Search results for: composite damage

Authors: Fatiha Mohammed Arab, Benoit Augier, Francois Deniset, Pascal Casari, Jacques Andre Astolfi

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For the top high performance foiling yachts, cavitation is often a limiting factor for take-off and top speed. This work investigates solutions to delay the onset of cavitation thanks to structural morphing. The structural morphing is based on compliant leading and trailing edge, with effect similar to flaps. It is shown here that the commonly accepted effect of flaps regarding the control of lift and drag forces can also be used to postpone the inception of cavitation. A numerical and experimental study is conducted in order to assess the effect of the geometric parameters of hydrofoil on their hydrodynamic performances and in cavitation inception. The effect of a 70% trailing edge and a 30% leading edge of NACA 0012 is investigated using Xfoil software at a constant Reynolds number 106. The simulations carried out for a range flaps deflections and various angles of attack. So, the result showed that the lift coefficient increase with the increase of flap deflection, but also with the increase of angle of attack and enlarged the bucket cavitation. To evaluate the efficiency of the Xfoil software, a 2D analysis flow over a NACA 0012 with leading and trailing edge flap was studied using Fluent software. The results of the two methods are in a good agreement. To validate the numerical approach, a passive adaptive composite model is built and tested in the hydrodynamic tunnel at the Research Institute of French Naval Academy. The model shows the ability to simulate the effect of flap by a LE and TE structural morphing due to hydrodynamic loading.

Keywords: cavitation, flaps, hydrofoil, panel method, xfoil

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Authors: Ibrahim Nasiru Dole, Audu Abdullahi, Dike Michiel Chidozie, Lawal Mansur

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Bambara groundnut is an important grain legume and the seeds in storage suffer infestation by Callosobruchus subinnotatus. Laboratory study was conducted to evaluate the efficacy of raw diatomaceous earth (RDE) and plant powders (Jatropha curcas (L.), Eucalyptus camaldulensis (Dehnh.) and Melia azedarach (L.) against C. subinnotatus infesting stored bambara groundnut seeds. Rearing of the insects and the experiments were conducted in Agricultural Biology Laboratory of the Usmanu Danfodiyo University, Sokoto - Nigeria under ambient conditions (29-33oC and a relative humidity of 44-56%). Four treatments at three levels: RDE at 0.5, 1.0 and 1.5 g while plant powders at 0.5, 1.0 and 2.0 g, standard/check (2.0 g of Actellic dust), and a control. These were separately admixed with 100 g of sterilized seeds in glass jars. Each jar was later infested with thirty, 1-2-days old C. subinnotatus of mixed sexes. Adult mortality was assessed 24, 48, 72 and 96 hours, F1 and F2 progenies, seed damage, weight loss and viability were also assessed after 90 days. Eighty-nine (89%) percent adult mortality was recorded in the highest dose of RDE after 96 hours of exposure. These treatments significantly (P < 0.05) suppressed F1 and F2 progenies emergence in relation to the control. The control suffered significantly (P < 0.05) higher seed damage (51.0 %) and weight loss (40.8%) thereby recording lower seed germination. Therefore, RDE and plant powders could be used against C. subinnotatus on stored bambara groundnut seeds.

Keywords: bambara, callosobruchus subinnotatus, plant powders, raw diatomaceous earth,

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Authors: Shima Nabinejad, Holger Schüttrumpf

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Farmers who are living in flood-prone areas such as coasts are exposed to storm surges increased due to climate change. Crop cultivation is the most important economic activity of farmers, and in the time of flooding, agricultural lands are subject to inundation. Additionally, overflow saline water causes more severe damage outcomes than riverine flooding. Agricultural crops are more vulnerable to salinity than other land uses for which the economic damages may continue for a number of years even after flooding and affect farmers’ decision-making for the following year. Therefore, it is essential to assess what extent the agricultural areas are flooded and how much the associated flood damage to each individual farmer is. To address these questions, we integrated farmers’ decision-making at farm-scale with flood risk management. The integrated model includes identification of hazard scenarios, failure analysis of structural measures, derivation of hydraulic parameters for the inundated areas and analysis of the economic damages experienced by each farmer. The present study has two aims; firstly, it attempts to investigate the flooded cropland and potential crop damages for the whole area. Secondly, it compares them among farmers’ field for three flood scenarios, which differ in breach locations of the flood protection structure. To achieve its goal, the spatial distribution of fields and cultivated crops of farmers were fed into the flood risk model, and a 100-year storm surge hydrograph was selected as the flood event. The study area was Pellworm Island that is located in the German Wadden Sea National Park and surrounded by North Sea. Due to high salt content in seawater of North Sea, crops cultivated in the agricultural areas of Pellworm Island are 100% destroyed by storm surges which were taken into account in developing of depth-damage curve for analysis of consequences. As a result, inundated croplands and economic damages to crops were estimated in the whole Island which was further compared for six selected farmers under three flood scenarios. The results demonstrate the significance and the flexibility of the proposed model in flood risk assessment of flood-prone areas by integrating flood risk management and decision-making.

Keywords: crop damages, flood risk analysis, individual farmer, inundated cropland, Pellworm Island, storm surges

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Authors: Lutfi Abosrra, Alseddeq Alabaoub, Nuri Elhaloudi

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Corrosion processes in the Oil & Gas industry can lead to failures that are usually costly to repair, costly in terms of loss of contaminated product, in terms of environmental damage and possibly costly in terms of human safety. This article describes the results of the corrosion review and criticality assessment done at Mellitah Gas (SRU unit) for pressure equipment and piping system. The information gathered through the review was intended for developing a qualitative RBI study. The corrosion criticality assessment has been carried out by applying company procedures and industrial recommended practices such as API 571, API 580/581, ASME PCC 3, which provides a guideline for establishing corrosion integrity assessment. The corrosion review is intimately related to the probability of failure (POF). During the corrosion study, the process units are reviewed by following the applicable process flow diagrams (PFDs) in the presence of Mellitah’s personnel from process engineering, inspection, and corrosion/materials and reliability engineers. The expected corrosion damage mechanism (internal and external) was identified, and the corrosion rate was estimated for every piece of equipment and corrosion loop in the process units. A combination of both Consequence and Likelihood of failure was used for determining the corrosion risk. A qualitative consequence of failure (COF) for each individual item was assigned based on the characteristics of the fluid as per its flammability, toxicity, and pollution into three levels (High, Medium, and Low). A qualitative probability of failure (POF)was applied to evaluate the internal and external degradation mechanism, a high-level point-based (0 to 10) for the purpose of risk prioritizing in the range of Low, Medium, and High.

Keywords: corrosion, criticality assessment, RBI, POF, COF

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Authors: Niloofar Bahramian, Mohammad Atai, Mohammad Reza Naimi-Jamal

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Rule of mixtures is the simple analytical model is used to predict various properties of composites before design. The aim of this study was to demonstrate the benefits and limitations of the Rule-of-Mixtures (ROM) for predicting bending modulus of a continuous and unidirectional fiber reinforced composites using in dental applications. The Composites were fabricated from light curing resin (with and without silica nanoparticles) and modified and non-modified fibers. Composite samples were divided into eight groups with ten specimens for each group. The bending modulus (flexural modulus) of samples was determined from the slope of the initial linear region of stress-strain curve on 2mm×2mm×25mm specimens with different designs: fibers corona treatment time (0s, 5s, 7s), fibers silane treatment (0%wt, 2%wt), fibers volume fraction (41%, 33%, 25%) and nanoparticles incorporation in resin (0%wt, 10%wt, 15%wt). To study the fiber and matrix interface after fracture, single edge notch beam (SENB) method and scanning electron microscope (SEM) were used. SEM also was used to show the nanoparticles dispersion in resin. Experimental results of bending modulus for composites made of both physical (corona) and chemical (silane) treated fibers were in reasonable agreement with linear ROM estimates, but untreated fibers or non-optimized treated fibers and poor nanoparticles dispersion did not correlate as well with ROM results. This study shows that the ROM is useful to predict the mechanical behavior of unidirectional dental composites but fiber-resin interface and quality of nanoparticles dispersion play important role in ROM accurate predictions.

Keywords: bending modulus, fiber reinforced composite, fiber treatment, rule-of-mixtures

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Authors: V. K. Gupta, Tejeet Singh

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In many whisker reinforced composites, anisotropy may result due to material flow during processing operations such as forging, extrusion etc. The consequence of anisotropy, introduced during processing of disc material, has been investigated on the steady state creep deformations of the rotating disc. The disc material is assumed to undergo plastic deformations according to Hill’s anisotropic criterion. Steady state creep has been analyzed in a constant thickness rotating disc made of functionally graded 6061Al-SiCw (where the subscript ‘w’ stands for whisker) using Hill’s The content of reinforcement (SiCw) in the disc is assumed to decrease linearly from the inner to outer radius. The stresses and strain rates in the disc are estimated by solving the force equilibrium equation along with the constitutive equations describing multi-axial creep. The results obtained for anisotropic FGM disc have been compared with those estimated for isotropic FGM disc having the same average whisker content. The anisotropic constants, appearing in Hill’s yield criterion, have been obtained from the available experimental results. The results show that the presence of anisotropy reduces the tangential stress in the middle of the disc but near the inner and outer radii the tangential stress is higher when compared to isotropic disc. On the other hand, the steady state creep rates in the anisotropic disc are reduced significantly over the entire disc radius, with the maximum reduction observed at the inner radius. Further, in the presence of anisotropy the distribution of strain rate becomes relatively uniform over the entire disc, which may be responsible for reducing the extent of distortion in the disc.

Keywords: anisotropy, creep, functionally graded composite, rotating disc

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Authors: Ramanpreet, Gursatej Gandhi

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Background: Dependence on electromagnetic radiations involved in communication and information technologies has incredibly increased in the personal and professional world. Among the numerous radiations, sources are fixed site transmitters, mobile phone base stations, and power lines beside indoor devices like cordless phones, WiFi, Bluetooth, TV, radio, microwave ovens, etc. Rather there is the continuous emittance of radiofrequency radiations (RFR) even to those not using the devices from mobile phone base stations. The consistent and widespread usage of wireless devices has build-up electromagnetic fields everywhere. In fact, the radiofrequency electromagnetic field (RF-EMF) has insidiously become a part of the environment and like any contaminant may pose to be health-hazardous requiring assessment. Materials and Methods: In the present study, cytogenetic damage was assessed using the Buccal Micronucleus Cytome (BMCyt) assay as a function of radiation exposure after Institutional Ethics Committee clearance of the study and written voluntary informed consent from the participants. On a pre-designed questionnaire, general information lifestyle patterns (diet, physical activity, smoking, drinking, use of mobile phones, internet, Wi-Fi usage, etc.) genetic, reproductive (pedigrees) and medical histories were recorded. For this, 24 hour-personal exposimeter measurements (PEM) were recorded for unrelated 60 healthy adults (40 cases residing in the vicinity of mobile phone base stations since their installation and 20 controls residing in areas with no base stations). The personal exposimeter collects information from all the sources generating EMF (TETRA, GSM, UMTS, DECT, and WLAN) as total RF-EMF uplink and downlink. Findings: The cases (n=40; 23-90 years) and the controls (n=20; 19-65 years) matched for alcohol drinking, smoking habits, and mobile and cordless phone usage. The PEM in cases (149.28 ± 8.98 mV/m) revealed significantly higher (p=0.000) electric field strength compared to the recorded value (80.40 ± 0.30 mV/m) in controls. The GSM 900 uplink (p=0.000), GSM 1800 downlink (p=0.000),UMTS (both uplink; p=0.013 and downlink; p=0.001) and DECT (p=0.000) electric field strength were significantly elevated in the cases as compared to controls. The electric field strength in the cases was significantly from GSM1800 (52.26 ± 4.49mV/m) followed by GSM900 (45.69 ± 4.98mV/m), UMTS (25.03 ± 3.33mV/m), DECT (18.02 ± 2.14mV/m) and was least from WLAN (8.26 ± 2.35mV/m). The higher significantly (p=0.000) increased exposure to the cases was from GSM (97.96 ± 6.97mV/m) in comparison to UMTS, DECT, and WLAN. The frequencies of micronuclei (1.86X, p=0.007), nuclear buds (2.95X, p=0.002) and cell death parameter (condensed chromatin cells) were significantly (1.75X, p=0.007) elevated in cases compared to that in controls probably as a function of radiofrequency radiation exposure. Conclusion: In the absence of other exposure(s), any cytogenetic damage if unrepaired is a cause of concern as it can cause malignancy. Larger sample size with the clinical assessment will prove more insightful of such an effect.

Keywords: Buccal micronucleus cytome assay, cytogenetic damage, electric field strength, personal exposimeter

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Authors: Shukla Ila, Azmi Lubna, S. S. Gupta, Ch. V. Rao

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Oxidative stress has been increasingly associated with the induction and progression of liver damage. The current study was conducted to record the effect of combination of Lactobacillus and Lichen rangiferinus extract (LRE + Lac) on the severity of injury in experimental alcoholic liver disease and how it affects plasma levels of prostaglandin E2, endotoxin, thromboxane B2, and leukotriene B4. Male Wistar rats were grouped into five comprising six animals in each group. Group 1 served as negative control. Groups 2-5 were administered 10% ethanol for six weeks. Group 3 was administered with extract (200 mg/kg), group 4 received the diet containing 10% ethanol plus a bolus of lactobacilli GG (1010 CFU), and group 5 animals were given silymarin along with alcohol and it served as positive control. Aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total protein content, γ-glutamyltransferase, glutathione S-transferase, oxidative stress markers, glutathione, malondialdehyde and glutathione reductase were determined using standard diagnostic kits. Histopathological analysis of liver tissue was also made. A positive relation was found between plasma endotoxin levels and degree of liver injury. The pathology records were also related positively with leukotriene B4 and thromboxane B2. But a negative correlation was obtained with PgE2 levels. This study led us to hypothesize that the increased endotoxin levels modulate liver metabolism of eicosanoid, which gradually leads to liver injury. Endotoxemia increases leukotriene and thromboxane levels in plasma.

Keywords: lactobacillus, Lichen rangiferinus, endotoxemia, silymarin

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Authors: Fatma Dridi, Mouna Marrakchi, Mohammed Gargouri, Alvaro Garcia Cruz, Sergei V. Dzyadevych, Francis Vocanson, Joëlle Saulnier, Nicole Jaffrezic-Renault, Florence Lagarde

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An original method has been successfully developed for the immobilization of thermolysin onto gold interdigitated electrodes for the detection of ochratoxin A (OTA) in olive oil samples. A mix of polyvinyl alcohol (PVA), polyethylenimine (PEI) and gold nanoparticles (AuNPs) was used. Cross-linking sensors chip was made by using a saturated glutaraldehyde (GA) vapor atmosphere in order to render the two polymers water stable. Performance of AuNPs/ (PVA/PEI) modified electrode was compared to a traditional immobilized enzymatic method using bovine serum albumin (BSA). Atomic force microscopy (AFM) experiments were employed to provide a useful insight into the structure and morphology of the immobilized thermolysin composite membranes. The enzyme immobilization method influence the topography and the texture of the deposited layer. Biosensors optimization and analytical characteristics properties were studied. Under optimal conditions AuNPs/ (PVA/PEI) modified electrode showed a higher increment in sensitivity. A 700 enhancement factor could be achieved with a detection limit of 1 nM. The newly designed OTA biosensors showed a long-term stability and good reproducibility. The relevance of the method was evaluated using commercial doped olive oil samples. No pretreatment of the sample was needed for testing and no matrix effect was observed. Recovery values were close to 100% demonstrating the suitability of the proposed method for OTA screening in olive oil.

Keywords: thermolysin, A. ochratoxin , polyvinyl alcohol, polyethylenimine, gold nanoparticles, olive oil

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Authors: Ivan D. Ortega, Juan D. Castro, Alberto Pertuz, Manuel Martinez

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One of the problems considered when scientists talk about climate change is the necessity of utilizing renewable sources of energy, on this category there are many approaches to the problem, one of them is wind energy and wind turbines whose designs have frequently changed along many years trying to achieve a better overall performance on different conditions. From that situation, we get the two main types known today: Vertical and Horizontal axis wind turbines, which have acronyms VAWT and HAWT, respectively. This research aims to understand how well suited a composite material, which is still in development, made with natural origin fibers is for its implementation on vertical axis wind turbines blades under certain wind loads. The study consisted on acquiring the mechanical properties of the materials to be used which where bactris guineenis, also known as pama de lata in Colombia, and adhesive that acts as the matrix which had not been previously studied to the point required for this project. Then, a simplified 3D model of the airfoil was developed and tested under some preliminary loads using finite element analysis (FEA), these loads were acquired in the Colombian Chicamocha Canyon. Afterwards, a more realistic pressure profile was obtained using computational fluid dynamics which took into account the 3D shape of the complete blade and its rotation. Finally, the blade model was subjected to the wind loads using what is known as one way fluidstructure interaction (FSI) and its behavior analyzed to draw conclusions. The observed overall results were positive since the material behaved fairly as expected. Data suggests the material would be really useful in this kind of applications in small to medium size turbines if it is given more attention and time to develop.

Keywords: CFD, FEA, FSI, natural fiber, VAWT

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Authors: Irina Belozerova

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In the recent years, the number of crimes against peace and humanity has constantly been increasing. The development of the international community is inseparably connected to the compliance with the law which protects the rights and interests of citizens in all of their manifestations. The provisions of the law of criminal procedure are no exception. The rights of the victims of genocide, of the war crimes and the crimes against humanity, require particular attention. These crimes fall within the jurisdiction of the International Criminal Court governed by the Rome Statute of the International Criminal Court. These crimes have the following features. First, any such crime has a mass character and therefore requires specific regulation in the international criminal law and procedure and the national criminal law and procedure of different countries. Second, the victims of such crimes are usually children, women and old people; the entire national, ethnic, racial or religious groups are destroyed. These features influence the classification of victims by the age criterion. Article 68 of the Rome Statute provides for protection of the safety, physical and psychological well-being, dignity and privacy of victims and witnesses and thus determines the procedural status of these persons. However, not all the persons whose rights have been violated by the commission of these crimes acquire the status of victims. This is due to the fact that such crimes affect a huge number of persons and it is impossible to mention them all by name. It is also difficult to assess the entire damage suffered by the victims. While assessing the amount of damages it is essential to take into account physical and moral harm, as well as property damage. The procedural status of victims thus gains an exclusive character. In order to determine the full extent of the damage suffered by the victims it is necessary to collect sufficient evidence. However, it is extremely difficult to collect the evidence that would ensure the full and objective protection of the victims’ rights. While making requests for the collection of evidence, the International Criminal Court faces the problem of protection of national security information. Religious beliefs and the family life of victims are of great importance. In some Islamic countries, it is impossible to question a woman without her husband’s consent which affects the objectivity of her testimony. Finally, the number of victims is quantified by hundreds and thousands. The assessment of these elements demands time and highly qualified work. These factors justify the creation of a mechanism that would help to collect the evidence and establish the truth in the international criminal proceedings. This mechanism will help to impose a just and appropriate punishment for the persons accused of having committed a crime, since, committing the crime, criminals could not misunderstand the outcome of their criminal intent.

Keywords: crimes against humanity, evidence in international criminal proceedings, international criminal proceedings, protection of victims

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Authors: Soukaina Ounss, Hamid Mounir, Abdellatif El Marjani

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Sandwich materials with composite reinforced skins are mostly required in advanced construction applications with a view to ensure resistant structures. Their lightweight, their high flexural stiffness and their optimal thermal insulation make them a suitable solution to obtain efficient structures with performing rigidity and optimal energy safety. In this paper, the mechanical behavior of a sandwich beam with composite skins reinforced by unidirectional carbon fibers is investigated numerically through analyzing the impact of reinforcements specifications on the longitudinal elastic modulus in order to select the adequate sandwich configuration that has an interesting rigidity and an accurate convergence to the analytical approach which is proposed to verify performed numerical simulations. Therefore, concerned study starts by testing flexion performances of skins with various fibers orientations and volume fractions to determine those to use in sandwich beam. For that, the combination of a reinforcement inclination of 30° and a volume ratio of 60% is selected with the one with 60° of fibers orientation and 40% of volume fraction, this last guarantees to chosen skins an important rigidity with an optimal fibers concentration and a great enhance in convergence to analytical results in the sandwich model for the reason of the crucial core role as transverse shear absorber. Thus, a resistant sandwich beam is elaborated from a face-sheet constituted from two layers of previous skins with fibers oriented in 60° and an epoxy core; concerned beam has a longitudinal elastic modulus of 54 Gpa (gigapascal) that equals to the analytical value by a negligible error of 2%.

Keywords: fibers orientation, fibers volume ratio, longitudinal elastic modulus, sandwich beam

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Authors: Chiagoziem A. Otuechere, Ebenezer O. Farombi

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The protective effect of dichloromethane: methanol extract of Pterocarpus mildbraedii (PME), a widely consumed Nigerian leafy vegetable, on the toxicity of propanil was investigated in male rats. Animals were distributed into eight groups of five each. Group 1 served as control and received normal saline while rats in groups 2, 3, and 4 received 100 mg/kg, 200 mg/kg, and 400 mg/kg extract doses respectively. Group 5 rats were orally administered 200 mg/kg propanil while groups 6, 7, and 8 rats were given propanil plus extract. Oral administration of propanil elicited a 14.8%, 5%, 122%, and 78% increase in the activity of serum enzymes; alanine aminotransferase (AST), alanine aminotransferase(ALT), Alkaline phoshatase (ALP) and Gamma glutamyl transferase (ﻻGT). There were also increase in Lactate dehydrogenase (LDH) activity, direct bilirubin and lipid peroxidation levels. Furthermore, PME significantly attenuated the marked hepatic oxidative damage that accompanied propanil treatment. The extract significantly decreased LDH activity and bilirubin levels following propanil treatment. Furthermore, propanil-induced alterations in the activities of antioxidant enzymes: Superoxide dismutase (SOD), catalase (CAT) and glutathione s-transferase (GST) in these rats were modulated by the extract. The percentage DPPH Radical Scavenging Activity of the extract was determined as 55% and compared to those of Gallic acid (49%). Hepatic histology examination further confirmed the damage to the liver as it revealed severe periportal cellular infiltration of the hepatocytes. These biochemical and morphological alterations were attenuated in rats pre-treated with 100 mg/kg and 200 mg/kg doses of the extract. These results suggest that PME possesses protective effect against propanil-induced hepatotoxicity.

Keywords: antioxidant, hepatoprotection, Pterocarpus mildbraedii, propanil

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Authors: Ahlem Bahi, Youcef Necib, Sakina Zerizer, Cherif Abdennour, Mohamed Salah Boulakoud

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Mercury (II) is a highly toxic metal which induces oxidative stress in the body. In this study, we aimed to investigate the possible protective effect of olive oil, an antioxidant agent, against experimental mercury toxicity in rat model. Administration of mercuric chloride induced significant increase in serum: ALT, AST, and LPA activities; interleukine1, interleukine6, tumor necrosis factor α (TNFα), creatinine, urea, and uric acid levels. Mercuric chloride also induced oxidative stress, as indicate by decreased tissue of GSH level, GSH-Px, and GST activities along with increase the level of lipid peroxidation. Furthermore, treatment with mercuric chloride caused a marked elevation of kidney and liver weight and decreased body weight. Virgin olive oil treatment markedly reduced elevated serum: AST, ALT, and LPA activities; interleukine1, interleukine6, tumor necrosis factor α (TNFα), creatinine, urea, and uric acid levels and contracted the deterious effects of mercuric chloride on oxidative stress markers changes caused by HgCl2 in tissue as compared to control group. Our results implicate that mercury induced oxidative damage in liver and kidney tissue protected by virgin olive oil, with its antioxidant effects.

Keywords: mercury, antioxidant enzymes, pro-inflammatory cytokine, virgin olive oil, lipid peroxidation

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Authors: S. Arabnejad, D. W. C. Cheong, H. Chaobin, V. P. W. Shim

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Debonding is the one of the fundamental damage mechanisms in particle field composites. This phenomenon gains more importance in nano composites because of the extensive interfacial region present in these materials. Understanding the debonding mechanism accurately, can help in understanding and predicting the response of nano composites as the interface deteriorates. The small length scale of the phenomenon makes the experimental characterization complicated and the results of it, far from real physical behavior. In this study the damage process in nylon-6/silica interface is examined through Molecular Dynamics (MD) modeling and simulations. The silica has been modeled with three forms of surfaces – without any surface treatment, with the surface treatment of 3-aminopropyltriethoxysilane (APTES) and with Hexamethyldisilazane (HMDZ) surface treatment. The APTES surface modification used to create functional groups on the silica surface, reacts and form covalent bonds with nylon 6 chains while the HMDZ surface treatment only interacts with both particle and polymer by non-bond interaction. The MD model in this study uses a PCFF force field. The atomic model is generated in a periodic box with a layer of vacuum on top of the polymer layer. This layer of vacuum is large enough that assures us from not having any interaction between particle and substrate after debonding. Results show that each of these three models show a different traction separation behavior. However, all of them show an almost bilinear traction separation behavior. The study also reveals a strong correlation between the length of APTES surface treatment and the cohesive strength of the interface.

Keywords: debonding, surface treatment, cohesive response, separation behaviour

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Authors: Caroline Kim

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Scholars have long disputed the relationship between the origins of language and human behavior. Historically, behaviorist psychologist B. F. Skinner argued that language is one instance of the general stimulus-response phenomenon that characterizes the essence of human behavior. Another, more recent approach argues, by contrast, that language is an innate cognitive faculty and does not arise from behavior, which might develop and reinforce linguistic facility but is not its source. Pinker, among others, proposes that linguistic defects arise from damage to the brain, both congenital and acquired in life. Much of his argument is based on case studies in which damage to the Broca’s and Wernicke’s areas of the brain results in loss of the ability to produce coherent grammatical expressions when speaking or writing; though affected speakers often utter quite fluent streams of sentences, the words articulated lack discernible semantic content. Pinker concludes on this basis that language is an innate component of specific, classically language-correlated regions of the human brain. Taking a notorious 1970s case of linguistic maladaptation, this paper queries the dominant materialist paradigm of language-correlated regions. Susan “Genie” Wiley was physically isolated from language interaction in her home and beaten by her father when she attempted to make any sort of sound. Though without any measurable resulting damage to the brain, Wiley was never able to develop the level of linguistic facility normally achieved in adulthood. Having received a negative reinforcement of language acquisition from her father and lacking the usual language acquisition period, in adulthood Wiley was able to develop language only at a quite limited level in later life. From a contemporary behaviorist perspective, this case confirms the possibility of language deficiency without brain pathology. Wiley’s potential language-determining areas in the brain were intact, and she was exposed to language later in her life, but she was unable to achieve the normal level of communication skills, deterring socialization. This phenomenon and others like it in the case limited literature on linguistic maladaptation pose serious clinical, scientific, and indeed philosophical difficulties for both of the major competing theories of language acquisition, innateness, and linguistic stimulus-response. The implications of such cases for future research in language acquisition are explored, with a particular emphasis on the interaction of innate capacity and stimulus-based development in early childhood.

Keywords: behaviorism, innateness hypothesis, language, Susan "Genie" Wiley

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Authors: Silvia Arrate, Waldo Salud, Eloy París

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The wear of cutting tools is one of the most decisive elements when planning tunneling works, programming the maintenance stops and saving the optimum stock of spare parts during the evolution of the excavation. Being able to predict the behavior of cutting tools can give a very competitive advantage in terms of costs and excavation performance, optimized to the needs of the TBM itself. The incredible evolution of data science in recent years gives the option to implement it at the time of analyzing the key and most critical parameters related to machinery with the purpose of knowing how the cutting head is performing in front of the excavated ground. Taking this as a case study, Metro Line 3 of Guadalajara in Mexico will develop the feasibility of using Specific Energy versus data science applied over parameters of Torque, Penetration, and Contact Force, among others, to predict the behavior and status of cutting tools. The results obtained through both techniques are analyzed and verified in the function of the wear and the field situations observed in the excavation in order to determine its effectiveness regarding its predictive capacity. In conclusion, the possibilities and improvements offered by the application of digital tools and the programming of calculation algorithms for the analysis of wear of cutting head elements compared to purely empirical methods allow early detection of possible damage to cutting tools, which is reflected in optimization of excavation performance and a significant improvement in costs and deadlines.

Keywords: cutting tools, data science, prediction, TBM, wear

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Authors: P. Abtahi, B. Samali

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Façade panels of various shapes, weights, and connections usually act as a barrier between the indoor and outdoor environments. They also play a major role in enhancing the aesthetics of building structures. They are attached by different types of connections to the primary structure or inner panels in double skin façade skins. Structural buildings designed to withstand seismic shocks have been undergoing a critical appraisal in recent years, with the emphasis changing from ‘strength’ to ‘performance’. Performance based design and analysis have found their way into research, development, and practice of earthquake engineering, particularly after the 1994 Northridge and 1995 Kobe earthquakes. The design performance of facades as non-structural elements has now focused mainly on evaluating the damage sustained by façade frames with fixed connections, not movable ones. This paper will review current design standards for structural buildings, including the performance of structural and non-structural components during earthquake excitations in order to overview and evaluate the damage assessment and behaviour of various façade systems in building structures during seismic activities. The proposed solutions for each facade system will be discussed case by case to evaluate their potential for incorporation with newly designed connections. Finally, Double-Skin-Facade systems can potentially be combined with movable facade technology, although other glazing systems would require minor to major changes in their design before being integrated into the system.

Keywords: building performance, earthquake engineering, glazing system, movable façade technology

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Authors: Savvas Varitis, Panagiotis Kavouras, George Vourlias, Eleni Pavlidou, Theodoros Karakostas, Philomela Komninou

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A chromium-loaded ash originating from incineration of tannery sludge under anoxic conditions was mixed with low grade soda-lime glass powder coming from commercial glass bottles. The relative weight proportions of ash over glass powder tested were 30/70, 40/60 and 50/50. The solid mixtures, formed in green state compacts, were sintered at the temperature range of 800oC up to 1200oC. The resulting products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDXS) and micro-indentation. The above methods were employed to characterize the various phases, microstructure and hardness of the produced materials. Thermal treatment at 800oC and 1000oC produced opaque ceramic products composed of a variety of chromium-containing and chromium-free crystalline phases. Thermal treatment at 1200oC gave rise to composite products, where only chromium-containing crystalline phases were detected. Hardness results suggest that specific products are serious candidates for structural applications. Acknowledgement: This research has been co-financed by the European Union (European Social Fund – ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) – Research Funding Program: THALES “WasteVal”: Reinforcement of the interdisciplinary and/or inter-institutional research and innovation.

Keywords: chromium-rich tannery residues, glass-ceramic materials, mechanical properties, microstructure

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Authors: Ahmed Z. Mazen, Nejat Rahmanian, Iqbal Mujtaba, Ali Hassanpour

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In oil and gas well drilling, the drill bit is an important part of the Bottom Hole Assembly (BHA), which is installed and designed to drill and produce a hole by several mechanisms. The efficiency of the bit depends on many drilling parameters such as weight on bit, rotary speed, and mud properties. When the bit is pulled out of the hole, the evaluation of the bit damage must be recorded very carefully to guide engineers in order to select the bits for further planned wells. Having a worn bit for hole drilling may cause severe damage to bit leading to cutter or cone losses in the bottom of hole, where a fishing job will have to take place, and all of these will increase the operating cost. The main factor to reduce the cost of drilling operation is to maximize the rate of penetration by analyzing real-time data to predict the drill bit wear while drilling. There are numerous models in the literature for prediction of the rate of penetration based on drilling parameters, mostly based on empirical approaches. One of the most commonly used approaches is Bourgoyne and Young model, where the rate of penetration can be estimated by the drilling parameters as well as a wear index using an empirical correlation, provided all the constants and coefficients are accurately determined. This paper introduces a new methodology to estimate the eight coefficients for Bourgoyne and Young model using the gPROMS parameters estimation GPE (Version 4.2.0). Real data collected form similar formations (12 ¼’ sections) in two different fields in Libya are used to estimate the coefficients. The estimated coefficients are then used in the equations and applied to nearby wells in the same field to predict the bit wear.

Keywords: Bourgoyne and Young model, bit wear, gPROMS, rate of penetration

Procedia PDF Downloads 150

Authors: Hossam Mohamed Abdelfattah Helal Hegazi

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Winds and storms are considered crucial weathering factors, representing primary causes of destruction and erosion for all materials on the Earth's surface. This naturally includes historical structures, with the impact of winds and storms intensifying their deterioration, particularly when carrying high-hardness sand particles during their passage across the ground. Ancient Egyptians utilized various methods to prevent wind damage to their ancient architecture throughout the ancient Egyptian periods . One of the techniques employed by ancient Egyptians was the use of clay or compacted earth as a filling material between opposing walls made of stone, bricks, or mud bricks. The walls made of reeds or woven tree branches were covered with clay to prevent the infiltration of winds and rain, enhancing structural integrity, this method was commonly used in hollow layers . Additionally, Egyptian engineers innovated a type of adobe brick with uniformly leveled sides, manufactured from dried clay. They utilized stone barriers, constructed wind traps, and planted trees in rows parallel to the prevailing wind direction. Moreover, they employed receptacles to drain rainwater resulting from wind-loaded rain and used mortar to fill gaps in roofs and structures. Furthermore, proactive measures such as the removal of sand from around historical and archaeological buildings were taken to prevent adverse effects

Keywords: winds, storms, weathering, destruction, erosion, materials, Earth's surface, historical structures, impact

Procedia PDF Downloads 54

Authors: Januar Parlaungan Siregar, Davindra Brabu Mathivanan, Dandi Bachtiar, Mohd Ruzaimi Mat Rejab, Tezara Cionita

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Natural fibres play a significant role in mass industries such as automotive, construction and sports. Many researchers have found that the natural fibres are the best replacement for the synthetic fibres in terms of cost, safety, and degradability due to the shortage of landfill and ingestion of non biodegradable plastic by animals. This study mainly revolved around pineapple leaf fibre (PALF) which is available abundantly in tropical countries and with excellent mechanical properties. The composite formed in this study is highly biodegradable as both fibre and matrix are both derived from natural based products. The matrix which is polylactic acid (PLA) is made from corn starch which gives the upper hand as both material are renewable resources are easier to degrade by bacteria or enzyme. The PALF is treated with different alkaline solution to remove excessive moisture in the fibre to provide better interfacial bonding with PLA. Thereafter the PALF is washed with distilled water several times before placing in vacuum oven at 80°C for 48 hours. The dried PALF later were mixed with PLA using extrusion method using fibre in percentage of 30 by weight. The temperature for all zone were maintained at 160°C with the screw speed of 50 rpm for better bonding and afterwards the products of the mixture were pelletized using pelletizer. The pellets were placed in the specimen-sized mould for hot compression under the temperature of 170°C at 5 MPa for 5 min and subsequently were cold pressed under room temperature at 5 MPa for 5 min. The specimen were tested for tensile and flexure strength according to American Society for Testing and Materials (ASTM) D638 and D790 respectively. The effect of surface modification on PALF with different alkali solution will be investigated and compared.

Keywords: natural fibre, PALF, PLA, composite

Procedia PDF Downloads 295

Authors: Debabrata Adhikari, Mikhail Matveev, Louise Brown, Andy Long, Jan Kočí

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A good understanding of mesoscale permeability of complex architectures in fibrous porous preforms is of particular interest in order to achieve efficient and cost-effective resin impregnation of liquid composite molding (LCM). Fabrics used in structural reinforcements are typically woven or stitched. However, 3D fabric reinforcement is of particular interest because of the versatility in the weaving pattern with the binder yarn and in-plain yarn arrangements to manufacture thick composite parts, overcome the limitation in delamination, improve toughness etc. To predict the permeability based on the available pore spaces between the inter yarn spaces, unit cell-based computational fluid dynamics models have been using the Stokes Darcy model. Typically, the preform consists of an arrangement of yarns with spacing in the order of mm, wherein each yarn consists of thousands of filaments with spacing in the order of μm. The fluid flow during infusion exchanges the mass between the intra and inter yarn channels, meaning there is no dead-end of flow between the mesopore in the inter yarn space and the micropore in the yarn. Several studies have employed the Brinkman equation to take into account the flow through dual-scale porosity reinforcement to estimate their permeability. Furthermore, to reduce the computational effort of dual scale flow, scale separation criteria based on the ratio between yarn permeability to the yarn spacing was also proposed to quantify the dual scale and negligible micro-scale flow regime for the prediction of mesoscale permeability. In the present work, the key parameter to identify the influence of intra yarn permeability on the mesoscale permeability has been investigated with the systematic study of weft and warp yarn spacing on the plane weave as well as the position of binder yarn and number of in-plane yarn layers on 3D weave fabric. The permeability tensor has been estimated using an OpenFOAM-based model for the various weave pattern with idealized geometry of yarn implemented using open-source software TexGen. Additionally, scale separation criterion has been established based on the various configuration of yarn permeability for the 3D fabric with both the isotropic and anisotropic yarn from Gebart’s model. It was observed that the variation of mesoscale permeability Kxx within 30% when the isotropic porous yarn is considered for a 3D fabric with binder yarn. Furthermore, the permeability model developed in this study will be used for multi-objective optimizations of the preform mesoscale geometry in terms of yarn spacing, binder pattern, and a number of layers with an aim to obtain improved permeability and reduced void content during the LCM process.

Keywords: permeability, 3D fabric, dual-scale flow, liquid composite molding

Procedia PDF Downloads 93

Authors: Mir Mohammad Badrul Hasan, Anwar Abdkader, Chokri Cherif

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With the increasing demand and use of carbon fibre reinforced composites (CFRC), disposal of the carbon fibres (CF) and end of life composite parts is gaining tremendous importance on the issue especially of sustainability. Furthermore, a number of processes (e. g. pyrolysis, solvolysis, etc.) are available currently to obtain recycled CF (rCF) from end-of-life CFRC. Since the CF waste or rCF are neither allowed to be thermally degraded nor landfilled (EU Directive 1999/31/EC), profitable recycling and re-use concepts are urgently necessary. Currently, the market for materials based on rCF mainly consists of random mats (nonwoven) made from short fibres. The strengths of composites that can be achieved from injection-molded components and from nonwovens are between 200-404 MPa and are characterized by low performance and suitable for non-structural applications such as in aircraft and vehicle interiors. On the contrary, spinning rCF to yarn constructions offers good potential for higher CFRC material properties due to high fibre orientation and compaction of rCF. However, no investigation is reported till yet on the direct comparison of the mechanical properties of thermoplastic CFRC manufactured from virgin CF filament yarn and spun yarns from staple rCF. There is a lack of understanding on the level of performance of the composites that can be achieved from hybrid yarns consisting of rCF and PA6 fibres. In this drop back, extensive research works are being carried out at the Textile Machinery and High-Performance Material Technology (ITM) on the development of new thermoplastic CFRC from hybrid yarns consisting of rCF. For this purpose, a process chain is developed at the ITM starting from fibre preparation to hybrid yarns manufacturing consisting of staple rCF by mixing with thermoplastic fibres. The objective is to apply such hybrid yarns for the manufacturing of load bearing textile reinforced thermoplastic CFRCs. In this paper, the development of innovative multi-component core-sheath hybrid yarn structures consisting of staple rCF and polyamide 6 (PA 6) on a DREF-3000 friction spinning machine is reported. Furthermore, Unidirectional (UD) CFRCs are manufactured from the developed hybrid yarns, and the mechanical properties of the composites such as tensile and flexural properties are analyzed. The results show that the UD composite manufactured from the developed hybrid yarns consisting of staple rCF possesses approximately 80% of the tensile strength and E-module to those produced from virgin CF filament yarn. The results show a huge potential of the DREF-3000 friction spinning process to develop composites from rCF for high-performance applications.

Keywords: recycled carbon fibres, hybrid yarn, friction spinning, thermoplastic composite

Procedia PDF Downloads 251

Authors: Sophia Shi

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Acute kidney injury (AKI) is the sudden onset of kidney damage in which the kidneys cannot filter waste from the blood, requiring emergency hospitalization. AKI patient mortality rate is high in the ICU and is virtually impossible for doctors to predict because it is so unexpected. Currently, there is no hybrid model predicting AKI that takes advantage of two types of data. De-identified patient data from the MIMIC-III database and de-identified kidney images and corresponding patient records from the Beijing Hospital of the Ministry of Health were collected. Using data features including serum creatinine among others, two numeric models using MIMIC and Beijing Hospital data were built, and with the hospital ultrasounds, an image-only model was built. Convolutional neural networks (CNN) were used, VGG and Resnet for numeric data and Resnet for image data, and they were combined into a hybrid model by concatenating feature maps of both types of models to create a new input. This input enters another CNN block and then two fully connected layers, ending in a binary output after running through Softmax and additional code. The hybrid model successfully predicted AKI and the highest AUROC of the model was 0.953, achieving an accuracy of 90% and F1-score of 0.91. This model can be implemented into urgent clinical settings such as the ICU and aid doctors by assessing the risk of AKI shortly after the patient’s admission to the ICU, so that doctors can take preventative measures and diminish mortality risks and severe kidney damage.

Keywords: Acute kidney injury, Convolutional neural network, Hybrid deep learning, Patient record data, ResNet, Ultrasound kidney images, VGG

Procedia PDF Downloads 126

Authors: Purva Nemavarkar, Badri Narain Pandey, Jitendra Kumar

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Introduction: The objective was to understand the effect of various radioprotectors on DNA damage repair enzyme and survival in gamma-irradiated wild and cdc mutants of S. pombe (fission yeast) cultured under permissive and restrictive conditions. DNA repair process, as influenced by radioprotectors, was measured by activity of DNA polymerase in the cells. The use of single cell gel electrophoresis assay (SCGE) or Comet Assay to follow gamma-irradiation induced DNA damage and effect of radioprotectors was employed. In addition, studying the effect of caffeine at different concentrations on S-phase of cell cycle was also delineated. Materials and Methods: S. pombe cells grown at permissive temperature (250C) and/or restrictive temperature (360C) were followed by gamma-radiation. Percentage survival and activity of DNA Polymerase (yPol II) were determined after post-irradiation incubation (5 h) with radioprotectors such as Caffeine, Curcumin, Disulphiram, and Ellagic acid (the dose depending on individual D 37 values). The gamma-irradiated yeast cells (with and without the radioprotectors) were spheroplasted by enzyme glusulase and subjected to electrophoresis. Radio-resistant cells were obtained by arresting cells in S-phase using transient treatment of hydroxyurea (HU) and studying the effect of caffeine at different concentrations on S-phase of cell cycle. Results: The mutants of S. pombe showed insignificant difference in survival when grown under permissive conditions. However, growth of these cells under restrictive temperature leads to arrest in specific phases of cell cycle in different cdc mutants (cdc10: G1 arrest, cdc22: early S arrest, cdc17: late S arrest, cdc25: G2 arrest). All the cdc mutants showed decrease in survival after gamma radiation when grown at permissive and restrictive temperatures. Inclusion of the radioprotectors at respective concentrations during post irradiation incubation showed increase in survival of cells. Activity of DNA polymerase enzyme (yPol II) was increased significantly in cdc mutant cells exposed to gamma-radiation. Following SCGE, a linear relationship was observed between doses of irradiation and the tail moments of comets. The radioprotection of the fission yeast by radioprotectors can be seen by the reduced tail moments of the yeast comets. Caffeine also exhibited its radio-protective ability in radio-resistant S-phase cells obtained after HU treatment. Conclusions: The radioprotectors offered notable radioprotection in cdc mutants when added during irradiation. The present study showed activation of DNA damage repair enzyme (yPol II) and an increase in survival after treatment of radioprotectors in gamma irradiated wild type and cdc mutants of S. pombe cells. Results presented here showed feasibility of applying SCGE in fission yeast to follow DNA damage and radioprotection at high doses, which are not feasible with other eukaryotes. Inclusion of caffeine at 1mM concentration to S phase cells offered protection and did not decrease the cell viability. It can be proved that at minimal concentration, caffeine offered marked radioprotection.

Keywords: radiation protection, cell cycle, fission yeast, comet assay, s-phase, DNA repair, radioprotectors, caffeine, curcumin, SCGE

Procedia PDF Downloads 103

Authors: Larissa M. Vargas, Julia M. Sacchi, Renata O. Pereira, Lucas S. Asano, Iara C. Araújo, Patricia Fiorino, Vera Farah

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The aim of this study was to evaluate the occurrence of subclinical organ injuries induced by high-fat diet. Male wistar rats (n=5/group) were divided in control diet group (CD), commercial rat chow, and hyperlipidic diet (30% lipids) group (HD) administrated during 8 weeks, starting after weaning. All the procedures followed the rules of the Committee of Research and Ethics of the Mackenzie University (CEUA Nº 077/03/2011). At the end of protocol the animals were euthanized by anesthesia overload and the left kidney was removed. Intrarenal lipid deposition was evaluated by histological analyses with oilred. Kidney slices were stained with picrosirius red to evaluate the area of the Bowman's capsule (AB) and space (SB), and glomerular tuft area (GT). The renal expression of sterol regulatory element–binding protein (SREBP-2) was performed by Western Blotting. Creatinine concentration (serum and urine) and lipid profile were determined by colorimetric kit (Labtest). At the end of the protocol there was no differences in body weight between the groups, however the HD showed a marked increase in lipid deposits, glomeruli and tubules, and biochemical analysis for cholesterol and triglycerides. Moreover, in the kidney, the high-fat diet induced a reduction in the AB (13%), GT (18%) and SB (17%) associated with a reduction in glomerular filtration rate (creatinine clearance). The renal SRBP2 expression was increased in HD group. These data suggests that consumption of high-fat diet starting in childhood is associated with subclinical renal damage and function.

Keywords: high-fat diet, kidney, intrarenal lipid deposition, SRBP2

Procedia PDF Downloads 295

Authors: Jose Ruiz, Jose Velasquez, Holger Lovon

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Peruvian university buildings are critical structures for which very little research about its seismic vulnerability is available. This paper develops a probabilistic methodology that predicts seismic loss for university buildings with simulated fragility functions. Two university buildings located in the city of Cusco were analyzed. Fragility functions were developed considering seismic and structural parameters uncertainty. The fragility functions were generated with the Latin Hypercube technique, an improved Montecarlo-based method, which optimizes the sampling of structural parameters and provides at least 100 reliable samples for every level of seismic demand. Concrete compressive strength, maximum concrete strain and yield stress of the reinforcing steel were considered as the key structural parameters. The seismic demand is defined by synthetic records which are compatible with the elastic Peruvian design spectrum. Acceleration records are scaled based on the peak ground acceleration on rigid soil (PGA) which goes from 0.05g to 1.00g. A total of 2000 structural models were considered to account for both structural and seismic variability. These functions represent the overall building behavior because they give rational information regarding damage ratios for defined levels of seismic demand. The university buildings show an expected Mean Damage Factor of 8.80% and 19.05%, respectively, for the 0.22g-PGA scenario, which was amplified by the soil type coefficient and resulted in 0.26g-PGA. These ratios were computed considering a seismic demand related to 10% of probability of exceedance in 50 years which is a requirement in the Peruvian seismic code. These results show an acceptable seismic performance for both buildings.

Keywords: fragility functions, university buildings, loss assessment, Montecarlo simulation, latin hypercube

Procedia PDF Downloads 138

Authors: T. S. Desak Ketut, A.n. Isna, A.a. Ayu, D. P. Ririn, Suharjono Hadiatullah

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The requirement of paper from year to year rise rapidly. The raising of cellulose requirement in paper production caused increasing of wood requirement with the effect that limited forest areal because of deforestation. Alternative cellulose that can be used for making paper is microbial cellulose. The objective of this research are to know the effectivity fermentation media Spirogyra sp. by Gluconacetobacter xylinum for cellulose production as material for the making of paper and to know effect composition bacterial cellulose composite product of Gluconacetobacter xylinum in Spirogyra sp. The method, was used, is as follow, 1) the effect assay from variation composition of fermentation media to bacterial cellulose production by Gluconacetobacter xylinum. 2) The effect assay of composition bacterial cellulose fermentation producted by Gluconacetobacter xylinum in extracted Spirogyra media to paper quality. The result of this research is variation fermentation media Spirogyra sp. affect to production of cellulose by Gluconacetobacter xylinum. Thus, result showed by the highest value and significantly different in thickness parameter, dry weight and wet weight of nata in sucrose concentration 7,5 % and urea 0,75 %. Composition composite of bacterial cellulose from fermentation product by Gluconacetobacter xylinum in media Spirogyra sp. affect to paper quality from wet nata and dry nata. Parameters thickness, weight, water absorpsion, density and gramatur showed highest result in sucrose concentration 7,5 % and urea concentration 0,75 %, except paper density from dry nata had highest result in sucrose and urea concentration 0%.

Keywords: cellulose, fermentation media, , Gluconacetobacter xylinum, paper, Spirogyra sp.

Procedia PDF Downloads 339

Authors: Sandra Regina Cavalcante, Rodolfo A. G. Vilela

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Introduction: Work accidents and occupational diseases are a big problem for public health around the world and the main health problem of workers with high social and economic costs. Brazil has shown progress over the last years, with the development of the regulatory system to improve safety and quality of life in the workplace. However, the situation is far from acceptable, because the occurrences remain high and there is a great gap between legislation and reality, generated by the low level of voluntary compliance with the law. Brazilian laws provide procedural legal instruments for both, to compensate the damage caused to the worker's health and to prevent future injuries. In the Judiciary, the prevention idea is in the collective action, effected through Brazilian Class Actions. Inhibitory guardianships may impose both, improvements to the working environment, as well as determine the interruption of activity or a ban on the machine that put workers at risk. Both the Labor Prosecution and trade unions have to stand to promote this type of action, providing payment of compensation for collective moral damage. Objectives: To verify how class actions (known as ‘public civil actions’), regulated in Brazilian legal system to protect diffuse, collective and homogeneous rights, are being used to protect workers' health and safety. Methods: The author identified and evaluated decisions of Brazilian Superior Court of Labor involving collective actions and work accidents. The timeframe chosen was December 2015. The online jurisprudence database was consulted in page available for public consultation on the court website. The categorization of the data was made considering the result (court application was rejected or accepted), the request type, the amount of compensation and the author of the cause, besides knowing the reasoning used by the judges. Results: The High Court issued 21,948 decisions in December 2015, with 1448 judgments (6.6%) about work accidents and only 20 (0.09%) on collective action. After analyzing these 20 decisions, it was found that the judgments granted compensation for collective moral damage (85%) and/or obligation to make, that is, changes to improve prevention and safety (71%). The processes have been filed mainly by the Labor Prosecutor (83%), and also appeared lawsuits filed by unions (17%). The compensation for collective moral damage had average of 250,000 reais (about US$65,000), but it should be noted that there is a great range of values found, also are several situations repaired by this compensation. This is the last instance resource for this kind of lawsuit and all decisions were well founded and received partially the request made for working environment protection. Conclusions: When triggered, the labor court system provides the requested collective protection in class action. The values of convictions arbitrated in collective actions are significant and indicate that it creates social and economic repercussions, stimulating employers to improve the working environment conditions of their companies. It is necessary to intensify the use of collective actions, however, because they are more efficient for prevention than reparatory individual lawsuits, but it has been underutilized, mainly by Unions.

Keywords: Brazilian Class Action, collective action, work accident penalization, workplace accident prevention, workplace protection law

Procedia PDF Downloads 269