Search results for: challenges in higher institutions

Authors: O. V. Vyazovska

Abstract:

Behavioral efficiency is one of the main principles to be successful in nature. Accuracy of visual discrimination is determined by the attention, learning experience, and memory. In the experimental condition, pigeons’ responses to visual stimuli presented on the screen of the monitor are behaviorally manifested by pecking or not pecking the stimulus, by the number of pecking, reaction time, etc. The higher the probability of rewarding is, the more likely pigeons will respond to the stimulus. We trained 8 pigeons (Columba livia) on a stagewise go/no-go visual discrimination task.16 visual stimuli were created from all possible combinations of four binary dimensions: brightness (dark/bright), size (large/small), line orientation (vertical/horizontal), and shape (circle/square). In the first stage, we presented S+ and 4 S-stimuli: the first that differed in all 4-dimensional values from S+, the second with brightness dimension sharing with S+, the third sharing brightness and orientation with S+, the fourth sharing brightness, orientation and size. Then all 16 stimuli were added. Pigeons rejected correctly 6-8 of 11 new added S-stimuli at the beginning of the second stage. The results revealed that pigeons’ behavior at the beginning of the second stage was controlled by probabilities of rewarding for 4 dimensions learned in the first stage. More or fewer mistakes with dimension discrimination at the beginning of the second stage depended on the number S- stimuli sharing the dimension with S+ in the first stage. A significant inverse correlation between the number of S- stimuli sharing dimension values with S+ in the first stage and the dimensional learning rate at the beginning of the second stage was found. Pigeons were more confident in discrimination of shape and size dimensions. They made mistakes at the beginning of the second stage, which were not associated with these dimensions. Thus, the received results help elucidate the principles of dimensional stimulus control during learning compound multidimensional visual stimuli.

Keywords: visual go/no go discrimination, selective attention, dimensional stimulus control, pigeon

Procedia PDF Downloads 127

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

Abstract:

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 438

Authors: Fouzia Ajmal

Abstract:

Global Citizenship Education (GCED) could prove to be the best solution to prevent violent extremism as it will sustain a respect for all and build up a feeling of having a place with humankind. To meet the target 4.7 of sustainable development goals, it is important to focus on global citizenship education at all levels of education in general and in pre-service teacher education in particular so that the message and practices reach the young masses. The pre-service education is imperative to develop knowledge, skills and disposition of prospective teachers. The current study was conducted to investigate the integration of GCED in pre-service teacher education curriculum of Pakistan. The study was delimited to B.Ed (hons) Elementary Education programme. The curriculum of B.Ed Elementary developed by Higher Education Commission was analyzed through Curriculum Alignment Matrix. 31 course outlines were analyzed, and percentage was used to analyze the level of integration of GCED in courses. The analyses depicted that the concepts of civic sense, tolerance, duties and rights of citizens and fundamental rights of humans are partially aligned in a few of the courses. The tolerance, active citizenship, and respect for cultural diversity and religious harmony are evident in Pakistan Studies and teaching of social studies courses. The relevant books are also mentioned as resources in these courses. The intercultural understanding is not very evident while globalization is mentioned in a few courses. It is recommended that a deliberate effort may be made to integrate concepts of Global Citizenship Education so as to enable the prospective teachers in developing necessary skills to play their active role in promoting peace and building resilience to extremism in elementary school students.

Keywords: curriculum analysis, global citizenship education, preservice teacher education, resilience building

Procedia PDF Downloads 136

Authors: Noor Ashikin Omar

Abstract:

The rapid growth and advancement in information and communication technology (ICT) at a global scene has greatly influenced and revolutionised interaction amongst society. The use of ICT has become second nature in managing everyday lives, particularly in the education environment. Traditional learning methods of using blackboards and chalks have been largely improved by the use of ICT devices such as interactive whiteboards and computers in school. This paper aims to explore the impacts of virtual learning environments (VLE) on teacher’s pedagogy and student’s learning in primary school settings. The research was conducted in two phases. Phase one of this study comprised a short interview with the school’s senior assistants to examine issues and challenges faced during planning and implementation of FrogVLE in their respective schools. Phase two involved a survey of a number of questionnaires directed to three major stakeholders; the teachers, students and parents. The survey intended to explore teacher’s and student’s perspective and attitude towards the use of VLE as a teaching and learning medium and as a learning experience as a whole. In addition, the survey from parents provided insights on how they feel towards the use of VLE for their child’s learning. Collectively, the two phases enable improved understanding and provided observations on factors that had affected the implementation of the VLE into primary schools. This study offers the voices of the students which were frequently omitted when addressing innovations as well as teachers who may not always be heard. It is also significant in addressing the importance of teacher’s pedagogy on students’ learning and its effects to enable more effective ICT integration with a student-centred approach. Finally, parental perceptions in the implementation of VLE in supporting their children’s learning have been implicated as having a bearing on educational achievement. The results indicate that the all three stakeholders were positive and highly supportive towards the use of VLE in schools. They were able to understand the benefits of moving towards the modern method of teaching using ICT and accept the change in the education system. However, factors such as condition of ICT facilities at schools and homes as well as inadequate professional development for the teachers in both ICT skills and management skills hindered exploitation of the VLE system in order to fully utilise its benefits. Social influences within different communities and cultures and costs of using the technology also has a significant impact. The findings of this study are important to the Malaysian Ministry of Education because it informs policy makers on the impact of the Virtual Learning Environment (VLE) on teacher’s pedagogy and learning of Malaysian primary school children. The information provided to policy makers allows them to make a sound judgement and enables an informed decision making.

Keywords: attitudes towards virtual learning environment (VLE), parental perception, student's learning, teacher's pedagogy

Procedia PDF Downloads 196

Authors: Livia Herle

Abstract:

A large part of the Principality of Liechtenstein is covered by forest. Three-quarters of this forest is defined as protective due to the alpine landscape of the country, which is deteriorating the quality of the wood. Nevertheless, the forest is one of the most important sources of raw material. However, out of the wood harvested annually in Liechtenstein, about two-thirds are used directly as an energy source, drastically shortening up the carbon storage cycle of wood. Furthermore, due to climate change, forest structures are changing. Predictions for the forest in Liechtenstein have stated that the spruce will mostly vanish in low altitudes, only being able to survive in the higher regions. In contrast, hardwood species will experience a rise, resulting in a more mixed forest. Thus, the main research focus will be put upon the potential of hardwood as well as prolonging the lifespan of a timber log before ending up as an energy source. An analysis of the local occurrence of hardwood species and their quality will serve as a tool to implement this knowledge upon constructional solutions. As a system that works with short spam timber and thus qualifies for the regional conditions of hardwood, reciprocal frame systems will be further investigated. These can be defined as load-bearing structures with only two beams connecting at a time, avoiding complex joining situations. Furthermore, every beam is mutually supporting. This allows the usage of short pieces of preferably massive wood. As a result, the system permits for an easy assembly but also disassembly. To promote a more circular application of wood, possible cascading scenarios of the structural solutions will be added. In a workshop at the School of Architecture of the University of Liechtenstein in the Sommer Semester 2024, prototypes in 1:1 of reciprocal frame systems using only local hardwood will help as a tool to further test the theoretical analyses.

Keywords: hardwood, cascading wood, reciprocal frames, crooked wood, forest structures, climate change

Procedia PDF Downloads 59

Authors: Nunila Ferreira de Oliveira, Silvana Martins Mishima

Abstract:

Diabetes mellitus type 2 (DM2) prevalence, is increasing on the world, in Brazil is considered a public health problem. Treatment focuses on glycemic control depending primarily of lifestyle changes - not drug treatment (NDT), may involve drug therapy (DT) and requires continuous health monitoring. In Brazil this monitoring is performed by the Unified Health System (SUS) through Primary Health Care (PHC), which stimulate people with DM2 empowerment for care management. SUS was approved in 1988 and the PHC operationalization was strengthened with the creation of the Family Health Strategy (FHS) in 1994. Our aim was to analyze the people with DM2 participation in front of the care management health monitoring in the FHS. Qualitative research was carried out through non-participant observation of attendance of 25 people with DM2 in the FHS and interviewed at home. Ethical guidelines were followed. It was found that people with DM2 only follow professionals’ recommendations that make sense according to their own conceptions of health/disease; most of them emphasize the importance of (DT) with little emphasis on the NDT, was found great difficulty in the NDT and lack of knowledge about the disease and care. As regards monitoring the FHS, were observed therapeutic practices based on the bio medical model, although the APS search for another care perspective; NDT is not systematically accompanied by the health team and takes place a few educational activities on the DM2 in the FHS, with low user adoption. The work of the FHS is done by multidisciplinary teams, but we see the need for greater participation of nurses in clinical-care follow-up of this population and may also act in adapting to the NDT. Finally we emphasize the need for professional practices that consider the difficulties to care management by people with DM2, especially because of the NDT. It is noticed that the measures recommended by the FHS professionals are not always developed by people with DM2. We must seek the empowerment of people with DM2 to manage the form of care associated with the FHS team, seeking to reduce the incidence of complications and higher quality of life.

Keywords: diabetes mellitus, primary health care, nursing, management of care

Procedia PDF Downloads 444

Authors: Nkwanyang L. Takem, Christopher M. Agyingi

Abstract:

Background and aim: An integrated interpretation of wireline logs and lithology of two selected wells (KF-1 and KF-2) of Kribi oil field within the southeastern offshore Douala/Kribi Campo Basin was carried out for sequence stratigraphic analysis of sediments penetrated by the wells. Methods: The stratigraphic units within the wells were subdivided into depositional sequences using characteristic well log patterns that were deposited between Tertiary Miocene to lower Cretaceous. Results: Nine (9) and eight (8) depositional sequences were identified respectively for KF-1 and KF-2. The sequences comprise LST (progradational packages), TSTs (retrogradational packages) and HSTs (aggradational packages), which reflect depositional systems deposited during different phases of base-level changes. The (LST) consists of Basin Floor Fans (BFF), Slope Fans and Channel Sands deposited when sea level was low and accommodation space lower than rate of sediment influx. TST consists of retrogradational marine shales deposited during high relative sea levels and when accommodation space was higher than rate of sediment influx. HST consisted of shoreface sands displaying mostly aggradational to progradational stacking patterns. Conclusion: The rapid facies changes between successive systems tracts provide potential stratigraphic traps. Reservoir stratification and continuity vary greatly between systems tracts and this enhanced development of stratigraphic traps in the area. Basin floor fans comprise sandstone of good reservoir quality, thus huge accumulation of HC can be trapped in this reservoirs.

Keywords: Douala-Kribi-Campo Basin, reservoirs, sequence strastigraphyy, system tracks

Procedia PDF Downloads 550

Authors: Annur Suhadi, Haris B. Harahap, Zaim Arrosyidi, Epan, Darmapala

Abstract:

Oilfields under waterflood often face the problem of plugging injectors either by internal filtration or external filter cake built up inside pore throats. The content of suspended solids shall be reduced to required level of filtration since corrective action of plugging is costly expensive. The performance of nutshell filters, where filtration takes place, is good using pecan and walnut shells. Candlenut shells were used instead of pecan and walnut shells since they were abundant in Indonesia, Malaysia, and East Africa. Physical and chemical properties of walnut, pecan, and candlenut shells were tested and the results were compared. Testing, using full-scale nutshell filters, was conducted to determine the oil content, turbidity, and suspended solid removal, which was based on designed flux rate. The performance of candlenut shells, which were deeply bedded in nutshell filters for filtration process, was monitored. Cleaned water outgoing nutshell filters had total suspended solids of 17 ppm, while oil content could be reduced to 15.1 ppm. Turbidity, using candlenut shells, was below the specification for injection water, which was less than 10 Nephelometric Turbidity Unit (NTU). Turbidity of water, outgoing nutshell filter, was ranged from 1.7-5.0 NTU at various dates of operation. Walnut, pecan, and candlenut shells had moisture content of 8.98 wt%, 10.95 wt%, and 9.95 wt%, respectively. The porosity of walnut, pecan, and candlenut shells was significantly affected by moisture content. Candlenut shells had property of toluene solubility of 7.68 wt%, which was much higher than walnut shells, reflecting more crude oil adsorption. The hardness of candlenut shells was 2.5-3 Mohs, which was close to walnut shells’ hardness. It was advantage to guarantee the cleaning filter cake by fluidization process during backwashing.

Keywords: candlenut shells, filtration, nutshell filter, pecan shells, walnut shells

Procedia PDF Downloads 94

Authors: Zatil Athaillah, Anastasia Devi, Dian Muzdalifah, Wirasuwasti Nugrahani, Linar Udin

Abstract:

During tempe fermentation, some chemical changes occurred and they contributed to sensory, appearance, and health benefits of soybeans. Many studies on health properties of tempe have specialized on their isoflavones. In this study, other components of tempe, particularly water soluble chemicals, was investigated for their biofunctionality. The study was focused on the ability to suppress MCF-7 breast cancer cell growth and antioxidant activity, as expressed by DPPH radical scavenging activity, total phenols and total flavonoids, of the water extracts. Fermentation time of tempe was extended up to 120 hr to increase the possibility to find the functional components. Extraction yield and soluble nitrogen content were also quantified as accompanying data. Our findings suggested that yield of water extraction of tempe increased as fermentation was extended up to 120 hr, except for a slight decrease at 72 hr. Water extracts of tempe showed inhibition of MCF-7 breast cancer cell growth, as shown by lower IC50 values when compared to control (unfermented soybeans). Among the varied fermentation timescales, 60-hr period showed the highest activity (IC50 of 8.7 ± 4.95 µg/ml). The anticancer activity of extracts obtained from different fermentation time was positively correlated with total soluble nitrogens, but less relevant with antioxidant data. During 48-72 hr fermentation, at which cancer suppression activity was significant, the antioxidant properties from the three assays were not higher than control. These findings indicated that water extracts of tempe from extended fermentation could inhibit breast cancer cell growth but further study to determine the mechanism and compounds that play important role in the activity should be conducted.

Keywords: tempe, anticancer, antioxidant, phenolic compounds

Procedia PDF Downloads 231

Authors: Roya Kelishadi, Mostafa Amini-Rarani, Mostafa Qorbani

Abstract:

Introduction: As a health-related behavior, physical activity (PA) has an unequal distribution relating to individual's socioeconomic status. This study aimed to assess socioeconomic inequality in PA among Iranian students and their parents at national level and according to socioeconomic status (SES) of the living regions. Method: This study was conducted as part of a national surveillance program conducted among 14400 Iranian students and their parents. Non-linear principal component analysis was used to construct the households' socioeconomic status, and the concentration index approach was applied to measure inequality in father, mother, and student’s PA. Results: The data of 13313 students and their parents were complete for the current study. At national level and SES regions, students had more PA than their parents (except in the lowest SES region), and fathers have more PA than mothers. The lowest means of mother and student's PA were find in the highest SES region. At national level, the concentration indices of father and mother’s PA were -0.050 (95 % CI: -0.067 ~ -0.030) and -0.028 (95% CI: -0.044 ~ -0.012), respectively; indicating pro-poor inequality and, the CI value of student PA was nearly equal to zero (P > 0.05). At SES regions, father and mother's PA were more concentrated in the poor, except for lower middle region. Regional concentration indices for students reveal that inequality not statistically significant at all regions. Conclusion: This study suggests that reliable evidence that comparing different aspects of inequality of PA, based on socioeconomic status and residence areas of students and their parents, could be used for better planning for health promotion programs. Moreover, given the average of mother's and student’s PA in the richer regions were low, it can be suggested that richer focused-PA planning may further increase the level of PA across higher SES and, consequently, reduce inequality in PA. These findings can be applied in the health system services.

Keywords: concentration index, health system services, physical activity, socioeconomic inequality

Procedia PDF Downloads 141

Authors: Niranjana Soperna, Shivangi Nigam

Abstract:

Violence against women is linked to their disadvantageous position in the society. It is rooted in unequal power relationships between men and women in society and is a global problem which is not limited to a specific group of women in society. An adolescent girl’s life is often accustomed to the likelihood of violence, and acts of violence exert additional power over girls because the stigma of violence often attaches more to a girl than to her doer. The experience of violence is distressing at the individual emotional and physical level. The field of research and programs for adolescent girls has traditionally focused on sexuality, reproductive health, and behavior, neglecting the broader social issues that underpin adolescent girls’ human rights, overall development, health, and well-being. This paper is an endeavor to address the understated or disguised form of violence which the adolescent girls experience within the social contexts. The parameters exposed under this research had been ignored to a large extent when it came to studying the dimension of violence under the social domain. Hence, the researchers attempted to explore this camouflaged form of violence and discovered some specific parameters such as: Diminished Self Worth and Esteem, Verbal Abuse, Menstruation Taboo and Social Rigidity, Negligence of Medical and Health Facilities and Complexion- A Prime Parameter for Judging Beauty. The study was conducted in the districts of Haryana where personal interviews were taken from both urban and rural adolescent girls (aged 13 to 19 years) based on structured interview schedule. The results revealed that the adolescent girls, both in urban as well as rural areas were quite affected with the above mentioned issues. In urban areas, however, due to the higher literacy rate, which resulted in more rational thinking, the magnitude was comparatively smaller, but the difference was still negligible.

Keywords: adolescent girls, education, social contexts, understated violence

Procedia PDF Downloads 301

Authors: Parvin Goli, Amirhosein Kefayat, Rezvan Goli

Abstract:

Background: It is well established that parents can influence their offspring's neurodevelopment. It is shown that paternal environment and lifestyle is beneficial for the progeny's fitness and might affect their metabolic mechanisms; however, the effects of paternal exercise on the brain in the offspring have not been explored in detail. Objective: This study aims to review the impact of paternal physical exercise on memory and learning, neuroplasticity, as well as DNA methylation levels in the off-spring's hippocampus. Study design: In this systematic review and meta-analysis, an electronic literature search was conducted in databases including PubMed, Scopus, and Web of Science. Eligible studies were those with an experimental design, including an exercise intervention arm, with the assessment of any type of memory function, learning ability, or any type of brain plasticity as the outcome measures. Standardized mean difference (SMD) and 95% confidence intervals (CI) were computed as effect size. Results: The systematic review revealed the important role of environmental enrichment in the behavioral development of the next generation. Also, offspring of exercised fathers displayed higher levels of memory ability and lower level of brain-derived neurotrophic factor. A significant effect of paternal exercise on the hippocampal volume was also reported in the few available studies. Conclusion: These results suggest an intergenerational effect of paternal physical activity on cognitive benefit, which may be associated with hippocampal epigenetic programming in offspring. However, the biological mechanisms of this modulation remain to be determined.

Keywords: hippocampal plasticity, learning ability, memory, parental exercise

Procedia PDF Downloads 195

Authors: Qimin Shi, Yi Sun, Constantinus Politis, Shoufeng Yang

Abstract:

In-situ preparation of particle-reinforced aluminium matrix composites (PRAMCs) by laser powder bed fusion (LPBF) additive manufacturing is a promising strategy to strengthen traditional Al-based alloys. The laser-driven thermite reaction can be a practical mechanism to in-situ synthesize PRAMCs. However, introducing oxygen elements through adding Fe₂O₃ makes the powder mixture highly sensitive to form porosity and Al₂O₃ film during LPBF, bringing challenges to producing dense Al-based materials. Therefore, this work develops a processing strategy combined with consecutive high-energy laser melting scanning and low-energy laser remelting scanning to prepare PRAMCs from a Fe₂O₃/AlSi12 powder mixture. The powder mixture consists of 5 wt% Fe₂O₃ and the remainder AlSi12 powder. The addition of 5 wt% Fe₂O₃ aims to achieve balanced strength and ductility. A high relative density (98.2 ± 0.55 %) was successfully obtained by optimizing laser melting (Emelting) and laser remelting surface energy density (Eremelting) to Emelting = 35 J/mm² and Eremelting = 5 J/mm². Results further reveal the necessity of increasing Emelting, to improve metal liquid’s spreading/wetting by breaking up the Al₂O₃ films surrounding the molten pools; however, the high-energy laser melting produced much porosity, including H₂₋, O₂₋ and keyhole-induced pores. The subsequent low-energy laser remelting could close the resulting internal pores, backfill open gaps and smoothen solidified surfaces. As a result, the material was densified by repeating laser melting and laser remelting layer by layer. Although with two-times laser scanning, the microstructure still shows fine cellular Si networks with Al grains inside (grain size of about 370 nm) and in-situ nano-precipitates (Al₂O₃, Si, and Al-Fe(-Si) intermetallics). Finally, the fine microstructure, nano-structured dispersion strengthening, and high-level densification strengthened the in-situ PRAMCs, reaching yield strength of 426 ± 4 MPa and tensile strength of 473 ± 6 MPa. Furthermore, the results can expect to provide valuable information to process other powder mixtures with severe porosity/oxide-film formation potential, considering the evidenced contribution of laser melting/remelting strategy to densify material and obtain good mechanical properties during LPBF.

Keywords: densification, laser powder bed fusion, metal matrix composites, microstructures, mechanical properties

Procedia PDF Downloads 142

Authors: Sophie Mills, Leila L. Touil, Richard Sisson

Abstract:

Introduction: The TNM classification is the global standard for the staging of head and neck cancers. Accurate clinical-radiological staging of tumours (cTNM) is essential to predict prognosis, facilitate surgical planning and determine the need for other therapeutic modalities. This study aims to determine the accuracy of pre-operative cTNM staging using pathological TNM (pTNM) and consider possible causes of TNM stage migration, noting any variation throughout the COVID-19 pandemic. Materials and Methods: A retrospective cohort study examined records of patients with surgical management of head and neck cancer at a tertiary head and neck centre from November 2019 to November 2020. Data was extracted from Somerset Cancer Registry and histopathology reports. cTNM and pTNM were compared before and during the first wave of COVID-19, as well as with other potential prognostic factors such as tumour site and tumour stage. Results: 119 cases were identified, of which 52.1% (n=62) were male, and 47.9% (n=57) were female with a mean age of 67 years. Clinical and pathological staging differed in 54.6% (n=65) of cases. Of the patients with stage migration, 40.4% (n=23) were up-staged and 59.6% (n=34) were down-staged compared with pTNM. There was no significant difference in the accuracy of cTNM staging compared with age, sex, or tumour site. There was a statistically highly significant (p < 0.001) correlation between cTNM accuracy and tumour stage, with the accuracy of cTNM staging decreasing with the advancement of pTNM staging. No statistically significant variation was noted between patients staged prior to and during COVID-19. Conclusions: Discrepancies in staging can impact management and outcomes for patients. This study found that the higher the pTNM, the more likely stage migration will occur. These findings are concordant with the oncology literature, which highlights the need to improve the accuracy of cTNM staging for more advanced tumours.

Keywords: COVID-19, head and neck cancer, stage migration, TNM staging

Procedia PDF Downloads 92

Authors: P. Leo, E. Cerri, L. Fratini, G. Buffa

Abstract:

The Friction Stir Welding process uses an inert rotating mandrel and a force on the mandrel normal to the plane of the sheets to generate the frictional heat. The heat and the stirring action of the mandrel create a bond between the two sheets without melting the base metal. As matter of fact, the use of a solid state welding process limits the insurgence of defects, due to the presence of gas in melting bath, and avoids the negative effects of materials metallurgical transformation strictly connected with the change of phase. The industrial importance of Ti-6Al-4V alloy is well known. It provides an exceptional good balance of strength, ductility, fatigue and fracture properties together with good corrosion resistance and good metallurgical stability. In this paper, the authors analyze the microstructure of friction stir welded joints of Ti-6Al-4V processed at the same travel speed (35 mm/min) but at different rotation speeds (300-500 rpm). The microstructure of base material (BM), as result from both optical microscope and scanning electron microscope analysis is not homogenous. It is characterized by distorted α/β lamellar microstructure together with smashed zone of fragmented β layer and β retained grain boundary phase. The BM has been welded in the-as received state, without any previous heat treatment. Even the microstructure of the transverse and longitudinal sections of joints is not homogeneous. Close to the top of weld cross sections a much finer microstructure than the initial condition has been observed, while in the center of the joints the microstructure is less refined. Along longitudinal sections, the microstructure is characterized by equiaxed grains and lamellae. Both the length and area fraction of lamellas increases with distance from longitudinal axis. The hardness of joints is higher than that of BM. As the process temperature increases the average microhardness slightly decreases.

Keywords: friction stir welding, microhardness, microstructure, Ti-6Al-4V

Procedia PDF Downloads 367

Authors: Sadie Namani, Lindita Ajazaj, Arjeta Zogaj, Vera Berisha, Bahrije Halili, Luljeta Hasani, Ajete Aliu

Abstract:

Background: The outcome of bacterial meningitis is strongly related to the resistance of bacterial pathogens to the initial antimicrobial therapy. The objective of the study was to analyze the initial antimicrobial therapy, the resistance of meningeal pathogens and the outcome of adults bacterial meningitis cases. Materials/methods: This prospective study enrolled 46 adults older than 16 years of age, treated for bacterial meningitis during the years 2009 and 2010 at the infectious diseases clinic in Prishtinë. Patients are categorized into specific age groups: > 16-26 years of age (10 patients), > 26-60 years of age (25 patients) and > 60 years of age (11 patients). All p-values < 0.05 were considered statistically significant. Data were analyzed using Stata 7.1 and SPSS 13. Results: During the two year study period 46 patients (28 males) were treated for bacterial meningitis. 33 patients (72%) had a confirmed bacterial etiology; 13 meningococci, 11 pneumococci, 7 gram-negative bacilli (Ps. aeruginosa 2, Proteus sp. 2, Acinetobacter sp. 2 and Klebsiella sp. 1 case) and 2 staphylococci isolates were found. Neurological complications developed in 17 patients (37%) and the overall mortality rate was 13% (6 deaths). Neurological complications observed were: cerebral abscess (7/46; 15.2%), cerebral edema (4/46; 8.7%); haemiparesis (3/46; 6.5%); recurrent seizures (2/46; 4.3%), and single cases of thrombosis sinus cavernosus, facial nerve palsy and decerebration (1/46; 2.1%). The most common meningeal pathogens were meningococcus in the youngest age group, gram negative-bacilli in second age group and pneumococcus in eldery age group. Initial single-agent antibiotic therapy (ceftriaxone) was used in 17 patients (37%): in 60% of patients in the youngest age group and in 44% of cases in the second age group. 29 patients (63%) were treated with initial dual-agent antibiotic therapy; ceftriaxone in combination with vancomycin or ampicillin. Ceftriaxone and ampicillin were the most commonly used antibiotics for the initial empirical therapy in adults > 50 years of age. All adults > 60 years of age were treated with the initial dual-agent antibiotic therapy as in this age group was recorded the highest mortality rate (M=27%) and adverse outcome (64%). Resistance of pathogens to antimicrobics was recorded in cases caused by gram-negative bacilli and was associated with greater risk for developing neurological complications (p=0.09). None of the gram-negative bacilli were resistant to carbapenems; all were resistant to ampicillin while 5/7 isolates were resistant to cefalosporins. Resistance of meningococci and pneumococci to beta-lactams was not recorded. There were no statistical differences in the occurrence of neurological complications (p > 0.05), resistance of meningeal pathogens to antimicrobics (p > 0.05) and the inital antimicrobial therapy (one vs. two antibiotics) concerning group-ages in adults. Conclusions: The initial antibiotic therapy with ceftriaxone alone or in combination with vancomycin or ampicillin did not cover cases caused by gram-negative bacilli.

Keywords: adults, bacterial meningitis, outcomes, therapy

Procedia PDF Downloads 160

Authors: Sun fang, Zhang Wenxin

Abstract:

This paper establishes an evaluation index system for spatio-temporal patterns of urbanization, with the county as research unit. We use the Entropy Weight method, coefficient variance, the Theil index and ESDA-GIS to analyze spatial patterns and evolutionary characteristics of New-Type Urbanization in the Central Plains Economic Region (CPER) between 2000 and 2011. Results show that economic benefit, non-agricultural employment level and level of market development are the most important factors influencing the level of New-Type Urbanization in the CPER; overall regional differences in New-Type Urbanization have declined while spatial correlations have increased from 2000 to 2011. The overall spatial pattern has changed little, however; differences between the western and eastern areas of the CPER are clear, and the pattern of a strong west and weak east did not change significantly over the study period. Areas with high levels of New-Type Urbanization were mostly distributed along the Beijing-Guangzhou and LongHai Railways on both sides, a new influx of urbanization was tightly clustered around ZhengZhou in the Central Henan Urban Agglomeration, but this trend was found to be weakening slightly. The level of New-Type Urbanization in municipal districts was found to be much higher than it was in the county generally. Provincial borders experienced a lower rate of growth and a lower level of New-Type Urbanization than did any other areas, consistently forming clusters of cold spots and sub-cold spots. The analysis confirms that historical development, location, and diffusion effects of urban agglomeration are the main drivers of changes in New-Type Urbanization patterns in CPER.

Keywords: new-type urbanization, spatial pattern, central plains economic region, spatial evolution

Procedia PDF Downloads 278

Authors: Nir Schreiber, Reuven Cohen, Simi Haber

Abstract:

The Potts model has been widely explored in the literature for the last few decades. While many analytical and numerical results concern with the traditional two site interaction model in various geometries and dimensions, little is yet known about models where more than two spins simultaneously interact. We consider a ferromagnetic four site interaction Potts model on the square lattice (FFPS), where the four spins reside in the corners of an elementary square. Each spin can take an integer value 1,2,...,q. We write the partition function as a sum over clusters consisting of monochromatic faces. When the number of faces becomes large, tracing out spin configurations is equivalent to enumerating large lattice animals. It is known that the asymptotic number of animals with k faces is governed by λᵏ, with λ ≈ 4.0626. Based on this observation, systems with q < 4 and q > 4 exhibit a second and first order phase transitions, respectively. The transition nature of the q = 4 case is borderline. For any q, a critical giant component (GC) is formed. In the finite order case, GC is simple, while it is fractal when the transition is continuous. Using simple equilibrium arguments, we obtain a (zero order) bound on the transition point. It is claimed that this bound should apply for other lattices as well. Next, taking into account higher order sites contributions, the critical bound becomes tighter. Moreover, for q > 4, if corrections due to contributions from small clusters are negligible in the thermodynamic limit, the improved bound should be exact. The improved bound is used to relate the critical point to the finite correlation length. Our analytical predictions are confirmed by an extensive numerical study of FFPS, using the Wang-Landau method. In particular, the q=4 marginal case is supported by a very ambiguous pseudo-critical finite size behavior.

Keywords: entropic sampling, lattice animals, phase transitions, Potts model

Procedia PDF Downloads 149

Authors: Hennie Boeije, Renate Verkaik, Joke Korevaar

Abstract:

In Dutch national policy, it is promoted that the elderly remain living at home longer. They are less often admitted to a nursing home or only later in life. While living at home, it is important that they experience a good quality of life. Care providers in primary care support this. In this study, it was investigated what quality of life means for the elderly and which characteristics care should have that supports living at home longer with quality of life. To explore this topic, a qualitative methodology was used. Four focus groups were conducted: two with elderly people who live at home and their family caregivers, one with district nurses employed in-home care services and one with elderly care physicians working in primary care. Next to this individual interviews were employed with general practitioners (GPs). In total 32 participants took part in the study. The data were thematically analysed with MaxQDA software for qualitative analysis and reported. Quality of life is a multi-faceted term for elderly. The essence of their description is that they can still undertake activities that matter to them. Good physical health, mental well-being and social connections enable them to do this. Own control over their life is important for some. They are of opinion that how they experience life and manage old age is related to their resilience and coping. Key terms in the definitions of quality of life by GPs are also physical and mental health and social contacts. These are the three pillars. Next, to this elderly care, physicians mention security and safety and district nurses add control over their own life and meaningful daily activities. They agree that with frail elderly people, the balance is delicate and a change in one of the three pillars can cause it to collapse like a house of cards. When discussing what support is needed, professionals agree on access to care with a low threshold, prevention, and life course planning. When care is provided in a timely manner, a worsening of the situation can be prevented. They agree that hospital care often is not needed since most of the problems with the elderly have to do with care and security rather than with a cure per se. GPs can consult elderly care physicians to lower their workload and to bring in specific knowledge. District nurses often signal changes in the situation of the elderly. According to them, the elderly predominantly need someone to watch over them and provide them with a feeling of security. Life course planning and advance care planning can contribute to uniform treatment in line with older adults’ wishes. In conclusion, all stakeholders, including elderly persons, agree on what entails quality of life and the quality of care that is needed to support that. A future challenge is to shape conditions for the right skill mix of professionals, cooperation between the professions and breaking down differences in financing and supply. For the elderly, the challenge is preparing for aging.

Keywords: elderly living at home, quality of life, quality of care, professional cooperation, life course planning, advance care planning

Procedia PDF Downloads 115

Authors: Khalid Omari, Rene Chenier, Enrique Blondel, Ryan Ahola

Abstract:

Northern Canadian coasts have vulnerable and very dynamic intertidal zones with very high tides occurring in several areas. The impact of climate change presents challenges not only for maintaining this biodiversity but also for navigation safety adaptation due to the high sediment mobility in these coastal areas. Thus, frequent mapping of shorelines and intertidal changes is of high importance. To help in quantifying the changes in these fragile ecosystems, remote sensing provides practical monitoring tools at local and regional scales. Traditional methods based on high-resolution optical sensors are often used to map intertidal areas by benefiting of the spectral response contrast of intertidal classes in visible, near and mid-infrared bands. Tidal areas are highly reflective in visible bands mainly because of the presence of fine sand deposits. However, getting a cloud-free optical data that coincide with low tides in intertidal zones in northern regions is very difficult. Alternatively, the all-weather capability and daylight-independence of the microwave remote sensing using synthetic aperture radar (SAR) can offer valuable geophysical parameters with a high frequency revisit over intertidal zones. Multi-polarization SAR parameters have been used successfully in mapping intertidal zones using incoherence target decomposition. Moreover, the crustal displacements caused by ocean tide loading may reach several centimeters that can be detected and quantified across differential interferometric synthetic aperture radar (DInSAR). Soil moisture change has a significant impact on both the coherence and the backscatter. For instance, increases in the backscatter intensity associated with low coherence is an indicator for abrupt surface changes. In this research, we present primary results obtained following our investigation of the potential of the fully polarimetric Radarsat-2 data for mapping an inter-tidal zone located on Tasiujaq on the south-west shore of Ungava Bay, Quebec. Using the repeat pass cycle of Radarsat-2, multiple seasonal fine quad (FQ14W) images are acquired over the site between 2016 and 2018. Only 8 images corresponding to low tide conditions are selected and used to build an interferometric stack of data. The observed displacements along the line of sight generated using HH and VV polarization are compared with the changes noticed using the Freeman Durden polarimetric decomposition and Touzi degree of polarization extrema. Results show the consistency of both approaches in their ability to monitor the changes in intertidal zones.

Keywords: SAR, degree of polarization, DInSAR, Freeman-Durden, polarimetry, Radarsat-2

Procedia PDF Downloads 128

Authors: V. A. Okenyi, K. Yang, P. A. M. Basheer

Abstract:

Concrete structures in service are constantly under the influence of load. Microstructural cracks often develop in them and considering those in the marine environment; these microcracks often serve as a means for transportation of harmful fluids into the concrete. This paper studies the influence of flexural tensile stress that structural elements undergo on the transport properties of such concrete in the tensile zone of the structural member. Reinforced concrete beams of 1200mm ⨉ 230mm ⨉ 150mm in dimension in a four-point bending set up were subjected to various levels of the loading required to cause a microcrack width of 100µm. The use of Autoclam permeability tests, sorptivity tests as well as the Permit chloride ion migration tests were employed, and results showed that air permeability, sorptivity and water permeability all increased as the load increased in the concrete tensile zone. For air permeability, an increase in stress levels led to more permeability, and the addition of steel macrofibers had no significant effect until at 75% of stress level where it decreased air permeability. For sorptivity, there was no absorption into concrete when no load was added, but water sorptivity index was high at 75% stress levels and higher in steel fiber reinforced concrete (SFRC). Steel macrofibers produced more water permeability into the concrete at 75% stress level under the 100µm crack width considered while steel macrofibers helped in slightly reducing the migration of chloride into concrete by 8.8% reduction, compared to control samples at 75% stress level. It is clear from this research that load-induced cracking leads to an increase in fluid permeability into concrete and the effect of the addition of steel macrofiber to concrete for durability is not significant under 100µm crack width.

Keywords: durability, microcracks, SFRC, stress Level, transport properties

Procedia PDF Downloads 111

Authors: Elsa Makue Nguuffo, Esther Del Florence Moni Ndedi, Jacky Njiki Bikoï, Jean Paul Assam Assam, Maximilienne Ascension Nyegue

Abstract:

Aims: The present study aims to evaluate the kinetic parameters of essential oils (EOs) and combinations fromDrypetes gossweileri Stem Bark, Ocimum gratissimum leaves, Cymbopogon citratusleaves after evaluation of their antibacterial activityonmultidrug-resistant strains ofShigella. Material and Methods:fiveclinical strains of Shigellaisolated from patients with diarrhoeaincluding Shigella flexneri, and 4 otherstrains of Shigella sppwere selected. Their antibiotic profile was established using agar test diffusion with seven antibiotics belonging to seven classes.EOs were extracted from each plant using hydrodistillation process. The activity of Ciprofloxacin®, OEs, and their combination formulatedinthe followingratios(w/w/w): C1: 1/1/1; C2: 2/1/1; C3: 1/2/1, C4:1/1/2 was evaluated microdilution assay. The various interactions of OEs in the different combinations were determined then the OE and the most active combination were retained to determine their kinetic parameters on S. flexneri. Results: Antibiotic susceptibility tests revealed that most Shigella isolates (n = 4) were resistant to six antibiotics tested. Ciprofloxacin (40%), Nalidixic acid (60%), Tetracycline (80%), Amoxicillin (100%), Cefotaxime (80%), Erythromycin (100%), and Cotrimoxazole (80%) were the profiles found in the different strains of Shigella. About the antibacterial activity of OEs, Drypetes gossweileriOE and C2 combination had shown a higher Shigellicide property with a Minimal Inhibitory Concentration(MIC) respectivelyranging from 0.078 mg/mL to 0.312 mg/mL and 0.012 to 1.562 mg/mL. Combinations of OEs showed various interactions whose synergistic effects were mostly encountered. The best deactivation was obtained by the combination C2 at 16 MIC withb= 1.962. Conclusion: the susceptibility of Shigella to OEs and their combinations justifies their use in traditional medicine in the treatment of shigellosis.

Keywords: shigella, multidrug-resistant, EOs, kinetic

Procedia PDF Downloads 82

Authors: Ma. Doreen E. Candelaria, Ma. Louise Margaret A. Ramos, Dr. Jaime Y. Hernandez, Jr

Abstract:

Bamboo has been introduced as a possible alternative to some construction materials nowadays. Its potential use in the field of engineering, however, is still not widely practiced due to insufficient engineering knowledge on the material’s properties and characteristics. Although there are researches and studies proving its advantages, it is still not enough to say that bamboo can sustain and provide the strength and capacity required of common structures. In line with this, a more detailed analysis was made to observe the layered structure of the bamboo, particularly the species of Kawayan Tinik. It is the main intent of this research to provide the necessary experiments to determine the tensile strength of dried bamboo samples. The test includes tensile strength parallel to fibers with samples taken at internodes only. Throughout the experiment, methods suggested by the International Organization for Standardization (ISO) were followed. The specimens were tested using 3366 INSTRON Universal Testing Machine, with a rate of loading set to 0.6 mm/min. It was then observed from the results of these experiments that dried bamboo samples recorded high layered tensile strengths, as high as 600 MPa. Likewise, along the culm’s length and across its cross section, higher tensile strength were observed at the top part and at its outer layers. Overall, the top part recorded the highest tensile strength per layer, with its outer layers having tensile strength as high as 600 MPa. The recorded tensile strength of its middle and inner layers, on the other hand, were approximately 450 MPa and 180 MPa, respectively. From this variation in tensile strength across the cross section, it may be concluded that an increase in tensile strength may be observed towards the outer periphery of the bamboo. With these preliminary investigations on the layered tensile strength of bamboo, it is highly recommended to conduct experimental investigations on the layered compressive strength properties as well. It is also suggested to conduct investigations evaluating perpendicular layered tensile strength of the material.

Keywords: bamboo strength, layered strength tests, strength test, tensile test

Procedia PDF Downloads 392

Authors: Merle Talvik, Taimi Tulva, Kristi Puusepp, Ülle Ernits

Abstract:

Background data. This is a study in the field of health humanities. The 1930s were years of rapid cultural and economic development in Europe and in Estonia. The urban way of life the glamorous lifestyle gained popularity, although the society of Estonia in the 1930s had traditionally been agrarian. People's free time increased, which needed to be filled with activities either at home or outside the home. Therefore, the number of popular magazines aimed at housewives increased. More than 200 magazines and bulletins were published in the Republic of Estonia before the Second World War (in 1934, the population of Estonia was 1,126,000). In the 1930s, the Republic of Estonia faced several challenges in healthcare. Infectious diseases, alcoholism, prostitution and child mortality had to be dealt with. Healers without medical education operated in the villages. For the average person, medical care was quite expensive, and despite efforts, by 1940, only 20% of the population was covered by health insurance. Advice published in popular family magazines provided help in solving, understanding and preventing health problems. Aim. The aim of the study is to analyze the health counseling through magazines during the Republic of Estonia (1930-1940) in historical and cultural context. Method. In total, 420 magazine issues were processed. An extensive textual analysis, as well as an analysis of photographs and illustrations from the aspect of health advice was carried out to achieve the research objective. Results. Health counseling was written by well-known doctors of the time, leaders of the abstinence movement and others. There was advice in various areas: prevention of infectious and non-infectious diseases and their treatment with simple methods, first aid, combating sexually transmitted diseases, women's and children's health, mental health, folk medicine techniques, abstinence, healthy eating, skin care, hygiene, introducing pharmacy products. Advice was offered in both written and visual form. Photos and illustrations helped to empower the health advice. Folk heritage and health knowledge of the time were relied upon, and a scientific point of view was popularized. Aspirations towards a European lifestyle were reflected in articles and illustrations. Contribution. The article has an ethnological attitude, and its impact comes down to understanding the history of health care in its socio-cultural context. The health counseling topics of the 1930s are also applicable in today's health education and research. Health counseling builds on the legacy of the past, and it helps to understand that the past is in the future and the main principles of health counseling arise from our history and background.

Keywords: estonian republic, health counseling, lifestyle, magazines, media

Procedia PDF Downloads 49

Authors: A. Sathish, N. N. Lingaraju, K. N. Geetha, C. A. Srinivasamurthy, S. Bhaskar

Abstract:

Under dryland conditions, it is observed that the soil organic matter is low due to low organic carbon content due to poor management with less use of inputs. On the other hand, disposal of sugar industry waste, i.e., spentwash is a major concern with limited space for land based treatment and disposal which causes environmental pollution. Spentwash is also a resource that can be applied for productive uses since it contains nutrients that have the potential for use in agriculture. The disposal of spent wash may lead to environmental pollution. Hence as an alternative mechanism, it was applied once to dry lands, and the experiments were conducted from 2012-13 to 2016-17 in kharif season in Maddur Taluk, Mandya District, Karnataka State, India. The study conducted was in 93 different farmers field (maize-11, finger millet-80 & horsegram-14). Spentwash was applied at the rate of 100 m³ ha⁻¹ before sowing of the crops. The results showed that yield of dryland crops like finger millet, horse gram and maize was recorded 14.75 q ha⁻¹, 6 q ha⁻¹ and 31.00 q ha⁻¹, respectively and the yield increase to an extent of 10-25 per cent with one time application of spentwash to dry lands compared to farmers practice, i.e., chemical fertilizer application. The higher yield may be attributed to slow and steady release of nutrients by spentwash throughout the crop growth period. In addition, the growth promoting and other beneficial substances present in spentwash might have also helped in better plant growth and yield. The soil sample analysis after harvest of the crops indicate acidic to neutral pH, EC of 0.11 dSm⁻¹ and Na of 0.20 C mol (P⁺) kg⁻¹ in the normal range which are not harmful. Hence, it can be applied to drylands at least once in 3 years which enhances yield as well as reduces environmental pollution.

Keywords: dryland crops, pollution, sugar industry waste, spentwash

Procedia PDF Downloads 227

Authors: Wa`d Odeh, Alon Tal, Alfred Abed Rabbo, Nader Al Khatib, Shai Arnon

Abstract:

The presence of endocrine disrupting compounds (EDCs) in raw sewage and effluents from wastewater treatment plants (WWTPs) has been increasingly studied in the last few decades. Higher risks are said to characterize situations where raw sewage streams are found to be flowing, or where partial and inadequate wastewater treatment exists. Such conditions are prevalent in the West Bank area of Palestine. To our knowledge, no previous data concerning the occurrence and fate of EDCs in the aquatic environment has ever been systematically evaluated in the region. Hence, the main objective of this study was to identify the occurrence and concentrations of major EDCs in raw sewage, wastewater effluents produced by treatment plants and in the receiving environments, including streams and groundwater in the West Bank, Palestine. Water samples were collected and analyzed for four times during the years of 2013 and 2014. Two large-scale conventional activated sludge WWTPs, two wastewater watercourses, one naturally perennial stream, and five groundwater locations close to wastewater sources were sampled and analyzed by GC/MS following EPA methods (525.2). Five EDCs (estriol, estrone, testosterone, bisphenol A, and octylphenol) were detected in trace concentrations (ng/l) in wastewater streams and at inputs to WWTPs. WWTPs were not able to achieve complete removal of all EDCs, and EDCs were still found in the effluents. In this regard, the most significant environmental estrogenic impact was due to estrone concentrations. Nevertheless, no EDCs were detected in groundwater. Yet, in order for effluents to be reused, significant improvement in treatment infrastructure should be a top priority for environmental managers in the region.

Keywords: endocrine disrupting compounds, raw sewage streams, conventional activated sludge WWTPs, WWTPs effluents

Procedia PDF Downloads 389

Authors: H. Nikzad, S. Yoshitomi

Abstract:

In this paper, the optimal seismic design of reinforced concrete shear wall-frame building structures was done using structural optimization. The optimal section sizes were generated through structural optimization based on linear static analysis conforming to American Concrete Institute building design code (ACI 318-14). An analytical procedure was followed to validate the accuracy of the proposed method by comparing stresses on structural members through output files of MATLAB and ETABS. In order to consider the difference of stresses in structural elements by ETABS and MATLAB, and to avoid over-stress members by ETABS, a stress constraint ratio of MATLAB to ETABS was modified and introduced for the most critical load combinations and structural members. Moreover, seismic design of the structure was done following the International Building Code (IBC 2012), American Concrete Institute Building Code (ACI 318-14) and American Society of Civil Engineering (ASCE 7-10) standards. Typical reinforcement requirements for the structural wall, beam and column were discussed and presented using ETABS structural analysis software. The placement and detailing of reinforcement of structural members were also explained and discussed. The outcomes of this study show that the modification of section sizes play a vital role in finding an optimal combination of practical section sizes. In contrast, the optimization problem with size constraints has a higher cost than that of without size constraints. Moreover, the comparison of optimization problem with that of ETABS program shown to be satisfactory and governed ACI 318-14 building design code criteria.

Keywords: structural optimization, seismic design, linear static analysis, etabs, matlab, rc shear wall-frame structures

Procedia PDF Downloads 157

Authors: Elvis Nyirenda

Abstract:

This research study work was done to evaluate and propose an optimum measure to enhance the uptake of clean energy technologies such as solar photovoltaics, the study also aims at enhancing the country’s energy mix from the overdependence on hydro power which is susceptible to droughts and climate change challenges The country in the years 2015 - 2016 and 2018 - 2019 had received rainfall below average due to climate change and a shift in the weather pattern; this resulted in prolonged power outages and load shedding for more than 10 hours per day. ZESCO Limited, the utility company that owns infrastructure in the generation, transmission, and distribution of electricity (state-owned), is seeking alternative sources of energy in order to reduce the over-dependence on hydropower stations. One of the alternative sources of energy is Solar Energy from the sun. However, solar power is intermittent in nature and to smoothen the load curve, investment in robust energy storage facilities is of great importance to enhance security and reliability of electricity supply in the country. The methodology of the study looked at the historical performance of the Kafue gorge upper power station and utilised the hourly generation figures as input data for generation modelling in Homer software. The average yearly demand was derived from the available data on the system SCADA. The two dams were modelled as natural battery with the absolute state of charging and discharging determined by the available water resource and the peak electricity demand. The software Homer Energy System is used to simulate the scheme incorporating a pumped storage facility and Solar photovoltaic systems. The pumped hydro scheme works like a natural battery for the conservation of water, with the only losses being evaporation and water leakages from the dams and the turbines. To address the problem of intermittency on the solar resource and the non-availability of water for hydropower generation, the study concluded that utilising the existing Hydro power stations, Kafue Gorge upper and Kafue Gorge Lower to work conjunctively with Solar energy will reduce power deficits and increase the security of supply for the country. An optimum capacity of 350MW of solar PV can be integrated while operating Kafue Gorge power station in both generating and pumping mode to enable efficient utilisation of water at Kafue Gorge upper Dam and Kafue Gorge Lower dam.

Keywords: hydropower, solar power systems, energy storage, photovoltaics, solar irradiation, pumped hydro storage system, supervisory control and data acquisition, Homer energy

Procedia PDF Downloads 100

Authors: Sulyman Abdulhakeem Olarewaju, S. O. Malomo, M. T. Yakubu, J. O. Akolade

Abstract:

The ameliorative effect of Celosia argentea var. cristata leaf extract against cadmium (Cd) induced oxidative stress and toxicity in selected tissues of rats was investigated. Toxicity coupled with oxidative stress was induced in rats by oral administration of Cd (8 mg/kg b. wt). Preliminary quantitative phytochemical and in vitro antioxidant analyses showed that the methanolic extract of C. argentea leaves was constituted by polyphenols (5.72%), saponins (3.20%), tannins (0.65%) and cadenolides (0.006%). IC50 of 9800, 7406, and 45.04 μg/ml were recorded for inhibition of linoleic acid oxidation, 2, 2-diphenyl-1-picrylhydrazyl and hydrogen peroxide radicals respectively. Simultaneous administration of C. argentea leaf extract with Cd significantly attenuated Cd-induced elevation of serum enzyme markers such as aspartate and alanine transaminase, alkaline and acid phosphatase as well as γ-glutaryltransferase in a dose-dependent fashion, while their reduced level in the liver were significantly increased. Higher levels of enzymatic antioxidants; superoxide dismutase and catalase activities were observed in the liver, brain, kidney and testes of the Cd-induced rats treated with C. argentea extract, while lipid peroxidation expressed in malondialdehyde concentrations were lower when compared to values in rats administered Cd only. Other Cd-induced toxicity and stress markers in the serum viz. reduced uric acid and albumin levels as well as elevated total and unconjugated bilirubin were attenuated by the extract and their values compared favorably with those animals co-administered cadmium with ascorbic acid. Data from the study showed that oral administration of extract from the leaf C. argentea may ameliorate Cd-induced oxidative stress and toxicity in rats.

Keywords: toxicity, cadmium, celosia, antioxidants, oxidative stress

Procedia PDF Downloads 324

Authors: Mohamed Yousef, Magdy Samuel, Maha El-Meligy, Taher El-Bitar

Abstract:

The present work is dealing with 2% Si-steel alloy. The alloy contains 0.05% C as well as 0.85% Al. The alloy under investigation would be used for electrical transformation purposes. A heating (expansion) - cooling (contraction) dilation investigation was executed to detect the a, a+g, and g transformation temperatures at the inflection points of the dilation curve. On heating, primary a  was detected at a temperature range between room temperature and 687 ^oC. The domain of a+g was detected in the range between 687 ^oC and 746 ^oC. g phase exists in the closed g region at the range between 746 ^oC and 1043 ^oC. The domain of a phase appears again at a temperature range between 1043 and 1105 ^oC, and followed by secondary a at temperature higher than 1105 ^oC. A physical simulation of thermo-mechanical processing on the as-cast alloy was carried out. The simulation process took into consideration the hot flat rolling pilot plant parameters. The process was executed on the thermo-mechanical simulator (Gleeble 3500). The process was designed to include seven consecutive passes. The 1^st pass represents the roughing stage, while the remaining six passes represent finish rolling stage. The whole process was executed at the temperature range from 1100 ^oC to 900 ^oC. The amount of strain starts with 23.5% at the roughing pass and decreases continuously to reach 7.5 % at the last finishing pass. The flow curve of the alloy can be abstracted from the stress-strain curves representing simulated passes. It shows alloy hardening from a pass to the other up to pass no. 6, as a result of decreasing the deformation temperature and increasing of cumulative strain. After pass no. 6, the deformation process enhances the dynamic recrystallization phenomena to appear, where the z-parameter would be high.

Keywords: si- steel, hot deformability, critical transformation temperature, physical simulation, thermo-mechanical processing, flow curve, dynamic softening.

Procedia PDF Downloads 230