide ◽  
Heat Release ◽  
Flame Retardant ◽  
Cone Calorimeter ◽  
Elevated Temperatures ◽  
Fire Retardant ◽  
Intumescent Flame Retardant ◽  
Gravimetric Analysis ◽  
Sem Images ◽  
Major Drawback

Epoxy resins (EP) have been used as a thermos-setting material in the field of coating, casting, bonding agent, and laminating. However, a major drawback associated with its use is the lack of good flaming properties, and it is responsible for heavy smoke along with hazardous gases considerably limiting its uses in various fields. In this study, N-ethanolamine triazine-piperizine, a melamine polymer (ETPMP), was established as a new charring-foaming agent and was successfully synthesized with ethanolamine, piperizine, cyanuric chloride, and melamine as precursor molecules via the nucleophilic substitution reaction method. Elemental analysis and Fourier transform infrared (FTIR) spectroscopy analysis were applied to approve the synthesis of ETPMP and confirmation of its structure and characterization. The epoxy coating of intumescent flame retardant (IFR) was equipped by introducing ETPMP, ammonium polyphosphate (APP), and copper oxide (CuO) in multiple composition ratios. CuO was loaded at various amounts into the IFR-coating system as a synergistic agent. The synergistic action of CuO on IFR coatings was scientifically examined by using different analytical tests such as vertical burning test (UL-94V), limited oxygen index (LOI), thermal gravimetric analysis (TGA), cone calorimeter, and scanning electron microscope (SEM). The results showed that small changes in the amount of CuO expressively amplified the LOI results and enhanced the V-0 ratings in the UL-94V test. The TGA data clearly demonstrate that the inclusion of CuO can transform the thermal deprivation behavior of coatings with a growing char slag proportion with elevated temperatures. Information from cone calorimeter data affirmed that CuO can decrease the burning factors by total heat release (THR) together with peak heat release rate (PHRR). The SEM images indicated that CuO can enrich the power and compression of the intumescent char that restricts the movement of heat and oxygen. Our results demonstrate a positive influence of CuO on the epoxy-headed intumescent flame retardant coatings.

Influence of Rate of Heating to Aging Temperature on Precipitation Hardening in a Metastable β Titanium Alloy

2014 ◽  
Vol 1025-1026 ◽  
pp. 445-450 ◽  
Author(s):  
Ashwary Pande ◽  
Salil Sainis ◽  
Santhosh Rajaraman ◽  
Geetha Manivasagam ◽  
M. Nageswara Rao
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Heating Rate ◽  
Aging Temperature ◽  
Alpha Phase ◽  
Slow Heating ◽  
Precipitation Reaction ◽  
Heating Rates ◽  
Rate Of Heating ◽  
Reduction In Area

A comparison between slow heating to aging temperature and direct charging at aging temperature on the microstructure and mechanical properties obtained after the aging was established for the metastable beta (β) titanium alloy Ti-15V-3Cr-3Al-3Sn. The alloy was subjected to two single aging (SA) and two duplex aging (DA) conditions, with two heating rates to aging temperature: (i) low heating rate of 5 oC/min (ii) direct charging into a furnace heated to aging temperature. The microstructure analysis was carried out using Field Emission Scanning Electron Microscopy. Mechanical Testing was carried to evaluate Ultimate Tensile Strength (UTS), 0.2% Yield Strength (YS), % Elongation (%El.), % Reduction in area (%RA) and hardness. In the case of SA samples aged at 500 °C for 8 h and 500 °C for 10 h, heating rate of 5 °C/min to aging temperature resulted in a finer microstructure but did not help in achieving better strength-ductility combination compared to direct charging. Lower rate of heating allows enough dwell time in the temperature range 250-300 oC for pre-precipitation reaction to occur which aids in fine scale precipitation of alpha phase during aging. In the case of DA samples aged at 250 oC for 24 h followed by 500 oC for 8 h and 300 oC for 10 h followed by 500 oC for 10 h, no tangible difference between lower rate of heating and direct charging was observed in mechanical properties or microstructure. This is believed to be due to the pre-aging steps 250 oC/24 h or 300 oC/10h in the two DA treatments, which create finely distributed precursors thereby leaving no scope for the heating rate to play a role.

scholarly journals Stability of Ready-to-Administer and Ready-to-Use Epinephrine and Norepinephrine Injection Solutions

2017 ◽  
Vol 2 (4) ◽  
Author(s):  
Rita Marina Heeb ◽  
Bettina Stollhof ◽  
Julia Reichhold ◽  
Judith Thiesen ◽  
Irene Krämer
Keyword(s):  
Shelf Life ◽  
Elevated Temperatures ◽  
Reversed Phase ◽  
Type I ◽  
Long Term Stability ◽  
Intensive Care Patients ◽  
Pharmacy Department ◽  
Physicochemical Stability ◽  
Light Protection ◽  
The University

AbstractBackgroundIn the University Medical Centre Mainz, standard concentrations are defined for medicinal products to be administered by continuous injection with syringe pumps in adult intensive care patients. The objective of this study was to evaluate the physicochemical stability of ready-to-use and ready-to-administer preparations containing Epinephrine (E) and Norepinephrine (NE) in standardized concentrations and prepared batch wise in the pharmacy department as basis for assigning shelf-lives.MethodsE 20 µg/mL and NE 10 µg/mL in disposable syringes and NE 40, 100, 200, 400 µg/ml in 50 ml amber type I glass vials were prepared batch wise and the concentrations were analyzed by stability-indicating, validated reversed-phase HPLC-PDA assays. Test solutions for long-term stability studies were stored under refrigeration (2–8 °C) for 6–12 months or at elevated temperatures (21–27 °C) light protected for up to 6 months or without light protection for up to one month. Osmolality and pH were measured on predefined intervals.ResultsThe concentrations of E in 50 mL syringes and NE in 10 mL syringes remained unchanged over a period of 6 months when stored at 2–8 °C. NE preparations of different concentrations prepared in amber glass vials remained stable over a study period of 12 months. At RT the shelf-life decreased to about 6 months and the exposure to mixed daylight at RT caused loss of stability in only few days.ConclusionsBatch wise preparation of ready-to-administer (RTA) preparations containing 20 µg/mL E or 10 µg/mL NE in disposable syringes as well as ready-to-use (RTU) preparations containing 40, 100, 200 and 400 µg/mL NE was successfully implemented in a pharmacy department. Storage of the preparations at refrigerated temperatures is required to obtain acceptable shelf-lives of 6–12 months. Elevated temperatures and especially exposure to mixed daylight significantly decreased the shelf life.

scholarly journals 4142 Implementation of Consent-to-Contact (CTC) initiative at an Academic Medical center: Initial operationalization and lessons learned

2020 ◽  
Vol 4 (s1) ◽  
pp. 73-73
Author(s):  
Chin Chin Lee ◽  
Helenmarie M. Blake ◽  
Carlos A. Canales ◽  
Stephen J. DeGennaro ◽  
Ishwar Ramsingh ◽  
...  
Keyword(s):  
Medical Center ◽  
Academic Medical Center ◽  
Initial Study ◽  
Lessons Learned ◽  
Eligibility Criteria ◽  
Academic Medical ◽  
Study Teams ◽  
The University ◽  
Demographic Distribution ◽  
Research Studies

OBJECTIVES/GOALS: The objectives of this presentation are to discuss 1) the implementation of Consent to Contact at an Academic Medical Center; 2) the access to lists of potential participants by study teams; and 3) the challenges and adjustments made to the initial conceptualized process. METHODS/STUDY POPULATION: Participant recruitment is critical to the success of all research studies. It is particularly challenging when investigators do not have a patient population from which to recruit. Thus, the University of Miami launched the CTC initiative in 2016 to facilitate study recruitment. Study investigators can request access to a registry of participants who agreed to be contacted and meet the initial study eligibility criteria. A multidisciplinary Operational Committee provides oversight and regulates access to the CTC registry. RESULTS/ANTICIPATED RESULTS: The registry has over 110K patients who have agreed to be contacted for eligible research studies. The demographic distribution of the patients in the registry mirrors the diversity of the UHealth population. As of January 2018, when the registry became available to the research community, 25 study teams from different departments, including the All of Us Research Program, have requested potential participant lists. The process of requesting access to patient lists is adapted to studies’ needs, with particular reference to sensitive populations, such as HIV/AIDS, substance abuse, etc. Results on utilization and satisfaction of the CTC initiative are being collected and will be presented. DISCUSSION/SIGNIFICANCE OF IMPACT: The CTC initiative allows UHealth patients to opt-in to the registry for research studies. The Operational Committee continues to monitor the successful consent of patients to participate in individual research studies and improving the request process.

scholarly journals Performance of Methyl-5-Benzoyl-2-Benzimidazole Carbamate (Mebendazole) as Corrosion Inhibitor for Mild Steel in Dilute Sulphuric Acid

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
F. O. Edoziuno ◽  
A. A. Adediran ◽  
B. U. Odoni ◽  
M. Oki ◽  
P. P. Ikubanni ◽  
...  
Keyword(s):  
Mild Steel ◽  
Inhibition Efficiency ◽  
Elevated Temperatures ◽  
Physical Adsorption ◽  
Electrochemical Techniques ◽  
Low Carbon Steel ◽  
Gravimetric Analysis ◽  
Low Carbon ◽  
Maximum Inhibition ◽  
Inhibitive Action

The inhibitive effect of mebendazole (MBZ) on the corrosion of low-carbon steel in H2SO4 was investigated by gravimetric and electrochemical techniques as well as examination of specimens in the scanning electron microscope with attached energy dispersive X-ray spectrometer (EDS). From gravimetric analysis, the highest inhibition efficiency of about 96.6% was obtained for 1.0 g of inhibitor in H2SO4 solution at 24 h, while with longer exposure times of between 72 to 120 h, the efficiencies averaged between 92 and 95%. Tafel extrapolations from the polarization curves showed that 1.0 g MBZ gave a maximum inhibition efficiency of approximately 99% for the investigation conducted at 30°C, whereas 1.5 g of MBZ gave a maximum inhibition efficiency of about 85% at 60°C. Inhibition efficiency increased with increasing concentrations of MBZ and decreased at elevated temperatures. The inhibitive action was attributed to physical adsorption of MBZ species on the mild steel surface which followed the Langmuir adsorption isotherm. MBZ performed as a mixed-type inhibitor on mild steel in dilute H2SO4.

scholarly journals Influence of Guayule Resin as a Bio-Based Additive on Asphalt–Rubber Binder at Elevated Temperatures

Recycling ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 38 ◽  
Author(s):  
Ahmed Hemida ◽  
Magdy Abdelrahman
Keyword(s):  
Rheological Properties ◽  
Elevated Temperatures ◽  
Thermo Gravimetric Analysis ◽  
Crumb Rubber ◽  
Environmental Concerns ◽  
Gravimetric Analysis ◽  
Thermo Gravimetric ◽  
Asphalt Cement ◽  
Asphalt Rubber ◽  
Liquid Phases

This study seeks to find the influence of replacing a portion of the asphalt–rubber binder with the bio-based material “guayule resin.” This replacement could be beneficial in terms of sustainability, economics, and environmental concerns related to the asphalt industry. Nine asphalt–rubber–guayule binders were investigated to find their rheological properties. Consecutively, the study proceeded with five selected binders being compared to the original asphalt (PG64-22). Investigations underwent whole matrices (crumb rubber modifier (CRM) residue included) and liquid phases (CRM residue extracted). Additionally, these properties were partially sought for their corresponding asphalt–rubber binders to compare and judge the contribution of the guayule resin. Likewise, a thermo-gravimetric analysis was done for the guayule resin to recognize its moisture and composition complexity. Such an analysis was also done for the as-received CRM and some extracted CRMs to determine the release and residue of rubber components. Outcomes showed that the guayule resin has the potential to compensate the performance required against the original asphalt at elevated temperatures while greatly decreasing the asphalt cement proportion. For instance, a blend of 62.5% asphalt, 12.5% CRM, and 25% guayule resin provided better performance than that of the original asphalt.

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