scholarly journals Theoretical Study on Thermal Release of Helium-3 in Lunar Ilmenite

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 319
Author(s):  
Hongqing Song ◽  
Jie Zhang ◽  
Yueqiang Sun ◽  
Yongping Li ◽  
Xianguo Zhang ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Concentration Profile ◽  
Heating Temperature ◽  
Lunar Soil ◽  
Heating Time ◽  
Release Time ◽  
Thermal Release ◽  
Helium 3 ◽  
Optimal Heating

The in-situ utilization of lunar helium-3 resource is crucial to manned lunar landings and lunar base construction. Ilmenite was selected as the representative mineral which preserves most of the helium-3 in lunar soil. The implantation of helium-3 ions into ilmenite was simulated to figure out the concentration profile of helium-3 trapped in lunar ilmenite. Based on the obtained concentration profile, the thermal release model for molecular dynamics was established to investigate the diffusion and release of helium-3 in ilmenite. The optimal heating temperature, the diffusion coefficient, and the release rate of helium-3 were analyzed. The heating time of helium-3 in lunar ilmenite under actual lunar conditions was also studied using similitude analysis. The results show that after the implantation of helium-3 into lunar ilmenite, it is mainly trapped in vacancies and interstitials of ilmenite crystal and the corresponding concentration profile follows a Gaussian distribution. As the heating temperature rises, the cumulative amounts of released helium-3 increase rapidly at first and then tend to stabilize. The optimal heating temperature of helium-3 is about 1000 K and the corresponding cumulative release amount is about 74%. The diffusion coefficient and activation energy of helium-3 increase with the temperature. When the energy of helium-3 is higher than the binding energy of the ilmenite lattice, the helium-3 is released rapidly on the microscale. Furthermore, when the heating temperature increases, the heating time for thermal release of helium-3 under actual lunar conditions decreases. For the optimal heating temperature of 1000 K, the thermal release time of helium-3 is about 1 s. The research could provide a theoretical basis for in-situ helium-3 resources utilization on the moon.

scholarly journals Study on Ultra-High Temperature Contact Solution Treatment of Al–Zn–Mg–Cu Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 842
Author(s):  
Wenming Jin ◽  
Jianhao Yu ◽  
Zhiqiang Zhang ◽  
Hongjie Jia ◽  
Mingwen Ren
Keyword(s):  
Heating Temperature ◽  
Solution Treatment ◽  
Strengthening Mechanism ◽  
Heating Time ◽  
Solution Time ◽  
Solution Temperature ◽  
Second Phase ◽  
Total Strength ◽  
Cu Alloys ◽  
Short Heating Time

Contact solution treatment (CST) of Al–Zn–Mg–Cu alloys can shorten solution time to within 40 s in comparison with 1800 s with traditional solution treatment using a heating furnace. Heating temperature is the key factor in solution treatment. Considering the short heating time of CST, the ultra-high solution temperature over 500 °C of Al–Zn–Mg–Cu alloys was studied in this work. The effects of solution temperatures on the microstructures and the mechanical properties were investigated. The evolution of the second phases was explored and the strengthening mechanisms were also quantitatively evaluated. The results showed that solution time could be reduced to 10 s with the solution temperature of 535 °C due to the increasing dissolution rate of the second phase and the tensile strength of the aged specimen could reach 545 MPa. Precipitation strengthening was the main strengthening mechanism, accounting for 75.4% of the total strength. Over-burning of grain boundaries occurred when the solution temperature increased to 555 °C, leading to the deterioration of the strength.

Numerical Simulation and Process Optimization of Automotive Friction Materials in Warm Pressing Forming

2013 ◽  
Vol 788 ◽  
pp. 57-60
Author(s):  
Chun Cao ◽  
Chun Dong Zhu ◽  
Chen Fu
Keyword(s):  
Process Optimization ◽  
Heating Temperature ◽  
Maximum Energy ◽  
Heating Time ◽  
Product Performance ◽  
Forming Process ◽  
Friction Materials ◽  
Forming Technology ◽  
The Relationship ◽  
Temperature Heating

Warm pressing forming technology has been gradually applied to the forming of automotive friction materials. How to ensure product performance to achieve the target at the same time achieve the maximum energy saving is the research focus of this study. In this paper, by using finite element method, the field of automotive friction materials in warm pressing forming was analyzed, reveals the relationship between the temperature field and the heating temperature/heating time. Furthermore, the energy consumption was analyzed and compared it with hot pressing forming process. The results will have significant guiding to the process optimization in warm pressing forming.

An Analytical Evaluation of the Optimal Thermal Dose Delivery Parameters for Thermal Therapies

2003 ◽  
Author(s):  
Kung-Shan Cheng ◽  
Robert B. Roemer
Keyword(s):  
Blood Flow ◽  
Treatment Time ◽  
Heating Time ◽  
Treatment Temperature ◽  
Thermal Dose ◽  
Dose Delivery ◽  
Thermal Therapies ◽  
Initial Power ◽  
High Treatment ◽  
Optimal Heating

This study derives the first analytic solution for evaluating the optimal treatment parameters needed for delivering a desired thermal dose during thermal therapies consisting of a single heating pulse. Each treatment is divided into four time periods (two power-on and two power-off), and the thermal dose delivered during each of those periods is evaluated using the non-linear Sapareto and Dewey equation relating thermal dose to temperature and time. The results reveal that the thermal dose delivered during the second power-on period when T>43C (TD2) and the initial power-off period when T>43C (TD3) contribute the major portions of the total thermal dose needed for a successful treatment (taken as 240 CEM43°C), and that TD3 dominates for treatments with higher peak temperatures. For a fixed perfusion value, the analytical results show that once the maximum treatment temperature and the total thermal dose (e.g., 240 CEM43°C) are specified, then the required heating time and the applied power magnitude are uniquely determined. These are the optimal heating parameters since lower/higher values result in under-dosing/over-dosing of the treated region. It is also shown that higher maximum treatment temperatures result in shorter treatment times, and for each patient blood flow there is a maximum allowable temperature that can be used to reach the desired thermal dose. In addition, since TD2 and TD3 contribute most of the total thermal dose, and they are both significantly affected by the blood flow present for high treatment temperatures, these results show that perfusion effects must be considered when attempting to optimize high temperature thermal therapy treatments (no excess thermal dose delivered, minimum power applied and shortest treatment time attained).

Low diffusion level within a fibroadenoma as the sole sign of ductal carcinoma in situ: A case report

2021 ◽  
pp. 1-4
Author(s):  
Corrado Tagliati ◽  
Giuseppe Lanni ◽  
Federico Cerimele ◽  
Antonietta Di Martino ◽  
Valentina Calamita ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Ductal Carcinoma In Situ ◽  
Carcinoma In Situ ◽  
Ductal Carcinoma ◽  
Surgical Excision ◽  
Small Region ◽  
Apparent Diffusion Coefficient Value ◽  
Apparent Diffusion

We present a case of ductal carcinoma in situ within a fibroadenoma. Breast cancer arising within fibroadenoma incidence ranges from 0.125% to 0.02%, and ductal carcinoma in situ is not the most frequent malignancy that can be found within a fibroadenoma. Dynamic contrast-enhanced magnetic resonance imaging showed an oval mass with circumscribed margins and dark internal septations, suspicious for fibroadenoma. According to European Society of Breast Radiology diffusion-weighted imaging consensus, mean apparent diffusion coefficient value obtained by drawing a small region of interest on the lesion apparent diffusion coefficient map showed a low diffusion level. Therefore, ductal carcinoma in situ within a fibroadenoma was diagnosed at final pathology after surgical excision.

In Situ XRD Study of Zirconia Phase Transformation Produced from Chemical and Mineral Processes

2016 ◽  
Vol 840 ◽  
pp. 375-380
Author(s):  
Meor Yusoff Meor Sulaiman ◽  
Khaironie Mohamed Takip ◽  
Ahmad Khairulikram Zahari
Keyword(s):  
High Temperature ◽  
Heating Temperature ◽  
Tetragonal Zirconia ◽  
Amorphous Structure ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Zirconyl Chloride ◽  
High Temperature Xrd ◽  
Temperature Phase Transition

The high temperature phase transition of zirconia produced from commercial zirconyl chloride chemical was compared with that produced from a Malaysian zircon mineral. Zirconyl chloride was produced from zircon by using the hydrothermal fusion method. Initial XRD diffractogram of these samples at room temperature show that they are of amorphous structure. High temperature XRD studies was then performed on these samples; heated up to 1500°C. The XRD diffractograms shows that the crystalline structure of tetragonal zirconia was first observed and the monoclinic zirconia becomes more visible at higher heating temperature.

Application Self-Regulating Heating Cable Curing of Concrete in Winter

2014 ◽  
Vol 638-640 ◽  
pp. 1531-1535 ◽  
Author(s):  
Jin Bao Guo ◽  
Lin Liu ◽  
Qiang Wang
Keyword(s):  
Heat Dissipation ◽  
Heating Temperature ◽  
Heating Time ◽  
Minimum Length ◽  
It Use ◽  
Heating Efficiency ◽  
Cable Length ◽  
Heating Cable ◽  
Curing Methods ◽  
Two Parameters

In order to solve the shortcomings of traditional methods of concrete curing in winter, proposed self-regulating heating cable new concrete curing methods. Several aspects were considered, about the heating cable length and heating time, heating temperature. According to energy conservation, heating and heat dissipation balance, derived formulas of heating cable normal use length and minimum. As conclusions is shown, first, the normal length design can controlled better heating temperature, it use the cable length and heating time, heating temperature two parameters to control the other parameters. Second, it is better heating efficiency, can be the overall warming state quickly. In addition, when the concrete pouring temperature is above 10 °C, it is not need additional heating, and it can choose minimum length design formula.

Resistance Welding Process Development and Optimization for Recycled High-Density Polyethylene (HDPE)

2015 ◽  
Author(s):  
Peter F. Baumann ◽  
Lucas Sendrowski
Keyword(s):  
Tensile Strength ◽  
Response Surface ◽  
High Density Polyethylene ◽  
Heating Temperature ◽  
Base Material ◽  
Heating Time ◽  
High Density ◽  
Hot Plate ◽  
Initial Testing ◽  
Hot Plate Welding

Large recycled high-density polyethylene (HDPE) structural members, difficult to manufacture by extrusion processes, have been created by the hot plate welding of simple plastic lumber sections. Hot plate welding generates better joint strength than any other welding method currently employed in plastic manufacturing. However, to achieve the desired temperature of the thick plate to melt the polymer uniformly, the process needs a high amount of heat energy requiring furnace (or resistance) heating of a considerable mass. A new method which could combine the heating element and a thin plate into one source could be more efficient in terms of heat loss and thus energy used. The premise of this investigation is to replace the hot plate with a very thin piece of high resistance nickel-chromium alloy ribbon to localize the application of heat within a plastic weld joint in order to reduce energy loss and its associated costs. This resistance ribbon method uses electrical current to reach an adequate temperature to allow for the welding of the HDPE plastic. The ribbon is only slightly larger than the welding surface and very thin to reduce the loss of excess heat through unused surface area and thick sides. The purpose of this project was to weld recycled high-density polyethylene (HDPE) using resistance welding and to match the tensile strength results considered acceptable in industry for hot plate welding, that is, equal to or greater than 80% of the base material strength. Information obtained through literature review and previous investigations in our laboratories established welding (heating) temperature and time as testing factors. Designed experimentation considered these factors in optimizing the process to maximize the weld tensile strength. A wide-ranging full-factorial experimental design using many levels was created for the initial testing plan. Tensile strengths obtained after welding under the various condition combinations of weld temperature and time revealed a region of higher strength values in the response surface. After the wide-range initial testing, the two control parameters, heating temperature and heating time, were ultimately set up in a focused Face Centered Cubic (FCC) Response Surface Method (RSM) testing design and the tensile strength response was then analyzed using statistical software. The results obtained indicated a strong correlation between heating time and heating temperature with strength. All welded samples in the final testing set exhibited tensile strength of over 90% base material, meeting the goal requirements. A full quadratic equation relationship for tensile strength as a function of welding time and temperature was developed and the maximum tensile strength was achieved when using 280°C for 60 seconds.

scholarly journals SPECTROPHOTOMETRIC DETERMINATION OF PYROCATHECOL AND PYROGALLOL BASED ON THEIR REDOX REACTION WITH IRON(III)/PHENANTHROLINE SYSTEM

2010 ◽  
Vol 2 (3) ◽  
pp. 161-166 ◽  
Author(s):  
Mudasir Mudasir ◽  
Mugiyanti Mugiyanti ◽  
Ngatidjo Hadipranoto
Keyword(s):  
Phenolic Compounds ◽  
Redox Reaction ◽  
Heating Temperature ◽  
Heating Time ◽  
Maximum Absorption ◽  
Optimum Conditions ◽  
Phenanthroline Complex ◽  
Maximum Absorption Wavelength ◽  
Absorption Wavelength

An analytical method for the spectrophotometric determination of some phenolic compounds, i.e.: pyrocathecol and pyrogallol based on their redox reaction with iron(III)-phenanthroline complex has been developed. These two compounds, in appropriate conditions, reduce iron(III)-phenanthroline complex to yield very stable and color-intense complex of iron(II)-phenanthroline, [Fe(phen)2]2+, whose concentration is equivalent to the amount of pyrocathecol or pyrogallol in the solution, and is easily detected by spectrophotometric method. Some parameters influencing the sensitivity of the determination were optimized. These included maximum absorption wavelength, pH of the solution, time and temperature of heatingand reagent to analyte minimum mole-ratio. Using the optimum conditions obtained, the analytical performance of the method was examined and the developed method was then applied to analyzed pyrocathecol and pyrogallol contents in several river water of Yogyakarta, Indonesia. Result of the study showed that the optimum conditions for the determination of pyrocathecol are as follows: maximum absorption wavelength (lmax) at 510 nm, pH of the solution = 4, heating time = 120 min, heating temperature = 70 0C and the minimum mole ratio of reagent to analyte is 8. On the other hand, the optimum conditions for the determination of pyrogallol are as follows: maximum absorption wavelength (lmax) at 510 nm, pH of the solution = 5, heating time = 90 min, heating temperature = 90 0C and the minimum mole ratio of reagent to analyte is 7. At the corresponding conditions of analysis, calibration curves for pyrocathecol and pyrogallol are linear in the range concentration of 0.00 - 0.16 ppm and 0.00 - 0.24 ppm, respectively. The correlation coefficients for both compounds were found to be higher than 0.998 and the detection limits went down below 0.07 ppm. It has been demonstrated that the developed method can be applied for the determination of pyrocathecol and pyrogallol contents in natural samples.   Keywords: Spectrophotometry, phenolic compounds, 1,10-phenanthroline, redox reaction

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