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Authors: C. Silvestros, K. Mellou, T. Georgakopoulou, A. Koustenis, E. Kokkinou, C. Botsi, A. Terzidis

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'PHILOS – Emergency health response to refugee crisis' is a programme of the Greek Ministry of Health, implemented by the Hellenic Center for Disease Control and Prevention (HCDCP) funded by the Asylum, Migration and Integration Fund (AMIF) of EU’s DG Migration and Home Affairs. One of the main objectives of the program is the immunization coverage of the target – population to assure the prevention of vaccine-preventable diseases. The program foresees vaccination needs assessment of children hosted at camps at the mainland and implementation of interventions to cover the vaccination gaps in co-operation with the Ministry of Health. The National Immunization Advisory Committee in Greece recommended that MMR (Measles, Mumps, and Rubella), PCV (Pneumococcal conjugate vaccine) and HEXA (diphtheria, tetanus, pertussis, polio, hepatitis B and Haemophilus influenzae type b) vaccines should be performed in priority. Recording was completed at 24 camps (May - June 2017); 3381 children (0-18 years) were recorded. The median number of children hosted at each camp was 95 (range: 5-553). For 68% of the children, the WHO vaccination booklet was available. 44%, 48.5% and 61% of the children were vaccinated with at least one dose of PCV, HEXA, and MMR, respectively. The proportion of vaccinated children for the three vaccines mentioned above is significantly lower for the remaining doses; PCV (second dose 8%, third dose 1.3%), HEXA (second dose 13%, third dose 2.7%, forth dose 0.1%) and MMR (second dose 23%). None of the 37 (10 from Afghanistan, 3 from Bangladesh, 23 from Pakistan, 1 from Syria) recorded unaccompanied children did not have a WHO vaccination booklet and were considered unvaccinated. There is no differentiation in vaccination coverage among different ethnicities. Massive catch up vaccination was performed at 4 camps, and 671 vaccinations were performed (245 PCV, 307 HEXA, and 119 MMR). Similar interventions are planned for all camps of the country. Recording reveled gaps in vaccination coverage of the population, mainly because of the mobility of the population, the influx of refugees- which is still ongoing- and new births. Mass vaccination campaigns are considered vital in order to increase vaccination coverage, and continuous efforts are needed in order all children living at the camps to have full access to the National Childhood Immunization Program.

Keywords: vaccine preventable, refugee–migrants camps, vaccination coverage, PCV, MMR, HEXA

Procedia PDF Downloads 181

Authors: Sri Suparwitri

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When an orthodontic force is applied to a tooth, an inflammatory response is initiated then lead to bone remodeling process, and the process accommodates tooth movement. One of cytokine that plays a prominent role in bone remodeling process was transforming growth factor-beta 1 (TGF-β1). The purpose of this study was to identify and compare changes of TGF-β1 in human gingival crevicular fluid during canine retraction using elastic chain and closed coil spring. Ten patients (mean age 20.7 ± 2.9 years) participated. The patients were entering the space closure phase of fixed orthodontic treatment. An upper canine of each patient was retracted using elastic chain, and the contralateral canine was retracted using closed coil spring. Gingival crevicular fluid samples were collected from the canine teeth before and 7 days after the force was applied. Transforming growth factor-beta 1 was determined by enzyme-linked immunosorbent assay (ELISA). The concentrations of TGF-β1 at 7 days were significantly higher compared to before canine retraction in both groups. In the evaluation of between-group difference, before retraction, the difference was insignificant, whereas at 7 days significantly higher values were determined in the closed coil spring group compared to elastic chain group. The result suggests that TGF-β1 is associated with the bone remodeling that occurs during canine distalization movement. Closed coil spring gave higher TGF-β1 concentrations thus more bone remodeling occurred and may be considered the treatment of choice.

Keywords: closed coil spring, elastic chain, gingival crevicular fluid, TGF-β1

Procedia PDF Downloads 168

Authors: Subodh Nath Patel, Raja Raman, Mananshi Adhikary, Jitendra Mathur, Sandip Bhattacharyya

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The composition adjustment by sealed argon bubbling–oxygen blowing (CAS-OB) process is a process designed for adjusting steel composition and temperature during secondary metallurgy. One of the equipment in the said process is a snorkel or bell, fixed to a movable bracket. Snorkel serves the purpose of feeding ferroalloys into the liquid metal simultaneously removing gases to the gas cleaning system through its port at its top. The bell-shaped snorkel consists of two parts. The upper part has an inside liner, and the lower part is lined on both side with high-alumina castable reinforced with 2% stainless steel needles. Both the parts are coupled with a flange bolt system. These flanges were found to get buckled during operation, and the gap was generating between them. This problem was chronic since its. It was expected to give a life of 80 heats, but it was failing within 45-50 heats. After every 25-30 heats, it had to be repaired by changing and/or tightening its nuts and bolts. Visual observation, microstructural analysis through optical microscopes and SEM, hardness measurement and thermal strain calculation were carried out to find out the root cause of this problem. The calculated thermal strain was compared with actual thermal strain; comparison of the two revealed that thermal strain was responsible for buckling. Finite element analysis (FEA) was carried out to reaffirm the effect temperature on the flanges. FEA was also used in the modification in the design of snorkel flange to accommodate thermal strain. Thermal insulation was also recommended which increased its life from 45 heats to 65 heats, impacting business process positively.

Keywords: CAS OB process, finite element analysis, snorkel, thermal strain

Procedia PDF Downloads 131

Authors: J.P. Henriques, E. R. Neto, G. Almeida, G. Ribeiro, J.V. Coutinho, A.B. Lugli

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Industry 4.0, or the Fourth Industrial Revolution, is transforming the relationship between people and machines. In this scenario, some technologies such as Cloud Computing, Internet of Things, Augmented Reality, Artificial Intelligence, Additive Manufacturing, among others, are making industries and devices increasingly intelligent. One of the most powerful technologies of this new revolution is the Digital Twin, which allows the virtualization of a real system or process. In this context, the present paper addresses the linear and nonlinear dynamic study of a didactic level plant using Digital Twin. In the first part of the work, the level plant is identified at a fixed point of operation, BY using the existing method of least squares means. The linearized model is embedded in a Digital Twin using Automation Studio® from Famous Technologies. Finally, in order to validate the usage of the Digital Twin in the linearized study of the plant, the dynamic response of the real system is compared to the Digital Twin. Furthermore, in order to develop the nonlinear model on a Digital Twin, the didactic level plant is identified by using the method proposed by Hammerstein. Different steps are applied to the plant, and from the Hammerstein algorithm, the nonlinear model is obtained for all operating ranges of the plant. As for the linear approach, the nonlinear model is embedded in the Digital Twin, and the dynamic response is compared to the real system in different points of operation. Finally, yet importantly, from the practical results obtained, one can conclude that the usage of Digital Twin to study the dynamic systems is extremely useful in the industrial environment, taking into account that it is possible to develop and tune controllers BY using the virtual model of the real systems.

Keywords: industry 4.0, digital twin, system identification, linear and nonlinear models

Procedia PDF Downloads 141

Authors: Saeed Poormoaied, Zumbul Atan

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Emergency shipments provide a powerful mechanism to alleviate the risk of imminent stock-outs and can result in substantial benefits in an inventory system. Customer satisfaction and high service level are immediate consequences of utilizing emergency shipments. In this paper, we consider a single-echelon periodic review inventory system consisting of a single local warehouse, being replenished from a central warehouse with ample capacity in an infinite horizon setting. Since the structure of the optimal policy appears to be complicated, we analyze this problem under an order-up-to-S inventory control policy framework, the (S, T) policy, with the emergency shipment consideration. In each period of the periodic review policy, there is a single opportunity at any point of time for the emergency shipment so that in case of stock-outs, an emergency shipment is requested. The goal is to determine the timing and amount of the emergency shipment during a period (emergency shipment policy) as well as the base stock periodic review policy parameters (replenishment policy). We show that how taking advantage of having an emergency shipment during periods improves the performance of the classical (S, T) policy, especially when fixed and unit emergency shipment costs are small. Investigating the structure of the objective function, we develop an exact algorithm for finding the optimal solution. We also provide a heuristic and an approximation algorithm for the periodic review inventory system problem. The experimental analyses indicate that the heuristic algorithm is computationally more efficient than the approximation algorithm, but in terms of the solution efficiency, the approximation algorithm performs very well. We achieve up to 13% cost savings in the (S, T) policy if we apply the proposed emergency shipment policy. Moreover, our computational results reveal that the approximated solution is often within 0.21% of the globally optimal solution.

Keywords: emergency shipment, inventory, periodic review policy, approximation algorithm.

Procedia PDF Downloads 136

Authors: M. Çevik, S. Sabancı, D. Tezcan, C. Çelebi, F. İçier

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Ultrasound technology is the one of the non-thermal food processing method in recent years which has been used widely in the food industry. Ultrasound application in the food industry is divided into two groups: low and high intensity ultrasound application. While low intensity ultrasound is used to obtain information about physicochemical properties of foods, high intensity ultrasound is used to extract bioactive components and to inactivate microorganisms and enzymes. In this study, the ultrasound pre-treatment at a constant power (1500 W) and fixed frequency (20 kHz) was applied to the red beetroot slices having the dimension of 25×25×50 mm at the constant temperature (25°C) for different application times (0, 5, 10, 15 and 20 min). The red beet root slices pretreated with ultrasonication was squeezed immediately. The changes on rheological properties of red beet root juice depending on ultrasonication duration applied to slices were investigated. Rheological measurements were conducted by using Brookfield viscometer (LVDV-II Pro, USA). Shear stress-shear rate data was obtained from experimental measurements for 0-200 rpm range by using spindle 18. Rheological properties of juice were determined by fitting this data to some rheological models (Newtonian, Bingham, Power Law, Herschel Bulkley). It was investigated that the best model was Power Law model for both untreated red beet root juice (R2=0.991, χ2=0.0007, RMSE=0.0247) and red beetroot juice produced from ultrasonicated slices (R2=0.993, χ2=0.0006, RMSE=0.0216 for 20 min pre-treatment). k (consistency coefficient) and n (flow behavior index) values of red beetroot juices were not affected from the duration of ultrasonication applied to the slices. Ultrasound treatment does not result in any changes on the rheological properties of red beetroot juice. This can be explained by lack of ability to homogenize of the intensity of applied ultrasound.

Keywords: ultrasonication, rheology, red beet root slice, juice

Procedia PDF Downloads 403

Authors: Choo Hong Ang

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The most popular approach to save energy for large commercial buildings in Malaysia is to replace the existing chiller plant of high kW/ton to one of lower kW/ton. This approach, however, entails large capital outlay with a long payment period of up to 7 years. This paper shows that by using multiple approaches, other than replacing the existing chiller plant, an energy saving of up to 20 %, is possible. The main methodology adopted was to identify and then plugged all heat ingress paths into a building, including putting up glass structures to prevent mixing of internal air-conditioned air with the ambient environment, and replacing air curtains with glass doors. This methodology could save up to 10 % energy bill. Another methodology was to change fixed speed motors of air handling units (AHU) to variable speed drive (VSD) and changing escalators to motion-sensor type. Other methodologies included reducing heat load by blocking air supply to non-occupied parcels, rescheduling chiller plant operation, changing of fluorescent lights to LED lights, and conversion from tariff B to C1. A case example of Komtar, the tallest building in Penang, is given here. The total energy bill for Komtar was USD2,303,341 in 2016 but was reduced to USD 1,842,927.39 in 2018, a significant saving of USD460,413.86 or 20 %. In terms of kWh, there was a reduction from 18, 302,204.00 kWh in 2016 to 14,877,105.00 kWh in 2018, a reduction of 3,425,099.00 kWh or 18.71 %. These methodologies used were relatively low cost and the payback period was merely 24 months. With this achievement, the Komtar building was awarded champion of the Malaysian National Energy Award 2019 and second runner up of the Asean Energy Award. This experience shows that a strong commitment to energy saving is the key to effective energy saving.

Keywords: chiller plant, energy saving measures, heat ingress, large building

Procedia PDF Downloads 99

Authors: H. M. Soroush

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The problem of scheduling products and services for on-time deliveries is of paramount importance in today’s competitive environments. It arises in many manufacturing and service organizations where it is desirable to complete jobs (products or services) with different weights (penalties) on or before their due dates. In such environments, schedules should frequently decide whether to schedule a job based on its processing time, due-date, and the penalty for tardy delivery to improve the system performance. For example, it is common to measure the weighted number of late jobs or the percentage of on-time shipments to evaluate the performance of a semiconductor production facility or an automobile assembly line. In this paper, we address the problem of scheduling a set of jobs on a server where processing times or due-dates of jobs are random variables and fixed weights (penalties) are imposed on the jobs’ late deliveries. The goal is to find the schedule that minimizes the expected weighted number of tardy jobs. The problem is NP-hard to solve; however, we explore three scenarios of the problem wherein: (i) both processing times and due-dates are stochastic; (ii) processing times are stochastic and due-dates are deterministic; and (iii) processing times are deterministic and due-dates are stochastic. We prove that special cases of these scenarios are solvable optimally in polynomial time, and introduce efficient heuristic methods for the general cases. Our computational results show that the heuristics perform well in yielding either optimal or near optimal sequences. The results also demonstrate that the stochasticity of processing times or due-dates can affect scheduling decisions. Moreover, the proposed problem is general in the sense that its special cases reduce to some new and some classical stochastic single machine models.

Keywords: number of late jobs, scheduling, single server, stochastic

Procedia PDF Downloads 493

Authors: Wondmnew Derebe Yohannis

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The enhanced utilization of modern beehives holds significant potential to enhance the livelihoods of smallholder farmers who heavily rely on mixed crop-livestock farming for their income. Recognizing this, the distribution of improved beehives has been implemented across various regions in Ethiopia, including the Bugina district. However, the precise impact of these improved beehives on farmers' income has received limited attention. To address this gap, this study aims to assess the influence of adopting upgraded beehives on rural households' income and asset accumulation. To conduct this research, survey data was gathered from a sample of 350 households selected through random sampling. The collected data was then analyzed using an econometric stochastic frontier model (ESRM) approach. The findings reveal that the adoption of improved beehives has resulted in higher annual income and asset growth for beekeepers. On average, those who adopted the improved beehives earned approximately 6,077 Ethiopian Birr (ETB) more than their counterparts who did not adopt these beehives. However, it is worth noting that the impact of adoption would have been even greater for non-adopters, as evidenced by the negative transitional heterogeneity effect of 1792 ETB. Furthermore, the analysis indicates that the decision to adopt or not adopt improved beehives was driven by individual self-selection. The adoption of improved beehives also led to an increase in fixed assets for households, establishing it as a viable strategy for poverty reduction. Overall, this study underscores the positive effect of adopting improved beehives on rural households' income and asset holdings, showcasing its potential to uplift smallholder farmers and serve as an alternative mechanism for reducing poverty.

Keywords: impact, adoption, endogenous switching regression, income, improved beehives

Procedia PDF Downloads 51

Authors: Tripti Nayak, R. K. Bajpai

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An ongoing field experiment was conducted at Long term fertilizer experiment, Raipur, to study the Effect of fertilization (both organic and inorganic) on soil Physical properties (infiltration rate) of Vertisol of ten treatments viz. The treatment combinations for were T1(Control),T2(50%NPK), T3(100%NPK), T4(150%NPK), T5(100%NPK+Zn), T6(100%NP), T7(100%N), T8(100%NPK+FYM), T9 (50%NPK+BGA) and T10(50%NPK+GM). Farmyard manure and green manure is applied at the treatment of T8 (100%NPK+FYM) and T10 (50%NPK+GM). Result showed that the highest infiltration rate recorded T8(100%NPK+FYM) and T10 (50%NPK+GM). These considerations have led to a renewed interest in the organic manures such as FYM, compost and green manures, which are formulations helps in sustainable agriculture production either by providing plants with fixed nitrogen, available P or by other plant growth promoting substances. Organic matter (OM) is the life of the soil because it contains all the essential elements required for plant growth. It also serves as food for soil bacteria. Decomposed OM, known as humus, improves the soil tilth, quality and helps the plant to grow. In general among all the other treatments and control gave poorest infiltration rate. Incorporation of organic sources considerably improved the soil physical properties such as decrease in bulk density and increase in infiltration rate and available NPK status of the soil. Study showed that wherever, nitrogen was substituted through GM, FYM or crop residue (rice straw) in rice, Corresponding decrease in bulk density favorably enhanced the infiltration rate and it was found to be highest in the green-manured plot, FYM and lowest in control. Concluded that Continuous monitoring of physical properties should be carried out for maintaining soil health and enhancing the crop production.

Keywords: long term effect, FYM, green manure, infiltration rate, soil health, crop productivity, vertisol

Procedia PDF Downloads 362

Authors: A. K. Faizah, G. Vadamalai, S. K. Balasundram, W. L. Lim

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Pineapple (Ananas comosus) is a common crop in tropical and subtropical areas of the world. Malaysia once ranked as one of the top 3 pineapple producers in the world in the 60's and early 70's, after Hawaii and Brazil. Moreover, government’s recognition of the pineapple crop as one of priority commodities to be developed for the domestics and international markets in the National Agriculture Policy. However, pineapple industry in Malaysia still faces numerous challenges, one of which is the management of disease and pest. Red tip disease on pineapple was first recognized about 20 years ago in a commercial pineapple stand located in Simpang Renggam, Johor, Peninsular Malaysia. Since its discovery, there has been no confirmation on its causal agent of this disease. The epidemiology of red tip disease is still not fully understood. Nevertheless, the disease symptoms and the spread within the field seem to point toward viral infection. Bioassay test on nucleic acid extracted from the red tip-affected pineapple was done on Nicotiana tabacum cv. Coker by rubbing the extracted sap. Localised lesions were observed 3 weeks after inoculation. Negative staining of the fresh inoculated Nicotiana tabacum cv. Coker showed the presence of membrane-bound spherical particles with an average diameter of 94.25nm under transmission electron microscope. The shape and size of the particles were similar to tospovirus. SDS-PAGE analysis of partial purified virions from inoculated N. tabacum produced a strong and a faint protein bands with molecular mass of approximately 29 kDa and 55 kDa. Partial purified virions of symptomatic pineapple leaves from field showed bands with molecular mass of approximately 29 kDa, 39 kDa and 55kDa. These bands may indicate the nucleocapsid protein identity of tospovirus. Furthermore, a handheld sensor, Greenseeker, was used to detect red tip symptoms on pineapple non-destructively based on spectral reflectance, measured as Normalized Difference Vegetation Index (NDVI). Red tip severity was estimated and correlated with NDVI. Linear regression models were calibrated and tested developed in order to estimate red tip disease severity based on NDVI. Results showed a strong positive relationship between red tip disease severity and NDVI (r= 0.84).

Keywords: pineapple, diagnosis, virus, NDVI

Procedia PDF Downloads 788

Authors: Usama Abdulwahab, Mohammed Wahab

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This paper presents the application of uncapacitated facility location problems (UFLP) and 1-median problems to support decision making in blood supply chain networks. A plethora of factors make blood supply-chain networks a complex, yet vital problem for the regional blood bank. These factors are rapidly increasing demand; criticality of the product; strict storage and handling requirements; and the vastness of the theater of operations. As in the UFLP, facilities can be opened at any of $m$ predefined locations with given fixed costs. Clients have to be allocated to the open facilities. In classical location models, the allocation cost is the distance between a client and an open facility. In this model, the costs are the allocation cost, transportation costs, and inventory costs. In order to address this problem the median algorithm is used to analyze inventory, evaluate supply chain status, monitor performance metrics at different levels of granularity, and detect potential problems and opportunities for improvement. The Euclidean distance data for some Ontario cities (demand nodes) are used to test the developed algorithm. Sitation software, lagrangian relaxation algorithm, and branch and bound heuristics are used to solve this model. Computational experiments confirm the efficiency of the proposed approach. Compared to the existing modeling and solution methods, the median algorithm approach not only provides a more general modeling framework but also leads to efficient solution times in general.

Keywords: approximate dynamic programming, facility location, perishable product, inventory model, blood platelet, P-median problem

Procedia PDF Downloads 505

Authors: Ravneet Kaur, Joydeep Acharya, Sudhanshu Gaur

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Artificial Intelligence (AI) has the potential to transform manufacturing by improving shop floor processes such as production, maintenance and quality. However, industrial datasets are notoriously difficult to extract in a real-time, streaming fashion thus, negating potential AI benefits. The main example is some specialized industrial controllers that are operated by custom software which complicates the process of connecting them to an Information Technology (IT) based data acquisition network. Security concerns may also limit direct physical access to these controllers for data acquisition. To connect the Operational Technology (OT) data stored in these controllers to an AI application in a secure, reliable and available way, we propose a novel Industrial IoT (IIoT) solution in this paper. In this solution, we demonstrate how video cameras can be installed in a factory shop floor to continuously obtain images of the controller HMIs. We propose image pre-processing to segment the HMI into regions of streaming data and regions of fixed meta-data. We then evaluate the performance of multiple Optical Character Recognition (OCR) technologies such as Tesseract and Google vision to recognize the streaming data and test it for typical factory HMIs and realistic lighting conditions. Finally, we use the meta-data to match the OCR output with the temporal, domain-dependent context of the data to improve the accuracy of the output. Our IIoT solution enables reliable and efficient data extraction which will improve the performance of subsequent AI applications.

Keywords: human machine interface, industrial internet of things, internet of things, optical character recognition, video analytics

Procedia PDF Downloads 106

Authors: Hanen Bouaziz, Françoise Croute, Najiba Zeghal

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In order to investigate the toxic effects of fluoride on cerebrum maturity of suckling mice, we treated adult female mice of Swiss Albinos strain by 500 ppm NaF in their drinking water from the 15th day of pregnancy until the day 14 after delivery. All mice were sacrificed on day 14 after parturition. During treatment, levels of thiobarbituric acid reactive substances, the marker of lipid peroxidation extend, increased, while the activities of the antioxidant enzymes such as glutathione peroxidase, superoxide dismutase and catalase and the level of glutathione decreased significantly in cerebellum compared with those of the control group. These results suggested that fluoride enhanced oxidative stress, thereby disturbing the antioxidant defense of nursing pups. In addition, acetylcholinesterase activity in cerebellum was inhibited after treatment with fluoride. In cerebellum of mice, migration of neurons from the external granular layer to the internal granular layer occurred postnatally. Key guidance signals to these migrating neurons were provided by laminin, an extracellular matrix protein fixed to the surface of astrocytes. In the present study, we examined the expression and distribution of laminin in cerebellum of 14-day-old mice. Immunoreactive laminin was disappeared by postnatal day 14 in cerebellum parenchyma of control pups and was restricted to vasculature despite the continued presence of granular cells in the external granular layer. In contrast, in cerebellum of NaF treated pups, laminin was deposited in organised punctuate clusters in the molecular layer. These data indicated that the disruption of laminin distribution might play a major role in the profound derangement of neuronal migration observed in cerebellum of NaF treated pups.

Keywords: acetylcholinesterase activity, cerebellum, laminin, oxidative stress, suckling mice

Procedia PDF Downloads 393

Authors: Bella Japoshvili, Zhanetta Shubitidze, Ani Bikashvili, Sophio Gabelashvili, Marina Gioshvili, Levan Mumladze

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Paravani and Saghamo Lakes are oligotrophic lentic systems located in Javakheti plateau (South Georgia) at 2073 m and 1996 m a.s.l. respectively. Javakheti plateau is known as a lakes region as there are located almost 60 small and medium size lakes. Paravani Lake is the biggest lake by its surface area in Georgia, 37 km 2. The Saghamo Lake is smaller and its surface area consists 4.58 km2. These two lakes are connected with Paravani River, because of this the main hydrobiological and ichthyological features are the same. More than 15-30 years were not studied macroinvertebrates of these lakes. Even the existing information is lack and very limited. The aim of our study was to identify main macroinvertebrate groups inhabiting both lakes and to compare obtaining results to existing information. Our investigation was carried out during 2014 and 2015, in 3 seasons of the year, in winter because of severe condition samples were not taken. Kick-net and Petersen grab were used for material collecting, 4 sites from Paravani Lake and 3–from Saghamo Lake were sampled. Collected invertebrates were fixed in ethanol and late taken to the laboratory, where organisms were identified to the lowest taxon possible, usually family. By our results identified 14 taxa for Paravani Lake and 12 taxa for Saghamo Lake. Our results differ from previous information; for Saghamo Lake previously 13 taxa and for Paravani Lake 12 taxa were described. The percentage of the groups also differ from existing information. Our investigation showed that in Paravani Lake most abundant are Apmhipoda, Hydrachnidae, and Hemiptera, in our samples the number of individuals for those 3 taxa was more than thousand, in each. For Saghamo Lake numerous taxon was Amphipoda-36.3%, following by Ephemeroptera-11.37%, Chironomidae-10.5% and Hydrachnidae-7.03% respectively. We also identified the dominant taxon for all studied seasons. Autumn is the period when the diversity of macroinvertebrates are higher in both lakes.

Keywords: Georgia, lakes, macroinvertebrates, monitoring

Procedia PDF Downloads 189

Authors: Lee Bih Ni, Zulfhikar Rabe, Nurul Asyikin Hassan

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The Ministry of Education Malaysia dynamically and drastically made the subject of History mandatory to be in force in 2013. This is in recognition of the nation's heritage and treasures in maintaining true facts and information for future generations of the State. History reveals the civilization of a nation and the fact of national cultural heritage. Civilization needs to be preserved as a legacy of sovereign heritage. Today's generation is the catalyst for future heirs who will support the principle and direction of the country. In line with the National Education Philosophy that aims to shape the potential development of individuals holistically and uniquely in order to produce a balanced and harmonious student in terms of intellectual, spiritual, emotional and physical. Hence, understanding the importance of studying the history subject as a pillar of identity and the history of nationhood is to be a priority in the pursuit of knowledge and empowering the spirit of statehood that is nurtured through continuous learning at school. Judging from the aspect of teacher leadership role in integrating history in a combined way based on Teacher Education Philosophy. It empowers the teaching profession towards the teacher to support noble character. It also supports progressive and scientific views. Teachers are willing to uphold the State's aspirations and celebrate the country's cultural heritage. They guarantee individual development and maintain a united, democratic, progressive and disciplined society. Teacher's role as a change and leadership agent in education begins in the classroom through formal or informal educational processes. This situation is expanded in schools, communities and countries. The focus of this paper is on the role of teacher leadership influencing the effectiveness of teaching and learning history in the classroom environment. Leadership guides to teachers' perceptions on the role of teacher leadership, teaching leadership, and the teacher leadership role and effective teacher leadership role. Discussions give emphasis on aspects of factors affecting the classroom environment, forming the classroom agenda, effective classroom implementation methods, suitable climate for historical learning and teacher challenges in implicating the effectiveness of teaching and learning processes.

Keywords: teacher leadership, leadership lessons, effective classroom, effective teacher

Procedia PDF Downloads 279

Authors: Yu-Min Chang, Kuo-Sheng Tsai, Hung-Te Tsai, Chia-Hsin Li

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This paper presents the early-warning lights classification management system for industrial parks promoted by the Taiwan Environmental Protection Administration (EPA) since 2011, including the definition of each early-warning light, objectives, action program and accomplishments. All of the 151 industrial parks in Taiwan were classified into four early-warning lights, including red, orange, yellow and green, for carrying out respective pollution management according to the monitoring data of soil and groundwater quality, regulatory compliance, and regulatory listing of control site or remediation site. The Taiwan EPA set up a priority list for high potential polluted industrial parks and investigated their soil and groundwater qualities based on the results of the light classification and pollution potential assessment. In 2011-2013, there were 44 industrial parks selected and carried out different investigation, such as the early warning groundwater well networks establishment and pollution investigation/verification for the red and orange-light industrial parks and the environmental background survey for the yellow-light industrial parks. Among them, 22 industrial parks were newly or continuously confirmed that the concentrations of pollutants exceeded those in soil or groundwater pollution control standards. Thus, the further investigation, groundwater use restriction, listing of pollution control site or remediation site, and pollutant isolation measures were implemented by the local environmental protection and industry competent authorities; the early warning lights of those industrial parks were proposed to adjust up to orange or red-light. Up to the present, the preliminary positive effect of the soil and groundwater quality management system for industrial parks has been noticed in several aspects, such as environmental background information collection, early warning of pollution risk, pollution investigation and control, information integration and application, and inter-agency collaboration. Finally, the work and goal of self-initiated quality management of industrial parks will be carried out on the basis of the inter-agency collaboration by the classified lights system of early warning and management as well as the regular announcement of the status of each industrial park.

Keywords: industrial park, soil and groundwater quality management, early-warning lights classification, SOP for reporting and treatment of monitored abnormal events

Procedia PDF Downloads 319

Authors: My Linh Hoang, Van Dung Hoang

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Environmental, Social, and Governance (ESG) factors have become a focus for companies globally, as businesses are now focusing on long-term sustainable goals rather than only operating for the goals of profit maximization. According to recent research, in several countries, companies have shown positive results in their financial performance by improving their ESG performance. The construction industry is one of the most crucial components of social and economic development; as a result, considerations for ESG factors are becoming more and more essential for companies in this sector. In Vietnam, the construction industry has been growing rapidly in recent years; however, it has yet to be discussed and studied extensively in Vietnam how ESG factors create impacts on corporate financial performance in general and construction corporations’ financial performance in particular. This research aims to examine the relationship between ESG factors and financial indicators in construction companies from 2011 to 2021 through panel data analysis of 75 listed construction companies in Vietnam and to provide insights into how these companies can better integrate ESG considerations into their operations to enhance their financial performance. The data was analyzed through 3 main methods: descriptive statistics, correlation coefficient analysis applied to all dependent, explanatory and control variables, and panel data analysis method. In panel data analysis, the study uses the fixed effects model (FEM) and random effects model (REM). The Hausman test will be used to select which model is suitable to be used. The findings indicate that maintaining a strong commitment to ESG principles can have a positive impact on financial performance. Finally, FGLS estimation will be performed when the problem of autocorrelation and variable variance appears in the model. This is significant for all parties involved, including investors, company managers, decision-makers, and industry regulators.

Keywords: ESG, financial performance, construction company, Vietnam

Procedia PDF Downloads 83

Authors: M. A. Askari, M. A. Nazari, P. Perrier, Y. Payan

Abstract:

Growth and remodeling of biological structures have gained lots of attention over the past decades. Determining the response of the living tissues to the mechanical loads is necessary for a wide range of developing fields such as, designing of prosthetics and optimized surgery operations. It is a well-known fact that biological structures are never stress-free, even when externally unloaded. The exact origin of these residual stresses is not clear, but theoretically growth and remodeling is one of the main sources. Extracting body organs from medical imaging, does not produce any information regarding the existing residual stresses in that organ. The simplest cause of such stresses is the gravity since an organ grows under its influence from its birth. Ignoring such residual stresses might cause erroneous results in numerical simulations. Accounting for residual stresses due to tissue growth can improve the accuracy of mechanical analysis results. In this paper, we have implemented a computational framework based on fixed-point iteration to determine the residual stresses due to growth. Using nonlinear continuum mechanics and the concept of fictitious configuration we find the unknown stress-free reference configuration which is necessary for mechanical analysis. To illustrate the method, we apply it to a finite element model of healthy human face whose geometry has been extracted from medical images. We have computed the distribution of residual stress in facial tissues, which can overcome the effect of gravity and cause that tissues remain firm. Tissue wrinkles caused by aging could be a consequence of decreasing residual stress and not counteracting the gravity. Considering these stresses has important application in maxillofacial surgery. It helps the surgeons to predict the changes after surgical operations and their consequences.

Keywords: growth, soft tissue, residual stress, finite element method

Procedia PDF Downloads 352

Authors: Athanasios A. Gavrilidis, Mihai R. Nita, Larissa N. Stoia, Diana A. Onose

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Contemporary global environmental challenges must be primarily addressed at local levels. Cities are under continuous pressure as they must ensure high quality of life levels for their citizens and at the same time to adapt and address specific environmental issues. Innovative solutions using natural features or mimicking natural systems are endorsed by the scientific community as efficient approaches for both mitigating climate change effects and the decrease of environmental quality and for maintaining high standards of living for urban dwellers. The aim of this study was to assess whether Romanian cities’ authorities are considering nature-based innovation as solutions for their planning, management, and environmental issues. Data were gathered by applying 140 questionnaires to urban authorities throughout the country. The questionnaire was designed for assessinglocal policy makers’ perspective over the efficiency of nature-based innovations as a tool to address specific challenges. It also focused on extracting data about financing sources and challenges they must overcome for adopting nature-based approaches. The gather results from the municipalities participating in our study were statistically processed, and they revealed that Romanian city managers acknowledge the benefits of nature-based innovations, but investments in this sector are not on top of their priorities. More than 90% of the selected cities have agreed that in the last 10 years, their major concern was to expand the grey infrastructure (roads and public amenities) using traditional approaches. When asked how they would react if faced with different socio-economic and environmental challenges, local urban managers indicated investments nature-based solutions as a priority only in case of biodiversity loss and extreme weather, while for other 14 proposed scenarios, they would embrace the business-as-usual approach. Our study indicates that while new concepts of sustainable urban planning emerge within the scientific community, local authorities need more time to understand and implement them. Without the proper knowledge, personnel, policies, or dedicated budgets, local administrators will not embrace nature-based innovations as solutions for their challenges.

Keywords: nature based innovations, perception analysis, policy making, urban planning

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Authors: John Michael Weber

Abstract:

The following research results spanned six months and 175 people addicted to some form of substance, from alcohol to heroin. One question was asked, and the answers were amazing and consistent. The following work is the detailed results of this writer’s answer to his own question and the 175 that followed. A constant pattern took shape throughout the bio-psycho-social assessments, these addicts had “first memories,” the memories were vivid and took place between the ages of three to six years old, to a person those first memories were traumatic. This writer’s personal search into his childhood was not to find an excuse for the way he became, but to explain the reason for becoming an addict. To treat addiction, these memories that have caused Post Traumatic Stress Disorder (PTSD), must be recognized as the catalyst that sparked a predisposition. Cognitive Behavioral Therapy (CBT), integrated with treatment specifically focused on PTSD, gives the addict a better chance at recovery sans relapse. This paper seeks to give the findings of first memories of the addicts assessed and provide the best treatment plan for such an addict, considering, the childhood trauma in congruence with treatment of the Substance Use Disorder (SUD). The question posed was concerning what their first life memory wa It is the hope of this author to take the knowledge that trauma is one of the main catalysts for addiction, will allow therapists to provide better treatment and reduce relapse from abstinence from drugs and alcohol. This research led this author to believe that if treatment of childhood trauma is not a priority, the twelve steps of Alcoholics Anonymous, specifically steps 4 and 5, will not be thoroughly addressed and odds for relapse increase. With this knowledge, parents can be educated on childhood trauma and the effect it has on their children. Parents could be mindful of the fact that the things they perceive as traumatic, do not match what a child, in the developmental years, absorbs as traumatic. It is this author’s belief that what has become the status quo in treatment facilities has not been working for a long time. It is for that reason this author believes things need to change. Relapse has been woven into the fabric of standard operating procedure and that, in this authors view, is not necessary. Childhood Trauma is not being addressed early in recovery and that creates an environment of inevitable relapse. This paper will explore how to break away from the status -quo and rethink the current “evidencebased treatments.” To begin breaking away from status-quo, this ends the Abstract, with hopes an interest has been peaked to read on.

Keywords: childood, trauma, treatment, addiction, change

Procedia PDF Downloads 75

Authors: Oljana Hoxhaj

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The integration process of Albania into the European family carries many difficulties. In this context, the Albanian legislator is inclined to implement in the domestic legal framework models which have been successful in other countries. Our paper aims to present an analytical and comparative approach to the health system in Albania and France, mainly focusing on citizen’s access to these services. Different standards and cultures between states, in the context of an approximate model, will be the first challenge of our paper. Over the last few years, the Albanian government has undertaken concrete reforms in this sector, aiming to transform the vision on which the previous health system was structured. In this perspective, the state fulfills not only an obligation to its citizens, but also consolidates progressive steps toward alignment with European Union standards. The necessity to undertake a genuine reform in this area has come as an exigency of society, which has permanently identified problems within this sector, considering it ineffective, out of standards, and corrupt. The inclusion of health services on the Albanian government agenda reflects its will in the function of good governance, transparency, and broadening access to the provision of quality health services in the public and private sectors. The success of any initiative in the health system consists of giving priority to patient needs. Another objective that should be in the state's consideration is to create the premise to provide a comprehensive process on whose foundations partnership and broader co-operation with beneficiary entities are established in any decision-making that is directly related to their interests. Some other important and widespread impacts on the effective realization of citizens' access to the healthcare system coincide with the construction of appropriate infrastructure, increasing the professionalism and qualification of medical staff, and the allocation of a higher budget. France has one of the most effective healthcare models in Europe. That is why we have chosen to analyze this country, aiming to highlight the advantages of this system, as well as the commitment of the French state to drafting effective health policies. In the framework of the process of harmonization of the Albanian legislation with that of the European Union, through our work, we aim to identify the space to implement the whole of these legislative innovations in the Albanian legislation.

Keywords: effective service, harmonization level, innovation, reform

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Authors: V. S. Bessa, I. S. Moreira, S. Murgolo, C. Piccirillo, G. Mascolo, P. M. L. Castro

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The occurrence of pharmaceuticals in the environment has been a topic of increasing concern. Pharmaceuticals are not completely mineralized in the human body and are released on the sewage systems as the pharmaceutical itself and as their “biologically active” metabolites through excretion, as well as by improper elimination and disposal. Conventional wastewater treatment plants (WWTPs) are not designed to remove these emerging pollutants and they are thus released into the environment. The antiepileptic drug carbamazepine (CBZ) and the non-steroidal anti-inflammatory diclofenac (DCF) are two widely used pharmaceuticals, frequently detected in water bodies, including rivers and groundwater, in concentrations ranging from ng L 1 to mg L 1. These two compounds were classified as medium to high-risk pollutants in WWTP effluents and surface waters. Also, CBZ has been suggested as a molecular marker of wastewater contamination in surface water and groundwater and the European Union included DCF in the watch list of substances Directive to be monitored. In the present study, biodegradation of CBZ and DCF by the bacterial strain Labrys portucalensis F11, a strain able to degrade other pharmaceutical compounds, was assessed; tests were performed with F11 as single carbon and energy source, as well as in presence of 5.9mM of sodium acetate. In assays supplemented with 2.0 and 4.0 µM of CBZ, the compound was no longer detected in the bulk medium after 24hr and 5days, respectively. Complete degradation was achieved in 21 days for 11.0 µM and in 23 days for 21.0 µM. For the highest concentration tested (43.0 µM), 95% of degradation was achieved in 30days. Supplementation with acetate increased the degradation rate of CBZ, for all tested concentrations. In the case of DCF, when supplemented as a single carbon source, approximately 70% of DCF (1.7, 3.3, 8.4, 17.5 and 34.0 µM) was degraded in 30days. Complete degradation was achieved in the presence of acetate for all tested concentrations, at higher degradation rates. The detection of intermediates produced during DCF biodegradation was performed by UPLC-QTOF/MS/MS, which allowed the identification of a range of metabolites. Stoichiometric liberation of chorine occurred and no metabolites were detected at the end of the biodegradation assays suggesting a complete mineralization of DCF. Strain Labrys portucalensis F11 proved to be able to degrade these two top priority environmental contaminants and may be potentially useful for biotechnological applications/environment remediation.

Keywords: biodegradation, carbamazepine, diclofenac, pharmaceuticals

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Authors: Rukayya Ibrahim Muazu, Aiduan Li Borrion, Julia A. Stegemann

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Biomass briquette gasification is regarded as a promising route for efficient briquette use in energy generation, fuels and other useful chemicals, however, previous research work has focused on briquette gasification in fixed bed gasifiers such as updraft and downdraft gasifiers. Fluidised bed gasifier has the potential to be effectively sized for medium or large scale. This study investigated the use of fuel briquettes produced from blends of rice husks and corn cobs biomass residues, in a bubbling fluidised bed gasifier. The study adopted a combination of numerical equations and Aspen Plus simulation software to predict the product gas (syngas) composition based on briquette's density and biomass composition (blend ratio of rice husks to corn cobs). The Aspen Plus model was based on an experimentally validated model from the literature. The results based on a briquette size of 32 mm diameter and relaxed density range of 500 to 650 kg/m3 indicated that fluidisation air required in the gasifier increased with an increase in briquette density, and the fluidisation air showed to be the controlling factor compared with the actual air required for gasification of the biomass briquettes. The mass flowrate of CO2 in the predicted syngas composition, increased with an increase in the air flow rate, while CO production decreased and H2 was almost constant. The H2/CO ratio for various blends of rice husks and corn cobs did not significantly change at the designed process air, but a significant difference of 1.0 for H2/CO ratio was observed at higher air flow rate, and between 10/90 to 90/10 blend ratio of rice husks to corn cobs. This implies the need for further understanding of biomass variability and hydrodynamic parameters on syngas composition in biomass briquette gasification.

Keywords: aspen plus, briquettes, fluidised bed, gasification, syngas

Procedia PDF Downloads 452

Authors: Shorena Sadzaglishvili, Teona Gotsiridze, Ketevan Lekishvili, Darejan Javakhishvili, Alida Bouris

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Globally, adolescents and young people experience high levels of HIV vulnerability and risk. Estimates suggest that AIDS-related deaths among young people are increasing, suggesting poor prioritization of adolescents in national plans for HIV testing and treatment services. HIV/AIDS is currently the sixth leading cause of death in people aged 10-24 years. Among young people, street connected youth are clearly distinguished as being among the most at risk for HIV infection. The present study recognizes the urgent need to scale up effective HIV responses that are tailored to the unique needs of street connected youth for the global HIV agenda and especially, the former Soviet country - Georgia, where 'street kids' are a new phenomenon and estimated to be about 2,500. During two months trained interviewers conducted individual semi-structured qualitative interviews with 22 key informants from the local governmental and nongovernmental service organizations, including psychologists, social workers, peer educators, mobile health workers, and managers. Informants discussed social network characteristics influencing street connected youth’s sexual risk behaviors. Data were analyzed using Dedoose. It was revealed that there are three types of homogeneous networks of street-connected youth aged 10-19 based on ethnical background: (1) Georgians; (2) migrant kids of Azeri-Kurdish origin, and (3) local Roma-Moldavian kids. These networks are distinguished with various HIV risk through both risky sexual and drug-related behaviors. In addition, there are several cases of HIV infection identified through reactive social services. Street connected youth do not have basic information about the HIV related sexual, alcohol and drug behaviors nor there are any systematic programs providing HIV testing and consultation for reducing the vulnerability of HIV infection. There is a need to systematically examine street-connected youth risk-taking behaviors by applying an integrated, multilevel framework to a population at great risk of HIV. Acknowledgment: This work was supported by Shota Rustaveli National Science Foundation of Georgia (SRNSFG) [#FR 17_31], Ilia State University.

Keywords: street connected youth, social networks, HIV/AIDS, HIV testing

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Authors: Daniel Llanes, Alfredo Reyes, Sonia E. Ruiz, Federico Valenzuela Beltran

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Steel frames have been used in building construction for more than one hundred years. Beam-column may be connected to columns using either stiffened or unstiffened angles at the top and bottom beam flanges. Designers often assume that these assemblies acted as “pinned” connections for gravity loads and that the stiffened connections would act as “fixed” connections for lateral loads. Observation of damages sustained by buildings during the 1994 Northridge earthquake indicated that, contrary to the intended behavior, in many cases, brittle fractures initiated within the connections at very low levels of plastic demand, and in some cases, while the structures remained essentially elastic. Due to the damage presented in these buildings other type of alternative connections have been proposed. According to a research funded by the Federal Emergency Management Agency (FEMA), the screwed connections have better performance when they are subjected to cyclic loads, but at the same time, these connections have some degree of flexibility. Due to this situation, some researchers ventured into the study of semi-rigid connections. In the present study three steel buildings, constituted by regular frames are analyzed. Two types of connections are considered: pinned and semi-rigid connections. With the aim to estimate their structural capacity, a number of incremental dynamic analyzes are performed. 3D structural models are used for the analyses. The seismic ground motions were recorded on sites near Los Angeles, California, where the structures are supposed to be located. The vulnerability curves of the building are obtained in terms of maximum inter-story drifts. The vulnerability curves (which correspond to the models with two different types of connections) are compared, and its implications on its structural design and performance is discussed.

Keywords: steel frame Buildings, vulnerability curves, semi-rigid connections, pinned connections

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Authors: Fu Jia

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The effects of soil-structure interaction (SSI) are often studied using axial-symmetric three-dimensional (3D) models to avoid the high computational cost of the more realistic, fully 3D models, which require 2-3 orders of magnitude more computer time and storage. This paper analyzes the error and presents correction factors for system frequency, system damping, and peak amplitude of structural response computed by axisymmetric models, embedded in uniform or layered half-space. The results are compared with those for fully 3D rectangular foundations of different aspect ratios. Correction factors are presented for a range of the model parameters, such as fixed-base frequency, structure mass, height and length-to-width ratio, foundation embedment, soil-layer stiffness and thickness. It is shown that the errors are larger for stiffer, taller and heavier structures, deeper foundations and deeper soil layer. For example, for a stiff structure like Millikan Library (NS response; length-to-width ratio 1), the error is 6.5% in system frequency, 49% in system damping and 180% in peak amplitude. Analysis of a case study shows that the NEHRP-2015 provisions for reduction of base shear force due to SSI effects may be unsafe for some structures and need revision. The presented correction factor diagrams can be used in practical design and other applications.

Keywords: 3D soil-structure interaction, correction factors for axisymmetric models, length-to-width ratio, NEHRP-2015 provisions for reduction of base shear force, rectangular embedded foundations, SSI system frequency, SSI system damping

Procedia PDF Downloads 259

Authors: Japhet N. Mwambusi

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High tropical forests deforestation for solid wood furniture industry is among of climate change contributing agents. This pressure indirectly is caused by furniture joints failure due to poor gluing technology based on improper use of different glues to different wood species which lead to low quality and weak wood-glue joints. This study was carried in order to run performance tests of wood glues on different wood species used in wood workshops: Morogoro Tanzania whereby three popular wood species of C. lusitanica, T. glandis and E. maidenii were tested against five glues of Woodfix, Bullbond, Ponal, Fevicol and Coral found in the market. The findings were necessary on developing a guideline for proper glue selection for a particular wood species joining. Random sampling was employed to interview carpenters while conducting a survey on the background of carpenters like their education level and to determine factors that influence their glues choice. Monsanto Tensiometer was used to determine bonding strength of identified wood glues to different wood species in use under British Standard of testing wood shear strength (BS EN 205) procedures. Data obtained from interviewing carpenters were analyzed through Statistical Package of Social Science software (SPSS) to allow the comparison of different data while laboratory data were compiled, related and compared by the use of MS Excel worksheet software as well as Analysis of Variance (ANOVA). Results revealed that among all five wood glues tested in the laboratory to three different wood species, Coral performed much better with the average shear strength 4.18 N/mm², 3.23 N/mm² and 5.42 N/mm² for Cypress, Teak and Eucalyptus respectively. This displays that for a strong joint to be formed to all tree wood species for soft wood and hard wood, Coral has a first priority in use. The developed table of guideline from this research can be useful to carpenters on proper glue selection to a particular wood species so as to meet glue-bond strength. This will secure furniture market as well as reduce pressure to the forests for furniture production because of the strong existing furniture due to their strong joints. Indeed, this can be a good strategy on reducing climate change speed in tropics which result from high deforestation of trees for furniture production.

Keywords: climate change, deforestation, gluing technology, joint failure, wood-glue, wood species

Procedia PDF Downloads 238

Authors: Pegah Ebrahimi, Farshad Oveissi, Iman Manavi-Tehrani, Sina Naficy, David F. Fletcher, Fariba Dehghani, David S. Winlaw

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Despite advances in modern surgery, congenital heart disease remains a medical challenge and a major cause of infant mortality. Cardiovascular prostheses are routinely used in surgical procedures to address congenital malformations, for example establishing a pathway from the right ventricle to the pulmonary arteries in pulmonary valvar atresia. Current off-the-shelf options including human and adult products have limited biocompatibility and durability, and their fixed size necessitates multiple subsequent operations to upsize the conduit to match with patients’ growth over their lifetime. Non-physiological blood flow is another major problem, reducing the longevity of these prostheses. These limitations call for better designs that take into account the hemodynamical and anatomical characteristics of different patients. We have integrated tissue engineering techniques with modern medical imaging and image processing tools along with mathematical modeling to optimize the design of cardiovascular grafts in a patient-specific manner. Computational Fluid Dynamics (CFD) analysis is done according to models constructed from each individual patient’s data. This allows for improved geometrical design and achieving better hemodynamic performance. Tissue engineering strives to provide a material that grows with the patient and mimic the durability and elasticity of the native tissue. Simulations also give insight on the performance of the tissues produced in our lab and reduce the need for costly and time-consuming methods of evaluation of the grafts. We are also developing a methodology for the fabrication of the optimized designs.

Keywords: computational fluid dynamics, cardiovascular grafts, design optimization, tissue engineering

Procedia PDF Downloads 237

Authors: S. Gupta, R. Sarkar, S. Pathak, D. H. Kela, A. Pramanick, P. Talukdar

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Low alloy quenched and tempered steels are typically used in cast railway components such as knuckles, yokes, and couplers. Since these components experience extensive impact loading during their service life, adequate impact toughness of these grades need to be ensured to avoid catastrophic failure of parts in service. Because of the general availability of Charpy V Test equipment, Charpy test is the most common and economical means to evaluate the impact toughness of materials and is generally used in quality control applications. With this backdrop, an experiment was designed to evaluate the effect of austenitizing temperature, soaking time and resultant grain size on the Charpy impact toughness and the related fracture mechanisms in a quenched and tempered low alloy steel, with the aim of optimizing the heat treatment parameters (i.e. austenitizing temperature and soaking time) with respect to impact toughness. In the first phase, samples were austenitized at different temperatures viz. 760, 800, 840, 880, 920 and 960°C, followed by quenching and tempering at 600°C for 4 hours. In the next phase, samples were subjected to different soaking times (0, 2, 4 and 6 hours) at a fixed austenitizing temperature (980°C), followed by quenching and tempering at 600°C for 4 hours. The samples corresponding to different test conditions were then subjected to instrumented Charpy tests at -40°C and energy absorbed were recorded. Subsequently, microstructure and fracture surface of samples corresponding to different test conditions were observed under scanning electron microscope, and the corresponding grain sizes were measured. In the final stage, austenitizing temperature, soaking time and measured grain sizes were correlated with impact toughness and the fracture morphology and mechanism.

Keywords: heat treatment, grain size, microstructure, retained austenite and impact toughness

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