Search results for: frost resistance of samples
7127 Processing, Nutritional Assessment and Sensory Evaluation of Bakery Products Prepared from Orange Fleshed Sweet Potatoes (OFSP) and Wheat Composite Flours
Authors: Hategekimana Jean Paul, Irakoze Josiane, Ishimweyizerwe Valentin, Iradukunda Dieudonne, Uwanyirigira Jeannette
Abstract:
Orange fleshed sweet potatoes (OFSP) are highly grown and are available plenty in rural and urban local markets and its contribution in reduction of food insecurity in Rwanda is considerable. But the postharvest loss of this commodity is a critical challenge due to its high perishability. Several research activities have been conducted on how fresh food commodities can be transformed into extended shelf life food products for prevention of post-harvest losses. However, such activity was not yet well studied in Rwanda. The aim of the present study was the processing of backed products from (OFSP)combined with wheat composite flour and assess the nutritional content and consumer acceptability of new developed products. The perishability of OFSP and their related lack during off season can be eradicated by producing cake, doughnut and bread with OFSP puree or flour. The processing for doughnut and bread were made by making OFSP puree and other ingredients then a dough was made followed by frying and baking while for cake OFSP was dried through solar dryer to have a flour together with wheat flour and other ingredients to make dough cake and baking. For each product, one control and three experimental samples, (three products in three different ratios (30,40 and50%) of OFSP and the remaining percentage of wheat flour) were prepared. All samples including the control were analyzed for the consumer acceptability (sensory attributes). Most preferred samples (One sample for each product with its control sample and for each OFSP variety) were analyzed for nutritional composition along with control sample. The Cake from Terimbere variety and Bread from Gihingumukungu supplemented with 50% OFSP flour or Puree respectively were most acceptable except Doughnut from Vita variety which was highly accepted at 50% of OFSP supplementation. The moisture, ash, protein, fat, fiber, Total carbohydrate, Vitamin C, reducing sugar and minerals (Sodium, Potassium and Phosphorus.) content was different among products. Cake was rich in fibers (14.71%), protein (6.590%), and vitamin c(19.988mg/100g) compared to other samples while bread found to be rich in reducing sugar with 12.71mg/100g compared to cake and doughnut. Also doughnut was found to be rich in fat content with 6.89% compared to other samples. For sensory analysis, doughnut was highly accepted in ratio of 60:40 compared to other products while cake was least accepted at ratio of 50:50. The Proximate composition and minerals content of all the OFSP products were significantly higher as compared to the control samples.Keywords: post-harvest loss, OFSP products, wheat flour, sensory evaluation, proximate composition
Procedia PDF Downloads 627126 Investigation of Dynamic Mechanical Properties of Jute/Carbon Reinforced Composites
Authors: H. Sezgin, O. B. Berkalp, R. Mishra, J. Militky
Abstract:
In the last few decades, due to their advanced properties, there has been an increasing interest in hybrid composite materials. In this study, the effect of different stacking sequences of jute and carbon fabric plies on dynamic mechanical properties of composite laminates were investigated. Vacuum bagging system was used to fabricate the composite samples. Each composite laminate was reinforced with two plies of jute fabric and two plies of carbon fabric by varying the position of layers. Dynamic mechanical analyzer (DMA) was used to examine the dynamic mechanical properties of composite laminates with increasing temperature. Results showed that the composite sample, which has carbon fabric at the outer layers, has the highest storage and loss modulus. Besides, it was observed that glass transition temperature (Tg) of samples are close to each other and at about 75 °C.Keywords: differential scanning calorimetry dynamic mechanical analysis, textile reinforced composites, thermogravimetric analysis
Procedia PDF Downloads 3037125 In Vivo Evaluation of the Therapeutic Effect on Intestinal Disorders by Thermophilic Streptococcus Isolated from Camel Milk
Authors: A. T. Laiche, M. L. Tlil, Benine B., S. Bechoua
Abstract:
The aim of this study is to isolate and select, from camel milk from El-Oued region in Algeria, a strains of lactic acid bacteria and possessing probiotic properties ; and to evaluate their potential effect on intestinal disorders in Wistar ratsmThe results relating to the selection of probiotic strains confirms that the Thermophilic streptococcus exhibits the best probiotic activity performance, with a resistance important to different degrees of pH and to bile salts, and a remarkable antibacterial activity and resistance to antibiotics compared to the other four isolated strains. In the in vivo study, diseases are induced in rats at the level of the digestive system, it was reported that the administration of Escherichia coli and castor oil caused an intestinal disorders. The microscopic observation of the histological section of the intestine showed a damaged intestinal structure and some symptoms of its irritation, including a decrease in the height of the villi and the presence of others destroyed cells, and after treatment with Streptococcus thermophilus, the microscopic observation of the cut of the histological section of the intestine showed almost complete disappearance of the mentioned symptoms, The dosage of the hematological parameters by complete blood count (CBC) is in agreement with the results of the histological sections.Keywords: camel milk, probiotic, pathogenic bacteria, intestinal disorders, lactic acid bacteria
Procedia PDF Downloads 1587124 An Improved Circulating Tumor Cells Analysis Method for Identifying Tumorous Blood Cells
Authors: Salvador Garcia Bernal, Chi Zheng, Keqi Zhang, Lei Mao
Abstract:
Circulating Tumor Cells (CTC) is used to detect tumoral cell metastases using blood samples of patients with cancer (lung, breast, etc.). Using an immunofluorescent method a three channel image (Red, Green, and Blue) are obtained. These set of images usually overpass the 11 x 30 M pixels in size. An aided tool is designed for imaging cell analysis to segmented and identify the tumorous cell based on the three markers signals. Our Method, it is cell-based (area and cell shape) considering each channel information and extracting and making decisions if it is a valid CTC. The system also gives information about number and size of tumor cells found in the sample. We present results in real-life samples achieving acceptable performance in identifying CTCs in short time.Keywords: Circulating Tumor Cells (CTC), cell analysis, immunofluorescent, medical image analysis
Procedia PDF Downloads 2147123 Insect Inducible Methanol Production in Plants for Insect Resistance
Authors: Gourav Jain, Sameer Dixit, Surjeet Kumar Arya, Praveen C. Verma
Abstract:
Plant cell wall plays a major role in defence mechanism against biotic and abiotic stress as it constitutes the physical barrier between the microenvironment and internal component of the cell. It is a complex structure composed of mostly carbohydrates among which cellulose and hemicelluloses are most abundant that is embedded in a matrix of pectins and proteins. Multiple enzymes have been reported which plays a vital role in cell wall modification, Pectin Methylesterase (PME) is one of them which catalyses the demethylesterification of homogalacturonans component of pectin which releases acidic pectin and methanol. As emitted methanol is toxic to the insect pest, we use PME gene for the better methanol production. In the current study we showed overexpression of PME gene isolated from Withania somnifera under the insect inducible promoter causes enhancement of methanol production at the time of insect feeds to plants, and that provides better insect resistance property. We found that the 85-90% mortality causes by transgenic tobacco in both chewing (Spodoptera litura larvae and Helicoverpa armigera) and sap-sucking (Aphid, mealybug, and whitefly) pest. The methanol content and emission level were also enhanced by 10-15 folds at different inducible time point interval (15min, 30min, 45min, 60min) which would be analysed by Purpald/Alcohol Oxidase method.Keywords: methanol, Pectin methylesterase, inducible promoters, Purpald/Alcohol oxidase
Procedia PDF Downloads 2447122 Characteristics of Pore Pressure and Effective Stress Changes in Sandstone Reservoir Due to Hydrocarbon Production
Authors: Kurniawan Adha, Wan Ismail Wan Yusoff, Luluan Almanna Lubis
Abstract:
Preventing hazardous events during oil and gas operation is an important contribution of accurate pore pressure data. The availability of pore pressure data also contribute in reducing the operation cost. Suggested methods in pore pressure estimation were mostly complex by the many assumptions and hypothesis used. Basic properties which may have significant impact on estimation model are somehow being neglected. To date, most of pore pressure determinations are estimated by data model analysis and rarely include laboratory analysis, stratigraphy study or core check measurement. Basically, this study developed a model that might be applied to investigate the changes of pore pressure and effective stress due to hydrocarbon production. In general, this paper focused velocity model effect of pore pressure and effective stress changes due to hydrocarbon production with illustrated by changes in saturation. The core samples from Miri field from Sarawak Malaysia ware used in this study, where the formation consists of sandstone reservoir. The study area is divided into sixteen (16) layers and encompassed six facies (A-F) from the outcrop that is used for stratigraphy sequence model. The experimental work was firstly involving data collection through field study and developing stratigraphy sequence model based on outcrop study. Porosity and permeability measurements were then performed after samples were cut into 1.5 inch diameter core samples. Next, velocity was analyzed using SONIC OYO and AutoLab 500. Three (3) scenarios of saturation were also conducted to exhibit the production history of the samples used. Results from this study show the alterations of velocity for different saturation with different actions of effective stress and pore pressure. It was observed that sample with water saturation has the highest velocity while dry sample has the lowest value. In comparison with oil to samples with oil saturation, water saturated sample still leads with the highest value since water has higher fluid density than oil. Furthermore, water saturated sample exhibits velocity derived parameters, such as poisson’s ratio and P-wave velocity over S-wave velocity (Vp/Vs) The result shows that pore pressure value ware reduced due to the decreasing of fluid content. The decreasing of pore pressure result may soften the elastic mineral frame and have tendency to possess high velocity. The alteration of pore pressure by the changes in fluid content or saturation resulted in alteration of velocity value that has proportionate trend with the effective stress.Keywords: pore pressure, effective stress, production, miri formation
Procedia PDF Downloads 2907121 Concentration of Zinc Micronutrients in Breast Milk Based on Determinant of Mother and Baby in Kassi-Kassi Health Center
Authors: Andi Tenri Ayu Rahman, Citrakesumasari, Devintha Virani
Abstract:
Breast milk is the complex biological fluid mix of macronutrient and micronutrient that are considered as perfect food for babies. Zinc has a role in various biological functions and physical growth. This research aims to know the average zinc (Zn) micronutrients content of breast milk by determinants of infant (birth weight) and mother (nutritional status and food intake) and description of the pattern of mothers breastfeeding. The type of research used is observational analytic with cross-sectional study design. The population was 41 mothers in Kassi-Kassi health center within one month. Sample research is mothers who gave birth at term and breastfed her baby. Sampling was done with random sampling technique involving 37 people. Samples of breast milk were analyzed in the laboratory by using the method of Atomic Absorption Spectrofotometry (AAS). This research find that from the samples (n=37) the average contents of zinc in the breast milk is 0,88±0,54 mg/L with the highest value on the group of low birth weight babies (1,13 ± 0,67mg/L), mothers who had normal nutritional status (0,981 ± 0,514 mg/L) and intake low zinc (0,94 ± 0,54 mg/L). Regarding breastfeeding pattern, 67,6% of the samples had had breastfeeding experience and 81,1% of breastfed more than eight times a day. In summary, the highest average value of the zinc content of breast milk was in the group of low birth weight babies, mother with normal nutritional status, and mothers having relatively low intake pattern.Keywords: zinc, breastmilk, mother, baby
Procedia PDF Downloads 1917120 Literature Review on the Antibacterial Effects of Salvia officinalis L.
Authors: Benguerine Zohra, Merzak Siham, Pr. Chelghoum
Abstract:
Introduction: The widespread production and consumption of antibiotics have raised significant concerns due to various adverse effects and the development of bacterial resistance. This increasing resistance to currently available antibiotics necessitates the search for new antibacterial agents. One alternative strategy to combat antibiotic-resistant bacteria is the use of natural antimicrobial substances such as plant extracts. This study aims to provide an overview of the antibacterial effects of Salvia officinalis (sage), a plant native to the Middle East and Mediterranean regions. Materials and Methods: This review was conducted by searching studies in databases such as PubMed, Scopus, JSTOR, and SpringerLink. The search terms were “Salvia officinalis L.” and “antibacterial effects.” Only studies that met our inclusion criteria (in English, focusing on the antibacterial effects of Salvia officinalis L., and primarily dated from 2012 to 2023) were considered for further review. Results and Discussion: The initial search strategy identified approximately 78 references, of which only 13 articles were included in this review. The synthesis of these articles revealed that multiple data sources confirm the antimicrobial effects of S. officinalis. Its essential oil and alcoholic extract exhibit strong bactericidal and bacteriostatic effects against both Gram-positive and Gram-negative bacteria. Conclusion: The significant value of the extract, oil, and leaves of S. officinalis demands further studies on other useful and unknown properties of this multipurpose plant.Keywords: salvia officinalis, literature review, antibacterial., botany
Procedia PDF Downloads 307119 Nonlinear Response of Infinite Beams on a Multilayer Tensionless Extensible Geosynthetic – Reinforced Earth Bed under Moving Load
Authors: K. Karuppasamy
Abstract:
In this paper analysis of an infinite beam resting on multilayer tensionless extensible geosynthetic reinforced granular fill - poor soil system overlying soft soil strata under moving the load with constant velocity is presented. The beam is subjected to a concentrated load moving with constant velocity. The upper reinforced granular bed is modeled by a rough membrane embedded in Pasternak shear layer overlying a series of compressible nonlinear Winkler springs representing the underlying the very poor soil. The multilayer tensionless extensible geosynthetic layer has been assumed to deform such that at the interface the geosynthetic and the soil have some deformation. Nonlinear behavior of granular fill and the very poor soil has been considered in the analysis by means of hyperbolic constitutive relationships. Governing differential equations of the soil foundation system have been obtained and solved with the help of appropriate boundary conditions. The solution has been obtained by employing finite difference method by means of Gauss-Siedel iterative scheme. Detailed parametric study has been conducted to study the influence of various parameters on the response of soil – foundation system under consideration by means of deflection and bending moment in the beam and tension mobilized in the geosynthetic layer. These parameters include the magnitude of applied load, the velocity of the load, damping, the ultimate resistance of the poor soil and granular fill layer. The range of values of parameters has been considered as per Indian Railways conditions. This study clearly observed that the comparisons of multilayer tensionless extensible geosynthetic reinforcement with poor foundation soil and magnitude of applied load, relative compressibility of granular fill and ultimate resistance of poor soil has significant influence on the response of soil – foundation system. However, for the considered range of velocity, the response has been found to be insensitive towards velocity. The ultimate resistance of granular fill layer has also been found to have no significant influence on the response of the system.Keywords: infinite beams, multilayer tensionless extensible geosynthetic, granular layer, moving load and nonlinear behavior of poor soil
Procedia PDF Downloads 4387118 Determining the Nitrogen Mineralization Rate by Industrially Manufactured Organic Fertilizers on Alfisol in Southwestern Nigeria
Authors: Ayeni Leye Samuel
Abstract:
Laboratory incubation study was carried out at Adeyemi College of Education, Ondo Southwestern Nigeria to determine the rate of NO3-N, NH4-N, total N, OC and available P released to the soil samples collected from Okitipupa mangrove forest. The soil samples were incubated with organic (OG), organomineral (OMF) and NPK 15:15:15 (NPKF) fertilizers. Organic and organomineral fertilizers were separately applied at the rate of 0, 0.25 and 0.5mg/100 g soil while NPKF was applied at the rate of 0.002g/100g soil. The treatments were replicated three times and arranged on CRD. The treatments were incubated for 90 days. Compared with control, OG and NPKF at all rates significantly increased (p<0.05) soil NH4-N, NO3-N, total N and available P. The order of increase in NH4-N were 10t/ha OMF> 5t/ha OMF> 5t/ha OG>10t/ha OG>control>400 kg/ha while the order of increase in NO3-N were 5t/ha OMF>10t/ha OMF>10t/ha OG>5t/ha OG>control>400 kg/ha NPKF. 5t/ha OMF had the highest, 5t/ha OMF recorded the highest pH, 5t/ha OG had the highest OC while 10t/ha OG had the highest available P.Keywords: c/n ratio, immobilization, incubation study, organomineral fertilizer
Procedia PDF Downloads 3257117 Intervention To Prevent Infections And Reinfections With Intestinal Parasites In People Living With Human Immunodeficiency Virus In Some Parts Of Eastern Cape, South Africa
Authors: Ifeoma Anozie, Teka Apalata, Dominic Abaver
Abstract:
Introduction: Despite use of Anti-retroviral therapy to reduce the incidence of opportunistic infections among HIV/AIDS patients, rapid episodes of re-infection after deworming are still common occurrences because pharmaceutical intervention alone does not prevent reinfection. Unsafe water and inadequate personal hygiene and parasitic infections are widely expected to accelerate the progression of HIV infection. This is because the chronic immunosuppression of HIV infection encourages susceptibility to opportunistic (including parasitic) infections which is linked to CD4+ cell count of <200 cells/μl. Intestinal parasites such as G. intestinalis and Entamoeba spp are ubiquitous protozoa that remain infectious over a long time in an environment and show resistance to standard disinfection. To control re-infection, the social factors that underpin the prevention need to be controlled. This study aims at prevention of intestinal parasites in people living with HIV/AIDS by using a treatment, hygiene education and sanitation (THEdS) bundle approach. Methods: This study was conducted in four clinics (Ngangelizwe health centre, Tsolo gateway clinic, Idutywa health centre and Nqamakwe health centre) across the seven districts in Eastern cape, South Africa. The four clinics were divided in two: experimental and control, for the purpose of intervention. Data was collected from March 2019 to February 2020. Six hundred participants were screened for intestinal parasitic infections. Stool samples were collected and analysed twice: before (Pre-test infection screening) and after (Post-test re-infection) THEdS bundle intervention. The experimental clinics received full intervention package, which include therapeutic treatment, health education on personal hygiene and sanitation training, while the control clinics received only therapeutic treatment for those found with intestinal parasitic infections. Results: Baseline prevalence of Intestinal Parasites isolated shows 12 intestinal parasites with overall frequency of 65, with Ascaris lumbricoides having most frequency (44.6%). The intervention had a cure rate of 60%, with odd ratio of 1.42, which indicates that the intervention group is 1.42 times more likely of parasite clearing as compared to the control group. The relative risk ratio of 1.17 signifies that there is 1.17 times more likelihood to clear intestinal parasite if there no intervention. Discussion and conclusion: Infection with multiple parasites can cause health defects, especially among HIV/AIDS patients. Efficiency of some HIV vaccines in HIV/AIDS patients is affected because treatment of re-infection amplifies drug resistance, affects the efficacy of the front-line drugs, and still permits transmission. In South Africa, treatment of intestinal parasites is usually offered to clinic attending HIV/AIDS patients upon suspicion but not as a mandate for patients being initiated into Antiretroviral (ART) program. The effectiveness of THEdS bundle advocates for inclusiveness of mandatory screening for intestinal parasitic infections among attendees of HIV/Aids clinics on regular basis.Keywords: cure rate, , HIV/AIDS patients, intestinal parasites, intervention studies, reinfection rate
Procedia PDF Downloads 767116 Comparative Analysis of the Antioxidant Capacities of Pre-Germinated and Germinated Pigmented Rice (Oryza sativa L. Cv. Superjami and Superhongmi)
Authors: Soo Im Chung, Lara Marie Pangan Lo, Yao Cheng Zhang, Su Jin Nam, Xingyue Jin, Mi Young Kang
Abstract:
Rice (Oryza sativa L.) is one of the most widely consumed grains. Due to the growing number of demand as a potential functional food and nutraceutical source and the increasing awareness of people towards healthy diet and good quality of living, more researches dwell upon the development of new rice cultivars for population consumption. However, studies on the antioxidant capacities of newly developed rice were limited as well as the effects of germination in these rice cultivars. Therefore, this study aimed to focus on analysis of the antioxidant potential of pre-germinated and germinated pigmented rice cultivars in South Korea such as purple cultivar Superjami (SJ) and red cultivar Super hongmi (SH) in comparison with the non-pigmented Normal Brown (NB) Rice. The powdered rice grain samples were extracted with 80% methanol and their antioxidant activities were determined. The Results showed that pre-germinated pigmented rice cultivars have higher Fe2+ Chelating Ability (Fe2+), Reducing Power (RP), 2,2´-azinobis[3-ethylbenzthiazoline]-6-sulfonic acid (ABTS) radical scavenging and Superoxide Dismutase activity than the control NB rice. Moreover, it is revealed that germination process induced a significant increased in the antioxidant activities of all the rice samples regardless of their strains. Purple rice SJ showed greater Fe2+ (88.82 + 0.53%), RP (0.82 + 0.01) , ABTS (143.63 + 2.38 mg VCEAC/100 g) and SOD (59.31 + 0.48%) activities than the red grain SH and the control NB having the lowest antioxidant potential among the three (3) rice samples examined. The Effective concentration at 50% (EC50) of 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) and Hydroxyradical (-OH) Scavenging activity for the rice samples were also obtained. SJ showed lower EC50 in terms of its DPPH (3.81 + 0.15 mg/mL) and –OH (5.19 + 0.08 mg/mL) radical scavenging activities than the red grain SH and control NB rice indicating that at lower concentrations, it can readily exhibit antioxidant effects against reactive oxygen species (ROS). These results clearly suggest the higher antioxidant potential of pigmented rice varieties as compared with the widely consumed NB rice. Also, it is revealed in the study that even at lower concentrations, pigmented rice varieties can exhibit their antioxidant activities. Germination process further enhanced the antioxidant capacities of the rice samples regardless of their types. With these results at hand, these new rice varieties can be further developed as a good source of bio functional elements that can help alleviate the growing number of cases of metabolic disorders.Keywords: antioxidant capacity, germinated rice, pigmented rice, super hongmi, superjami
Procedia PDF Downloads 4447115 Identification of Babesia ovis Through Polymerase Chain Reaction in Sheep and Goat in District Muzaffargarh, Pakistan
Authors: Muhammad SAFDAR, Mehmet Ozaslan, Musarrat Abbas Khan
Abstract:
Babesiosis is a haemoparasitic disease due to the multiplication of protozoan’s parasite, Babesia ovis in the red blood cells of the host, and contributes numerous economical losses, including sheep and goat ruminants. The early identification and successful treatment of Babesia Ovis spp. belong to the key steps of control and health management of livestock resources. The objective of this study was to construct a polymerase chain reaction (PCR) based method for the detection of Babesia spp. in small ruminants and to determine the risk factors involved in the spreading of babesiosis infections. A total of 100 blood samples were collected from 50 sheep and 50 goats along with different areas of Muzaffargarh, Pakistan, from randomly selected herds. Data on the characteristics of sheep and goats were collected through questionnaires. Of 100 blood samples examined, 18 were positive for Babesia ovis upon microscopic studies, whereas 11 were positive for the presence of Babesia spp. by PCR assay. For the recognition of parasitic DNA, a set of 500bp oligonucleotide was designed by PCR amplification with sequence 18S rRNA gene for B. ovis. The prevalence of babesiosis in small ruminant’s sheep and goat detected by PCR was significantly higher in female animals (28%) than male herds (08%). PCR analysis of the reference samples showed that the detection limit of the PCR assay was 0.01%. Taken together, all data indicated that this PCR assay was a simple, fast, specific detection method for Babesia ovis species in small ruminants compared to other available methods.Keywords: Babesia ovis, PCR amplification, 18S rRNA, sheep and goat
Procedia PDF Downloads 1277114 Assessment of Knowledge, Attitude and Perception of Drug Resistance in Rural Communities of ADA District, Central Ethiopia
Authors: Argaw Amare, Abbuna Fuffa, Stringer Andy
Abstract:
Improving public knowledge and changing their attitudes towards antibiotic use will be a crucial early strategy to contain Antibiotic resistance. The current study was undertaken from November 2015 to June 2016. A cross-sectional survey using a pretested questionnaire was conducted on 392 residents (330 male and 62 female) aged 18 and above. Participants were selected randomly. Data was analyzed using simple descriptive statistics; the Chi-square test was used to determine any significant difference. The majority of participants (81%) were farmers in their occupation. Most of the respondents (76%) were not able to define the difference between antimicrobials and antibiotics. Furthermore, (61%) of participants were not able to define what antibiotics and for what purpose they are used. Thirty-four percent of participants do not know the names of antibiotics they have used for their animals and for themselves. Nearly 68% have no knowledge about the disease they have been treated for. The majority of participants (73.5%) agree to complete their course of treatment even if they feel better. About 72.5% of participants disagree that antibiotics are safe and can be used to treat different diseases, without prescription. Most of the participants (95%) treat their animals after diagnosis; more than 80% of them agree to not purchase veterinary drugs from local traders. This study showed that the participants have poor knowledge and good attitude, with an average score of 41.3±16.1% and 79.6±16, respectively. Knowledge and attitude are significantly correlated (p<0.01). The participants in this study had a good attitude toward the rational use of antibiotics. Whereas they lack knowledge with regard to the kinds of antibiotics and the diseases they are prescribed for. Therefore, further educational interventions are necessary to improve their understanding of the antibiotics currently available and the major bacterial diseases they are prescribed.Keywords: AMR, knoweledge, attitude, perception
Procedia PDF Downloads 677113 Experimental Investigation and Analysis of Wear Parameters on Al/Sic/Gr: Metal Matrix Hybrid Composite by Taguchi Method
Authors: Rachit Marwaha, Rahul Dev Gupta, Vivek Jain, Krishan Kant Sharma
Abstract:
Metal matrix hybrid composites (MMHCs) are now gaining their usage in aerospace, automotive and other industries because of their inherent properties like high strength to weight ratio, hardness and wear resistance, good creep behaviour, light weight, design flexibility and low wear rate etc. Al alloy base matrix reinforced with silicon carbide (10%) and graphite (5%) particles was fabricated by stir casting process. The wear and frictional properties of metal matrix hybrid composites were studied by performing dry sliding wear test using pin on disc wear test apparatus. Experiments were conducted based on the plan of experiments generated through Taguchi’s technique. A L9 Orthogonal array was selected for analysis of data. Investigation to find the influence of applied load, sliding speed and track diameter on wear rate as well as coefficient of friction during wearing process was carried out using ANOVA. Objective of the model was chosen as smaller the better characteristics to analyse the dry sliding wear resistance. Results show that track diameter has highest influence followed by load and sliding speed.Keywords: Taguchi method, orthogonal array, ANOVA, metal matrix hybrid composites
Procedia PDF Downloads 3297112 Seroprevalence of Cytomegalovirus among Pregnant Women in Islamabad, Pakistan
Authors: Hassan Waseem
Abstract:
Cytomegalovirus (CMV) is ubiquitously distributed viral agent responsible for different clinical manifestations that may vary according to the immunologic status of the patient. CMV can cause morbidity and mortality among fetuses and patients with compromised immune system. A cross-sectional study was carried out in Islamabad to investigate the prevalence and risk factors associated with CMV infection among pregnant women. Blood samples of 172 pregnant women visiting Mother and Child Healthcare, Pakistan Institute of Medical Sciences (PIMS) Islamabad were taken. In present study, serum samples of the women were checked for CMV-specific IgG and IgM antibodies by enzyme linked immunosorbent assay (ELISA). Clinical, obstetrical and socio-demographical characteristics of the women were collected by using structured questionnaires. Out of 172 pregnant women included in the study, 171 (99.4%) were CMV specific IgG positive and 30 (17.4%) were found positive for CMV-IgM antibodies. The CMV has taken an endemic form in Pakistan so, routine screening of CMV among pregnant women is recommended.Keywords: Cytomegalovirus, blood transfusion, ELISA, seroprevalence
Procedia PDF Downloads 3657111 Multi-Elemental Analysis Using Inductively Coupled Plasma Mass Spectrometry for the Geographical Origin Discrimination of Greek Giant Beans “Gigantes Elefantes”
Authors: Eleni C. Mazarakioti, Anastasios Zotos, Anna-Akrivi Thomatou, Efthimios Kokkotos, Achilleas Kontogeorgos, Athanasios Ladavos, Angelos Patakas
Abstract:
“Gigantes Elefantes” is a particularly dynamic crop of giant beans cultivated in western Macedonia (Greece). This variety of large beans growing in this area and specifically in the regions of Prespes and Kastoria is a protected designation of origin (PDO) species with high nutritional quality. Mislabeling of geographical origin and blending with unidentified samples are common fraudulent practices in Greek food market with financial and possible health consequences. In the last decades, multi-elemental composition analysis has been used in identifying the geographical origin of foods and agricultural products. In an attempt to discriminate the authenticity of Greek beans, multi-elemental analysis (Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, Ge, K, Li, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, Re, Se, Sr, Ta, Ti, Tl, U, V, W, Zn, Zr) was performed by inductively coupled plasma mass spectrometry (ICP-MS) on 320 samples of beans, originated from Greece (Prespes and Kastoria), China and Poland. All samples were collected during the autumn of 2021. The obtained data were analysed by principal component analysis (PCA), an unsupervised statistical method, which allows for to reduce of the dimensionality of the enormous datasets. Statistical analysis revealed a clear separation of beans that had been cultivated in Greece compared with those from China and Poland. An adequate discrimination of geographical origin between bean samples originating from the two Greece regions, Prespes and Kastoria, was also evident. Our results suggest that multi-elemental analysis combined with the appropriate multivariate statistical method could be a useful tool for bean’s geographical authentication. Acknowledgment: This research has been financed by the Public Investment Programme/General Secretariat for Research and Innovation, under the call “YPOERGO 3, code 2018SE01300000: project title: ‘Elaboration and implementation of methodology for authenticity and geographical origin assessment of agricultural products.Keywords: geographical origin, authenticity, multi-elemental analysis, beans, ICP-MS, PCA
Procedia PDF Downloads 787110 Multivariate Analysis of Spectroscopic Data for Agriculture Applications
Authors: Asmaa M. Hussein, Amr Wassal, Ahmed Farouk Al-Sadek, A. F. Abd El-Rahman
Abstract:
In this study, a multivariate analysis of potato spectroscopic data was presented to detect the presence of brown rot disease or not. Near-Infrared (NIR) spectroscopy (1,350-2,500 nm) combined with multivariate analysis was used as a rapid, non-destructive technique for the detection of brown rot disease in potatoes. Spectral measurements were performed in 565 samples, which were chosen randomly at the infection place in the potato slice. In this study, 254 infected and 311 uninfected (brown rot-free) samples were analyzed using different advanced statistical analysis techniques. The discrimination performance of different multivariate analysis techniques, including classification, pre-processing, and dimension reduction, were compared. Applying a random forest algorithm classifier with different pre-processing techniques to raw spectra had the best performance as the total classification accuracy of 98.7% was achieved in discriminating infected potatoes from control.Keywords: Brown rot disease, NIR spectroscopy, potato, random forest
Procedia PDF Downloads 1907109 Chemical, Structural and Mechanical Optimization of Zr-Based Bulk Metallic Glass for Biomedical Applications
Authors: Eliott Guérin, Remi Daudin, Georges Kalepsi, Alexis Lenain, Sebastien Gravier, Benoit Ter-Ovanessian, Damien Fabregue, Jean-Jacques Blandin
Abstract:
Due to interesting compromise between mechanical and corrosion properties, Zr-based BMGs are attractive for biomedical applications. However, the enhancement of their glass forming ability (GFA) is often achieved by addition of toxic elements like Ni or Be, which is of course a problem for such applications. Consequently, the development of Ni-free Be-free Zr-based BMGs is of great interest. We have developed a Zr-based (Ni and Be-free) amorphous metallic alloy with an elastic limit twice the one of Ti-6Al-4V. The Zr56Co28Al16 composition exhibits a yield strength close to 2 GPa and low Young’s modulus (close to 90 GPa) [1-2]. In this work, we investigated Niobium (Nb) addition through substitution of Zr up to 8 at%. Cobalt substitution has already been reported [3], but we chose Zr substitution to preserve the glass forming ability. In this case, we show that the glass forming ability for 5 mm diameters rods is maintained up to 3 at% of Nb substitution using suction casting in cooper moulds. Concerning the thermal stability, we measure a strong compositional dependence on the glass transition (Tg). Using DSC analysis (heating rate 20 K/min), we show that the Tg rises from 752 K for 0 at% of Nb to 759 K for 3 at% of Nb. Yet, the thermal range between Tg and the crystallisation temperature (Tx) remains almost unchanged from 33 K to 35 K. Uniaxial compression tests on 2 mm diameter pillars and 3 points bending (3PB) tests on 1 mm thick plates are performed to study the Nb addition on the mechanical properties and the plastic behaviour. With these tests, an optimal Nb concentration is found, improving both plasticity and fatigue resistance. Through interpretations of DSC measurements, an attempt is made to correlate the modifications of the mechanical properties with the structural changes. The optimized chemical, structural and mechanical properties through Nb addition are encouraging to develop the potential of this BMG alloy for biomedical applications. For this purpose, we performed polarisation, immersion and cytotoxicity tests. The figure illustrates the polarisation response of Zr56Co28Al16, Zr54Co28Al16Nb2 and TA6V as a reference after 2h of open circuit potential. The results show that the substitution of Zr by a small amount of Nb significantly improves the corrosion resistance of the alloy.Keywords: metallic glasses, amorphous metal, medical, mechanical resistance, biocompatibility
Procedia PDF Downloads 1497108 Chromium-Leaching Study of Cements in Various Environments
Authors: Adriana Estokova, Lenka Palascakova, Martina Kovalcikova
Abstract:
Cement is a basic material used for building construction. Chromium as an indelible non-volatile trace element of raw materials occurs in cement clinker in the trivalent or hexavalent form. Hexavalent form of chromium is harmful and allergenic having very high water solubility and thus can easily come into contact with the human skin. The paper is aimed at analyzing the content of total chromium in Portland cements and leaching rate of hexavalent chromium in various leachants: Deionized water, Britton-Robinson buffer, used to simulate the natural environment, and hydrochloric acid (HCl). The concentration of total chromium in Portland cement samples was in a range from 173.2 to 218.5 mg/kg. The content of dissolved hexavalent chromium ranged 0.23-3.19, 2.0-5.78 and 8.88-16.25 mg/kg in deionized water, Britton-Robinson solution and hydrochloric acid, respectively. The calculated leachable fraction of Cr(VI) from cement samples was observed in the range 0.1--7.58 %.Keywords: environment, cement, chromium, leaching
Procedia PDF Downloads 2777107 Bulk Electrical Resistivity of Geopolymer Mortars: The Effect of Binder Composition and Alkali Concentration
Authors: Mahdi Babaee, Arnaud Castel
Abstract:
One of the main hurdles for commercial adaptation of geopolymer concrete (GPC) as a low-embodied-carbon alternative for Portland cement concrete (PCC) is the durability aspects and its long-term performance in aggressive/corrosive environments. GPC is comparatively a new engineering material and in the absence of a track record of successful durability performance, proper experimental studies to investigate different durability-related characteristics of GPC seem inevitable. In this context, this paper aims to study the bulk electrical resistivity of geopolymer mortars fabricated of blends of low-calcium fly ash (FA) and ground granulated blast-furnace slag (GGBS). Bulk electrical resistivity is recognized as one of the most important parameters influencing the rate of corrosion of reinforcing bars during the propagation phase of corrosion. To investigate the effect of alkali concentration on the resistivity of the samples, 100x200 mm mortar cylinders were cast at different alkali concentration levels, whereas the modulus ratio (the molar ratio of SiO2/Na2O) was fixed for the mixes, and the bulk electrical resistivity was then measured. Also, the effect of the binder composition was assessed with respect to the ratio of FA to GGBS used. Results show a superior performance of samples with higher GGBS content. Lower concentration of the solution has increased the resistivity by reducing the amount of mobile alkali ions in the pore solution. Moreover, GGBS-based samples showed a much sharper increase in the electrical resistivity with decreasing the moisture content.Keywords: bulk resistivity, corrosion, durability, geopolymer concrete
Procedia PDF Downloads 2657106 Suspended Sediment Sources Fingerprinting in Ashebeka River Catchment, Assela, Central Ethiopia
Authors: Getachew Mekaa, Bezatu Mengisteb, Tena Alamirewc
Abstract:
Ashebeka River is the main source of drinking water supply for Assela City and its surrounding inhabitants. Apart from seasonal water reliability disruption, the cost of treating water downstream of the river has been increasing over time due to increased pollutants and suspended sediments. Therefore, this research aimed to identify geo-location and prioritize suspended sediment sources in the Ashebeka River catchment using sediment fingerprinting. We collected 58 composite soil samples and a river water sample for suspended sediment samples from the outlet, which were then filtered using Whatman filter paper. The samples were quantified for geochemical tracers with multi-element capability, and inductively coupled plasma-optical emission spectrometry (ICP-OES). Tracers with significant p-value and that passed the Kruskal-Wallis (KW) test were analyzed for stepwise discriminant function analysis (DFA). The DFA results revealed tracers with good discrimination were subsequently used for the mixed model analysis. The relative significant sediment source contributions from sub-catchments (km2): 3, 4, 1, and 2 were estimated as 49.31% (8), 26.71% (5), 23.65% (5.6), and 0.33% (28.4) respectively. The findings of this study will help the water utilities to prioritize areas of intervention, and the approach used could be followed for catchment prioritization in water safety plan development. Moreover, the findings of this research shed light on the integration of sediment fingerprinting into water safety plans to ensure the reliability of drinking water supplies.Keywords: disruption of drinking water reliability, ashebeka river catchment, sediment fingerprinting, sediment source contribution, mixed model
Procedia PDF Downloads 257105 Extraction and Quantification of Triclosan in Wastewater Samples Using Molecularly Imprinted Membrane Adsorbent
Authors: Siyabonga Aubrey Mhlongo, Linda Lunga Sibali, Phumlane Selby Mdluli, Peter Papoh Ndibewu, Kholofelo Clifford Malematja
Abstract:
This paper reports on the successful extraction and quantification of an antibacterial and antifungal agent present in some consumer products (Triclosan: C₁₂H₇Cl₃O₂)generally found in wastewater or effluents using molecularly imprinted membrane adsorbent (MIMs) followed by quantification and removal on a high-performance liquid chromatography (HPLC). Triclosan is an antibacterial and antifungal agent present in some consumer products like toothpaste, soaps, detergents, toys, and surgical cleaning treatments. The MIMs was fabricated usingpolyvinylidene fluoride (PVDF) polymer with selective micro composite particles known as molecularly imprinted polymers (MIPs)via a phase inversion by immersion precipitation technique. This resulted in an improved hydrophilicity and mechanical behaviour of the membranes. Wastewater samples were collected from the Umbogintwini Industrial Complex (UIC) (south coast of Durban, KwaZulu-Natal in South Africa). central UIC effluent treatment plant and pre-treated before analysis. Experimental parameters such as sample size, contact time, stirring speed were optimised. The resultant MIMs had an adsorption efficiency of 97% of TCS with reference to NIMs and bare membrane, which had 92%, 88%, respectively. The analytical method utilized in this review had limits of detection (LoD) and limits of quantification (LoQ) of 0.22, 0.71µgL-1 in wastewater effluent, respectively. The percentage recovery for the effluent samples was 68%. The detection of TCS was monitored for 10 consecutive days, where optimum TCS traces detected in the treated wastewater was 55.0μg/L inday 9 of the monitored days, while the lowest detected was 6.0μg/L. As the concentrations of analytefound in effluent water samples were not so diverse, this study suggested that MIMs could be the best potential adsorbent for the development and continuous progress in membrane technologyand environmental sciences, lending its capability to desalination.Keywords: molecularly imprinted membrane, triclosan, phase inversion, wastewater
Procedia PDF Downloads 1247104 Investigating the Stylistic Features of Advertising: Ad Design and Creation
Authors: Asma Ben Abdallah
Abstract:
Language has a powerful influence over people and their actions. The language of advertising has a very great impact on the consumer. It makes use of different features from the linguistic continuum. The present paper attempts to apply the theories of stylistics to the analysis of advertising texts. In order to decipher the stylistic features of the advertising discourse, 30 advertising text samples designed by MA Business students have been selected. These samples have been analyzed at the level of design and content. The study brings insights into the use of stylistic devices in advertising, and it reveals that both linguistic and non-linguistic features of advertisements are frequently employed to develop a well-thought-out design and content. The practical significance of the study is to highlight the specificities of the advertising genre so that people interested in the language of advertising (Business students and ESP teachers) will have a better understanding of the nature of the language used and the techniques of writing and designing ads. Similarly, those working in the advertising sphere (ad designers) will appreciate the specificities of the advertising discourse.Keywords: the language of advertising, advertising discourse, ad design, stylistic features
Procedia PDF Downloads 2387103 Delamination Fracture Toughness Benefits of Inter-Woven Plies in Composite Laminates Produced through Automated Fibre Placement
Authors: Jayden Levy, Garth M. K. Pearce
Abstract:
An automated fibre placement method has been developed to build through-thickness reinforcement into carbon fibre reinforced plastic laminates during their production, with the goal of increasing delamination fracture toughness while circumventing the additional costs and defects imposed by post-layup stitching and z-pinning. Termed ‘inter-weaving’, the method uses custom placement sequences of thermoset prepreg tows to distribute regular fibre link regions in traditionally clean ply interfaces. Inter-weaving’s impact on mode I delamination fracture toughness was evaluated experimentally through double cantilever beam tests (ASTM standard D5528-13) on [±15°]9 laminates made from Park Electrochemical Corp. E-752-LT 1/4” carbon fibre prepreg tape. Unwoven and inter-woven automated fibre placement samples were compared to those of traditional laminates produced from standard uni-directional plies of the same material system. Unwoven automated fibre placement laminates were found to suffer a mostly constant 3.5% decrease in mode I delamination fracture toughness compared to flat uni-directional plies. Inter-weaving caused significant local fracture toughness increases (up to 50%), though these were offset by a matching overall reduction. These positive and negative behaviours of inter-woven laminates were respectively found to be caused by fibre breakage and matrix deformation at inter-weave sites, and the 3D layering of inter-woven ply interfaces providing numerous paths of least resistance for crack propagation.Keywords: AFP, automated fibre placement, delamination, fracture toughness, inter-weaving
Procedia PDF Downloads 1847102 Modelling of Phase Transformation Kinetics in Post Heat-Treated Resistance Spot Weld of AISI 1010 Mild Steel
Authors: B. V. Feujofack Kemda, N. Barka, M. Jahazi, D. Osmani
Abstract:
Automobile manufacturers are constantly seeking means to reduce the weight of car bodies. The usage of several steel grades in auto body assembling has been found to be a good technique to enlighten vehicles weight. This few years, the usage of dual phase (DP) steels, transformation induced plasticity (TRIP) steels and boron steels in some parts of the auto body have become a necessity because of their lightweight. However, these steels are martensitic, when they undergo a fast heat treatment, the resultant microstructure is essential, made of martensite. Resistance spot welding (RSW), one of the most used techniques in assembling auto bodies, becomes problematic in the case of these steels. RSW being indeed a process were steel is heated and cooled in a very short period of time, the resulting weld nugget is mostly fully martensitic, especially in the case of DP, TRIP and boron steels but that also holds for plain carbon steels as AISI 1010 grade which is extensively used in auto body inner parts. Martensite in its turn must be avoided as most as possible when welding steel because it is the principal source of brittleness and it weakens weld nugget. Thus, this work aims to find a mean to reduce martensite fraction in weld nugget when using RSW for assembling. The prediction of phase transformation kinetics during RSW has been done. That phase transformation kinetics prediction has been made possible through the modelling of the whole welding process, and a technique called post weld heat treatment (PWHT) have been applied in order to reduce martensite fraction in the weld nugget. Simulation has been performed for AISI 1010 grade, and results show that the application of PWHT leads to the formation of not only martensite but also ferrite, bainite and pearlite during the cooling of weld nugget. Welding experiments have been done in parallel and micrographic analyses show the presence of several phases in the weld nugget. Experimental weld geometry and phase proportions are in good agreement with simulation results, showing here the validity of the model.Keywords: resistance spot welding, AISI 1010, modeling, post weld heat treatment, phase transformation, kinetics
Procedia PDF Downloads 1187101 Effect of Saponin Enriched Soapwort Powder on Structural and Sensorial Properties of Turkish Delight
Authors: Ihsan Burak Cam, Ayhan Topuz
Abstract:
Turkish delight has been produced by bleaching the plain delight mix (refined sugar, water and starch) via soapwort extract and powdered sugar. Soapwort extract which contains high amount of saponin, is an additive used in Turkish delight and tahini halvah production to improve consistency, chewiness and color due to its bioactive saponin content by acting as emulsifier. In this study, soapwort powder has been produced by determining optimum process conditions of soapwort extract by using response-surface method. This extract has been enriched with saponin by reverse osmosis (contains %63 saponin in dry bases). Büchi mini spray dryer B-290 was used to produce spray-dried soapwort powder (aw=0.254) from the enriched soapwort concentrate. Processing steps optimization and saponin content enrichment of soapwort extract has been tested on Turkish Delight production. Delight samples, produced by soapwort powder and commercial extract (control), were compared in chewiness, springiness, stickiness, adhesiveness, hardness, color and sensorial characteristics. According to the results, all textural properties except hardness of delights produced by powder were found to be statistically different than control samples. Chewiness, springiness, stickiness, adhesiveness and hardness values of samples (delights produced by the powder / control delights) were determined to be 361.9/1406.7, 0.095/0.251, -120.3/-51.7, 781.9/1869.3, 3427.3g/3118.4g, respectively. According to the quality analysis that has been ran with the end products it has been determined that; there is no statistically negative effect of the soapwort extract and the soapwort powder on the color and the appearance of Turkish Delight.Keywords: saponin, delight, soapwort powder, spray drying
Procedia PDF Downloads 2537100 Rapid Proliferation of Tissue Culture Using of Olive (Olea Europea L.) cv.Zard
Authors: Majid Gharaipour Abbasabad
Abstract:
This research is studying the effects that various densities of Zeatin, and BA hormones may have on the scale of transformation of plant nodes to new shoots, among seedlings produced by seed germination, and also surveys the amount of produced shoots and their lengths, inside the specific Olive seed lab medium (OM). It is also concerned with the effects that various densities of IBA hormone, and inoculating the shoots with Agrobacterium Rhizogenez A4 can have on shoots' root production. This is a totally random research, and each attendance group has had three occurrences, and ten samples per a hectare. The average amounts have been compared using Duncan's test method, which was done in 5% level. The results indicated that the highest rate of transformation of micro samples to shoots happened in the seed germination environments, containing Zetain with 5 mg, and also 15 mg per a liter densities. (respectively, 95% and 94%), while the highest rate of plants' stem production ,in micro samples, happened in the lab medium environments with 5mg per a liter Zetain density (4.5). In lab medium environments with 15 mg Zetain per liter, a decrease was observed in the number of produced stems (3.88). According to the produced stems' lenght, the longest stem length was observed in environments with 5 mg and also 15 mg per a liter Zetain, and 25 mg per a liter BA densities (respectively, 8.45 cm, 45.66 cm, 8.53 cm). Meanwhile, the lowest amount of transformation of micro samples to shoots, the lowest number of produced shoots, and the shortest shoots were observed in the environments without any hormones (respectively, 3.32 cm, 1.13, 19.66%). The results of root production in Olive indicated that attendance groups which were exposed to different hormones did not vary, and Agrobacterium Rhizogenez A4 had no effect on them, as well. The lowest root's growth rate (22%) happened in environments without any hormones and also, in environment with Agrobacterium Rhizogenez A4 (19.66%). The largest number of roots was observed in the environments, containing Agrobacterium Rhizogenez A4 plus IBA (10 mg/l) and Agrobacterium Rhizogenez A4 plus IBA (10 mg/l), (respectively, 8.46 and 8.70), which had a significant difference with environments merely containing 10 mg and 20 mg of IBA per a litre (respectively, 3.06 and 3.2). So it can be concluded that even though Agrobacterium Rhizogenez A4 had no impact on root's growth among shoots, it had an impact on the number of produced roots. It should be noted that even when the environment contained merely Agrobacterium Rhizogenez A4 without any hormones, only (1.16) roots were produced, which is significantly different from the attendance group with hormones (1.06).Keywords: olive-effect of hormones-germination of seed, densities of zeatin, BA hormones, agriculture
Procedia PDF Downloads 2927099 Comparison of Acid and Base Pretreatment of Switchgrass (Panicum virgatum L.) for Bioethanol Production
Authors: Mustafa Ümi̇t Ünal, Nafi̇z Çeli̇ktaş, Aysun Şener, Sara Betül Dolgun, Duygu Keser
Abstract:
The aim of this study was to compare acid and base pretreatment of switchgrass for bioethanol production. Switchgrass was pretreated with sulfuric acid and sodium hydroxide at 0.5, 1.0 and 1.5% (v/v) at 120, 140, 180 °C for 10, 60 and 90. Optimization of enzymatic hydrolysis of the pretreated switchgrass samples were carried out using three different enzyme mixtures (22.5 mg cellulase and 75 mg cellobiase /g biomass; 45 mg cellulase and 150 mg cellobiase /g biomass; 90 mg cellulase and 300 mg cellobiase /g biomass). Samples were removed at 24-h interval for fermentable sugar analyses with HPLC. The results showed that use of 90 mg cellulase and 300 mg cellobiase/g biomass resulted in the highest fermentable sugar formation. Furthermore, the highest fermentable sugar yield was obtained by pretreatment at 120 °C for 10 min using 1.0 % sodium hydroxide.Keywords: switchgrass, acid pretreatment, enzymatic hydrolysis, base pretreatment, ethanol production
Procedia PDF Downloads 5307098 Room Temperature Electron Spin Resonance and Raman Study of Nanocrystalline Zn(1-x)Cu(x)O (0.005 < x < 0.05) Synthesized by Pyrophoric Method
Authors: Jayashree Das, V. V. Srinivasu , D. K. Mishra, A. Maity
Abstract:
Owing to the important potential applications over decades, transition metal (TM: Mn, Fe, Ni, Cu, Cr, V etc.) doped ZnO-based diluted magnetic semiconductors (DMS) always attract research attention for more and newer investigations. One of the interesting aspects of these materials is to study and understand the magnetic property at room temperature properly, which is very crucial to select a material for any related application. In this regard, Electron spin resonance (ESR) study has been proven to be a powerful technique to investigate the spin dynamics of electrons inside the system, which are responsible for the magnetic behaviour of any system. ESR as well as the Raman and Photoluminescence spectroscopy studies are also helpful to study the defects present or created inside the system in the form of oxygen vacancy or cluster instrumental in determining the room temperature ferromagnetic property of transition metal doped ZnO system, which can be controlled through varying dopant concentration, appropriate synthesis technique and sintering of the samples. For our investigation, we synthesised Cu-doped ZnO nanocrystalline samples with composition Zn1-xCux ( 0.005< x < 0.05) by pyrophoric method and sintered at a low temperature of 650 0C. The microwave absorption is studied by the Electron Spin Resonance (ESR) of X-band (9.46 GHz) at room temperature. Systematic analysis of the obtained ESR spectra reveals that all the compositions of Cu-doped ZnO samples exhibit resonance signals of appreciable line widths and g value ~ 2.2, typical characteristic of ferromagnetism in the sample. Raman scattering and the photoluminescence study performed on the samples clearly indicated the presence of pronounced defect related peaks in the respective spectra. Cu doping in ZnO with varying concentration also observed to affect the optical band gap and the respective absorption edges in the UV-Vis spectra. FTIR spectroscopy reveals the Cu doping effect on the stretching bonds of ZnO. To probe into the structural and morphological changes incurred by Cu doping, we have performed XRD, SEM and EDX study, which confirms adequate Cu substitution without any significant impurity phase formation or lattice disorder. With proper explanation, we attempt to correlate the results observed for the structural optical and magnetic behaviour of the Cu-doped ZnO samples. We also claim that our result can be instrumental for appropriate applications of transition metal doped ZnO based DMS in the field of optoelectronics and Spintronics.Keywords: diluted magnetic semiconductors, electron spin resonance, raman scattering, spintronics.
Procedia PDF Downloads 313