Cellulose nitrate (CN) has been used in the past as support for photographic negatives and cinematographic films. This material is particularly unstable and can undergoes severe degradation due to ...thermal, photocatalytic and hydrolytic loss of nitro groups from the lateral chain. Thus, to prevent the disappearance of the movies, their scanning and digitalization become a priority.
However, CN bases degradation may prevent the scanning of the films. The decrease in pH, for instance, lowers the viscosity of gelatin, which becomes softer. This causes the formation of gelatin residues which stick on the back of the superimposed frames inside the reels creating a deposit.
Traditional approaches to clean gelatin residues from the surface of CN bases include the mechanical removal with scalpels and the use of organic solvents (such as isopropyl alcohol). However, these methods are either slow and ineffective or could potentially damage the degraded CN supports.
To overcome these drawbacks, we have evaluated the performance of three choline chloride and betaine-based Deep Eutectic Solvent (DES) formulations as alternative for the removal of gelatine residues from CN supports. These solvents are inexpensive (when compared to traditional solvents), easy to prepare, green (non volatile, safe towards the operators and the environment, and potentially recyclable), non flammable and have been previously proposed for the extraction of proteinaceous materials, but their use for the restoration of photographic negatives or cinematographic films has not been reported yet.
Selected areas over the frames of a real deteriorated CN cinematographic film were cleaned comparing the DES performances with the ones obtained using isopropyl alcohol as an example of a traditional method.
In particular, the tested DES formulations showed superior cleaning power compared to isopropyl alcohol and, at the selected application times, resulted capable to remove the gelatin residues without affecting the CN film supports.
Graphical abstract
•Analysis of seven masonry churches damaged by the Emilia Romagna (2012) seismic event.•Non-linear dynamic analyses conducted by means of full 3D FE models.•Evaluation of vulnerable parts and active ...partial mechanisms.•Non-linear isotropic damage–plasticity material used to model masonry.•Comparison with results obtained with standard eigen-frequency, pushover and limit analyses.
This study presents a detailed failure analysis of seven masonry churches, which were severely damaged during the 2012 Emilia-Romagna (Italy) seismic sequence, by means of 3D FE non-linear dynamic simulations. The main aims of the numerical investigations are: (1) to carry out a sufficiently wide sensitivity study on different specific case studies to have an insight into the role played by the geometry – which is always unique for churches – and by the irregularities; (2) to validate or address the limits of applicability of the most widespread conventional static approaches recommended by Italian Code, i.e. kinematic limit and pushover analyses. Non-linear dynamic analyses are carried out assuming that masonry behaves as a non-linear material exhibiting softening and damage, frictional behavior and different strength in tension and compression. The set of case studies investigated in this work shows how conventional static approaches are still capable of roughly identifying the most critical macro-elements that usually activate a failure mechanism, but that the results (e.g. collapse acceleration, behavior factor) are affected by a level of approximation that may considerably depend on in-plan irregularity and hypotheses done on the interlocking between contiguous walls. From the comparative analyses carried out, it is authors’ opinion that it is always beneficial to perform different types of analysis in order to have a comprehensive insight into the portions of the structure that can suffer a partial collapse with high probability. Once the active mechanism is identified, non-linear dynamic analyses, with more sophisticated material models and with refined FE discretizations of the critical regions, may be useful to deepen the knowledge of the behavior of such complex structures under seismic actions.
•Analysis of seven masonry churches damaged during Emilia Romagna (2012) earthquake.•Non-linear dynamic analyses NLADA conducted through full 3D FE models in ABAQUS.•Detailed survey of damages and ...crack patterns.•Non-linear isotropic damage-plasticity material used to model masonry.•Comparison with results from standard approaches and post-processed NLDA considerations.
The seismic performance assessment of historical masonry structures is still a complex issue in civil engineering. This paper investigates the seismic response of seven masonry churches, which are located in the province of Ferrara (Northern Italy) and suffered extensive damage during the 2012 Emilia earthquake. Different field surveys, which were conducted after the earthquake to collect information on typical damage patterns, provided a preliminary knowledge of utmost importance for developing detailed FE models of the churches and for better understanding the results of advanced numerical simulations. First, modal analyses were performed to have a preliminary insight into the dynamic behavior of the churches. Then, non-linear dynamic analyses with different peak ground accelerations were carried out in order to obtain the damage distribution in the churches and to identify the most vulnerable macro-elements. The results highlighted the influence of morphological and geometrical characteristics on the seismic behavior of the different macro-elements composing the churches.
Predicting software defects with causality tests Couto, Cesar; Pires, Pedro; Valente, Marco Tulio ...
Journal of systems and software/The Journal of systems and software,
07/2014, Letnik:
93
Journal Article
Recenzirano
Odprti dostop
•We propose an approach for predicting defects using Granger causality tests.•We extend a public dataset to evaluate defect prediction techniques.•We describe a first study to evaluate the ...feasibility of our approach.•We report a second study to evaluate our model for triggering defects alarms.•We compare our approach with baselines that are not based on causality tests.
In this paper, we propose a defect prediction approach centered on more robust evidences towards causality between source code metrics (as predictors) and the occurrence of defects. More specifically, we rely on the Granger causality test to evaluate whether past variations in source code metrics values can be used to forecast changes in time series of defects. Our approach triggers alarms when changes made to the source code of a target system have a high chance of producing defects. We evaluated our approach in several life stages of four Java-based systems. We reached an average precision greater than 50% in three out of the four systems we evaluated. Moreover, by comparing our approach with baselines that are not based on causality tests, it achieved a better precision.
In case of a mass casualty radiation event, there is a need to distinguish total-body irradiation (TBI) and partial-body irradiation (PBI) to concentrate overwhelmed medical resources to the ...individuals that would develop an acute radiation syndrome (ARS) and need hematologic support (i.e., mostly TBI victims). To improve the identification and medical care of TBI versus PBI individuals, reliable biomarkers of exposure could be very useful. To investigate this issue, pairs of baboons (n = 18) were exposed to different situations of TBI and PBI corresponding to an equivalent of either 5 Gy 60Co gamma irradiation (5 Gy TBI; 7.5 Gy left hemibody/2.5 right hemibody TBI; 5.55 Gy 90% PBI; 6.25 Gy 80% PBI; 10 Gy 50% PBI, 15 Gy 30% PBI) or 2.5 Gy (2.5 Gy TBI; 5 Gy 50% PBI). More than fifty parameters were evaluated before and after irradiation at several time points up to 200 days. A partial least square discriminant analysis showed a good distinction of TBI from PBI situations that were equivalent to 5 Gy. Furthermore, all the animals were pooled in two groups, TBI (n = 6) and PBI (n = 12), for comparison using a logistic regression and a non parametric statistical test. Nine plasmatic biochemical markers and most of hematological parameters turned out to discriminate between TBI and PBI animals during the prodromal phase and the manifest illness phase. The most significant biomarkers were aspartate aminotransferase, creatine kinase, lactico dehydrogenase, urea, Flt3-ligand, iron, C-reactive protein, absolute neutrophil count and neutrophil-to-lymphocyte ratio for the early period, and Flt3-ligand, iron, platelet count, hemoglobin, monocyte count, absolute neutrophil count and neutrophil-to-lymphocyte ratio for the ARS phase. These results suggest that heterogeneity could be distinguished within a range of 2.5 to 5 Gy TBI.
For effective medical management of radiation-exposed persons after a radiological/nuclear event, blood-based screening measures in the first few days that could predict hematologic acute radiation ...syndrome (HARS) are needed. For HARS severity prediction, we used microRNA (miRNA) expression changes measured on days one and two after irradiation in a baboon model. Eighteen baboons underwent different patterns of partial or total body irradiation, corresponding to an equivalent dose of 2.5 or 5 Gy. According to changes in blood cell counts (BCC) the surviving baboons (n = 17) exhibited mild (H1-2, n = 4) or more severe (H2-3, n = 13) HARS. In a two Stage study design we screened 667 miRNAs using a quantitative real-time polymerase chain reaction (qRT-PCR) platform. In Stage II we validated candidates where miRNAs had to show a similar regulation (up- or down-regulated) and a significant 2-fold miRNA expression difference over H0. Seventy-two candidate miRNAs (42 for H1-2 and 30 for H2-3) were forwarded for validation. Forty-two of the H1-2 miRNA candidates from the screening phase entered the validation step and 20 of them showed a statistically significant 2-4 fold up-regulation relative to the unexposed reference (H0). Fifteen of the 30 H2-3 miRNAs were validated in Stage II. All miRNAs appeared 2-3 fold down-regulated over H0 and allowed an almost complete separation of HARS categories; the strongest candidate, miR-342-3p, showed a sustained and 10-fold down-regulation on both days 1 and 2. In summary, our data support the medical decision making of the HARS even within the first two days after exposure where diagnostic tools for early medical decision are required but so far missing. The miRNA species identified and in particular miR-342-3p add to the previously identified mRNAs and complete the portfolio of identified mRNA and miRNA transcripts for HARS prediction and medical management.
We examined the transcriptome/post-transcriptome for persistent gene expression changes after radiation exposure in a baboon model. Eighteen baboons were irradiated with a whole body equivalent dose ...of 2.5 or 5 Gy. Blood samples were taken before, 7, 28 and 75-106 days after radiation exposure. Stage I was a whole genome screening for mRNA combined with a qRT-PCR platform for detection of 667 miRNAs. Candidate mRNAs and miRNAs differentially up- or down-regulated in stage I were chosen for validation in stage II using the remaining samples. Only 12 of 32 candidate genes provided analyzable results with two mRNAs showing significant 3-5-fold differences in gene expression over the reference (p < 0.0001). From 667 candidate miRNAs, 290 miRNA were eligible for analysis with 21 miRNAs independently validated using qRT-PCR. These miRNAs showed persistent expression changes on each day and over days 7-106 days after exposure (n = 7). In particular miR-212 involved in radiosensitivity and immune modulation appeared persistently and 48-77-fold up-regulated over the entire time period. We are finally trying to put our results into a context of clinical implications and provide possible hints on underlying molecular mechanisms to be examined in future studies.
Low-voltage carbon films deposition by electro-exfoliation of graphite into graphene oxide is reported. By simply employing two different anodes, Pt or graphite, it is demonstrated that the carbon ...film deposition takes place by the graphite electro-exfoliation and not by the carbonic molecules from the electrolyte as has been frequently reported. By means of Raman spectroscopy, scanning electron microscopy (SEM), cyclic voltammetry (CV), X-ray diffractometry (XRD), atomic force microscopy (AFM), and dynamic light scattering (DLS), graphene oxide is successfully characterized. In addition, this electro-exfoliation process may be an alternative green route for the production of graphene oxide.
Low-voltage carbon films deposition by electro-exfoliation of graphite into graphene oxide is reported.
Use of plasma proteomic and hematological biomarkers represents a promising approach to provide useful diagnostic information for assessment of the severity of hematopoietic acute radiation syndrome. ...Eighteen baboons were evaluated in a radiation model that underwent total-body and partial-body irradiations at doses of Co gamma rays from 2.5 to 15 Gy at dose rates of 6.25 cGy min and 32 cGy min. Hematopoietic acute radiation syndrome severity levels determined by an analysis of blood count changes measured up to 60 d after irradiation were used to gauge overall hematopoietic acute radiation syndrome severity classifications. A panel of protein biomarkers was measured on plasma samples collected at 0 to 28 d after exposure using electrochemiluminescence-detection technology. The database was split into two distinct groups (i.e., "calibration," n = 11; "validation," n = 7). The calibration database was used in an initial stepwise regression multivariate model-fitting approach followed by down selection of biomarkers for identification of subpanels of hematopoietic acute radiation syndrome-responsive biomarkers for three time windows (i.e., 0-2 d, 2-7 d, 7-28 d). Model 1 (0-2 d) includes log C-reactive protein (p < 0.0001), log interleukin-13 (p < 0.0054), and procalcitonin (p < 0.0316) biomarkers; model 2 (2-7 d) includes log CD27 (p < 0.0001), log FMS-related tyrosine kinase 3 ligand (p < 0.0001), log serum amyloid A (p < 0.0007), and log interleukin-6 (p < 0.0002); and model 3 (7-28 d) includes log CD27 (p < 0.0012), log serum amyloid A (p < 0.0002), log erythropoietin (p < 0.0001), and log CD177 (p < 0.0001). The predicted risk of radiation injury categorization values, representing the hematopoietic acute radiation syndrome severity outcome for the three models, produced least squares multiple regression fit confidences of R = 0.73, 0.82, and 0.75, respectively. The resultant algorithms support the proof of concept that plasma proteomic biomarkers can supplement clinical signs and symptoms to assess hematopoietic acute radiation syndrome risk severity.
► The impact performances of basalt/aramid interply hybrid composites were studied. ► Effect of two different stacking sequences on impact resistance was investigated. ► Residual flexural strength ...after impact for the different lay-ups was analyzed. ► Intercalated hybrids exhibited the best energy absorption capability. ► Sandwich hybrids offered the best flexural strength at all impact energies.
The low-velocity impact behaviour of hybrid laminates reinforced with woven aramid and basalt fabrics and manufactured by resin transfer moulding was studied. Specimens with different stacking sequences were tested at three different energies, namely 5, 12.5 and 25J. Residual post-impact properties of the different configurations of aramid/basalt hybrid laminates were characterized by quasi static four point bending tests. Post-impact flexural tests have been monitored using acoustic emission in order to get further information on failure mechanisms. Results indicate that hybrid laminates with intercalated configuration (alternating sequence of basalt and aramid fabrics) have better impact energy absorption capability and enhanced damage tolerance with respect to the all-aramid laminates, while basalt and hybrid laminates with sandwich-like configuration (seven basalt fabric layers at the centre of the laminate as core and three aramid fabric layers for each side of the composite as skins) present the most favourable flexural behaviour.
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