•New Schiff bases tested as bronze corrosion inhibitors in concentrated acid rain.•2-(Salicylideneimino) thiophenol (SITP) afforded η = 100% after 480 h immersion.•Duplex protective film formed: ...adsorbed SITP molecules over a Cu(I)-SITP layer.•Phosphates (P) added to SITP produced higher resistance against localized attack.•SITP and SITP + P hindered bronze decuprification in concentrated acid rain.
In this research, different Schiff bases were synthesized and tested as bronze corrosion inhibitors in concentrated synthetic acid rain at pH 3.3. Some of them showed good inhibiting effects, as detected by EIS and polarization curve recording. The most efficient inhibitor (2-(salicylideneimino) thiophenol, SITP) was also tested with addition of sodium dihydrogen phosphate (P). P improved the surface film resistance against breakdown phenomena. XPS and SEM investigations showed that SITP and SITP + P significantly hinder decuprification. Moreover, SITP forms a protective layer on bronze, composed of both Cu(I)-SITP complexes and adsorbed inhibitor molecules. Cu(II) phosphates were also detected with P addition.
•The limits for LDX 2101® duplex stainless steel application in H2S-containing environments.•The susceptibility to SCC of LDX 2101® duplex stainless steel in the presence of Cl− and SO32-.•The ...possibility of substituting H2S with thiosulphate for the study of the SCC susceptibility.•The selective corrosion of ferrite phase during crack propagation process in the tested media.
SCC behaviour of a LDX 2101® stainless steel was studied through SSRT in a 20% NaCl solution at 80°C and in the standard NACE TM-0177 solution at 25°C in the presence of S2O32-. Some tests were also performed in the NACE solution at various pH or temperatures. The LDX 2101® was susceptible to SCC in the presence of small thiosulphate concentrations. The selective corrosion of the ferrite phase became the main cause of failure when the thiosulphate concentration was increased to 0.1M in the 20% NaCl at 80°C or when NACE solution temperature was raised to 80°C.
Estimation of the postmortem interval in advanced postmortem stages is a challenging task. Although there are several approaches available for addressing postmortem changes of a (human) body or its ...environment (ecologically and/or biochemically), most are restricted to specific timeframes and/or individual and environmental conditions. It is well known, for instance, that buried bodies decompose in a remarkably different manner than on the ground surface. However, data on how established methods for PMI estimation perform under these conditions are scarce. It is important to understand whether and how postmortem changes are affected under burial conditions, if corrective factors could be conceived, or if methods have to be excluded for respective cases. We present the first multi-methodological assessment of human postmortem decomposition carried out on buried body donors in Europe, at the Amsterdam Research Initiative for Sub-surface Taphonomy and Anthropology (ARISTA) in the Netherlands. We used a multidisciplinary approach to investigate postmortem changes of morphology, skeletal muscle protein decomposition, presence of insects and other necrophilous animals as well as microbial communities (i.e., microbiomes) from August to November 2018 associated with two complete body exhumations and eight partial exhumations. Our results clearly display the current possibilities and limitations of methods for PMI estimation in buried remains and provide a baseline for future research and application.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This study concerns the corrosion behavior of steel in different room temperature cured alkali-activated fly ash mortars exposed to chloride solution. The corrosion process was monitored by ...polarization resistance and corrosion potential measurements and the results were interpreted in the light of a complete microstructural, mechanical and chemical characterization of the mortars. The most compact alkali-activated mortars have higher porosity and lower mechanical properties than a cement-based mortar (CEM), but the protectiveness afforded to the rebars is slightly higher than that obtained in CEM. The reason for this discrepancy is connected to a lower chloride content accumulated in the former mortar type and to a specific inhibition of the rebar corrosion afforded by the pore electrolyte in alkali-activated mortars.
Background
A precise determination of time since death plays a major role in forensic routine. Currently available techniques for estimating the postmortem interval (PMI) are restricted to specific ...time periods or cannot be applied for individual case-specific reasons. During recent years, it has been repeatedly demonstrated that Western blot analysis of postmortem muscle protein degradation can substantially contribute to overcome these limitations in cases with different background. Enabling to delimit time points at which certain marker proteins undergo distinct degradation events, the method has become a reasonable new tool for PMI delimitation under various forensic scenarios. However, additional research is yet required to improve our understanding of protein decomposition and how it is affected by intrinsic and extrinsic factors.
Since there are temperature limits for proteolysis, and investigators are confronted with frozen corpses, investigation of the effects of freezing and thawing on postmortem protein decomposition in the muscle tissue is an important objective to firmly establish the new method. It is also important because freezing is often the only practical means to intermittently preserve tissue samples from both true cases and animal model research.
Methods
Sets of dismembered pig hind limbs, either freshly detached non-frozen, or thawed after 4 months of freeze-storage (
n
= 6 each), were left to decompose under controlled conditions at 30 °C for 7 days and 10 days, respectively. Samples of the M. biceps femoris were regularly collected at predefined time points. All samples were processed via SDS-PAGE and Western blotting to identify the degradation patterns of previously characterized muscle proteins.
Results
Western blots show that the proteins degrade predictably over time in precise patterns that are largely unaffected by the freeze-and-thaw process. Investigated proteins showed complete degradation of the native protein band, partly giving rise to degradation products present in distinct time phases of the decomposition process.
Conclusion
This study provides substantial new information from a porcine model to assess the degree of bias that freezing and thawing induces on postmortem degradation of skeletal muscle proteins. Results support that a freeze–thaw cycle with prolonged storage in frozen state has no significant impact on the decomposition behavior. This will help to equip the protein degradation–based method for PMI determination with a robust applicability in the normal forensic setting.
•Study of the effect of brief-time aging within 650÷850°C on LDSS 2101 SCC resistance.•Thermal aging determined precipitation of chromium carbides and especially nitrides.•LDSS 2101 was susceptible ...to SCC in NACE TM-0177 without/with S2O32− ions.•SCC susceptibility in the presence of S2O32− increased after thermal aging.•Interstitial nitrogen impoverishment negatively affected SCC susceptibility.
In this paper, the effect of brief aging within the 650–850°C temperature range on the resistance of lean duplex stainless steel (LDSS) 2101 to stress corrosion cracking (SCC) was discussed. The thermal aging induced a decrease in Vickers microhardness and an increase in alloy ductility. This behaviour was connected to depletion of interstitial nitrogen in austenite. LDSS 2101 was found to suffer SCC in NACE TM-0177 solution, particularly under specific thermal aging and in the presence of thiosulphate ions (S2O32−) at 10−4 and 10−3M. Crack nucleation and propagation were linked to microstructural variations connected to thermal aging.
► Prefilming agents have been applied on bronze, as alternatives to BTA. ► The best protective properties have been achieved with a silane compound. ► Preliminary tests suggest it can hinder the ...degradation of gilded bronze. ► The inhibition mechanism of silane is investigated by FTIR, EDS and Raman.
Corrosion inhibitors, associated or not with protective coatings, may be a good solution for planned conservation activities in the case of bronze and gilded bronze artworks.
In this work, alternatives to BTA for the inhibition of bronzes and gilded bronze are investigated. The experimentation includes a screening of many organic substances as film-forming corrosion inhibitors for a copper alloy reproducing the composition and the microstructure of a Renaissance leaded bronze. The results, obtained after exposure to 3.5wt.% NaCl solution or concentrated artificial rain, show that, if proper curing conditions are adopted, excellent protective properties are offered by 3-mercaptopropyl-trimetoxysilane.
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•Protectiveness of organosilane coating (PropS-SH) on patinated bronze was assessed.•Patina of cuprous oxide and sulphide does not protect the bronze against corrosion.•Both sprayed ...PropS-SH and Incralac® offer a good protection to patinated bronze.•PropS-SH shows excellent performance under UV light and simulated outdoor exposure.•Higher wettability of PropS-SH favours its penetration in porous patina structure.
A 3-mercapto-propyl-trimethoxysilane coating (PropS-SH) applied on Cu-Si-Mn bronze, patinated by “liver of sulphur”, was investigated as a non-toxic alternative to Incralac®, usually applied on outdoor artistic bronzes. Electrochemical testing was performed in synthetic acid rain. Exposure to temperature/UV cycles and accelerated corrosion test simulating unsheltered exposure to rainwater was also carried out. The exposed samples were characterised by FEG-SEM coupled with EDS on FIB cross-sections and XPS on free surfaces. The black patina without protective coating was scarcely protective against bronze corrosion and easily transformed into cuprous oxide. PropS-SH coating fully preserved the black patina microstructure and phase constituents (cuprous oxide and cuprous sulphide). The PropS-SH coating also resulted more protective than Incralac® when aged under run-off conditions. Selective dissolution of copper from the silicon bronze alloy was observed on both uncoated and Incralac®-coated bronze, leading to the formation of an internal Si-rich corrosion layer.
We provide a systematic review of the literature to evaluate the current research status of protein degradation-based postmortem interval (PMI) estimation. Special attention is paid to the ...applicability of the proposed approaches/methods in forensic routine practice.
A systematic review of the literature on protein degradation in tissues and organs of animals and humans was conducted. Therefore, we searched the scientific databases Pubmed and Ovid for publications until December 2019. Additional searches were performed in Google Scholar and the reference lists of eligible articles.
A total of 36 studies were included. This enabled us to consider the degradation pattern of over 130 proteins from 11 different tissues, studied with different methods including well-established and modern approaches. Although comparison between studies is complicated by the heterogeneity of study designs, tissue types, methods, proteins and outcome measurement, there is clear evidence for a high explanatory power of protein degradation analysis in forensic PMI analysis.
Although only few approaches have yet exceeded a basic research level, the current research status provides strong evidence in favor of the applicability of a protein degradation-based PMI estimation method in routine forensic practice. Further targeted research effort towards specific aims (also addressing influencing factors and exclusion criteria), especially in human tissue will be required to obtain a robust, reliable laboratory protocol, and collect sufficient data to develop accurate multifactorial mathematical decomposition models.
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