Search results for: Michal Lower
Commenced in January 2007
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Paper Count: 5818

Search results for: Michal Lower

5368 Dynamic Response of Magnetorheological Fluid Tapered Laminated Beams Reinforced with Nano-Particles

Authors: Saman Momeni, Abolghassem Zabihollah, Mehdi Behzad

Abstract:

Non-uniform laminated composite structures are being used in many engineering applications where the structures are subjected to unpredicted vibration. To mitigate the vibration response of these structures, recently, magnetorheological fluid (MR), is added to non-uniform (tapered) thickness laminated composite structures to achieve a new generation of the smart composite as MR tapered beam. However, due to the nature of MR fluid, especially the low stiffness, MR tapered beam exhibit lower stiffness and in turn, lower natural frequencies. To achieve the basic design requirements of the structure without MR fluid, one may need to apply a predefined magnetic energy to the structures, requiring a constant source of energy. In the present work, a passive initial stiffness control of MR tapered beam has been studied. The effects of adding nanoparticles on the dynamic response of MR tapered beam has been investigated. It is observed that adding nanoparticles up to 3% may significantly modify the natural frequencies of the structures and achieve dynamic behavior of the structures before addition of MR fluid. Two Models of tapered structures have been taken into consideration. It is observed that adding only 3% of nanoparticles backs the structures to its initial dynamic behavior.

Keywords: non uniform laminated structures, MR fluid, nanoparticles, vibration, stiffness

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5367 Analysis of Efficacy and Safety of Abatacept for Rheumatoid Arthritis: A Systematic Review and Meta Analysis

Authors: Hamida Memon

Abstract:

Rheumatoid arthritis (RA) is a persistent inflammation of the joints caused by an aggressive immune reaction leading to pain, stiffness, and limited function. Abatacept, a selective co-modulator, is a promising option for treatment and may have better safety profiles compared to other interventions. This meta-analysis aims at assessing the effectiveness and safety of abatacept in contrast to various RA treatments such as placebos, biological DMARDs and conventional DMARDs. The analysis assesses how abatacept influences disease activity, pain intensity and overall patient functionality. It weighs the risk factor of abatacept with other drugs such as tocilizumab, with the numbers being lower for abatacept. This meta-analysis aims at assessing the effectiveness and safety of abatacept in contrast to various RA treatments such as placebos, biological DMARDs and conventional DMARDs. The analysis assesses how abatacept influences disease activity, pain intensity and overall patient functionality. It weighs the risk factor of abatacept with other drugs such as tocilizumab, with the numbers being lower for abatacept.

Keywords: Rheumatoid arthritis, abatacept, control group, bone disease

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5366 Features of Normative and Pathological Realizations of Sibilant Sounds for Computer-Aided Pronunciation Evaluation in Children

Authors: Zuzanna Miodonska, Michal Krecichwost, Pawel Badura

Abstract:

Sigmatism (lisping) is a speech disorder in which sibilant consonants are mispronounced. The diagnosis of this phenomenon is usually based on the auditory assessment. However, the progress in speech analysis techniques creates a possibility of developing computer-aided sigmatism diagnosis tools. The aim of the study is to statistically verify whether specific acoustic features of sibilant sounds may be related to pronunciation correctness. Such knowledge can be of great importance while implementing classifiers and designing novel tools for automatic sibilants pronunciation evaluation. The study covers analysis of various speech signal measures, including features proposed in the literature for the description of normative sibilants realization. Amplitudes and frequencies of three fricative formants (FF) are extracted based on local spectral maxima of the friction noise. Skewness, kurtosis, four normalized spectral moments (SM) and 13 mel-frequency cepstral coefficients (MFCC) with their 1st and 2nd derivatives (13 Delta and 13 Delta-Delta MFCC) are included in the analysis as well. The resulting feature vector contains 51 measures. The experiments are performed on the speech corpus containing words with selected sibilant sounds (/ʃ, ʒ/) pronounced by 60 preschool children with proper pronunciation or with natural pathologies. In total, 224 /ʃ/ segments and 191 /ʒ/ segments are employed in the study. The Mann-Whitney U test is employed for the analysis of stigmatism and normative pronunciation. Statistically, significant differences are obtained in most of the proposed features in children divided into these two groups at p < 0.05. All spectral moments and fricative formants appear to be distinctive between pathology and proper pronunciation. These metrics describe the friction noise characteristic for sibilants, which makes them particularly promising for the use in sibilants evaluation tools. Correspondences found between phoneme feature values and an expert evaluation of the pronunciation correctness encourage to involve speech analysis tools in diagnosis and therapy of sigmatism. Proposed feature extraction methods could be used in a computer-assisted stigmatism diagnosis or therapy systems.

Keywords: computer-aided pronunciation evaluation, sigmatism diagnosis, speech signal analysis, statistical verification

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5365 Vitamin A Status and Its Correlation with the Dietary Intake of Young Females of Lahore, Pakistan

Authors: Sarah Fatima, Ahmad A. Malik, Saima Sadaf

Abstract:

This study was conducted in order to assess the dietary record and vitamin A status of young females of Lahore. A total sample of 376 consisted of 16 – 20 years of unmarried college going females. Three main tools were adopted: questionnaire, 3-day food diary and serum retinol test. The anthropometric measurements showed that a total of 32.6% of the sample was underweight (BMI < 18.5) and 54.5% had a healthy weight (BMI 18.5 – 22.9). The average Vitamin A intake of the sample was 257.95 µg/day while the RDA for the selected age group was 700 µg/day. The mean energy intake of the adolescents was 1153.64 kcal/ day, whereas the Estimated Energy Requirement (EER) for this age group was 2368 kcal/day. The mean serum Vitamin A level was 24.81µg/dL. 69.6% of the sample was deficient in serum Vitamin A i.e. serum retinol < 24 µg/dL. 30.4% had serum retinol in normal limit (24 – 84 µg/dL) from which 25.3% lied in lower limit (24 – 44 µg/dL) and only 5.1% had serum retinol in 44 – 64 µg/dL range. A slightly negative correlation (r = - 0.21, 95% confidence interval) was found between dietary intake of Vitamin A and serum Vitamin A It was concluded that the dietary intake of major nutrients and vitamin A is not adequate in the selected group. This is also confirmed by the lower serum retinol levels. Hence, vitamin An intake and status are generally inadequate, and vitamin deficiency is prevalent in the unmarried young females of Lahore.

Keywords: vitamin A, young Females, vitamin deficiency, Lahore

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5364 Effects of Porosity Logs on Pore Connectivity and Volumetric Estimation

Authors: Segun S. Bodunde

Abstract:

In Bona Field, Niger Delta, two reservoirs across three wells were analyzed. The research aimed at determining the statistical dependence of permeability and oil volume in place on porosity logs. Of the three popular porosity logs, two were used; the sonic and density logs. The objectives of the research were to identify the porosity logs that vary more with location and direction, to visualize the depth trend of both logs and to determine the influence of these logs on pore connectivity determination and volumetric analysis. The focus was on density and sonic logs. It was observed that the sonic derived porosities were higher than the density derived porosities (in well two, across the two reservoir sands, sonic porosity averaged 30.8% while density derived porosity averaged 23.65%, and the same trend was observed in other wells.). The sonic logs were further observed to have lower co-efficient of variation when compared to the density logs (in sand A, well 2, sonic derived porosity had a co-efficient of variation of 12.15% compared to 22.52% from the density logs) indicating a lower tendency to vary with location and direction. The bulk density was observed to increase with depth while the transit time reduced with depth. It was also observed that for an 8.87% decrease in porosity, the pore connectivity was observed to decrease by about 38%.

Keywords: pore connectivity, co-efficient of variation, density derived porosity, sonic derived porosity

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5363 Caspase-11 and AIM2 Inflammasome are Involved in Smoking-Induced COPD and Lung Adenocarcinoma

Authors: Chiara Colarusso, Michela Terlizzi, Aldo Pinto, Rosalinda Sorrentino

Abstract:

Cigarette smoking is the main cause and the most common risk factor for both COPD and lung cancer. In our previous studies, we proved that caspase-11 in mice and its human analogue, caspase-4, are involved in lung carcinogenesis and that AIM2 inflammasome might play a pro-cancerous role in lung cancer. Therefore, the aim of this study was to investigate potential crosstalk between COPD and lung cancer, focusing on AIM2 and caspase-11-dependent inflammasome signaling pathway. To mimic COPD, we took advantage of an experimental first-hand smoking mouse model and, to confirm what was observed in mice, we used human samples of lung adenocarcinoma patients stratified according to the smoking and COPD status. We demonstrated that smoke exposure led to emphysema-like features, bronchial tone impairment, and release of IL-1-like cytokines (IL-1α, IL-1β, IL-33, IL-18) in a caspase-1 independent manner in C57Bl/6N. Rather, a dysfunctional caspase-11 in smoke-exposed 129Sv mice was associated to lower bronchial inflammation, collagen deposition, and IL-1-like inflammation. In addition, for the first time, we found that AIM2 inflammasome is involved in lung inflammation in smoking and COPD, in that its expression was higher in smoke-exposed C57Bl/6N compared to 129Sv smoking mice, who instead did not show any alteration of AIM2 in both macrophages and dendritic cells. Moreover, we found that AIM2 expression in the cancerous tissue, albeit higher than non-cancerous tissue, was not statistically different according to the COPD and smoking status. Instead, the higher expression of AIM2 in non-cancerous tissue of smoker COPD patients than smokers who did not have COPD was correlated to a higher hazard ratio of poor survival rate than patients who presented lower levels of AIM2. In conclusion, our data highlight that caspase-11 in mice is associated to smoke-induced lung latent inflammation which could drive the establishment of lung cancer, and that AIM2 inflammasome plays a role at the crosstalk between smoking/COPD and lung adenocarcinoma in that its higher presence is correlated to lower survival rate of smoker COPD adenocarcinoma.

Keywords: COPD, inflammasome, lung cancer, lung inflammation, smoke

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5362 Determinants of Hospital Obstetric Unit Closures in the United States 2002-2013: Loss of Hospital Obstetric Care 2002-2013

Authors: Peiyin Hung, Katy Kozhimannil, Michelle Casey, Ira Moscovice

Abstract:

Background/Objective: The loss of obstetric services has been a pressing concern in urban and rural areas nationwide. This study aims to determine factors that contribute to the loss of obstetric care through closures of a hospital or obstetric unit. Methods: Data from 2002-2013 American Hospital Association annual surveys were used to identify hospitals providing obstetric services. We linked these data to Medicare Healthcare Cost Report Information for hospital financial indicators, the US Census Bureau’s American Community Survey for zip-code level characteristics, and Area Health Resource files for county- level clinician supply measures. A discrete-time multinomial logit model was used to determine contributing factors to obstetric unit or hospital closures. Results: Of 3,551 hospitals providing obstetrics services during 2002-2013, 82% kept units open, 12% stopped providing obstetrics services, and 6% closed down completely. State-level variations existed. Factors that significantly increased hospitals’ probability of obstetric unit closures included lower than 250 annual birth volume (adjusted marginal effects [95% confidence interval]=34.1% [28%, 40%]), closer proximity to another hospital with obstetric services (per 10 miles: -1.5% [-2.4, -0.5%]), being in a county with lower family physician supply (-7.8% [-15.0%, -0.6%), being in a zip code with higher percentage of non-white females (per 10%: 10.2% [2.1%, 18.3%]), and with lower income (per $1,000 income: -0.14% [-0.28%, -0.01%]). Conclusions: Over the past 12 years, loss of obstetric services has disproportionately affected areas served by low-volume urban and rural hospitals, non-white and low-income communities, and counties with fewer family physicians, signaling a need to address maternity care access in these communities.

Keywords: access to care, obstetric care, service line discontinuation, hospital, obstetric unit closures

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5361 Laying Hens' Feed Fortified with Pectin, Xanthan Gum and Guar Gum Aims to Reduce the Cholesterol in Muscle and Egg Yolk

Authors: Novia Dwi Prabandari, Diah Ayu Asmarani

Abstract:

Soluble fiber can accelerate the metabolism of cholesterol. Pectin and gum has been used in the form of substance additive for material stabilizer and emulsifier. Pectin supplementation in laying hens can decimate the cholesterol content in egg yolk and muscle. Therefore, this laying hens’ feed is regular feed chickens enriched with soluble fiber (Pectin, Xanthan gum, and Guar gum) to produce eggs and muscle with lower cholesterol than usual.The ingredients are mixed in the ratio of concentrate 45%, corn flour 25%, soybean meal 20%, and extract of soluble fiber 10%. Once all the ingredients are mixed and then evaporated with temperature < 80 °C. Then put in the grinding machine resulting in a circular shape with holes 2-3 mm in diameter, after it dried up the water content in the feed is less than 14%. Eggs from laying hen with soluble fiber fortification feed intake will have lower cholesterol levels in eggs than regular feed. So even with the cholesterol content in the muscle, it is because chicken feed fortified with soluble fiber will accelerate the metabolism of cholesterol and cause cholesterol deposits in the chicken less. The use of this kind of laying hens feed is produce eggs with high protein content can be consumed more for people who have hypercholesterolemia.

Keywords: pectin, xanthan gum, guar gum, laying hen, cholesterol

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5360 A Marxist Analysis of Toni Morrison's Novel, The Bluest Eye

Authors: Irfan Mehmood

Abstract:

The goal of this study is to examine The Bluest Eye (1979) by Toni Morrison from a Marxist perspective, a literary theory developed by Louis Althusser, which emphasizes capitalism and class conflict in the modern world. Marxist literary philosophy holds that the absence of opportunities for lower-class people to own and earn properties and resources of production is the main cause of their repression. In The Communist Manifesto (1848), Karl Marx divided society into two main classes, the proletariat (the lowest class) and the bourgeois (the ruling class). Marx contends that the proletarian class has been brutally exploited by the bourgeois class in all facets of existence. The exploitation of the lower class by means of hegemony and capitalism is covered by Toni Morrison in her first novel, The Bluest Eye (1979). The goal of this study is to determine how Morrison's chosen work highlights the struggle of oppressed African Americans against entrenched systems of hegemony, interpellation, and state apparatuses. This study will look more closely at the claim that all of the miseries experienced by Afro-Americans are mostly the result of the capitalist class structure and that they can also enjoy the blessings of life through unity, hard work, and economic stability.

Keywords: class conflict; African American culture; hegemony; interpellation; state apparatuses

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5359 Mineralisation and Fluid Inclusions Studies of the Fluorite Deposit at Jebel Mecella, North Eastern Tunisia

Authors: Miladi Yasmine, Bouhlel Salah, Garnit Hechmi, David Banks

Abstract:

The Jebel Mecella F (Ba-Pb-Zn) ore deposits of the Zaghouan district are located in northeastern Tunisia, 60 km south of Tunis. The host rocks belong to the Ressas Formation of Kimmeridgian-Tithonian age and lower Cretaceous layers. Mineralisations occur as stratiform lenses and fracture fillings. The ore mineral assemblage is composed of fluorite, barite, sphalerite galena, and quartz. Primary fluid inclusions in sphalerite have homogenization temperatures ranging from 129 to 145°C final melting temperature range from -14.9 to -10.0, corresponding to salinities of 14.0 to 17.7 wt% NaCl equivalent. Fluid inclusions in fluorite homogenize to the liquid phase between 116 and 160°C. The final ice melting temperature ranges from -23 to -15 °C, corresponding to salinities between 17 and 24 wt% NaCl equivalent. The LAICP-MS analyses of the fluid inclusions in fluorite show that these fluids are dominated by Na>K>Mg. Furthermore, the high K/Na values from fluid inclusions suggest the brine interacted with K-rich rocks in the basement or in siliciclastic sediments in the basins. The ore fluids in Jebel Mecella are highly saline and Na-K dominated with lower Mg concentrations, and come from the leaching of the dolomitic host rocks. These results are compatible with Mississippi-Valley-type mineralizing fluids.

Keywords: Jebel Mecella, fluid inclusions, micro thermometry, LA-ICP-MS

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5358 Rainfall and Temperature Characteristics of the Middle and Lower Awash Areas of Ethiopia

Authors: Melese Tadesse Morebo

Abstract:

Pastoral and agro-pastoral communities in East Africa, particularly in Ethiopia, are vulnerable to climate-related risks. The aim of this study is to characterize the annual, seasonal, and monthly rainfall and temperature of the middle and lower awash areas of Ethiopia. Start of season (SOS), end of season (EOS), length of growing season (LGS), number of rainy days, and probability of dry spell occurrences were analyzed using INSTAT Plus (v3.7) software. Daily rainfall and temperature data for 33 years (1990–2022) from six stations were analyzed. The result of the study revealed that the annual rainfall in the study area as a whole showed an increasing trend, but its trend was statistically non-significant. During the study period, the Kiremt rainfall at Amibara station showed statistically significant increasing trends. The trend analysis of SOS, EOS, and LGS shows up and down trends at all stations. The mean lengths of growing seasons in the study area ranged from 20 to 61 days during the study period. In the study area, the annual mean maximum temperature ranged between 34.1°C and 38.3°C over the last three decades. All stations within the research area during the study period, the annual minimum temperature exhibited a substantial impact.

Keywords: annual rainfall, LGS, minimum temperature, Mann-Kendall test

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5357 A Comparison and Discussion of Modern Anaesthetic Techniques in Elective Lower Limb Arthroplasties

Authors: P. T. Collett, M. Kershaw

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Introduction: The discussion regarding which method of anesthesia provides better results for lower limb arthroplasty is a continuing debate. Multiple meta-analysis has been performed with no clear consensus. The current recommendation is to use neuraxial anesthesia for lower limb arthroplasty; however, the evidence to support this decision is weak. The Enhanced Recovery After Surgery (ERAS) society has recommended, either technique can be used as part of a multimodal anesthetic regimen. A local study was performed to see if the current anesthetic practice correlates with the current recommendations and to evaluate the efficacy of the different techniques utilized. Method: 90 patients who underwent total hip or total knee replacements at Nevill Hall Hospital between February 2019 to July 2019 were reviewed. Data collected included the anesthetic technique, day one opiate use, pain score, and length of stay. The data was collected from anesthetic charts, and the pain team follows up forms. Analysis: The average of patients undergoing lower limb arthroplasty was 70. Of those 83% (n=75) received a spinal anaesthetic and 17% (n=15) received a general anaesthetic. For patients undergoing knee replacement under general anesthetic the average day, one pain score was 2.29 and 1.94 if a spinal anesthetic was performed. For hip replacements, the scores were 1.87 and 1.8, respectively. There was no statistical significance between these scores. Day 1 opiate usage was significantly higher in knee replacement patients who were given a general anesthetic (45.7mg IV morphine equivalent) vs. those who were operated on under spinal anesthetic (19.7mg). This difference was not noticeable in hip replacement patients. There was no significant difference in length of stay between the two anesthetic techniques. Discussion: There was no significant difference in the day one pain score between the patients who received a general or spinal anesthetic for either knee or hip replacements. The higher pain scores in the knee replacement group overall are consistent with this being a more painful procedure. This is a small patient population, which means any difference between the two groups is unlikely to be representative of a larger population. The pain scale has 4 points, which means it is difficult to identify a significant difference between pain scores. Conclusion: There is currently little standardization between the different anesthetic approaches utilized in Nevill Hall Hospital. This is likely due to the lack of adherence to a standardized anesthetic regimen. In accordance with ERAS recommends a standard anesthetic protocol is a core component. The results of this study and the guidance from the ERAS society will support the implementation of a new health board wide ERAS protocol.

Keywords: anaesthesia, orthopaedics, intensive care, patient centered decision making, treatment escalation

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5356 Development of an Instructional Model for Health Education Based On Social Cognitive Theory and Strategic Life Planning to Enhance Self-Regulation and Learning Achievement of Lower Secondary School Students

Authors: Adisorn Bansong, Walai Isarankura Na Ayudhaya, Aumporn Makanong

Abstract:

A Development of an Instructional Model for Health Education was the aim to develop and study the effectiveness of an instructional model for health education to enhance self-regulation and learning achievement of lower secondary school students. It was the Quasi-Experimental Designs, used a Single-group Interrupted Time-series Designs, conducted by 2 phases: 1. To develop an instructional model based on Social Cognitive Theory and Strategic Life Planning. 2. To trial and evaluate effectiveness of an instructional model. The results as the following: i. An Instructional Model for Health Education consists of five main components: a) Attention b) Forethought c) Tactic Planning d) Execution and e) Reflection. ii. After an Instructional Model for Health Education has used for a semester trial, found the 4.07 percent of sample’s Self-Regulation higher and learning achievement on post-test were significantly higher than pre-test at .05 levels (p = .033, .000).

Keywords: social cognitive theory, strategic life planning, self-regulation, learning achievement

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5355 Distribution Urban Public Spaces Among Riyadh Residential Neighborhoods

Authors: Abdulwahab Alalyani, Mahbub Rashid

Abstract:

Urban Open Space (UOS) a central role to promotes community health, including daily activities, but these resources may not available, accessible enough, and or equitably be distributed. This paper measures and compares spatial equity of the availability and accessibility UOS among low, middle, and high-income neighborhoods in Riyadh city. The measurement mothdulgy for the UOSavailability was by calculating the total of UOS with respect to the population total (m2/inhabitant) and the accessibility indicted by using walking distance of a 0.25 mi (0.4 km) buffering streets network.All UOS were mapped and measured using geographical information systems. To evaluate the significant differences in UOS availability and accessibility across low, medium, and high-income Riyadh neighborhoods, we used a One-way ANOVA analysis of covariance to test the differences.The findings are as follows; finding, UOSavailability was lower than global standers. Riyadh has only 1.13 m2 per capita of UOS, and the coverage accessible area by walking distance to UOS was lower than 50%. The final finding, spatial equity of the availability and accessibility, were significantly different among Riyadh neighborhoods based on socioeconomic status. The future development of UOS should be focused on increasing Urban park availability and should be given priority to those low-income and unhealthy communities.

Keywords: distribution urban open space, urban open space accessibility, spatial equity, riyadh city

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5354 The Effects of SCMs on the Mechanical Properties and Durability of Fibre Cement Plates

Authors: Ceren Ince, Berkay Zafer Erdem, Shahram Derogar, Nabi Yuzer

Abstract:

Fibre cement plates, often used in construction, generally are made using quartz as an inert material, cement as a binder and cellulose as a fibre. This paper first of all investigates the mechanical properties and durability of fibre cement plates when quartz is both partly and fully replaced with diatomite. Diatomite does not only have lower density compared to quartz but also has high pozzolanic activity. The main objective of this paper is the investigation of the effects of supplementary cementing materials (SCMs) on the short and long term mechanical properties and durability characteristics of fibre cement plates prepared using diatomite. Supplementary cementing materials such as ground granulated blast furnace slug (GGBS) and fly ash (FA) are used in this study. 10, 20, 30 and 40% of GGBS and FA are used as partial replacement materials to cement. Short and long term mechanical properties such as compressive and flexural strengths as well as capillary absorption, sorptivity characteristics and mass were investigated. Consistency and setting time at each replacement levels of SCMs were also recorded. The effects of using supplementary cementing materials on the carbonation and sulphate resistance of fibre cement plates were then experimented. The results, first of all, show that the use of diatomite as a full or partial replacement to quartz resulted in a systematic decrease in total mass of the fibre cement plates. The reduction of mass was largely due to the lower density and finer particle size of diatomite compared to quartz. The use of diatomite did not only reduce the mass of these plates but also increased the compressive strength significantly as a result of its high pozzolanic activity. The replacement levels of both GGBS and FA resulted in a systematic decrease in short term compressive strength with increasing replacement levels. This was essentially expected as the total heat of hydration is much lower in GGBS and FA than that of cement. Long term results however, indicated that the compressive strength of fibre cement plates prepared using both GGBS and FA increases with time and hence the compressive strength of plates prepared using SCMs is either equivalent or more than the compressive strength of plates prepared using cement alone. Durability characteristics of fibre cement plates prepared using SCMs were enhanced significantly. Measurements of capillary absorption and sopritivty characteristics were also indicated that the plates prepared using SCMs has much lower permeability compared to plates prepared cement alone. Much higher resistance to carbonation and sulphate attach were observed with plates prepared using SCMs. The results presented in this paper show that the use of SCMs does not only support the production of more sustainable construction materials but also enhances the mechanical properties and durability characteristics of fibre cement plates.

Keywords: diatomite, fibre, strength, supplementary cementing material

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5353 Analysis of Possible Draught Size of Container Vessels on the Lower Danube

Authors: Todor Bačkalić, Marinko Maslarić, Milosav Georgijević, Sanja Bojić

Abstract:

Water transport could be the backbone of the future European combined transport system. The future transport policy in landlocked countries from the Danube Region has to be based on inland waterway transport (IWT). The development of the container transport on inland waterways depends directly on technical-exploitative characteristics of the network of inland waterways. Research of navigational abilities of inland waterways is the basic step in transport planning. The size of the vessel’s draught (T) is the limiting value in project tasks and it depends on the depth of the waterway. Navigation characteristics of rivers have to be determined as precise as possible, especially from the aspect of determination of the possible draught of vessels. This article outlines a rationale, why it is necessary to develop competence about infrastructure risk in water transport. Climate changes are evident and require special attention and global monitoring. Current risk assessment methods for Inland waterway transport just consider some dramatic events. We present a new method for the assessment of risk and vulnerability of inland waterway transport where river depth represents a crucial part. The analysis of water level changes in the lower Danube was done for two significant periods (1965-1979 and 1998-2012).

Keywords: container vessel, draught, probability, the Danube

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5352 On the Lithology of Paleocene-Lower Eocene Deposits of the Achara-Trialeti Fold Zone: The Lesser Caucasus

Authors: Nino Kobakhidze, Endi Varsimashvili, Davit Makadze

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The Caucasus is a link of the Alpine-Himalayan fold belt and involves the Greater Caucasus and the Lesser Caucasus fold systems and the Intermountain area. The study object is located within the northernmost part of the Lesser Caucasus orogen, in the eastern part of Achara-Trialeti fold -thrust belt. This area was rather well surveyed in 70th of the twentieth century in terms of oil-and-gas potential, but to our best knowledge, detailed sedimentological studies have not been conducted so far. In order to fill this gap, the authors of the present thesis started research in this direction. One of the objects selected for the research was the deposits of the Kavtura river valley situated on the northern slope of the Trialeti ridge. Paleocene-Lower Eocene deposits known in scientific literature as ‘Borjomi Flysch’ (Turbidites) are exposed in the mentioned area. During the research, the following methodologies were applied: selection of key cross sections, a collection of rock samples, microscopic description of thin sections, mineralogical and petrological analysis of material and identification of trace fossils. The study of Paleocene-Lower Eocene deposits starts with Kavtura river valley in the east, where they are well characterized by microfauna. The cross-section of the deposits starts with Danian variegated marlstone conformably overlain by the alternation of thick and thin-bedded sandstones (thickness 40-50 cm). They are continued with interbedded of thin-bedded sandstones and shales(thickness 4-5 m). On the sole surface of sandstones ichnogenera ‘Helmintopsis’ and ‘Scolicia’ are recorded and within the bed –‘Chondrites’ is found. Towards the Riverhead, there is a 1-2 m gap in sedimentation; then again the Paleocene-Lower Eocene sediments crop out. They starting with alternation of grey-green medium-grained sandstones and shales enclosing dark color plant detritus. They are overlain by the interbedded of calcareous sandstones and marls, where the thickness of sandstones is variable (20-70 cm). Ichnogenus – ‘Scolicia’ is found here. Upwards the above-mentioned deposits pass into Middle Eocenian volcanogenic-sedimentary suits. In the Kavtura river valley, the thickness of the Paleocene-Lower Eocene deposits is 300-400 m. In the process of research, the following activities are conducted: the facial analysis of host rocks, correlation of the study section with other cross sections and interpretation of depositional environment of the area. In the area the authors have found and described ichnogenera; their preliminary determination have shown that they belong to pre-depositional (‘Helmintopsis’) and post-depositional (‘Chondrites’) forms. As known, during the Cretaceous-Paleogene time, the Achara-Trialeti fold-thrust belt extensional basin was the accumulation area with great thicknesses (from shallow to deep marine sediments). It is confirmed once more by the authors investigations preliminary results of paleoichnological studies inclusive.

Keywords: flysh deposits, lithology, The Lesser Caucasus, trace fossils

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5351 Impact of Dairy Polysaccharides on Caloric Intake and Postprandial Metabolic Responses in Young Adults

Authors: Muhammad Umair Arshad, Saima Ishtiaq, Ali Imran

Abstract:

Different polysaccharides contribute towards the management of glycemic and satiety and consequently manage the metabolic syndrome. In the present study, we compared the postprandial glycemic and satiety responses of different dietary polysaccharides when added to milk (2% Milk Fat). The objective of this study was to evaluate different polysaccharides against postprandial glucose, appetite responses, and food intake at subsequent meals. In a repeated measures crossover design, 30 females (18–30 years) consumed 250 ml milk with 2% M.F. (control), or milk with carrageenan (2.5 g), guar gum (2.5 g) and alginate (2.5 g), followed by an ad libitum pizza meal after 120 min. Alginate and guar gum addition resulted in lower caloric intake at subsequent pizza meal. The post-treatment (0–120 min) glucose and average appetite were suppressed by alginate and guar gum (p < 0.0001), with a more pronounced effect of guar gum. However, alginate resulted in lower blood glucose (p < 0.0001) compared with control and carrageenan during post-treatment. Alginate and guar gum, added milk, and other beverages would be beneficial in the short-term regulation of postprandial glycemia and satiety.

Keywords: satiety, glycemic control, milk polysaccharides, food intake

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5350 Assessing the Mass Concentration of Microplastics and Nanoplastics in Wastewater Treatment Plants by Pyrolysis Gas Chromatography−Mass Spectrometry

Authors: Yanghui Xu, Qin Ou, Xintu Wang, Feng Hou, Peng Li, Jan Peter van der Hoek, Gang Liu

Abstract:

The level and removal of microplastics (MPs) in wastewater treatment plants (WWTPs) has been well evaluated by the particle number, while the mass concentration of MPs and especially nanoplastics (NPs) remains unclear. In this study, microfiltration, ultrafiltration and hydrogen peroxide digestion were used to extract MPs and NPs with different size ranges (0.01−1, 1−50, and 50−1000 μm) across the whole treatment schemes in two WWTPs. By identifying specific pyrolysis products, pyrolysis gas chromatography−mass spectrometry were used to quantify their mass concentrations of selected six types of polymers (i.e., polymethyl methacrylate (PMMA), polypropylene (PP), polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET), and polyamide (PA)). The mass concentrations of total MPs and NPs decreased from 26.23 and 11.28 μg/L in the influent to 1.75 and 0.71 μg/L in the effluent, with removal rates of 93.3 and 93.7% in plants A and B, respectively. Among them, PP, PET and PE were the dominant polymer types in wastewater, while PMMA, PS and PA only accounted for a small part. The mass concentrations of NPs (0.01−1 μm) were much lower than those of MPs (>1 μm), accounting for 12.0−17.9 and 5.6− 19.5% of the total MPs and NPs, respectively. Notably, the removal efficiency differed with the polymer type and size range. The low-density MPs (e.g., PP and PE) had lower removal efficiency than high-density PET in both plants. Since particles with smaller size could pass the tertiary sand filter or membrane filter more easily, the removal efficiency of NPs was lower than that of MPs with larger particle size. Based on annual wastewater effluent discharge, it is estimated that about 0.321 and 0.052 tons of MPs and NPs were released into the river each year. Overall, this study investigated the mass concentration of MPs and NPs with a wide size range of 0.01−1000 μm in wastewater, which provided valuable information regarding the pollution level and distribution characteristics of MPs, especially NPs, in WWTPs. However, there are limitations and uncertainties in the current study, especially regarding the sample collection and MP/NP detection. The used plastic items (e.g., sampling buckets, ultrafiltration membranes, centrifugal tubes, and pipette tips) may introduce potential contamination. Additionally, the proposed method caused loss of MPs, especially NPs, which can lead to underestimation of MPs/NPs. Further studies are recommended to address these challenges about MPs/NPs in wastewater.

Keywords: microplastics, nanoplastics, mass concentration, WWTPs, Py-GC/MS

Procedia PDF Downloads 281
5349 Investigation p53 Codon 72 Polymorphism and miR-146a rs2910164 Polymorphism in Breast Cancer

Authors: Marjan Moradi Fard, Hossein Rassi, Masoud Houshmand

Abstract:

Aim: Breast cancer is one of the most common cancers affecting the morbidity and mortality of Iranian women. This disease is a result of collective alterations of oncogenes and tumor suppressor genes. Studies have produced conflicting results concerning the role of p53 codon 72 polymorphism (G>C) and miR-146a rs2910164 polymorphism (G>C) on the risk of several cancers; therefore, a research was performed to estimate the association between the p53 codon 72 polymorphism and miR-146a rs2910164 polymorphism in breast cancer. Methods and Materials: A total of 45 archival breast cancer samples from khatam hospital and 40 healthy samples were collected. Verification of each cancer reported in a relative was sought through the pathology reports of the hospital records. Then, DNA extracted from all samples by standard methods and p53 codon 72 polymorphism genotypes and miR-146a rs2910164 polymorphism genotypes were analyzed using multiplex PCR. The tubules, mitotic activity, necrosis, polymorphism and grade of breast cancer were staged by Nottingham histological grading and immunohistochemical staining of the sections from the paraffin wax embedded tissues for the expression of ER, PR and p53 was carried out using a standard method. Finally, data analysis was performed using the 7 version of the Epi Info(TM) 2012 software and test chi-square(x2) for trend. Results: Successful DNA extraction was assessed by PCR amplification of b-actin gene (99 bp). According to the results, p53 GG genotype and miR-146a rs2910164 CC genotype was significantly associated with increased risk of breast cancer in the study population. In this study, we established that tumors of p53 GG genotype and miR-146a rs2910164 CC genotype exhibited higher mitotic activity, higher polymorphism, lower necrosis, lower tubules, higher ER- and PR-negatives and lower TP53-positives than the other genotypes. Conclusion: The present study provided preliminary evidence that a p53 GG genotype may effect breast cancer risk in the study population, interacting synergistically with miR-146a rs2910164 CC genotype. Our results demonstrate that the testing of p53 codon 72 polymorphism genotypes and miR-146a rs2910164 polymorphism genotypes in combination with clinical parameters can serve as major risk factors in the early identification of breast cancers.

Keywords: breast cancer, p53 codon 72 polymorphism, miR-146a rs2910164 polymorphism, genotypes

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5348 Reliability and Probability Weighted Moment Estimation for Three Parameter Mukherjee-Islam Failure Model

Authors: Ariful Islam, Showkat Ahmad Lone

Abstract:

The Mukherjee-Islam Model is commonly used as a simple life time distribution to assess system reliability. The model exhibits a better fit for failure information and provides more appropriate information about hazard rate and other reliability measures as shown by various authors. It is possible to introduce a location parameter at a time (i.e., a time before which failure cannot occur) which makes it a more useful failure distribution than the existing ones. Even after shifting the location of the distribution, it represents a decreasing, constant and increasing failure rate. It has been shown to represent the appropriate lower tail of the distribution of random variables having fixed lower bound. This study presents the reliability computations and probability weighted moment estimation of three parameter model. A comparative analysis is carried out between three parameters finite range model and some existing bathtub shaped curve fitting models. Since probability weighted moment method is used, the results obtained can also be applied on small sample cases. Maximum likelihood estimation method is also applied in this study.

Keywords: comparative analysis, maximum likelihood estimation, Mukherjee-Islam failure model, probability weighted moment estimation, reliability

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5347 Dental Students’ Self-Assessment of Their Performance in a Preclinical Endodontic Practice

Authors: Minseock Seo

Abstract:

Dental education consists of both theoretical and practical learning for students. When dental students encounter practical courses as a new educational experience, they must also learn to evaluate themselves. The aim of this study was to investigate the self-assessment scores of third-year dental students and compare with the scores graded by the faculty in preclinical endodontic practice in a dental school in Korea. Faculty- and student-assigned scores were calculated from preclinical endodontic practice performed on phantom patients. The students were formally instructed on grading procedures for endodontic treatment. After each step, each item was assessed by the student. The students’ self-assessment score was then compared to the score by the faculty. The students were divided into 4 groups by analyzing the scores of self-assessment and faculty-assessment and statistically analyzed by summing the theoretical and practical examination scores. In the theoretical exam score, the group who over-estimated their performance (H group) was lower than the group with lower evaluation (L group). When comparing the first and last score determined by the faculty, H groups didn’t show any improvement, while the other group did. In H group, the less improvement of the self-assessment, the higher the theoretical exam score. In L group, the higher improvement of the self-assessment, the better the theoretical exam score. The results point to the need to develop students’ self-insight with more exercises and practical training.

Keywords: dental students, endodontic, preclinical practice, self-assessment

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5346 Approximate Spring Balancing for the Arm of a Humanoid Robot to Reduce Actuator Torque

Authors: Apurva Patil, Ashay Aswale, Akshay Kulkarni, Shubham Bharadiya

Abstract:

The potential benefit of gravity compensation of linkages in mechanisms using springs to reduce actuator requirements is well recognized, but practical applications have been elusive. Although existing methods provide exact spring balance, they require additional masses or auxiliary links, or all the springs used originate from the ground, which makes the resulting device bulky and space-inefficient. This paper uses a method of static balancing of mechanisms with conservative loads such as gravity and spring loads using non-zero-free-length springs with child–parent connections and no auxiliary links. Application of this method to the developed arm of a humanoid robot is presented here. Spring balancing is particularly important in this case because the serial chain of linkages has to work against gravity.This work involves approximate spring balancing of the open-loop chain of linkages using minimization of potential energy variance. It uses the approach of flattening the potential energy distribution over the workspace and fuses it with numerical optimization. The results show the considerable reduction in actuator torque requirement with practical spring design and arrangement. Reduced actuator torque facilitates the use of lower end actuators which are generally smaller in weight and volume thereby lowering the space requirements and the total weight of the arm. This is particularly important for humanoid robots where the parent actuator has to handle the weight of the subsequent actuators as well. Actuators with lower actuation requirements are more energy efficient, thereby reduce the energy consumption of the mechanism. Lower end actuators are lower in cost and facilitate the development of low-cost devices. Although the method provides only an approximate balancing, it is versatile, flexible in choosing appropriate control variables that are relevant to the design problem and easy to implement. The true potential of this technique lies in the fact that it uses a very simple optimization to find the spring constant, free-length of the spring and the optimal attachment points subject to the optimization constraints. Also, it uses physically realizable non-zero-free-length springs directly, thereby reducing the complexity involved in simulating zero-free-length springs from non-zero-free-length springs. This method allows springs to be attached to the preceding parent link, which makes the implementation of spring balancing practical. Because auxiliary linkages can be avoided, the resultant arm of the humanoid robot is compact. The cost benefits and reduced complexity can be significant advantages in the development of this arm of the humanoid robot.

Keywords: actuator torque, child-parent connections, spring balancing, the arm of a humanoid robot

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5345 Geothermal Energy Evaluation of Lower Benue Trough Using Spectral Analysis of Aeromagnetic Data

Authors: Stella C. Okenu, Stephen O. Adikwu, Martins E. Okoro

Abstract:

The geothermal energy resource potential of the Lower Benue Trough (LBT) in Nigeria was evaluated in this study using spectral analysis of high-resolution aeromagnetic (HRAM) data. The reduced to the equator aeromagnetic data was divided into sixteen (16) overlapping blocks, and each of the blocks was analyzed to obtain the radial averaged power spectrum which enabled the computation of the top and centroid depths to magnetic sources. The values were then used to assess the Curie Point Depth (CPD), geothermal gradients, and heat flow variations in the study area. Results showed that CPD varies from 7.03 to 18.23 km, with an average of 12.26 km; geothermal gradient values vary between 31.82 and 82.50°C/km, with an average of 51.21°C/km, while heat flow variations range from 79.54 to 206.26 mW/m², with an average of 128.02 mW/m². Shallow CPD zones that run from the eastern through the western and southwestern parts of the study area correspond to zones of high geothermal gradient values and high subsurface heat flow distributions. These areas signify zones associated with anomalous subsurface thermal conditions and are therefore recommended for detailed geothermal energy exploration studies.

Keywords: geothermal energy, curie-point depth, geothermal gradient, heat flow, aeromagnetic data, LBT

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5344 A Web Application for Screening Dyslexia in Greek Students

Authors: Antonios Panagopoulos, Stamoulis Georgios

Abstract:

Dyslexia's diagnosis is made taking into account reading and writing skills and is carried out by qualified scientific staff. In addition, there are screening tests that are designed to give an indication of possible dyslexic difficulties. Their main advantage is that they create a pleasant environment for the user and reduce the stress that can lead to false results. An online application was created for the first time, as far as authors' knowledge, for screening Dyslexia in Greek high school students named «DyScreTe». Thus, a sample of 240 students between 16 and 18 years old in Greece was taken, of which 120 were diagnosed with dyslexia by an official authority in Greece, and 120 were typically developed. The main hypothesis that was examined is that students who were diagnosed with dyslexia by official authorities in Greece had significantly lower performance in the respective software tests. The results verified the hypothesis we made those children with dyslexia in each test had a lower performance com-pared to the type developed in successful responses, except for the intelligence test. After random sampling, it was shown that the new online application was a useful tool for screening dyslexia. However, computer evaluation cannot replace the diagnosis by a professional expert, but with the results of this application, the interdisciplinary team that deals with the differential diagnosis will create and evaluate, at a later time, the appropriate intervention program.

Keywords: dyslexia, screening tests, deficits, application

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5343 Cultural Orientation as a Moderator between Social Support Needs and Psychological Well-Being among Canadian University Students

Authors: Allison Streutker, Josephine Tan

Abstract:

Universities across Canada have experienced unprecedented growth in international student enrollment from across the world. As cultural diversity in Canada and other countries increases, understanding the social support needs of all students is important for providing them with the assistance they need to thrive psychologically and academically. Those from individualistic cultural orientations tend to seek explicit social support, which involves expressly asking for assistance in times of stress. However, those from collectivistic cultural orientations are more likely to seek implicit social support, where encouragement is obtained from spending time among valued social groups without explicitly talking about problems. This study explored whether the relationship between the type of social support needs (implicit or explicit) and psychological and academic functioning might be moderated by cultural orientations (individualistic, collectivistic) among university students. Participants were 110 university students (70 women, 40 men; mean age = 24.8 years, SD = 6.6). They completed the Individualism and Collectivism Scale (ICS), Perceived Stress Scale (PSS), Interpersonal Support Evaluation List (ISEL) which assesses implicit and explicit social support, Satisfaction with Life Scale (SWLS), Scale of Positive and Negative Experience (SPANE) which yields positive and negative experience scores, Flourishing Scale (FS), and reported their grade point average (GPA) as a measure of academic performance. Moderated regression analysis demonstrated that, for those scoring lower on individualism, reporting lower level of implicit support predicted higher levels of perceived stress. For those scoring higher on individualism, lower levels of explicit social support predicted higher levels of perceived stress and a greater number of negative experiences. Generally, higher levels of implicit support were associated with greater satisfaction with life for all students, with the association becoming stronger among students with higher collectivism scores. No other significant findings were found. The results point to the value of considering the cultural orientations of students when designing programs to maintain and improve their sense of well-being.

Keywords: cultural orientation, social support, university students, well-being

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5342 The Influence of Applying Mechanical Chest Compression Systems on the Effectiveness of Cardiopulmonary Resuscitation in Out-of-Hospital Cardiac Arrest

Authors: Slawomir Pilip, Michal Wasilewski, Daniel Celinski, Leszek Szpakowski, Grzegorz Michalak

Abstract:

The aim of the study was to evaluate the effectiveness of cardiopulmonary resuscitation taken by Medical Emergency Teams (MET) at the place of an accident including the usage of mechanical chest compression systems. In the period of January-May 2017, there were 137 cases of a sudden cardiac arrest in a chosen region of Eastern Poland with 360.000 inhabitants. Medical records and questionnaires filled by METs were analysed to prove the effectiveness of cardiopulmonary resuscitations that were considered to be effective when an early indication of spontaneous circulation was provided and the patient was taken to hospital. A chest compression system used by METs was applied in 60 cases (Lucas3 - 34 patients; Auto Pulse - 24 patients). The effectiveness of cardiopulmonary resuscitation among patients who were employed a chest compression system was much higher (43,3%) than the manual cardiac massage (36,4%). Thus, the usage of Lucas3 chest compression system resulted in 47% while Auto Pulse was 33,3%. The average ambulance arrival time could have had a significant impact on the subsequent effectiveness of cardiopulmonary resuscitation in these cases. Ambulances equipped with Lucas3 reached the destination within 8 minutes, and those with Auto Pulse needed 12,1 minutes. Moreover, taking effective basic life support (BLS) by bystanders before the ambulance arrival was much more frequent for ambulances with Lucas3 than Auto Pulse. Therefore, the percentage of BLS among the group of patients who were employed Lucas3 by METs was 26,5%, and 20,8% for Auto Pulse. The total percentage of taking BLS by bystanders before the ambulance arrival resulted in 25% of patients who were later applied a chest compression system by METs. Not only was shockable cardiac rhythm obtained in 47% of these cases, but an early indication of spontaneous circulation was also provided in all these patients. Both Lucas3 and Auto Pulse were evaluated to be significantly useful in improving the effectiveness of cardiopulmonary resuscitation by 97% of Medical Emergency Teams. Therefore, implementation of chest compression systems essentially makes the cardiopulmonary resuscitation even more effective. The ambulance arrival time, taking successful BLS by bystanders before the ambulance arrival and the presence of shockable cardiac rhythm determine an early indication of spontaneous circulation among patients after a sudden cardiac arrest.

Keywords: cardiac arrest, effectiveness, mechanical chest compression systems, resuscitation

Procedia PDF Downloads 249
5341 Wear Assessment of SS316l-Al2O3 Composites for Heavy Wear Applications

Authors: Catherine Kuforiji, Michel Nganbe

Abstract:

The abrasive wear of composite materials is a major challenge in highly demanding wear applications. Therefore, this study focuses on fabricating, testing and assessing the properties of 50wt% SS316L stainless steel–50wt% Al2O3 particle composites. Composite samples were fabricated using the powder metallurgy route. The effects of the powder metallurgy processing parameters and hard particle reinforcement were studied. The microstructure, density, hardness and toughness were characterized. The wear behaviour was studied using pin-on-disc testing under dry sliding conditions. The highest hardness of 1085.2 HV, the highest theoretical density of 94.7% and the lowest wear rate of 0.00397 mm3/m were obtained at a milling speed of 720 rpm, a compaction pressure of 794.4 MPa and sintering at 1400 °C in an argon atmosphere. Compared to commercial SS316 and fabricated SS316L, the composites had 7.4 times and 11 times lower wear rate, respectively. However, the commercial 90WC-10Co showed 2.2 times lower wear rate compared to the fabricated SS316L-Al2O3 composites primarily due to the higher ceramic content of 90 wt.% in the reference WC-Co. However, eliminating the relatively high porosity of about 5 vol% using processes such as HIP and hot pressing can be expected to lead to further substantial improvements of the composites wear resistance.

Keywords: SS316L, Al2O3, powder metallurgy, wear characterization

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5340 The Nature of Mineralizing Fluids in the Hammam Zriba Deposit (F-Ba-Sr-Pb-Zn) in North-eastern Tunisia

Authors: Miladi Yasmine, Bouhlel Salah, David Banks

Abstract:

The Hammam Zriba (F-Ba-Sr-Pb-Zn) ore deposits of the Zaghouan district are located in northeast Tunisia, 60 Km south of Tunis. The host rocks belong to the Ressas Formation (Tithonian age) and lower Cretaceous layers. Mineralization occurs as stratiform replacement heaps and lenses. The mineral assemblage is composed of fluorite, barite, sphalerite, and galena. Primary fluid inclusions in sphalerite have homogenization temperatures ranging from 83 to 140°C, final melting temperature range from −18 to −7.0, corresponding to salinities of 5 to 21 wt % NaCl equivalent. Fluid inclusions in fluorite homogenize to the liquid phase between 132 and 178°C. Final ice melting temperatures range from −25 to −6.8 °C, corresponding to salinities between 17 and 24 wt% NaCl Equivalent. The LA-ICP-MS analyses of the fluid inclusions in fluorite show that these fluids are dominated by Na>Ca>K>Mg, with the concentration of Fe being equivalent to that of Mg. Microthermometric analyses of the fluid inclusions observed in fluorite and sphalerite show that two distinct fluids were involved in the mineralization deposition: a warmer saline fluid (132-178°C, 17-24 wt % NaCl equivalent) and cooler saline fluid (83°C-140, 5-21 wt %NaCl equivalent). The ore fluid result from highly saline and Na-Ca dominated with lower Mg concentrations come from the leaching of the dolomitic host rocks by the fluids.

Keywords: Hammam Zriba , fluid inclusions, LA-ICP-MS, Zaghouan district

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5339 Kinematics and Dynamics Analysis of Crank-Piston System of a High-Power, Nine-Cylinder Aircraft Engine

Authors: Michal Biały, Konrad Pietrykowski, Rafal Sochaczewski

Abstract:

The kinematics and dynamics analysis of crank-piston system of aircraft engine. The object of the study was the high power aircraft engine ASz 62-IR. This engine is produced by a Polish company WSK "PZL-KALISZ" S.A.". All analyzes were performed numerically using CAD and CAE environment. Three-dimensional model of the crank-piston system was developed based on real engine located in the Laboratory of Centre of Innovation and Advanced Technologies of Lublin University of Technology. During the development of the model, the technique of reverse engineering - 3D scanning was used. ASz 62-IR engine is characterized by a radial type of crank-piston system. In this system the cylinders are arranged radially around the circle. This crank-piston system consists of a main connecting rod and eight additional connecting rods. In addition, three-dimensional model consists of a piston pins, pistons and piston rings. As a result of the specific engine design, characteristics of the piston individual movement are slightly different from each other. But the model assumes that they are the same during the analysis. Three-dimensional model of the engine was implemented into the MSC Adams software. The environment of MSC Adams allows for multibody simulation of the dynamic phenomena. This determines the state parameters of the moving elements, among which the load or force distribution on each kinematic node can be distinguished. Materials and characteristic materials parameters were adopted on the basis of commonly used materials for engine parts. The mass values of individual elements were adopted on the basis of real engine parts. The piston gas forces were replaced by calculation of pressure variations recorded during engine tests on the engine test bench. The research the changes of forces acting in the individual kinematic pairs of crank-piston system. The model allows to determine the load on the crankshaft main bearings. This gives the possibility for the main supports forces analysis The model allows for testing and simulation of kinematics and dynamics of a radial aircraft engine. This is the first stage of the work, which aims to numerical simulation of vibration of multi-cylinder aircraft engine. This work has been financed by the Polish National Centre for Research and Development, INNOLOT, under Grant Agreement No. INNOLOT/I/1/NCBR/2013.

Keywords: aircraft engine, CAD, CAE, dynamics, kinematics, MSC Adams, numerical simulation

Procedia PDF Downloads 389