Search results for: post traumatic stress

Authors: Edward Poluyi, Eghosa Morgan, Charles Poluyi, Chibuikem Ikwuegbuenyi, Grace Imaguezegie

Abstract:

Background: Current epidemiological studies have examined the associations between moderate and severe traumatic brain injury (TBI) and their risks of developing neurodegenerative diseases. Concussion, also known as mild TBI (mTBI), is however quite distinct from moderate or severe TBIs. Only few studies in this burgeoning area have examined concussion—especially repetitive episodes—and neurodegenerative diseases. Thus, no definite relationship has been established between them. Objectives : This review will discuss the available literature linking concussion and amyotrophic lateral sclerosis (ALS) and Alzheimer’s disease (AD). Materials and Methods: Given the complexity of this subject, a realistic review methodology was selected which includes clarifying the scope and developing a theoretical framework, developing a search strategy, selection and appraisal, data extraction, and synthesis. A detailed literature matrix was set out in order to get relevant and recent findings on this topic. Results: Presently, there is no objective clinical test for the diagnosis of concussion because the features are less obvious on physical examination. Absence of an objective test in diagnosing concussion sometimes leads to skepticism when confirming the presence or absence of concussion. Intriguingly, several possible explanations have been proposed in the pathological mechanisms that lead to the development of some neurodegenerative disorders (such as ALS and AD) and concussion but the two major events are deposition of tau proteins (abnormal microtubule proteins) and neuroinflammation, which ranges from glutamate excitotoxicity pathways and inflammatory pathways (which leads to a rise in the metabolic demands of microglia cells and neurons), to mitochondrial function via the oxidative pathways.

Keywords: amyotrophic lateral sclerosis, Alzheimer's disease, mild traumatic brain injury, neurodegeneration

Procedia PDF Downloads 83

Authors: Ali Haghiri

Abstract:

This research has been to investigate the cause of the stress corrosion cracking on dryer equipment (2DR-1745 and DR-1402) in Shahid Tondguyan Petrochemical Company (STPC). These dryers are as a drying powder Terphetalic acid in CTA2 and CTA1 unit. After passing through RVF equipment, wet cake moisture content of about 14% and temperature of 90C changed into a dry cake with a moisture content of less than 0.1% and the final temperature of about 140C and sent out Final Silo (FS-1820). After the declaration of the operation department concerning the observation of acid leakage under the primary insulation was decided that at the first opportunity, this issue must be investigated. So, after the shutdown of a unit at the date 2012/10/20 (2DR-1745) and 2021/11/24 (DR-1402) and after washing the dryer wall, insulation around the wall opened and it was found to crack and leakage from some points.

Keywords: stress corrosion cracking, residual stress, austenitic stainless steel, Br- ion

Procedia PDF Downloads 151

Authors: Ligia Nascimento, Manuela Faia Correia

Abstract:

Nowadays, Information and Communication Technologies (ICT) are embedded in most professions. Technostress - or stress induced by the use of ICTs, has been studied in various sectors of activity and in different geographical areas, mainly from the perspective of its harmful impacts. In the context of work, the technological contexts capable of causing stress have been examined in-depth, as well as the type of individuals most likely to experience its negative effects. However, new lines of the research argue that the stress generated by the use of ICTs may not necessarily be detrimental (technodistress), admitting that, in contrast, and in addition, it may actually be beneficial to organizations and their employees (technoeustress). Any measures that succeed in reducing technodistress do not necessarily lead to the creation of technoeustress, justifying the study of this phenomenon in a focused and independent manner. Adopting the transactional model of stress as the basic theoretical framework, an ongoing research project aims to study technoeustress independently. Given the role played in the qualification and progress of society and the economy, it becomes particularly critical to care for the well-being of the higher education teacher. Particularly in recent times, when teleworking is prevalent, these professionals have made a huge, compulsive effort to adapt to a new teaching reality. Rather than limiting itself to mitigating adverse effects of ICT use, which featured earlier approaches, the present study seeks to understand how to activate the positive side of technostress in higher education teachers in order to obtain favorable personal and organizational outcomes from ICT use at work. The research model seeks to understand, upstream, the ICT characteristics that increase the perception of technoeustress among higher education teachers, studying the direct and moderating effects of individual and organizational variables and, downstream, the impacts that technoeustress has on job satisfaction and performance. This research contributes both to expanding the knowledge of the technostress phenomenon and to identify possible recommendations for management.

Keywords: higher education teachers, ICT, stress, technoeustress

Procedia PDF Downloads 140

Authors: Angela Cristina Da F. De Oliveira, Salma E. Asmar, Norbert P. Battlori, Yaz Vera, Uriel R. Valencia, Tâmara D. Borges, Antoni D. Bueno, Leandro B. Costa

Abstract:

The present study aimed to evaluate the replacement of 5% of starch per 5% of sunflower oil (SO) on meat quality and animal welfare of growing and finishing pigs (Iberic x Duroc), exposed to a heat stress environment. The experiment lasted 90 days, and it was carried out in a randomized block design, in a 2 x 2 factorial, composed of two diets (starch or sunflower oil (with or without) and two feed intake management (ad libitum and restriction). Seventy-two crossbred males (51± 6,29 kg body weight - BW) were housed in climate-controlled rooms, in collective pens and exposed to heat stress environment (32°C; 35% to 50% humidity). The treatments studies were: 1) control diet (5% starch x 0% SO) with ad libitum intake (n = 18); 2) SO diet (replacement of 5% of starch per 5% of SO) with ad libitum intake (n = 18); 3) control diet with restriction feed intake (n = 18); or 4) SO diet with restriction feed intake (n = 18). Feed were provided in two phases, 50-100 Kg BW for growing and 100-140 Kg BW for finishing, respectively. Within welfare evaluations, dirtiness score was evaluated all morning during ninety days of the experiment. The presence of manure was individually measured based on one side of the pig´s body and scored according to: 0 (less than 20% of the body surface); 1 (more than 20% but less than 50% of the body surface); 2 (over 50% of the body surface). After the experimental period, when animals reach 130-140 kg BW, they were slaughtered using carbon dioxide (CO2) stunning. Carcass weight, leanness and fat content, measured at the last rib, were recorded within 20 min post-mortem (PM). At 24h PM, pH, electrical conductivity and color measures (L, a*, b*) were recorded in the Longissimus thoracis and Semimembranosus muscles. Data shown no interaction between diet (control x SO) and management feed intake (ad libitum x restriction) on the meat quality parameters. Animals in ad libitum management presented an increase (p < 0.05) on BW, carcass weight (CW), back fat thickness (BT), and intramuscular fat content (IM) when compared with animals in restriction management. In contrast, animals in restriction management showing a higher (p < 0.05) carcass yield, percentage of lean and loin thickness. To welfare evaluations, the interaction between diet and management feed intake did not influence the degree of dirtiness. Although, the animals that received SO diet, independently of the management, were cleaner than animals in control group (p < 0,05), which, for pigs, demonstrate an important strategy to reduce body temperature. Based in our results, the diet and management feed intake had a significant influence on meat quality and animal welfare being considered efficient nutritional strategies to reduce heat stress and improved meat quality.

Keywords: dirtiness, environment, meat, pig

Procedia PDF Downloads 255

Authors: Nishant Shrivastava, D. K. Sehgal

Abstract:

In Finite Element Technique nodal stresses are calculated through displacement as nodes. In this process, the displacement calculated at nodes is sufficiently good enough but stresses calculated at nodes are not sufficiently accurate. Therefore, the accuracy in the stress computation in FEM models based on the displacement technique is obviously matter of concern for computational time in shape optimization of engineering problems. In the present work same is focused to find out unique points within the element as well as the boundary of the element so, that good accuracy in stress computation can be achieved. Generally, major optimal stress points are located in domain of the element some points have been also located at boundary of the element where stresses are fairly accurate as compared to nodal values. Then, it is subsequently concluded that there is an existence of unique points within the element, where stresses have higher accuracy than other points in the elements. Therefore, it is main aim is to evolve a generalized procedure for the determination of the optimal stress location inside the element as well as at the boundaries of the element and verify the same with results from numerical experimentation. The results of quadratic 9 noded serendipity elements are presented and the location of distinct optimal stress points is determined inside the element, as well as at the boundaries. The theoretical results indicate various optimal stress locations are in local coordinates at origin and at a distance of 0.577 in both directions from origin. Also, at the boundaries optimal stress locations are at the midpoints of the element boundary and the locations are at a distance of 0.577 from the origin in both directions. The above findings were verified through experimentation and findings were authenticated. For numerical experimentation five engineering problems were identified and the numerical results of 9-noded element were compared to those obtained by using the same order of 25-noded quadratic Lagrangian elements, which are considered as standard. Then root mean square errors are plotted with respect to various locations within the elements as well as the boundaries and conclusions were drawn. After numerical verification it is noted that in a 9-noded element, origin and locations at a distance of 0.577 from origin in both directions are the best sampling points for the stresses. It was also noted that stresses calculated within line at boundary enclosed by 0.577 midpoints are also very good and the error found is very less. When sampling points move away from these points, then it causes line zone error to increase rapidly. Thus, it is established that there are unique points at boundary of element where stresses are accurate, which can be utilized in solving various engineering problems and are also useful in shape optimizations.

Keywords: finite elements, Lagrangian, optimal stress location, serendipity

Procedia PDF Downloads 102

Authors: Petra Hurbišová, Monika Davidová

Abstract:

The article deals with the readiness of military professionals for challenging situations. It discusses higher requirements on the psychical endurance of military professionals arising from the specific nature of the military occupation, which is typical for being very difficult to maintain regularity, which is in accordance with the hygiene of work alternated by relaxation. The soldier must be able to serve in the long term and constantly intense performance that goes beyond human tolerance to stress situations. A challenging situation is always associated with overcoming difficulties, obstacles and complicated circumstances or using unusual methods, ways and means to achieve the desired (expected) objectives, performing a given task or satisfying an important need. This paper describes the categories of challenging situations, their classification and characteristics. Attention is also paid to the formation of personality in challenging situations, coping with stress in challenging situations, Phases of solutions of stressful situations, resistance to challenging life situations and its factors. Finally, the article is focused on increasing the readiness of military professionals for challenging situations.

Keywords: coping, challenging situations, stress, stressful situations, military professionals, resilience

Procedia PDF Downloads 313

Authors: Marianna De Almeida

Abstract:

Greek secondary education is a highly selective system with regard to the access of students to Greek universities. Since access from elementary to lower secondary education and afterward to upper secondary education is rather liberal and almost free of selective mechanisms, the basic selection process comes after graduating from upper secondary school into play when students go through a highly selective process for university entry. This structure is responsible for the experience of extreme stress on the part of the candidates during a period of at least two years before the entrance examination leading to a radical change in students' everyday life routines. Instead of the school being an important agent for academic and psychological support, it seems that other agents, such as the informal private preparatory school and the student's families, take on the supportive role.

Keywords: stress, entrance examinations, family support, secondary education

Procedia PDF Downloads 63

Authors: George D. Ranis, Valasia Iakovoglou, George N. Zaimes

Abstract:

Fires are one of the main types of disturbances that shape ecosystems in the Mediterranean region. However nowadays, climate alterations towards higher temperature regimes results on the increased levels of the intensity, frequency and the spread of fires inducing obstacles for the natural regeneration. Thasos Island is one of the Greek islands that have experienced those problems. Since 1984, a series of wildfires led to the reduction of forest cover from 61.6% to almost 20%. The negative impacts were devastating in many different aspects for the island. The absence of plant cover, post-wildfire precipitation and steep slopes were the major factors that induced severe soil erosion and intense flooding events. That also resulted to serious economic problems to the local communities and the ability of the burnt areas to regenerate naturally. Despite the substantial amount of published work regarding Thasos wildfires, there is no information related to post-wildfire effects on the hydrology and soil erosion. More research related to post-fire effects should help to an overall assessment of the negative impacts of wildfires on land degradation through processes such as soil erosion and flooding.

Keywords: erosion, land degradation, Mediterranean islands, regeneration, Thasos, wildfires

Procedia PDF Downloads 320

Authors: Mojtaba Esmaeilzad Limoudehi, Ebrahim Amiri

Abstract:

Water scarcity is now one of the leading challenges for human societies. In this regard, recognizing the relationship between soil, water, plant growth, and plant response to stress is very significant. In this paper, considering the importance of drought stress and the role of choosing suitable cultivars in resistance against drought, a split-plot experiment using early, intermediate, and late-maturing cultivars was carried out in Katul filed, Golestan province during two cultivation years of 2015 and 2016. The main factor was irrigation intervals at four levels, including 7 days, 14 days, 21 days, and 28 days. The subfactor was the subplot of six maize cultivars (two early maturing cultivars, two medium maturing cultivars, and two late-maturing cultivars). The results of variance analysis have revealed that irrigation interval and cultivars treatment have significant effects on the number of grain in each corn, number of rows in each corn, number of grain per row, the weight of 1000 grains, grain yield, and biomass yield. Although, the interaction of these two factors on the mentioned attributes was meaningful. The best grain yield was achieved at 7 days irrigation interval and late maturing maize cultivars treatment, which was equal to 12301 kg/ha.

Keywords: corn, growth period, optimization, stress

Procedia PDF Downloads 133

Authors: Scott A. Abbott

Abstract:

This paper examines the increase in the occurrence of natural disasters worldwide and the need to support vulnerable communities in post-disaster recovery. Preparation and implementation of post-disaster recovery projects need to be improved to allow communities to recover infrastructure, housing, economically and socially following a catastrophe. With the continual rise in catastrophic events worldwide due to climate change, impacts on construction resources affect the ability for post-disaster recovery to be undertaken. This research focuses on case studies of catastrophic events in Queensland, Australia, to contribute to the body of knowledge and gain valuable insights on lessons learned from past events and how they have been managed. The aim of this research is to adopt qualitative data using semi-structured interviews from participants predominantly from the insurance sector to understand barriers that have previously and currently exist in post-disaster recovery. Existing literature was reviewed to reveal gaps in knowledge that needed to be tested. Qualitative data was collected and summarised from field research with the results analysed and discussed. Barriers that impacted post-disaster recovery included time, cost, and resource capability and capacity. Causal themes that impacted time and cost were identified as decision making, pre-planning, and preparedness, as well as effective communication across stakeholders. The research study applied a qualitative approach to the existing literature and case studies across Queensland, Australia, to identify existing and new barriers that impact post-disaster recovery. It was recommended to implement effective procurement strategies to assist in cost control; implement pre-planning and preparedness strategies across funder, contractor, and local governments; more effective and timely decision making to reduce time and cost impacts.

Keywords: construction recovery, cost, disaster recovery, resources, time

Procedia PDF Downloads 122

Authors: Dalia Atallah, Lamiaa Ahmed, Hala Zaki, Mahmoud Khattab

Abstract:

Background: Isoprenaline (ISO) administration induces myocardial damage via oxidative stress and endothelial dysfunction. Atorvastatin (ATV) treatment improves both oxidative stress and endothelial dysfunction yet recent studies have reported a pro-oxidant effect upon ATV administration on both clinical and experimental studies. The present study was directed to investigate the effect of ATV pre-treatment and treatment on ISO-induced myocardial damage. Methods: Male rats were divided into five groups (n = 10). Rats were given ISO (5mg/kg/day, i.p.) for one week with or without ATV (10mg/kg/day, p.o.). ATV was given either as pre-treatment for one week before its co-administration with ISO for another week or as a treatment for two weeks at the end of the ISO administration. At the end of the experiment, the electrocardiographic examination was done and blood was isolated for the estimation of plasma creatine kinase MB (CK-MB) activity. Rats were then sacrificed and the whole ventricles were isolated for histological examination and the estimation of lipid peroxides as malondialdehyde (MDA) level, reduced glutathione (GSH) level, catalase activity, total nitrate-nitrite (NOx), as well as the estimation of both endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) protein expression. Results: ISO-induced myocardial damage showed a significant elevation in ST segment, an increase in CK-MB activity, as well as increased oxidative stress biomarkers. Also, ISO-treated rats showed a significant decrease in myocardial NOx level and eNOS as well as degeneration in the myocardium. ATV pre-treatment didn’t show any protection to ISO-treated rats. On the other hand, ATV treatment showed a significant decrease in both the elevated ST wave and CK-MB activity. Moreover, ATV Treatment succeeded to improve oxidative stress biomarkers, tissue NOx, and eNOS protein expression, as well as amelioration of the histological alterations. Conclusion: Pre-treatment with ATV failed to protect against ISO-induced damage. This might suggest a synergistic pro-oxidant effect upon administration of the pro-oxidant ISO along with ATV as demonstrated by the increased oxidative stress and endothelial dysfunction. On the other side, ATV treatment succeeded to significantly improve oxidative stress biomarkers, endothelial dysfunction and myocardial degeneration.

Keywords: atorvastatin, endothelial dysfunction, isoprenaline, oxidative stress

Procedia PDF Downloads 444

Authors: K. Chalernpon, P. Aroonjarattham, K. Aroonjarattham

Abstract:

Total hip replacement had been one of the most successful operations in hip arthritis surgery. The purpose of this research had been to develop a dynamic hip contact of Thai femoral bone to analyze the stress distribution on the implant and the strain distribution on the bone model under daily activities and compared with the static load simulation. The results showed the different of maximum von Mises stress 0.14 percent under walking and 0.03 percent under climbing stair condition and the different of equivalent total strain 0.52 percent under walking and 0.05 percent under climbing stair condition. The muscular forces should be evaluated with dynamic condition to reduce the maximum von Mises stress and equivalent total strain.

Keywords: dynamic loading, static load, hip prosthesis, Thai femur, femoral bone, finite element analysis

Procedia PDF Downloads 344

Authors: Amritha Nair, Fleur Visser, Ian Maddock, Jonas Schoelynck

Abstract:

Inland waters such as streams sustain a rich variety of species and are essentially hotspots for biodiversity. Submerged aquatic vegetation, also known as SAV, forms an important part of ecologically healthy river systems. Direct and indirect human influences, such as climate change are putting stress on aquatic plant communities, ranging from the invasion of non-native species and grazing, to changes in the river flow conditions and temperature. There is a need to monitor SAV, because they are in a state of deterioration and their disappearance will greatly impact river ecosystems. Like terrestrial plants, SAV can show visible signs of stress. However, the techniques used to map terrestrial vegetation from its spectral reflectance, are not easily transferable to a submerged environment. Optical remote sensing techniques are employed to detect the stress from remotely sensed images through multispectral imagery and Structure from Motion photogrammetry. The effect of the overlying water column in the form of refraction, attenuation of visible and near infrared bands in water, as well as highly moving targets, are NIR) key challenges that arise when remotely mapping SAV. This study looks into the possibility of mapping the changes in spectral signatures from SAV and their response to certain stresses.

Keywords: submerged aquatic vegetation, structure from motion, photogrammetry, multispectral, spectroscopy

Procedia PDF Downloads 85

Authors: T. O. Ajewole, K. S. Olorunmiaye, D. A. Animasaun, M. Okpeku

Abstract:

Drought impact on the production of food crops for the benefit of mankind cannot be overemphasized. This study shows the different kind of genes expressed at various level of drought regimes on Basella alba and rubra using a real-time PCR machine. The planting was done in the screen house while the gene expression study was carried out in the laboratory. Sandy-loamy soil was collected and four levels of drought regime was used as treatment and a control experiment was set up for the two vegetables. Drought interval of 5, 10, 15 and 20 days were used as treatments while a control experiment which was not starved of water at any point was also set up, five replicates were set up for each treatment. Stress was introduced at 12 Weeks after planting (WAP). From the result of this study, Basella alba shows the highest amplicon size of 34.6 and 52.32 for GmPCS5 and HVA1 respectively which by implication means these genes were expressed the more as the stress period interval increases.

Keywords: water stress, basella alba, basella rubra, HVA1

Procedia PDF Downloads 36

Authors: Engy S. El-Kayal, Mohamed M. S. Arafa

Abstract:

There are various causes of ankle pain including traumatic and non-traumatic causes. Various imaging techniques are available for assessment of AP. MRI is considered to be the imaging modality of choice for ankle joint evaluation with an advantage of its high spatial resolution, multiplanar capability, hence its ability to visualize small complex anatomical structures around the ankle. However, the high costs and the relatively limited availability of MRI systems, as well as the relatively long duration of the examination all are considered disadvantages of MRI examination. Therefore there is a need for a more rapid and less expensive examination modality with good diagnostic accuracy to fulfill this gap. HRU has become increasingly important in the assessment of ankle disorders, with advantages of being fast, reliable, of low cost and readily available. US can visualize detailed anatomical structures and assess tendinous and ligamentous integrity. The aim of this study was to compare the diagnostic accuracy of HRU with MRI in the assessment of patients with AP. We included forty patients complaining of AP. All patients were subjected to real-time HRU and MRI of the affected ankle. Results of both techniques were compared to surgical and arthroscopic findings. All patients were examined according to a defined protocol that includes imaging the tendon tears or tendinitis, muscle tears, masses, or fluid collection, ligament sprain or tears, inflammation or fluid effusion within the joint or bursa, bone and cartilage lesions, erosions and osteophytes. Analysis of the results showed that the mean age of patients was 38 years. The study comprised of 24 women (60%) and 16 men (40%). The accuracy of HRU in detecting causes of AP was 85%, while the accuracy of MRI in the detection of causes of AP was 87.5%. In conclusions: HRU and MRI are two complementary tools of investigation with the former will be used as a primary tool of investigation and the latter will be used to confirm the diagnosis and the extent of the lesion especially when surgical interference is planned.

Keywords: ankle pain (AP), high-resolution ultrasound (HRU), magnetic resonance imaging (MRI) ultrasonography (US)

Procedia PDF Downloads 185

Authors: Tolulope Babawarun, Harry Ngwangwa

Abstract:

The wind turbine blade may sustain structural damage from external loads such as high winds or collisions, which could compromise its aerodynamic efficiency. The wind turbine blade vibrates at significant intensities and amplitudes under these conditions. The effect of these vibrations on the dynamic flow field surrounding the blade changes the forces operating on it. The structural dynamic analysis of a small wind turbine blade is considered in this study. It entails creating a finite element model, validating the model, and doing structural analysis on the verified finite element model. The analysis is based on the structural reaction of a small-scale wind turbine blade to various loading sources. Although there are many small-scale off-shore wind turbine systems in use, only preliminary structural analysis is performed during design phases; these systems' performance under various loading conditions as they are encountered in real-world situations has not been properly researched. This will allow us to record the same Equivalent von Mises stress and deformation that the blade underwent. A higher stress contour was found to be more concentrated near the middle span of the blade under the various loading scenarios studied. The highest stress that the blade in this study underwent is within the range of the maximum stress that blade material can withstand. The maximum allowable stress of the blade material is 1,770 MPa. The deformation of the blade was highest at the blade tip. The critical speed of the blade was determined to be 4.3 Rpm with a rotor speed range of 0 to 608 Rpm. The blade's mode form under loading conditions indicates a bending mode, the most prevalent of which is flapwise bending.

Keywords: ANSYS, finite element analysis, static loading, dynamic analysis

Procedia PDF Downloads 80

Authors: Chandra Shekhar Maurya, Chiranjit Sarkar

Abstract:

The transient response of rheological properties of a carbonyl iron (CI)-water-based magnetorheological fluid (MRF) was studied under shear rate, shear stress, and shear strain working mode subjected to step-change in an applied magnetic field. MR fluid is a kind of smart material whose rheological properties change under an applied magnetic field. We prepared an MR fluid comprising of CI 65 weight %, water 35 weight %, and OPTIGEL WX used as an additive by changing the weight %. It was found that the MR effect of the CI/water suspension was enhanced by using an additive. A transient shear stress response was observed by switched on and switched off of the magnetic field to see the stability, relaxation behavior, and resulting change in rheological properties. When the magnetic field is on, a sudden increase in the shear stress was observed due to the fast motion of magnetic structures that describe the transition from the liquidlike state to the solid-like state due to an increase in dipole-dipole interaction of magnetic particles. Simultaneously, the complete reverse transition occurs due to instantaneous breakage of the chain structure once the magnetic field is switched off.

Keywords: magnetorheological fluid, rheological properties, shears stress, shears strain, viscosity

Procedia PDF Downloads 169

Authors: Aram Yakoby, Yossef H. Hatzor, Shmulik Pinkert

Abstract:

This work presents an applied engineering method for evaluating the stability of underground openings under conditions of uncertainty. The developed method is demonstrated by a comprehensive parametric study on a case of large-diameter vertical borehole stability analysis, with uncertainties regarding the in-situ stress distribution. To this aim, a safety factor analysis is performed for the stability of both supported and unsupported boreholes. In the analysis, we used analytic geomechanical calculations and advanced numerical modeling to evaluate the estimated stress field. In addition, the work presents the development of a boundary condition for the numerical model that fits the nature of the problem and yields excellent accuracy. The borehole stability analysis is studied in terms of (1) the stress ratio in the vertical and horizontal directions, (2) the mechanical properties and geometry of the support system, and (3) the parametric sensitivity. The method's results are studied in light of a real case study of an underground waste disposal site. The conclusions of this study focus on the developed method for capturing the parametric uncertainty, the definition of critical geological depths, the criteria for implementing structural support, and the effectiveness of further in-situ investigations.

Keywords: borehole stability, in-situ stress, parametric study, factor of safety

Procedia PDF Downloads 58

Authors: Chizzoniti Domenico, Beggiora Klizia, Cattani Letizia, Moscatelli Monica

Abstract:

This paper concerns the study of sustainable construction materials applied on the "Health Post", a prototype for the primary health care situated in alienated areas of the world. It's suitable for social and climatic Sub-Saharan context; however, it could be moved in other countries of the world with similar urgent needs. The idea is to create a Health Post with local construction materials that have a low environmental impact and promote the local workforce allowing reuse of traditional building techniques lowering production costs and transport. The aim of Primary Health Care Centre is to be a flexible and expandable structure identifying a modular form that can be repeated several times to expand its existing functions. In this way it could be not only a health care centre but also a socio-cultural facility.

Keywords: low costs building, sustainable construction materials, green construction system, prototype, health care, emergency

Procedia PDF Downloads 475

Authors: Chia-Ching Tsai

Abstract:

In the literature, the positive effect of service co-recovery has been evidenced, and which customers’ attribution is the key successful factor has also been indicated. There is also literature investigating on initiation of co-recovery for finding out the superior way to co-recovery, and indicating co-recovery initiated by employees causes better effect of co-recovery. This research postulates the consequences of co-recovery by different initiators affect customers’ attribution and the resultant results. Thus, this research uses a 3x2 factorial design to investigate the impact of initiator of co-recovery and consequence of co-recovery on customers’ attribution and post-recovery satisfaction. The results show initiation of co-recovery has a significant influence on internal attribution, and the employee initiator causes the highest internal attribution. The consequences of co-recovery interact with initiators of co-recovery on internal attribution significantly. Moreover, internal attribution significantly affects post-recovery satisfaction.

Keywords: service co-recovery, initiation of co-recovery, attribution, post-recovery satisfaction

Procedia PDF Downloads 259

Authors: Taposh Roy, Anna Paradowska, Ralph Abrahams, Quan Lai, Michael Law, Peter Mutton, Mehdi Soodi, Wenyi Yan

Abstract:

In this investigation, a laser cladding process with a powder feeding was used to deposit stainless steel 410L (high strength, excellent resistance to abrasion and corrosion, and great laser compatibility) onto railhead (higher strength, heat treated hypereutectoid rail grade manufactured in accordance with the requirements of European standard EN 13674 Part 1 for R400HT grade), to investigate the development and controllability of process-induced residual stress in the cladding, heat-affected zone (HAZ) and substrate and to analyse their correlation with hardness profile during two different laser cladding directions (across and along the track). Residual stresses were analysed by neutron diffraction at OPAL reactor, ANSTO. Neutron diffraction was carried out on the samples in longitudinal (parallel to the rail), transverse (perpendicular to the rail) and normal (through thickness) directions with high spatial resolution through the thickness. Due to the thick rail and thin cladding, 4 mm thick reference samples were prepared from every specimen by Electric Discharge Machining (EDM). Metallography across the laser claded sample revealed four distinct zones: The clad zone, the dilution zone, HAZ and the substrate. Compressive residual stresses were found in the clad zone and tensile residual stress in the dilution zone and HAZ. Laser cladding in longitudinally cladding induced higher tensile stress in the HAZ, whereas transversely cladding rail showed lower tensile behavior.

Keywords: laser cladding, residual stress, neutron diffraction, HAZ

Procedia PDF Downloads 269

Authors: V. Antevska, B. Dejanova, L. Todorovska, J. Pluncevic, E. Sivevska, S. Petrovska, S. Mancevska, I. Karagjozova

Abstract:

Introduction: The aim of this study was to optimise the laboratory oxidative stress (OS) markers in soccer players. Material and methods: In a number of 37 soccer players (21±3 years old) and 25 control subjects (sedenters), plasma samples were taken for d-ROMs (reactive oxygen metabolites) and NO (nitric oxide) determination. The d-ROMs test was performed by measurement of hydroperoxide levels (Diacron, Italy). For NO determination the method of nitrate enzyme reduction with the Greiss reagent was used (OXIS, USA). The parameters were taken after the training of the soccer players and were compared with the control group. Training was considered as maximal exercise treadmill test. The criteria of maximum loading for each subject was established as >95% maximal heart rate. Results: The level of d-ROMs was found to be increased in the soccer players vs. control group but no significant difference was noticed. After the training d-ROMs in soccer players showed increased value of 299±44 UCarr (p<0.05). NO showed increased level in all soccer players vs. controls but significant difference was found after the training 102±29 μmol (p<0.05). Conclusion: Due to these results we may suggest that the measuring these OS markers in sport medicine may be useful for better estimation and evaluation of the training program. More oxidative stress should be used to clarify optimization of the training intensity program.

Keywords: oxidative stress markers, soccer players, training, sport

Procedia PDF Downloads 441

Authors: Supannika Klangphukhiew, Roongnapa Srichana, Rina Patramanon

Abstract:

Cortisol has been used as a well-known commercial stress biomarker. A homeostasis response to psychological stress is indicated by an increased level of cortisol produced in hypothalamus-pituitary-adrenal (HPA) axis. Chronic psychological stress contributing to the high level of cortisol relates to several health problems. In this study, the cortisol biosensor was fabricated that mimicked the natural receptors. The artificial antibodies were prepared using molecular imprinted polymer technique that can imitate the performance of natural anti-cortisol antibody with high stability. Cortisol-molecular imprinted polymer (cortisol-MIP) was obtained using the multi-step swelling and polymerization protocol with cortisol as a target molecule combining methacrylic acid:acrylamide (2:1) with bisacryloyl-1,2-dihydroxy-1,2-ethylenediamine and ethylenedioxy-N-methylamphetamine as cross-linkers. Cortisol-MIP was integrated to the sensor. It was coated on the disposable screen-printed carbon electrode (SPCE) for portable electrochemical analysis. The physical properties of Cortisol-MIP were characterized by means of electron microscope techniques. The binding characteristics were evaluated via covalent patterns changing in FTIR spectra which were related to voltammetry response. The performance of cortisol-MIP modified SPCE was investigated in terms of detection range, high selectivity with a detection limit of 1.28 ng/ml. The disposable cortisol biosensor represented an application of MIP technique to recognize steroids according to their structures with feasibility and cost-effectiveness that can be developed to use in point-of-care.

Keywords: stress biomarker, cortisol, molecular imprinted polymer, screen-printed carbon electrode

Procedia PDF Downloads 264

Authors: Salwa M. Almomen, Mona A. Almaghrabi, Saja M. Alhabardi, Adel A. Alrwisan

Abstract:

Background: Hepatotoxicity is a major reason for medication withdrawal from the markets. Unfortunately, serious adverse hepatic effects can occur after marketing with limited indicators during clinical development. Therefore, finding possible predictors for hepatotoxicity might guide the monitoring program of various stakeholders. Methods: We examined the clinical review documents for drugs approved in the US from 2011 to 2016 to evaluate their hepatic safety profile. Predictors: we assessed whether these medications meet Hy’s Law with hepatotoxicity grade ≥ 3, labeled hepatic adverse effects at approval, or accelerated approval status. Outcome: post-marketing regulatory action related to hepatotoxicity, including product withdrawal or updates to warning, precaution, or adverse effects sections. Statistical analysis: drugs were included in the analysis from the time of approval until the end of 2019 or the first post-marketing regulatory action related to hepatotoxicity, whichever occurred first. The hazard ratio (HR) was estimated using Cox-regression analysis. Results: We included 192 medications in the study. We classified 48 drugs as having grade ≥ 3 hepatotoxicities, 43 had accelerated approval status, and 74 had labeled information about hepatotoxicity prior to marketing. The adjusted HRs for post-marketing regulatory action for products with grade ≥ 3 hepatotoxicity was 0.61 (95% confidence interval [CI], 0.17-2.23), 0.92 (95%CI, 0.29-2.93) for a drug approved via accelerated approval program, and was 0.91 (95%CI, 0.33-2.56) for drugs with labeled hepatotoxicity information at approval time. Conclusion: This study does not provide conclusive evidence on the association between post-marketing regulatory action and grade ≥ 3 hepatotoxicity, accelerated approval status, or availability of labeled information at approval due to sampling size and channeling bias.

Keywords: accelerated approvals, hepatic adverse effects, drug-induced liver injury, hepatotoxicity predictors, post-marketing withdrawal

Procedia PDF Downloads 148

Authors: Hong Li, Tingxian Li, Xudong Wang, Qinghuo Lin

Abstract:

Excess-iron (Fe) stresses involved in legume symbiotic nitrogen fixation are not understood. Our objectives were to investigate the tolerance of yardlong-bean plants to soil excess-Fe stress and antagonistic effects of organic amendments and rhizobial inoculants on plant root nodulation and stem ureide formation. The study was conducted in the tropical Hainan Island during 2012-2013. The soil was strongly acidic (pH 5.3±0.4) and highly variable in Fe concentrations(596±79 mg/kg). The treatments were arranged in a split-plot design with three blocks. The treatment effects were significant on root nodulation, stem ureide, amino acids, plant N/Fe accumulation and bean yields (P<0.05). The yardlong-bean stem allantoin, amino acids and nitrate concentrations and relative ureide % declined with high soil Fe concentrations (>300 mg/kg). It was concluded that the co-variance of excess Fe stress could inhibit legume symbiotic N fixation efficiency. Organic amendments and rhizobial inoculants could help improve crop tolerance to excess Fe stress.

Keywords: atmospheric N fixation, root nodulation, soil Fe co-variance, stem ureide, yardlong-bean plants

Procedia PDF Downloads 275

Authors: Sajjad Hassanpour, Vicente A. González, Yang Zou, Jiamou Liu

Abstract:

Earthquakes pose a significant threat to both structural and non-structural elements in buildings, putting human lives at risk. Effective post-earthquake evacuation is critical for ensuring the safety of building occupants. However, current design practices often neglect the integration of post-earthquake evacuation considerations into the early-stage architectural design process. To address this gap, this paper presents a novel automated internal architectural layout generation tool that optimizes post-earthquake evacuation performance. The tool takes an initial plain floor plan as input, along with specific requirements from the user/architect, such as minimum room dimensions, corridor width, and exit lengths. Based on these inputs, firstly, the tool randomly generates different architectural layouts. Secondly, the human post-earthquake evacuation behaviour will be thoroughly assessed for each generated layout using the advanced Agent-Based Building Earthquake Evacuation Simulation (AB2E2S) model. The AB2E2S prototype is a post-earthquake evacuation simulation tool that incorporates variables related to earthquake intensity, architectural layout, and human factors. It leverages a hierarchical agent-based simulation approach, incorporating reinforcement learning to mimic human behaviour during evacuation. The model evaluates different layout options and provides feedback on evacuation flow, time, and possible casualties due to earthquake non-structural damage. By integrating the AB2E2S model into the automated layout generation tool, architects and designers can obtain optimized architectural layouts that prioritize post-earthquake evacuation performance. Through the use of the tool, architects and designers can explore various design alternatives, considering different minimum room requirements, corridor widths, and exit lengths. This approach ensures that evacuation considerations are embedded in the early stages of the design process. In conclusion, this research presents an innovative automated internal architectural layout generation tool that integrates post-earthquake evacuation simulation. By incorporating evacuation considerations into the early-stage design process, architects and designers can optimize building layouts for improved post-earthquake evacuation performance. This tool empowers professionals to create resilient designs that prioritize the safety of building occupants in the face of seismic events.

Keywords: agent-based simulation, automation in design, architectural layout, post-earthquake evacuation behavior

Procedia PDF Downloads 94

Authors: Zahidul Islam

Abstract:

This study investigates the effectiveness of resourcing in post-disaster housing reconstruction with reference to Cyclones Sidr and Aila in Bangladesh. Through evaluating three key theories- Build Back Better approach, Balance Scorecard approach and Dynamic Competency theories, the synthesis of literature, and empirical fieldwork, this research develops a dynamic theoretical framework that moves the trajectory of post-disaster housing reconstruction towards the reconstruction of more resilient houses. The ultimate goal of any post-disaster housing reconstruction project is to provide quality houses and to achieve high levels of satisfaction for beneficiaries. However, post-disaster reconstruction projects often fail in their stated objectives; only 10-20% housing needs are met, with most houses constructed on a temporary rather than permanent basis. A number of scholars have argued that access to resources can significantly increase the capacity and capability of disaster victims to rebuild their lives, including the construction of new homes. This study draws on structured interviews of 285 villagers affected by cyclones to investigate the effectiveness of resourcing in rebuilding houses after Cyclone Sidr in 2007 and Cyclone Aila in 2009. Furthermore, semi-structured interviews were conducted with 20 key stakeholders in UNDP, Oxfam, government officials, and national and international NGOs. The results of this study show that recovery rate of cyclone resilient houses that can withstand cyclone is very low and majority of the population are still vulnerable. Furthermore, hierarchical regression of survey data and thematic analyses of qualitative data indicate that access to resources, level of education, quality of building materials and income generating activities of the respondents are critical for effective post-disaster recovery. Conversely, resource availability, lack of coordination among participant organisations, corruption and lack of access to appropriate land constituted significant obstacles to livelihood recovery. Finally, this study makes significant theoretical contributions to theories of post-disaster recovery by introducing new variables and measures for evaluating the quality and effectiveness of post-disaster housing.

Keywords: disaster, resourcing, housing, resilience

Procedia PDF Downloads 142

Authors: Jinlai Bian, Zailin Yang, Guanxixi Jiang, Xinzhu Li

Abstract:

The problem of elastic wave propagation in inhomogeneous medium has always been a classic problem. Due to the frequent occurrence of earthquakes, many economic losses and casualties have been caused, therefore, to prevent earthquake damage to people and reduce damage, this paper studies the dynamic response around the circular inclusion in the whole space with inhomogeneous modulus, the inhomogeneity of the medium is reflected in the shear modulus of the medium with the spatial position, and the density is constant, this method can be used to solve the problem of the underground buried pipeline. Stress concentration phenomena are common in aerospace and earthquake engineering, and the dynamic stress concentration factor (DSCF) is one of the main factors leading to material damage, one of the important applications of the theory of elastic dynamics is to determine the stress concentration in the body with discontinuities such as cracks, holes, and inclusions. At present, the methods include wave function expansion method, integral transformation method, integral equation method and so on. Based on the complex function method, the Helmholtz equation with variable coefficients is standardized by using conformal transformation method and wave function expansion method, the displacement and stress fields in the whole space with circular inclusions are solved in the complex coordinate system, the unknown coefficients are solved by using boundary conditions, by comparing with the existing results, the correctness of this method is verified, based on the superiority of the complex variable function theory to the conformal transformation, this method can be extended to study the inclusion problem of arbitrary shapes. By solving the dynamic stress concentration factor around the inclusions, the influence of the inhomogeneous parameters of the medium and the wavenumber ratio of the inclusions to the matrix on the dynamic stress concentration factor is analyzed. The research results can provide some reference value for the evaluation of nondestructive testing (NDT), oil exploration, seismic monitoring, and soil-structure interaction.

Keywords: circular inclusions, complex variable function, dynamic stress concentration factor (DSCF), inhomogeneous medium

Procedia PDF Downloads 132

Authors: Shazia Anwer Bukhari, Madiha Javeed Ghani, Muhammad Ibrahim Rajoka

Abstract:

Objective: Biochemical, environmental, physical and genetic factors have a strong effect on the development of coronary disease (CAD). Plasma homocysteine (Hcy) level and DNA damage play a pivotal role in its development and progression. The aim of this study was to investigate the predictive strength of an oxidative stress, clinical biomarkers and total antioxidant status (TAS) in CAD patients to find the correlation of homocysteine, TOS and oxidative DNA damage with other clinical parameters. Methods: Sixty confirmed patients with CAD and 60 healthy individuals as control were included in this study. Different clinical and laboratory parameters were studied in blood samples obtained from patients and control subjects using commercially available biochemical kits and statistical software Results: As compared to healthy individuals, CAD patients had significantly higher concentrations of indices of oxidative stress: homocysteine (P=0.0001), total oxidative stress (TOS) (P=0.0001), serum cholesterol (P=0.04), low density lipoprotein cholesterol (LDL) (P=0.01), high density lipoprotein-cholesterol (HDL) (P=0.0001), and malondialdehyde (MDA) (P=0.001) than those of healthy individuals. Plasma homocysteine level and oxidative DNA damage were positively correlated with cholesterol, triglycerides, systolic blood pressure, urea, total protein and albumin (P values= 0.05). Both Hcy and oxidative DNA damage were negatively correlated with TAS and proteins. Conclusion: Coronary artery disease patients had a significant increase in homocysteine level and DNA damage due to increased oxidative stress. In conclusion, our study shows a significantly increase in lipid peroxidation, TOS, homocysteine and DNA damage in the erythrocytes of patients with CAD. A significant decrease level of HDL-C and TAS was observed only in CAD patients. Therefore these biomarkers may be useful diagnosis of patients with CAD and play an important role in the pathogenesis of CAD.

Keywords: antioxidants, coronary artery disease, DNA damage, homocysteine, oxidative stress, malondialdehyde, 8-Hydroxy-2’deoxyguanosine

Procedia PDF Downloads 482

Authors: Amir R. Askari, Masoud Tahani

Abstract:

The objective of the present paper is to investigate the effect of size on the vibrational behavior of fully clamped rectangular micro-plates based on the modified couple stress theory (MCST). To this end, a size-dependent Kirchhoff plate model is considered and the equation of motion which accounts for the effect of residual and couple stress components is derived using the Hamilton's principle. The eigenvalue problem associated with the free vibrations of fully clamped micro-plates is extracted and solved analytically using the extended Kantorovich method (EKM). The present findings are compared and validated by available results in the literature and an excellent agreement between them is observed. A parametric study is also conducted to show the significant effects of couple stress components on natural frequencies of fully clamped micro-plates. It is found that the ratio of MCST natural frequencies to those obtained by the classical theory (CT) only depends on the Poisson's ratio of the plate and is totally independent of plate's aspect ratio for cases with no residual stresses.

Keywords: vibrational analysis, modified couple stress theory, fully clamped rectangular micro-plates, extended Kantorovich method.

Procedia PDF Downloads 380