Search results for: erosion rate prediction

Authors: Vimanyu Chadha, Ranganath M. Singari

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Drilling composite materials is a frequently practiced machining process during assembling in various industries such as automotive and aerospace. However, drilling of glass fiber reinforced plastic (GFRP) composites is significantly affected by damage tendency of these materials under cutting forces such as thrust force and torque. The aim of this paper is to investigate the influence of the various cutting parameters such as cutting speed and feed rate; subsequently also to study the influence of number of layers on delamination produced while drilling a GFRP composite. A plan of experiments, based on Taguchi techniques, was instituted considering drilling with prefixed cutting parameters in a hand lay-up GFRP material. The damage induced associated with drilling GFRP composites were measured. Moreover, Analysis of Variance (ANOVA) was performed to obtain minimization of delamination influenced by drilling parameters and number layers. The optimum drilling factor combination was obtained by using the analysis of signal-to-noise ratio. The conclusion revealed that feed rate was the most influential factor on the delamination. The best results of the delamination were obtained with composites with a greater number of layers at lower cutting speeds and feed rates.

Keywords: analysis of variance, delamination, design optimization, drilling, glass fiber reinforced plastic composites, Taguchi method

Procedia PDF Downloads 262

Authors: A. O. Oluwajobi, O. A. Falusi, N. A. Zubbair, T. Owoeye, F. Ladejobi, M. C. Dangana, A. Abubakar

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The technology of mobile telephony has positively enhanced human life and reports on the bio safety of the radiation from their antennae have been contradictory, leading to serious litigations and violent protests by residents in several parts of the world. The crave for more information, as requested by WHO in order to resolve this issue, formed the basis for this study on the effect of the radiation from 900 MHz GSM antenna on the DNA of Hibiscus sabdariffa. Seeds of H. sabdariffa were raised in pots placed in three replicates at 100, 200, 300 and 400 metres from the GSM antennae in three selected test locations and a control where there was no GSM signal. Temperature (˚C) and the relative humidity (%) of study sites were measured for the period of study (24 weeks). Fresh young leaves were harvested from each plant at two, eight and twenty-four weeks after sowing and the DNA extracts were subjected to RAPD-PCR analyses. There were no significant differences between the weather conditions (temperature and relative humidity) in all the study locations. However, significant differences were observed in the intensities of radiations between the control (less than 0.02 V/m) and the test (0.40-1.01 V/m) locations. Data obtained showed that DNA of samples exposed to rays from GSM antenna had various levels of distortions, estimated at 91.67%. Distortions occurred in 58.33% of the samples between 2-8 weeks of exposure while 33.33% of the samples were distorted between 8-24 weeks exposure. Approximately 8.33% of the samples did not show distortions in DNA while 33.33% of the samples had their DNA damaged twice, both at 8 and at 24 weeks of exposure. The study showed that radiation from the 900 MHz GSM antenna is potent enough to cause distortions to DNA of H. sabdariffa even within 2-8 weeks of exposure. DNA damage was also independent of the distance from the antenna. These observations would qualify emissions from GSM mast as environmental hazard to the existence of plant biodiversities and all life forms in general. These results will trigger efforts to prevent further erosion of plant genetic resources which have been threatening food security and also the risks posed to living organisms, thereby making our environment very safe for our existence while we still continue to enjoy the benefits of the GSM technology.

Keywords: damage, DNA, GSM antenna, radiation

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Authors: Maryam Mirzaei, Sinisa Krajnovic´

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The paper reports a study about the prediction of flows around simplified vehicles using Partially-Averaged Navier-Stokes (PANS). Numerical simulations are performed for two simplified vehicles: A slanted-back Ahmed body at Re=30 000 and a square back Ahmed body at Re=300 000. A comparison of the resolved and modeled physical flow scales is made with corresponding LES and experimental data for a better understanding of the performance of the PANS model. The PANS model is compared for coarse and fine grid resolutions and it is indicated that even a coarse-grid PANS simulation is able to produce fairly close flow predictions to those from a well-resolved LES simulation. The results indicate the possibility of improvement of the predictions by employing a finer grid resolution.

Keywords: partially-averaged Navier-Stokes, large eddy simulation, PANS, LES, Ahmed body

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Authors: Braimah Joseph Odunayo, Jiju Gillariose

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This paper is aimed at developing a sampling plan that uses information from precedent and successive lots for lot disposition with a pretention that the life-time of a particular product assumes a Log-logistic distribution. A Two-pronged Truncated Deferred Sampling Plan (TTDSP) for Log-logistic distribution is proposed when the testing is truncated at a precise time. The best possible sample sizes are obtained under a given Maximum Allowable Percent Defective (MAPD), Test Suspension Ratios (TSR), and acceptance numbers (c). A formula for calculating the operating characteristics of the proposed plan is also developed. The operating characteristics and mean-ratio values were used to measure the performance of the plan. The findings of the study show that: Log-logistic distribution has a decreasing failure rate; furthermore, as mean-life ratio increase, the failure rate reduces; the sample size increase as the acceptance number, test suspension ratios and maximum allowable percent defective increases. The study concludes that the minimum sample sizes were smaller, which makes the plan a more economical plan to adopt when cost and time of production are costly and the experiment being destructive.

Keywords: consumers risk, mean life, minimum sample size, operating characteristics, producers risk

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Authors: Waqas Ali

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Concrete is broadly used as a structural material in the construction of buildings. When the concrete is exposed to elevated temperature, its strength evaluation is very necessary in the existing structure. In this study, the effect of temperature and the reliability of the core test has been evaluated. For this purpose, the cylindrical cores were extracted from High strength concrete (HSC) specimens that were exposed to the temperature ranging from 300 ℃ to 900 ℃ with a constant duration of 4 hr. This study compares the difference between the standard heated cylinders and the cores taken from them after curing of 90 days. The difference of cylindrical control and binary mix samples and extracted cores revealed that there is 12.19 and 12.38% difference at 300℃, while this difference was found to increase up to 12.89%, 13.03% at 500 ℃. Furthermore, this value is recorded as 12.99%, 13.57% and 14.40%, 14.38% at 700 ℃ and 900 ℃, respectively. A total of four equations were developed through a regression model for the prediction of the strength of concrete for both standard cylinders and extracted cores whose R square values were 0.9733, 0.9627 and 0.9473, 0.9452, respectively.

Keywords: high strength, temperature, core, reliability

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Authors: Badiy Elmabrouk, Abdelhamid Boujarif, Zhiguo Zeng, Stephane Borrel, Robert Heidsieck

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In an era where sustainability is paramount, this paper introduces a machine learning-driven testing protocol to accurately predict diode failures, merging reliability engineering with failure physics to enhance repair operations efficiency. Our approach refines the burn-in process, significantly curtailing its duration, which not only conserves energy but also elevates productivity and mitigates component wear. A case study from GE HealthCare’s repair center vividly demonstrates the method’s effectiveness, recording a high prediction of diode failures and a substantial decrease in energy consumption that translates to an annual reduction of 6.5 Tons of CO2 emissions. This advancement sets a benchmark for environmentally conscious practices in the electronics repair sector.

Keywords: maintenance, burn-in, failure physics, reliability testing

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Authors: Philippa Sambevski

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Breast cancer is the most common cancer diagnosed in Australian women. The incidence of breast cancer for Aboriginal and Torres Strait Islander (ATSI) women is lower than for non-indigenous women. However, the mortality rate for ATSI women is higher. The participation rate of ATSI women in BreastScreen Australia is below the general population. In this thematic literature review, the author collates viable strategies to increase breast screening rates among culturally and linguistically diverse individuals and provide culturally competent care. Barriers to accessing BreastScreen for ATSI women include language or communication limits, isolation, and a lack of culturally sensitive information. Culturally competent strategies require healthcare workers with an appropriate cultural and social background, clear messages, and the embedding of cultural respect within healthcare organisations. Cultural safety is determined by partnering with local indigenous groups, recognising the consumer experience, and allowing people to raise their concerns. The corresponding academic poster identifies strategies for healthcare workers to provide culturally competent care in a BreastScreen setting.

Keywords: breast screen, closing the gap, Australia, cultural safety, Aboriginal and Torres Strait Islander

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Authors: Bouharati Lokman, Bouharati Imen, Bouharati Khaoula, Bouharati Oussama, Bouharati Saddek

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Ionizing radiation exposure is an established cancer risk factor. Compared to other common environmental carcinogens, it is relatively easy to determine organ-specific radiation dose and, as a result, radiation dose-response relationships tend to be highly quantified. Nevertheless, there can be considerable uncertainty about questions of radiation-related cancer risk as they apply to risk protection and public policy, and the interpretations of interested parties can differ from one person to another. Examples of tools used in the analysis of the risk of developing cancer due to radiation are characterized by uncertainty. These uncertainties are related to the history of exposure and different assumptions involved in the calculation. We believe that the results of statistical calculations are characterized by uncertainty and imprecision. Having regard to the physiological variation from one person to another. In this study, we develop a tool based on fuzzy logic inference. As fuzzy logic deals with imprecise and uncertain, its application in this area is adequate. We propose a fuzzy system with three input variables (age, sex and body attainable cancer). The output variable expresses the risk of infringement rate of each organ. A base rule is established from recorded actual data. After successful simulation, this will instantly predict the risk of infringement rate of each body following chronic exposure to 0.1 Gy.

Keywords: radiation exposure, cancer, modeling, fuzzy logic

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Authors: Ali Zazi, Ouiza Cherifi

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Natural gas currently represents a raw material of choice for the manufacture of a wide range of chemical products via synthesis gas, among the routes of transformation of methane into synthesis gas The reaction of the oxidation of methane by gas vapor 'water. This work focuses on the study of the effect of cerieum on the nickel-based catalyst supported by silica for the methane vapor reforming reaction, with a variation of certain parameters of the reaction. The reaction temperature, the H₂O / CH₄ ratio and the flow rate of the reaction mixture (CH₄-H₂O). Two catalysts were prepared by impregnation of Degussa silica with a solution of nickel nitrates and a solution of cerium nitrates [Ni (NO₃) 2 6H₂O and Ce (NO₃) 3 6H₂O] so as to obtain the 1.5% nickel concentrations. For both catalysts and plus 1% cerium for the second catalyst. These Catalysts have been characterized by physical and chemical analysis techniques: BET technique, Atomic Absorption, IR Spectroscopy, X-ray diffraction. These characterizations indicated that the nitrates had impregnated the silica. And that the NiO and Ce₂O3 phases are present and Ni°(after reaction). The BET surface of the silica decreases without being affected. The catalytic tests carried out on the two catalysts for the steam reforming reactions show that the addition of cerium to the nickel improves the catalytic performances of the nickel. And that these performances also depend on the parameters of the reaction, namely the temperature, the rate of the reaction mixture, and the ratio (H₂O / CH₄).

Keywords: heterogeneous catalysis, steam reforming, Methane, Nickel, Cerium, synthesis gas, hydrogen

Procedia PDF Downloads 168

Authors: Sadeem Aljamaan, Reem Hariri, Rahaf Alghamdi, Batool Alotaibi, Batool Alsenan, Lama Althunayyan, Areej Alnemer

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The aim of this study is to correlate between radiological findings and histopathological results in regard to the breast imaging-reporting and data system scores, size of breast masses, molecular subtypes and suspicious radiological features, as well as to assess the concordance rate in histological grade between core biopsy and surgical excision among breast cancer patients, followed by analyzing the change of concordance rate in relation to neoadjuvant chemotherapy in a Saudi population. A retrospective review was conducted over 6-year period (2017-2022) on all breast core biopsies of women preceded by radiological investigation. Chi-squared test (χ2) was performed on qualitative data, the Mann-Whitney test for quantitative non-parametric variables, and the Kappa test for grade agreement. A total of 641 cases were included. Ultrasound, mammography, and magnetic resonance imaging demonstrated diagnostic accuracies of 85%, 77.9% and 86.9%; respectively. magnetic resonance imaging manifested the highest sensitivity (72.2%), and the lowest was for ultrasound (61%). Concordance in tumor size with final excisions was best in magnetic resonance imaging, while mammography demonstrated a higher tendency of overestimation (41.9%), and ultrasound showed the highest underestimation (67.7%). The association between basal-like molecular subtypes and the breast imaging-reporting and data system score 5 classifications was statistically significant only for magnetic resonance imaging (p=0.04). Luminal subtypes demonstrated a significantly higher percentage of speculation in mammography. Breast imaging-reporting and data system score 4 manifested a substantial number of benign pathologies in all the 3 modalities. A fair concordance rate (k= 0.212 & 0.379) was demonstrated between excision and the preceding core biopsy grading with and without neoadjuvant therapy, respectively. The results demonstrated a down-grading in cases post-neoadjuvant therapy. In cases who did not receive neoadjuvant therapy, underestimation of tumor grade in biopsy was evident. In summary, magnetic resonance imaging had the highest sensitivity, specificity, positive predictive value and accuracy of both diagnosis and estimation of tumor size. Mammography demonstrated better sensitivity than ultrasound and had the highest negative predictive value, but ultrasound had better specificity, positive predictive value and accuracy. Therefore, the combination of different modalities is advantageous. The concordance rate of core biopsy grading with excision was not impacted by neoadjuvant therapy.

Keywords: breast cancer, mammography, MRI, neoadjuvant, pathology, US

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Authors: J. Martin Leal-Graciano, Juan J. Pérez-Gavilán, A. Reyes-Salazar, J. H. Castorena, J. L. Rivera-Salas

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The experimental results about the global behavior of twelve 1:2 scaled reinforced concrete frame subject to in-plane lateral load are presented. The main objective was to generate experimental evidence about the use of steel bars within mortar bed-joints as shear reinforcement in infill walls. Similar to the Canadian and New Zealand standards, the Mexican code includes specifications for this type of reinforcement. However, these specifications were obtained through experimental studies of load-bearing walls, mainly confined walls. Little information is found in the existing literature about the effects of joint reinforcement on the seismic behavior of infill masonry walls. Consequently, the Mexican code establishes the same equations to estimate the contribution of joint reinforcement for both confined walls and infill walls. A confined masonry construction and a reinforced concrete frame infilled with masonry walls have similar appearances. However, substantial differences exist between these two construction systems, which are mainly related to the sequence of construction and to how these structures support vertical and lateral loads. To achieve the objective established, ten reinforced concrete frames with masonry infill walls were built and tested in pairs, having both specimens in the pair identical characteristics except that one of them included joint reinforcement. The variables between pairs were the type of units, the size of the columns of the frame and the aspect ratio of the wall. All cases included tie-columns and tie-beams on the perimeter of the wall to anchor the joint reinforcement. Also, two bare frame with identical characteristic to the infilled frames were tested. The purpose was to investigate the effects of the infill wall on the behavior of the system to in-plane lateral load. In addition, the experimental results were compared with the prediction of the Mexican code. All the specimens were tested in cantilever under reversible cyclic lateral load. To simulate gravity load, constant vertical load was applied on the top of the columns. The results indicate that the contribution of the joint reinforcement to lateral strength depends on the size of the columns of the frame. Larger size columns produce a failure mode that is predominantly a sliding mode. Sliding inhibits the production of new inclined cracks, which are necessary to activate (deform) the joint reinforcement. Regarding the effects of joint reinforcement in the performance of confined masonry walls, many facts were confirmed for infill walls: this type of reinforcement increases the lateral strength of the wall, produces a more distributed cracking and reduces the width of the cracks. Moreover, it reduces the ductility demand of the system at maximum strength. The prediction of the lateral strength provided by the Mexican code is property in some cases; however, the effect of the size of the columns on the contribution of joint reinforcement needs to be better understood.

Keywords: experimental study, Infill wall, Infilled frame, masonry wall

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Authors: Apolinar Picado, Steve Alfaro, Rafael Gamero

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Energy and exergy analyses of thin-layer drying of pineapple slices (Ananas comosus L.) were conducted in a laboratory tunnel dryer. Drying experiments were carried out at three temperatures (100, 115 and 130 °C) and an air velocity of 1.45 m/s. The effects of drying variables on energy utilisation, energy utilisation ratio, exergy loss and exergy efficiency were studied. The enthalpy difference of the gas increased as the inlet gas temperature increase. It is observed that at the 75 minutes of the drying process the outlet gas enthalpy achieves a maximum value that is very close to the inlet value and remains constant until the end of the drying process. This behaviour is due to the reduction of the total enthalpy within the system, or in other words, the reduction of the effective heat transfer from the hot gas flow to the vegetable being dried. Further, the outlet entropy exhibits a significant increase that is not only due to the temperature variation, but also to the increase of water vapour phase contained in the hot gas flow. The maximum value of the exergy efficiency curve corresponds to the maximum value observed within the drying rate curves. This maximum value represents the stage when the available energy is efficiently used in the removal of the moisture within the solid. As the drying rate decreases, the available energy is started to be less employed. The exergetic efficiency was directly dependent on the evaporation flux and since the convective drying is less efficient that other types of dryer, it is likely that the exergetic efficiency has relatively low values.

Keywords: efficiency, energy, exergy, thin-layer drying

Procedia PDF Downloads 258

Authors: Nur Dayana Khairunnisa Rosli, Seripah Awang Kechil

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Swirling flows with velocity slip are important in nature and industrial processes. The present work considers the effects of velocity slip, temperature jump and suction/injection on the flow and heat transfer of power-law fluids due to a rotating disk in the presence of magnetic field. The system of the partial differential equations is highly non-linear. The number of independent variables is reduced by transforming the system into a system of coupled non-linear ordinary differential equations using similarity transformations. The effects of suction/injection, velocity slip and temperature jump on the flow rates are investigated for various cases of shear thinning and shear thickening power law fluids. The thermal and velocity jump strongly reduce the heat transfer rate and skin friction coefficient. Suction decreases the radial and tangential skin friction coefficient and the rate of heat transfer. It is also observed that the effects are more pronounced in the case of shear thinning fluids as compared to shear thickening fluids.

Keywords: heat transfer, power-law fluids, rotating disk, suction or injection, temperature jump, velocity slip

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Authors: Michael Wagner, Philipp Steinbauer, Andrea Katharina Lietz, Alexander Hoffelner, Johannes Fessler

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Background: Cardiopulmonary resuscitations are stressful situations in which vital decisions must be made within seconds. Lack of routine due to the infrequency of pediatric emergencies can lead to serious medical and communication errors. Virtual reality can fundamentally change the way simulation training is conducted in the future. It appears to be a useful learning tool for technical and non-technical skills. It is important to investigate the use of VR in providing a strong sense of presence within simulations. Methods: In this randomized study, we will enroll doctors and medical students from the Medical University of Vienna, who will receive learning material regarding the resuscitation of a one-year-old child. The study will be conducted in three phases. In the first phase, 20 physicians and 20 medical students from the Medical University of Vienna will be included. They will perform simulation-based training with a standardized scenario of a critically ill child with a hypovolemic shock. The main goal of this phase is to establish a baseline for the following two phases to generate comparative values regarding cognitive load and stress. In phase 2 and 3, the same participants will perform the same scenario in a VR setting. In both settings, on three set points of progression, one of three predefined events is triggered. For each event, three different stress levels (easy, medium, difficult) will be defined. Stress and cognitive load will be analyzed using the NASA Task Load Index, eye-tracking parameters, and heart rate. Subsequently, these values will be compared between VR training and traditional simulation-based training. Hypothesis: We hypothesize that the VR training and the traditional training groups will not differ in physiological response (cognitive load, heart rate, and heart rate variability). We further assume that virtual reality training can be used as cost-efficient additional training. Objectives: The aim of this study is to measure cognitive load and stress level during a real-life simulation training and compare it with VR training in order to show that VR training evokes the same physiological response and cognitive load as real-life simulation training.

Keywords: virtual reality, cognitive load, simulation, adaptive virtual reality training

Procedia PDF Downloads 119

Authors: Weerinda Appamana, Jirapong Keawkoon, Yamonporn Pacthong, Jirathiti Chitsanguansuk, Yanyong Sookklay

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In the present work, spinning disc reactor has been used for the intensification of synthesis of biodiesel from refined palm oil (RPO) based on the transesterification reaction. Experiments have been performed using different spinning disc surface and under varying operating parameters viz. molar ratio of oil to methanol (over the range of 1:4.5–1:9), rotational speed (over the range of 500–2,000 rpm), total flow rate (over the range of 260-520 ml/min), and KOH catalyst loading of 1.50% by weight of oil. Maximum FAME (fatty acid methyl esters) yield (97.5 %) of biodiesel from RPO was obtained at oil to methanol ratio of 1:6, temperature of 60 °C, and rotational speed of 1500 rpm and flow rate of 520 mL/min using groove disc at KOH catalyst loading of 1.5 wt%. Also, higher yield efficiency (biodiesel produced per unit energy consumed) was obtained for using the spinning disc reactor based approach as compared to the ultrasound hydrodynamic cavitation and conventional mechanical stirrer reactors. It obviously offers a significant reduction in the reaction time for the transesterification, especially when compared with the reaction time of 90 minutes required for the conventional mechanical stirrer. It can be concluded that the spinning disk reactor is a promising alternative method for continuous biodiesel production.

Keywords: spinning disc reactor, biodiesel, process intensification, yield efficiency

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Authors: Robert Caulk

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A generalized framework for adaptive machine learning deployments in algorithmic trading is introduced, tested, and released as open-source code. The presented software aims to test the hypothesis that recent data contains enough information to form a probabilistically favorable short-term price prediction. Further, the framework contains various adaptive machine learning techniques that are geared toward generating profit during strong trends and minimizing losses during trend changes. Results demonstrate that this adaptive machine learning approach is capable of capturing trends and generating profit. The presentation also discusses the importance of defining the parameter space associated with the dynamic training data-set and using the parameter space to identify and remove outliers from prediction data points. Meanwhile, the generalized architecture enables common users to exploit the powerful machinery while focusing on high-level feature engineering and model testing. The presentation also highlights common strengths and weaknesses associated with the presented technique and presents a broad range of well-tested starting points for feature set construction, target setting, and statistical methods for enforcing risk management and maintaining probabilistically favorable entry and exit points. The presentation also describes the end-to-end data processing tools associated with FreqAI, including automatic data fetching, data aggregation, feature engineering, safe and robust data pre-processing, outlier detection, custom machine learning and statistical tools, data post-processing, and adaptive training backtest emulation, and deployment of adaptive training in live environments. Finally, the generalized user interface is also discussed in the presentation. Feature engineering is simplified so that users can seed their feature sets with common indicator libraries (e.g. TA-lib, pandas-ta). The user also feeds data expansion parameters to fill out a large feature set for the model, which can contain as many as 10,000+ features. The presentation describes the various object-oriented programming techniques employed to make FreqAI agnostic to third-party libraries and external data sources. In other words, the back-end is constructed in such a way that users can leverage a broad range of common regression libraries (Catboost, LightGBM, Sklearn, etc) as well as common Neural Network libraries (TensorFlow, PyTorch) without worrying about the logistical complexities associated with data handling and API interactions. The presentation finishes by drawing conclusions about the most important parameters associated with a live deployment of the adaptive learning framework and provides the road map for future development in FreqAI.

Keywords: machine learning, market trend detection, open-source, adaptive learning, parameter space exploration

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Authors: Utsamani Cintyamena, Sandra Frans Olivia, Shita Lisyadewi, Ariane Utomo

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Family planning is one of fundamental aspects in preventing maternal morbidity and mortality. However, the prevalence rate of Indonesia’s married women in choosing contraception is low. This study purpose to assess opportunities and challenges in family planning. Methodology: We conducted a qualitative study in Banyumas District which has huge reduction of maternal mortality rate from 2013 to 2015. Four focus group discussions and four small group discussions were conducted to assess knowledge and attitude of women in using contraceptive and their method of choice, as well as in-depth interview to four health workers and two family planning field officers as triangulation. Thematic content analysis was done manually. Results: Key themes emerge across interviews including (1) first choice of contraception is the one that they previously had, provided that they did not encountered problems with it, (2) rumor and fear of side effect affected their method of choice, (3) selection of contraceptive method was influenced by approval of husband, believes, and role model in community. Conclusion: Collaboration of health worker, family planning field officers, community, as well as support from stakeholder, must be increased to socializing family planning.

Keywords: attitude, challenge, chance, family planning, knowledge

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Authors: Sharadha G., Suresh Kanakkanavar

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Background: Placenta previa is a condition characterized by partial or complete implantation of the placenta in the lower uterine segment. It is one of the main causes of vaginal bleeding in the third trimester and a significant cause of maternal and perinatal morbidity and mortality. Materials and Methods: This is an observational study involving 130 patients diagnosed with placenta previa and satisfying inclusion criteria. The demographic data, clinical, surgical, and treatment, along with maternal and neonatal outcome parameters, were noted in proforma. Results: The incidence of placenta previa among scarred uterus was 1.32%, and in unscarred uterus was 0.67%. The mean age of the study population was 27.12±4.426years. High parity, high abortion rate, multigravida status, and less gestational age at delivery were commonly seen in scarred uterus compared to unscarred uterus. Complete placenta previa, anterior placental position, and adherent placenta were significantly associated with a scarred uterus compared to an unscarred uterus. The rate of caesarean hysterectomy was higher in the scarred uterus, along with statistical association to previous lower-segment caesarean sections. Intraoperative procedures like uterine artery ligation, bakri balloon insertion, and iliac artery ligation were higher in the scarred group. The maternal intensive care unit admission rate was higher in the scarred group and also showed its statistical association with previous lower segment caesarean section. Neonatal outcomes in terms of pre-term birth, still birth, neonatal intensive care unit admission, and neonatal death, though higher in the scarred group, did not differ statistically among the groups. Conclusion: Advancing maternal age, multiparity, prior uterine surgeries, and abortions are independent risk factors for placenta previa. Maternal morbidity is higher in the scarred uterus group compared to the unscarred group. Neonatal outcomes did not differ statistically among the groups. This knowledge would help the obstetricians to take measures to reduce the incidence of placenta previa and scarred uterus which would improve the fetomaternal outcome of placenta previa.

Keywords: placenta previa, scarred uterus, unscarred uterus, adherent placenta

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Authors: A. Jatau, Q. Majeed, H. M. Bandiya

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The efficacy of five local spices, namely; Hot pepper (Capsicum annum L.), Black pepper (Piper guinese Schum and Thonn), Sweet basil (Occimum canum Sim), African nut-meg (Monodora myristica Dunal), and Ginger (Zingiber officianale Ross) with conventional insecticide against the D. maculatus was studied under ambient laboratory conditions. The plants were pulverized into powders and applied at the rate of 1.0, 2.0 and 3.0g per 25g of disinfected dried fish. The same amount of fish (25g) was treated with 5ml of 1.0, 2.0 and 3.0 percent solution of conventional insecticide (dichlorvos) and air dried for 2hrs. Ten newly hatched 1st instar larvae (24hrs old) were introduced into each powdered smoked fish in separate beakers. Untreated control was also set up. Observation on the mortality and development were recorded daily until the larvae pupated. Each of the treated smoked fish showed significant (p<0.05) effect on the larval mortality and development when compared with the control. The Piper guinense was as efficacious as dichlorvos in killing all the larvae (100%) at all concentrations before pupation. Ocimum Canunm gave the second best results (50.00, 63.33 and 100%), while the other three spices resulted in less than 50% mortalities at all rate of application. The spice powders were also observed to have extended the larval developmental period. Thus, the spices tested can be recommended for the control of D. maculatus.

Keywords: development, dermestes maculatus, insecticide, local spices, mortality

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Authors: Oluwasefunmi Eunice Irewole, Enrique Armas Arévalos

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Agriculture has played a crucial role in the economy and the development of many countries. Moreover, the basic needs for human survival are; food, shelter, and cloth are link on agricultural production. Most developed countries see that agriculture provides them with food and raw materials for different goods such as (shelter, medicine, fuel and clothing) which has led to an increase in incomes, livelihoods and standard of living. This study aimed at analysing the relationship between International competitiveness of agricultural products, with the area, fertilizer, labour force, economic growth, foreign direct investment, exchange rate and inflation rate in Latin America during the period of 1991-to 2019. In this study, panel data econometric methods were used, as well as cross-section dependence (Pesaran test), unit root (cross-section Augumented Dickey Fuller and Cross-sectional Im, Pesaran, and Shin tests), cointergration (Pedroni and Fisher-Johansen tests), and heterogeneous causality (Pedroni and Fisher-Johansen tests) (Hurlin and Dumitrescu test). The results reveal that the model has cross-sectional dependency and that they are integrated at one I. (1). The "fully modified OLS and dynamic OLS estimators" were used to examine the existence of a long-term relationship, and it was found that a long-term relationship existed between the selected variables. The study revealed a positive significant relationship between International Competitiveness of the agricultural raw material and area, fertilizer, labour force, economic growth, and foreign direct investment, while international competitiveness has a negative relationship with the advantages of the exchange rate and inflation. The economy policy recommendations deducted from this investigation is that Foreign Direct Investment and the labour force have a positive contribution to the increase of International Competitiveness of agricultural products.

Keywords: revealed comparative advantage, agricultural products, area, fertilizer, economic growth, granger causality, panel unit root

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Authors: M. Bidi, H. Akhbari, S. Eslami, A. Bakhtiari

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Due to the high potential of solar energy utilization in Iran, development of related technologies is of great necessity. Linear parabolic collectors are among the most common and most efficient means to harness the solar energy. The main goal of this paper is design and construction of a parabolic trough collector to produce hot water and steam in Tehran. To provide precise and practical plans, 3D models of the collector under consideration were developed using Solidworks software. This collector was designed in a way that the tilt angle can be adjusted manually. To increase concentraion ratio, a small diameter absorber tube is selected and to enhance solar absorbtion, a shape of U-tube is used. One of the outstanding properties of this collector is its simple design and use of low cost metal and plastic materials in its manufacturing procedure. The collector under consideration was installed in Shahid Beheshti University of Tehran and the values of solar irradiation, ambient temperature, wind speed and collector steam production rate were measured in different days and hours of July. Results revealed that a 1×2 m parabolic trough collector located in Tehran is able to produce steam by the rate of 300ml/s under the condition of atmospheric pressure and without using a vacuum cover over the absorber tube.

Keywords: desalination, parabolic trough collector, direct steam production, solar water heater, design and construction

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Authors: Daniel S. Brox

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Starting from earthquake fault dynamic equations, a correspondence between earthquake occurrence statistics in a seismic region before a major earthquake and eigenvalue statistics of a differential operator whose bound state eigenfunctions characterize the distribution of stress in the seismic region is derived. Modeling these eigenvalue statistics with a 2D Coulomb gas statistical physics model, previously reported deviation of seismic activation earthquake occurrence statistics from Gutenberg-Richter statistics in time intervals preceding the major earthquake is derived. It also explains how statistical physics modeling predicts a finite-dimensional nonlinear dynamic system that describes real-time velocity model evolution in the region undergoing seismic activation and how this prediction can be tested experimentally.

Keywords: seismic activation, statistical physics, geodynamics, signal processing

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Authors: Jiahe Liu, Hongyang Yu, Miao Luo, Feng Qian

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The widespread application of 3D human body reconstruction spans various fields. Smplify-X, an algorithm reliant on single-image input, employs three distinct body parameter templates, necessitating gender classification of individuals within the input image. Researchers employed a ResNet18 network to train a gender classifier within the Smplify-X framework, setting the threshold at 0.9, designating images falling below this threshold as having neutral gender. This model achieved 62.38% accurate predictions and 7.54% incorrect predictions. Our improvement involved refining the MobileNet network, resulting in a raised threshold of 0.97. Consequently, we attained 78.89% accurate predictions and a mere 0.2% incorrect predictions, markedly enhancing prediction precision and enabling more precise 3D human body reconstruction.

Keywords: SMPLX, mobileNet, gender classification, 3D human reconstruction

Procedia PDF Downloads 105

Authors: Ghodhbani Salah, Jemili Farah

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With the growth of cyber attacks, information safety has become an important issue all over the world. Many firms rely on security technologies such as intrusion detection systems (IDSs) to manage information technology security risks. IDSs are considered to be the last line of defense to secure a network and play a very important role in detecting large number of attacks. However the main problem with today’s most popular commercial IDSs is generating high volume of alerts and huge number of false positives. This drawback has become the main motivation for many research papers in IDS area. Hence, in this paper we present a data mining technique to assist network administrators to analyze and reduce false positive alarms that are produced by an IDS and increase detection accuracy. Our data mining technique is unsupervised clustering method based on hybrid ANT algorithm. This algorithm discovers clusters of intruders’ behavior without prior knowledge of a possible number of classes, then we apply K-means algorithm to improve the convergence of the ANT clustering. Experimental results on real dataset show that our proposed approach is efficient with high detection rate and low false alarm rate.

Keywords: intrusion detection system, alarm filtering, ANT class, ant clustering, intruders’ behaviors, false alarms

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Authors: Mahmoud Tarek, Alaa Obeida, Mai Magdy, Khalid Hussein, Aly Shalaby

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Background: More doctors are complaining of burnout than before, Burnout is a state of physical and mental exhaustion caused by the doctor’s lifestyle, unfortunately, Medical errors are also more likely in those suffering from burnout and these may result in malpractice suits. Methodology: It is a retrospective audit of burnout response on all neonatologists over a 9 months period. We gathered data using burnout questionnaire, it was obtained from 23 physicians, the physicians divided into 5 categories according to the final score of the 28 questions in the questionnaire. Category 1 with score from 28-38 with almost no work stress, category 2 with score (38-50) who express a low amount of job related stress, category 3 with score (51-70) with moderate amount of stress, category 4 with score (71-90) those express a high amount of job stress and begun to burnout, category 5 with score (91 and above) who are under a dangerous amount of stress and advanced stage of burnout. Results: 33 neonatologists have received the questionnaire, 23 responses were sent back with a response rate of 69.6%. The results showed that 61% of physicians fall in category 4, 31% of the physician in category 5, while 8% of physicians equally distributed between category 2 and 3 (4% each of them). On the other hand, there is no physician present in category 1. Conclusion: Burnout is prevalent in SNICUs, So interventions to minimize burnout prevalence may be of greater importance as this may be reflected indirectly on medical conditions of the patients and physicians, efforts should be done to decrease this high rate of burnout.

Keywords: Cairo, work overload, exhaustion, surgery, neonatal ICU

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Authors: Solaine Hachem, Frédéric Bourquin, Dominique Siegert

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The brutal collapse of bridges is mainly due to scour. Indeed, the soil erosion in the riverbed around a pier modifies the embedding conditions of the structure, reduces its overall stiffness and threatens its stability. Hence, finding an efficient technique that allows early scour detection becomes mandatory. Vibration analysis is an indirect method for scour detection that relies on real-time monitoring of the bridge. It tends to indicate the presence of a scour based on its consequences on the stability of the structure and its dynamic response. Most of the research in this field has focused on the dynamic behavior of a single pile and has examined the depth of the scour. In this paper, a bridge is fully modeled with all piles and spans and the scour is represented by a reduction in the foundation's stiffnesses. This work aims to identify the vibration modes sensitive to the rigidity’s loss in the foundations so that their variations can be considered as a scour indicator: the decrease in soil-structure interaction rigidity leads to a decrease in the natural frequencies’ values. By using the first-order perturbation method, the expression of sensitivity, which depends only on the selected vibration modes, is established to determine the deficiency of foundations stiffnesses. The solutions are obtained by using the singular value decomposition method for the regularization of the inverse problem. The propagation of uncertainties is also calculated to verify the efficiency of the inverse problem method. Numerical simulations describing different scenarios of scour are investigated on a simplified model of a real composite steel-concrete bridge located in France. The results of the modal analysis show that the modes corresponding to in-plane and out-of-plane piers vibrations are sensitive to the loss of foundation stiffness. While the deck bending modes are not affected by this damage.

Keywords: bridge’s piers, inverse problems, modal sensitivity, scour detection, vibration analysis

Procedia PDF Downloads 113

Authors: A. Mohamed, A. El-Aziz

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The pH of the body plays a great role in the degradation kinetics of biodegradable Mg-Ca orthopedic implants. At the location of fracture, the pH of the body becomes no longer neutral which draws the attention towards studying a range of different pH values of the body fluid. In this study, the pH of Hank’s balanced salt solution (HBSS) was modified by phosphate buffers into an aggressive acidic pH 1.8, a slightly acidic pH 5.3 and an alkaline pH 8.1. The biodegradation of Mg-0.8Ca implant was tested in those three different media using immersion test and electrochemical polarization means. It was proposed that the degradation rate has increased with decreasing the pH of HBSS. The immersion test revealed weight gain for all the samples followed by weight loss as the immersion time increased. The highest weight gain was pronounced for the acidic pH 1.8 and the least weight gain was observed for the alkaline pH 8.1. This was in agreement with the electrochemical polarization test results where the degradation rate was found to be high (7.29 ± 2.2 mm/year) in the aggressive acidic solution of pH 1.8 and relatively minimum (0.31 ± 0.06 mm/year) in the alkaline medium of pH 8.1. Furthermore, it was confirmed that the pH of HBSS has reached a steady state of an alkaline pH (~pH 11) at the end of the two-month immersion period regardless of the initial pH of the solution. Finally, the corrosion products formed on the samples’ surface were investigated by SEM, EDX and XRD analyses that revealed the formation of magnesium and calcium phosphates with different morphologies according to the pH.

Keywords: biodegradable, electrochemical polarization means, orthopedics, immersion test, simulated body fluid

Procedia PDF Downloads 128

Authors: Nina Tsvetkova, Rumen Harizanov, Aleksandra Ivanova, Iskra Rainova, Nina Yancheva-Petrova, Dimitar Strashimirov, Raina Enikova, Mihaela Videnova, Eleonora Kaneva, Iskren Kaftandjiev, Viktoria Levterova, Ivan Simeonovski, Nikolay Yanev, Georgi Hinkov

Abstract:

The Pneumocystis jirovecii (P. jirovecii) and protozoan of the genera Acanthamoeba, Cryptosporidium, and Toxoplasma gondii are opportunistic pathogens that can cause life-threatening infections in immunocompromised patients. Aim of the study was to evaluate the coinfection rate with opportunistic protozoal agents among Bulgarian patients diagnosed with P. jirovecii pneumonia. Thirty-eight pulmonary samples were collected from 38 patients (28 HIV-infected) with P. jirovecii infection. P. jirovecii DNA was detected by real-time PCR targeting the large mitochondrial subunit ribosomal RNA gene. Acanthamoeba was determined by genus-specific conventional PCR assay. Real-time PCR for the detection of a Toxoplasma gondii and Cryptosporidium DNA fragment was used. Pneumocystis DNA was detected in all 38 specimens; 28 (73.7%) were from HIV-infected patients. Three (10,7%) of them were co-infected with T. gondii and 1 (3.6%) with Cryptosporidium. In the group of non-HIV-infected (n=10), Cryptosporidium DNA was detected in an infant (10%). Acanthamoeba DNA was not found in the tested samples. The current study showed a relatively low rate of coinfections of Cryptosporidium spp./T. gondii and P. jirovecii in the Bulgarian patients studied.

Keywords: coinfection, opportunistic protozoal agents, Pneumocystis jirovecii, pulmonary infections

Procedia PDF Downloads 161

Authors: Sheraz Ahmad, Li Yiming, Li XiangFang, Xia Wei, Zeen Chen

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Holding CO₂ at massive scale in the enclathrated solid matter called hydrate can be perceived as one of the most reliable methods for CO₂ sequestration to take greenhouse gases emission control measures and global warming preventive actions. In this study, a dynamically coupled mass and heat transfer mathematical model is developed which elaborates the unsteady behavior of CO₂ flowing into a porous medium and converting itself into hydrates. The combined numerical model solution by implicit finite difference method is explained and through coupling the mass, momentum and heat conservation relations, an integrated model can be established to analyze the CO₂ hydrate growth within P-T equilibrium conditions. CO₂ phase transition, effect of hydrate nucleation by exothermic heat release and variations of thermo-physical properties has been studied during hydrate nucleation. The results illustrate that formation pressure distribution becomes stable at the early stage of hydrate nucleation process and always remains stable afterward, but formation temperature is unable to keep stable and varies during CO₂ injection and hydrate nucleation process. Initially, the temperature drops due to cold high-pressure CO₂ injection since when the massive hydrate growth triggers and temperature increases under the influence of exothermic heat evolution. Intermittently, it surpasses the initial formation temperature before CO₂ injection initiates. The hydrate growth rate increases by increasing injection pressure in the long formation and it also expands overall hydrate covered length in the same induction period. The results also show that the injection pressure conditions and hydrate growth rate affect other parameters like CO₂ velocity, CO₂ permeability, CO₂ density, CO₂ and H₂O saturation inside the porous medium. In order to enhance the hydrate growth rate and expand hydrate covered length, the injection temperature is reduced, but it did not give satisfactory outcomes. Hence, CO₂ injection in vacated natural gas hydrate porous sediment may form hydrate under low temperature and high-pressure conditions, but it seems very challenging on a huge scale in lengthy formations.

Keywords: CO₂ hydrates, CO₂ injection, CO₂ Phase transition, CO₂ sequestration

Procedia PDF Downloads 143

Authors: Joachim Onyike

Abstract:

The Federal Government of Nigeria in 2012 came up with a new National Housing Policy; one of its major objectives was to make housing affordable to the poor. Six years down the line, this study was carried out to find out whether the poor have fared better under the new housing policy. Owerri, the capital of Imo State, was adopted as a case study to mirror the situation nationwide. The study population was made up of low-income civil servants, i.e., grade levels 1–6 in the Imo State Civil Service. The study looked at household size, household income, rental levels, house prices, costs of major building materials, land values, land tenure, the interest rate on mortgages, inflation rate, and the status of government interventions, owing to their obvious effect on housing affordability by the low-income earners. The study made use of physical observations, questionnaires, and interviews as well as library studies to elicit relevant information. Housing affordability by the subject population did not improve. It rather dropped. The study came to the conclusion that in spite of the new National Housing Policy, housing affordability by the low-income earners has not improved. The policy as it affects the poor has not been duly implemented by both Federal and State Governments.

Keywords: house prices, housing affordability, housing policy, land values, low-income earners

Procedia PDF Downloads 207