scholarly journals How Thermal Aging Affects Ignition and Combustion Properties of Reactive Al/CuO Nanolaminates: A Joint Theoretical/Experimental Study

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2087 ◽  
Author(s):  
A. Estève ◽  
G. Lahiner ◽  
B. Julien ◽  
S. Vivies ◽  
N. Richard ◽  
...  
Keyword(s):  
Thermal Aging ◽  
Ignition Time ◽  
Thermal Conditions ◽  
Heat Of Reaction ◽  
Bilayer Thickness ◽  
Long Term Storage ◽  
Combustion Properties ◽  
Ignition And Combustion ◽  
Burn Rate ◽  
The Impact

The paper reports a joint experimental/theoretical study on the aging of reactive Al/CuO nanolaminates, investigating both structural modifications and combustion properties of aged systems. We first show theoretically that the long-term storage (over several decades) in ambient temperature marginally affects nanolaminates structural properties with an increase in an interfacial layer of only 0.3 nm after 30 years. Then, we observe that the first thermal aging step occurs after 14 days at 200 °C, which corresponds to the replacement of the natural Al/CuO interfaces by a proper ~11 nm thick amorphous alumina. We show that this aging step does impact the nanolaminates structure, leading, for thin bilayer thicknesses, to a substantial loss of the energetic reservoir: considering a stoichiometric Al/CuO stack, the heat of reaction can be reduced by 6–40% depending on the bilayer thickness ranging from 150 nm (40%) to 1 µm (6%). The impact of such thermal aging (14 days at 200 °C) and interfacial modification on the initiation and combustion properties have been evaluated experimentally and theoretically. Varying Al to CuO ratio of nanolaminates from 1 to 3, we show that ignition time of aged systems does not increase over 10% at initiation power densities superior to 15 W·mm−2. In contrast, burn rate can be greatly impacted depending on the bilayer thickness: annealing a stoichiometric nanolaminates with a bilayer thickness of 300 nm at 200 °C for 14 days lowers its burn rate by ~25%, whereas annealing a fuel rich nanolaminates with the same bilayer thickness under the same thermal conditions leads to a burn rate decrease of 20%. When bilayer thickness is greater than 500 nm, the burn rate is not really affected by the thermal aging. Finally, this paper also proposes a time–temperature diagram to perform accelerated thermal aging.

scholarly journals Comfort within Budget: Assessing the Cost-Effectiveness of Envelope Improvements in Single-Family Affordable Housing

2021 ◽  
Vol 13 (6) ◽  
pp. 3054
Author(s):  
Renata Tubelo ◽  
Lucelia Rodrigues ◽  
Mark Gillott ◽  
May Zune
Keyword(s):  
Cost Effectiveness ◽  
Affordable Housing ◽  
Energy Use ◽  
Thermal Conditions ◽  
Building Envelope ◽  
Single Family ◽  
Design Strategies ◽  
Housing Type ◽  
The Cost ◽  
The Impact

In Brazil, the delivery of homes for low-inc ome households is dictated by costs rather than performance. Issues such as the impact of climate change, affordability of operational energy use, and lack of energy security are not taken into account, even though they can severely impact the occupants. In this work, the authors evaluated the thermal performance of two affordable houses as-built and after the integration of envelope improvements. A new replicable method to evaluate the cost-effectiveness of these improvements was proposed. The case study houses comprise the most common affordable housing type delivered widely across Brazil and a proposition of a better affordable housing solution, built in Porto Alegre, southern Brazil, integrating passive design strategies to increase thermal comfort. The findings reveal a potential for improving indoor thermal conditions by up to 76% and 73%, respectively, if costs are not a concern, and 40% and 45% with a cost increase of 12% and 9% if a comfort criterion of 20–25 °C was considered. Equations to estimate costs of improvements in affordable housing were developed. The authors concluded that there is a great scope for building envelope optimisation, and that this is still possible without significant impact on budget.

scholarly journals LES study on mixing and combustion in a Direct Injection Spark Ignition engine

2018 ◽  
Vol 73 ◽  
pp. 32
Author(s):  
Nicolas Iafrate ◽  
Anthony Robert ◽  
Jean-Baptiste Michel ◽  
Olivier Colin ◽  
Benedicte Cuenot ◽  
...  
Keyword(s):  
Ignition Time ◽  
Direct Injection ◽  
Combustion Process ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Pollutant Emissions ◽  
Spark Ignition Engines ◽  
Eddy Simulation ◽  
Mixture Preparation ◽  
The Impact

Downsized spark ignition engines coupled with a direct injection strategy are more and more attractive for car manufacturers in order to reduce pollutant emissions and increase efficiency. However, the combustion process may be affected by local heterogeneities caused by the interaction between the spray and turbulence. The aim for car manufacturers of such engine strategy is to create, for mid-to-high speeds and mid-up-high loads, a mixture which is as homogeneous as possible. However, although injection occurs during the intake phase, which favors homogeneous mixing, local heterogeneities of the equivalence ratio are still observed at the ignition time. The analysis of the mixture preparation is difficult to perform experimentally because of limited optical accesses. In this context, numerical simulation, and in particular Large Eddy Simulation (LES) are complementary tools for the understanding and analysis of unsteady phenomena. The paper presents the LES study of the impact of direct injection on the mixture preparation and combustion in a spark ignition engine. Numerical simulations are validated by comparing LES results with experimental data previously obtained at IFPEN. Two main analyses are performed. The first one focuses on the fuel mixing and the second one concerns the effect of the liquid phase on the combustion process. To highlight these phenomena, simulations with and without liquid injection are performed and compared.

Different breeding conditions affect the morphological variability in larvae of Platytrombidium fasciatum (Trombidiformes: Microtrombidiidae)

2021 ◽  
Vol 26 (6) ◽  
pp. 1055-1066
Author(s):  
Anna Derdak ◽  
Magdalena Felska ◽  
Joanna Mąkol ◽  
Paula Zajkowska
Keyword(s):  
Quantitative Traits ◽  
Morphological Variability ◽  
Thermal Conditions ◽  
Dark Cycle ◽  
Posterior Edge ◽  
Morphometric Traits ◽  
Egg Incubation ◽  
The Impact ◽  
Metric Traits ◽  
Duration Of Development

The impact of temperature and light/dark cycle on morphological traits of Platytrombidium fasciatum was examined in larvae obtained from field-collected females. The eggs laid by 65 females at laboratory conditions were assigned to four experimental groups. Varied thermal conditions affected the values of nine out of 46 (nonparametric MANOVA) and 26 out of 37 (LDA) morphometric traits in larvae. As many as six quantitative traits differed significantly irrespective of the method (MANOVA, LDA) applied. The analysis of the metric traits within the dorsal sclerites revealed that the lower mean temperature over the period of egg incubation, translated into longer duration of development, was associated with an increase in distance between the bases of 3rd pair of non-sensillary setae on scutum at the decrease in distance between the bases of 2nd pair of non-sensillary setae as well as in distance between the level of sensilla and the posterior edge of the sclerite. In the case of 40 measurable traits in larvae of P. fasciatum, the variability going beyond the hitherto knowledge on the species was observed.

scholarly journals Influence of Mo Additions on the Mechanical Properties of Cast Duplex Stainless Steels before and after Thermal Aging

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 295
Author(s):  
Shilei Li ◽  
Yanli Wang ◽  
Xitao Wang
Keyword(s):  
Mechanical Properties ◽  
Stainless Steels ◽  
Thermal Aging ◽  
Decomposition Kinetics ◽  
Before And After ◽  
Mo Content ◽  
Impact Energies ◽  
The Impact ◽  
Hardness Values ◽  
Mo Additions

The influence of Mo additions on the mechanical properties of cast duplex stainless steel (CDSS) before and after thermal aging was investigated using a series of model alloys with different Mo contents ranging from 0 to 1.75 wt%. By increasing Mo content, the content, morphology, and distribution of ferrite in CDSS change significantly. After thermal aging at 400 °C for 3000 h, the impact properties of all CDSS specimens obviously decline, and their hardness values in ferrite significantly increase. The impact energies of the aged CDSS decline, and the proportion of cleavage features significantly increases with Mo content increasing. The spinodal decomposition kinetics in ferrite is not significantly affected by the Mo contents. High content and interconnected ferrite will lead to the severe embrittlement in CDSS after thermal aging.

scholarly journals Rapid, Reproducible, Quantifiable NMR Metabolomics: Methanol and Methanol: Chloroform Precipitation for Removal of Macromolecules in Serum and Whole Blood

Metabolites ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 93 ◽  
Author(s):  
Cora McHugh ◽  
Thomas Flott ◽  
Casey Schooff ◽  
Zyad Smiley ◽  
Michael Puskarich ◽  
...  
Keyword(s):  
Human Serum ◽  
1H Nmr ◽  
Whole Blood ◽  
Nmr Spectra ◽  
High Quality ◽  
Healthy Human ◽  
Long Term Storage ◽  
The Impact ◽  
Term Storage

Background: Though blood is an excellent biofluid for metabolomics, proteins and lipids present in blood can interfere with 1d-1H NMR spectra and disrupt quantification of metabolites. Here, we present effective macromolecule removal strategies for serum and whole blood (WB) samples. Methods: A variety of macromolecule removal strategies were compared in both WB and serum, along with tests of ultrafiltration alone and in combination with precipitation methods. Results: In healthy human serum, methanol:chloroform:water extraction with ultrafiltration was compared to methanol precipitation with and without ultrafiltration. Methods were tested in healthy pooled human serum, and in serum from patients with sepsis. Effects of long-term storage at −80 °C were tested to explore the impact of macromolecule removal strategy on serum from different conditions. In WB a variety of extraction strategies were tested in two types of WB (from pigs and baboons) to examine the impact of macromolecule removal strategies on different samples. Conclusions: In healthy human serum methanol precipitation of serum with ultrafiltration was superior, but was similar in recovery and variance to methanol:chloroform:water extraction with ultrafiltration in pooled serum from patients with sepsis. In WB, high quality, quantifiable spectra were obtained with the use of a methanol: chloroform precipitation.

scholarly journals 3′ MACE RNA-sequencing allows for transcriptome profiling in human tissue samples after long-term storage

2020 ◽  
Vol 100 (10) ◽  
pp. 1345-1355 ◽  
Author(s):  
Stefaniya Boneva ◽  
Anja Schlecht ◽  
Daniel Böhringer ◽  
Hans Mittelviefhaus ◽  
Thomas Reinhard ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Storage Time ◽  
Transcriptome Profiling ◽  
Rna Seq ◽  
Fresh Tissue ◽  
Long Term Storage ◽  
Ffpe Samples ◽  
The Impact ◽  
Term Storage

Abstract This study aims to compare the potential of standard RNA-sequencing (RNA-Seq) and 3′ massive analysis of c-DNA ends (MACE) RNA-sequencing for the analysis of fresh tissue and describes transcriptome profiling of formalin-fixed paraffin-embedded (FFPE) archival human samples by MACE. To compare MACE to standard RNA-Seq on fresh tissue, four healthy conjunctiva from four subjects were collected during vitreoretinal surgery, halved and immediately transferred to RNA lysis buffer without prior fixation and then processed for either standard RNA-Seq or MACE RNA-Seq analysis. To assess the impact of FFPE preparation on MACE, a third part was fixed in formalin and processed for paraffin embedding, and its transcriptional profile was compared with the unfixed specimens analyzed by MACE. To investigate the impact of FFPE storage time on MACE results, 24 FFPE-treated conjunctival samples from 24 patients were analyzed as well. Nineteen thousand six hundred fifty-nine transcribed genes were detected by both MACE and standard RNA-Seq on fresh tissue, while 3251 and 2213 transcripts were identified explicitly by MACE or RNA-Seq, respectively. Standard RNA-Seq tended to yield longer detected transcripts more often than MACE technology despite normalization, indicating that the MACE technology is less susceptible to a length bias. FFPE processing revealed negligible effects on MACE sequencing results. Several quality-control measurements showed that long-term storage in paraffin did not decrease the diversity of MACE libraries. We noted a nonlinear relation between storage time and the number of raw reads with an accelerated decrease within the first 1000 days in paraffin, while the numbers remained relatively stable in older samples. Interestingly, the number of transcribed genes detected was independent on FFPE storage time. RNA of sufficient quality and quantity can be extracted from FFPE samples to obtain comprehensive transcriptome profiling using MACE technology. We thus present MACE as a novel opportunity for utilizing FFPE samples stored in histological archives.

Thermal Ageing Embrittlement of Casting Duplex Stainless Steels for Nuclear Power Plant

2010 ◽  
Author(s):  
Yuhong Yao ◽  
Jianfeng Wei ◽  
Jiangnan Liu ◽  
Zhengpin Wang ◽  
Yu Wang
Keyword(s):  
Stainless Steels ◽  
Thermal Aging ◽  
Nuclear Power ◽  
Power Plants ◽  
Ageing Time ◽  
Thermal Ageing ◽  
Duplex Stainless Steels ◽  
Impact Properties ◽  
Α Phase ◽  
The Impact

Cast duplex stainless steels (CSS) used for PWR pipes are degraded due to thermal ageing embrittlement during long-term service at 288 °C to 327 °C. Z3CN20-09M Cast duplex Stainless Steels (CSS) made in France for domestic nuclear power plants were thermally aged at 400 °C for 100 h, 300 h, 1000 h, 3000 h and 10000 h. The tensile properties and the impact properties at different thermal aging duration were measured and the effects of the thermal aging time on the microscopic structures and substructures of Z3CN20-09M were respectively investigated by optical microscopy and transmission electron microscopy. The results showed that the tensile strengths of Z3CN20-09M CSS increased gradually with the increment of the thermal ageing time, whereas the impact properties decreased with the prolonging of the thermal ageing time. After long thermal ageing time the dislocation configurations were greatly changed in austenite, and there were precipitates along the austenite-ferrite interface. Moreover, the iron-rich α phase and the chromium-rich α phase precipitated in ferrite aged for 10000h by nucleation and growth rather than the spinodal decomposition. All of above revealed that Z3CN20-09M CSS became brittle during thermal ageing.

Sign in / Sign up

Export Citation Format

Share Document