Search results for: tensile failure load

Authors: Sait Ozsoy, Asude Gokmen, Mehtap Yondem, Hanife A. Alkan, Gulnaz T. Javan

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Deep neck infection often develops due to upper respiratory tract and odontogenic infections. Gastrointestinal System perforation can occur for many reasons and is in need of the early diagnosis and prompt surgical treatment. In both cases late or incorrect diagnosis may lead to increase morbidity and high mortality. A patient with a diagnosis of deep neck abscess died while under treatment due to sepsis and multiple organ failure. Autopsy finding showed duodenal ulcer and this is reported in the literature.

Keywords: peptic ulcer perforation, peritonitis, retropharyngeal abscess, sepsis

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Authors: Defne Uz

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Horizontal Tail of helicopter is exposed to repeated oscillatory loading generated by aerodynamic and inertial loads, and bending moments depending on operating conditions and maneuvers of the helicopter. In order to ensure that maximum stress levels do not exceed certain fatigue limit of the material and to prevent damage, a numerical analysis approach can be utilized through the Finite Element Method. Therefore, in this paper, fatigue analysis of the Horizontal Tail model is studied numerically to predict high-cycle and low-cycle fatigue life related to defined loading. The analysis estimates the stress field at stress concentration regions such as around fastener holes where the maximum principal stresses are considered for each load case. Critical element identification of the main load carrying structural components of the model with rivet holes is performed as a post-process since critical regions with high-stress values are used as an input for fatigue life calculation. Once the maximum stress is obtained at the critical element and the related mean and alternating components, it is compared with the endurance limit by applying Soderberg approach. The constant life straight line provides the limit for several combinations of mean and alternating stresses. The life calculation based on S-N (Stress-Number of Cycles) curve is also applied with fully reversed loading to determine the number of cycles corresponds to the oscillatory stress with zero means. The results determine the appropriateness of the design of the model for its fatigue strength and the number of cycles that the model can withstand for the calculated stress. The effect of correctly determining the critical rivet holes is investigated by analyzing stresses at different structural parts in the model. In the case of low life prediction, alternative design solutions are developed, and flight hours can be estimated for the fatigue safe operation of the model.

Keywords: fatigue analysis, finite element method, helicopter horizontal tail, life prediction, stress concentration

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Authors: Kevlin Govender, Anthony Walker, Glen Bright

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Mass customization is an area of increased importance and the development of rapid tooling applications is pivotal to the success of mass customization. This paper presents a laminated object manufacturing (LOM) process for rapid tooling. The process is termed 3D metal laminate printing and utilizes domestic-grade aluminum foil and epoxy for layered manufacturing. A detailed explanation of the process is presented to produce complex metal laminated composite parts. Aluminum-epoxy composite specimens were manufactured from 0.016mm aluminum and subjected to tensile tests to determine the mechanical properties of the manufactured composite in relation to solid metal specimens. The fracture zone of the specimens was analyzed under scanning electron microscopy (SEM) in order to characterize the fracture mode and study the interfacial bonding of the manufactured laminate specimens.

Keywords: 3D metal laminate printer, aluminum-epoxy composite, laminated object manufacturing, rapid tooling

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Authors: Abd El Hady N. Ebraheim

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This paper introduces a new generalization of the two parameter Weibull distribution. To this end, the quadratic rank transmutation map has been used. This new distribution is named exponentiated transmuted Weibull (ETW) distribution. The ETW distribution has the advantage of being capable of modeling various shapes of aging and failure criteria. Furthermore, eleven lifetime distributions such as the Weibull, exponentiated Weibull, Rayleigh and exponential distributions, among others follow as special cases. The properties of the new model are discussed and the maximum likelihood estimation is used to estimate the parameters. Explicit expressions are derived for the quantiles. The moments of the distribution are derived, and the order statistics are examined.

Keywords: exponentiated, inversion method, maximum likelihood estimation, transmutation map

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Authors: A. Lakshumu Naidu, K. Krishna Kishor

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This paper examines the results of an experimental study based on the engineering properties of banana peel reinforced epoxy composites. Experiments are carried out to study the effect of weight fraction on mechanical behavior of epoxy based polymer composites. The composites were made by varying the weight fraction of banana peel from 0 to 30% and banana peel were made using hand layup method. The fabricated composite samples were cut according to the ASTM standards for different experiments. Hardness test and density test were carried out at the samples. The maximum hardness, density, tensile strength, flexural strength and ILSS are getting for the material prepared with the 20 % reinforced banana peel epoxy composite. The detailed test results and observations are discussed sequentially in the paper.

Keywords: engineering properties, polymer, composite, mechanical behavior of banana peel

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Authors: Michelle Themalil, Celia Bueno, Rulla Al- Araji

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Objective and Study: There are no established guidelines for antibiotic prophylaxis in children with central venous catheters (CVCs) on home parenteral nutrition (HPN), leading to varying practices across UK Centres. We hypothesize that children with intestinal failure are at increased risk for bacteraemia due to altered anatomy, dysmotility, inflammation, biofilm formation in long-term CVCs, and the use of central lines during procedures. Given the bacteraemia rates of up to 8% in upper and 25% in lower endoscopy for adults without central lines, we argue that prophylactic antibiotics are reasonable, given the increased risks faced by this high-risk group of children. Methods: We conducted a five-year review of patients with central venous access receiving home parenteral nutrition (HPN) who underwent endoscopies with antibiotic prophylaxis at our center (tertiary). We documented and analyzed post-procedure infections and their associated risk factors. Results: A total of 15 patients on HPN underwent 29 endoscopic procedures, including 4 upper, 9 combined upper and lower, and 16 combined upper, lower, and ileoscopy. Confirmed infection rates remained at 0% up to 28 days post-procedure. The agreed-upon prophylaxis regimen was implemented, with ciprofloxacin and metronidazole administered as the primary antibiotics. Notably, only 51.7% of patients received a peripheral cannula despite recommendations to avoid central line use during anesthesia, and 20.6% had small intestinal bacterial overgrowth. Conclusions: This study is the first to investigate post-endoscopy infection rates in pediatric patients on HPN. Despite a small sample size, we observed a 0% infection rate, significantly lower than reported rates in adults. These findings suggest that further research is warranted to explore the implications of antibiotic prophylaxis in this unique patient cohort and to establish guidelines that may enhance patient safety during endoscopic procedures.

Keywords: post endosopy infections, central venous access, home parenteral nutrition, intestinal failure

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Authors: Afri Ananda Nugroho

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Privatization is one of the public policies closely related to the role of government in the economy due to the failure of the centralized system in the communist countries. This paper will discuss the basic issues of privatization as a global trend, the purpose of privatization, implementation, and impact on the success of State-Owned Enterprises (BUMN) in Indonesia. The analysis is done by looking at some important issues about the privatization problem, and some public policies are being applied such as why and how privatization is necessary and what impact it has. This paper also discusses the implications for top leaders of State-Owned Enterprises.

Keywords: privatization, state-owned enterprises, Indonesia, public policy

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Authors: Mario Robinson, Moe Rabea

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This research examines the effects of heat treatment processes on the mechanical properties and corrosion resistanceof1045 and 4140 Steel Alloysfor industrial applications. Heat treatment processes of full annealing, normalizing, quenching, and tempering are carried out on the alloy samples. The mechanical and corrosion resistance tests of the heat treated samples are carried out, and the results obtained are related to their SEMmorphologies analysis. The results show that the heat treatment processes have an effect on the tensile strength, impact, and a significant effect on the corrosion resistance of the alloy samples. With respect to the strain characteristics, significant improvement in the ductility of the samples is recorded in the full annealing and alloy tempered samples. Thus, for application requiring strength and ductility, such as in aerospace industries, this tempered heat treated alloy could be used. In addition, the quenched sample shows a significant improvement in hardness.

Keywords: heat treatment, corrosion resistance, steel, industrial appilcations

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Authors: Abdel Hadi Ebraheim

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This paper introduces a new extension of the Inverse Pareto distribution in the framework of Marshal-Olkin (1997) family of distributions. This model is capable of modeling various shapes of aging and failure data. The statistical properties of the new model are discussed. Several methods are used to estimate the parameters involved. Explicit expressions are derived for different types of moments of value in reliability analysis are obtained. Besides, the order statistics of samples from the new proposed model have been studied. Finally, the usefulness of the new model for modeling reliability data is illustrated using two real data sets with simulation study.

Keywords: pareto distribution, marshal-Olkin, reliability, hazard functions, moments, estimation

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Authors: Nupur Karmaker, Hasin Aupama Azhari, Abdul Al Mortuza, Abhijit Chanda, Golam Abu Zakaria

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Purpose: The purpose of gait analysis is to determine the biomechanics of the joint, phases of gait cycle, graphical and analytical analysis of degree of rotation, analysis of the electrical activity of muscles and force exerted on the hip joint at different locomotion during walking, running and cart pulling. Methods and Materials: Visual gait analysis and electromyography method has been used to detect the degree of rotation of joints and electrical activity of muscles. In cinematography method an object is observed from different sides and takes its video. Cart pulling length has been divided into frames with respect to time by using video splitter software. Phases of gait cycle, degree of rotation of joints, EMG profile and force analysis during walking and running has been taken from different papers. Gait cycle and degree of rotation of joints during cart pulling has been prepared by using video camera, stop watch, video splitter software and Microsoft Excel. Results and Discussion: During the cart pulling the force exerted on hip is the resultant of various forces. The force on hip is the vector sum of the force Fg= mg, due the body of weight of the person and Fa= ma, due to the velocity. Maximum stance phase shows during cart pulling and minimum shows during running. During cart pulling shows maximum degree of rotation of hip joint, knee: running, and ankle: cart pulling. During walking, it has been observed minimum degree of rotation of hip, ankle: during running. During cart pulling, dynamic force depends on the walking velocity, body weight and load weight. Conclusions: 80% people suffer gait related disease with increasing their age. Proper care should take during cart pulling. It will be better to establish the gait laboratory to determine the gait related diseases. If the way of cart pulling is changed i.e the design of cart pulling machine, load bearing system is changed then it would possible to reduce the risk of limb loss, flat foot syndrome and varicose vein in lower limb.

Keywords: kinematic, gait, gait lab, phase, force analysis

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Authors: Chihab Benmoussa

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Could the Work System Approach (WSA) function as a framework for designing high-impact knowledge mobilization systems? This paper put forward arguments in favor of the applicability of WSA for knowledge mobilization design based on evidences from a practical research. Normative approaches for practitioners are highly needed especially in the field of knowledge management (KM), given the abysmal rate of disappointment and failure of KM projects. The paper contrasts knowledge management and knowledge mobilization, presents the WSA and showed how the WSA’s concepts and ideas fit with the approach adopted by a multinational company in designing a successful knowledge mobilization initiative.

Keywords: knowledge management, knowledge mobilizations, work system method

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Authors: Reham Hajomer, Ikram Elsiddig, Amna Hamad

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Lepidium sativum (Garden Cress) belonging to Brassicaceae family is an annual herb locally known as El-rshad. In Ayurveda it is an important medicinal plant, traditionally used for the treatment of jaundice, liver problems, spleen diseases, gastrointestinal disorders, menstrual problems, fracture, arthritis, inflammatory conditions and for treatment of hypothyroidism. Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormones (Triiodithyronine T3 and Thyroxine T4) which are commonly caused by iodine deficiency. It’s divided into primary and secondary hypothyroidism, the primary caused by failure of thyroid function and secondary due to the failure of adequate thyroid-stimulating hormone (TSH) secretion from the pituitary gland or thyroid -releasing hormone (TRH) from the hypothalamus. The disease is most common in women over age 60. The objective regarding this study is to know whether Lepidium sativum would affect the level of thyroid hormones. The extract was prepared with 96% ethanol using Soxhlet apparatus. The anti-hypothyroidism activity was tested by using thirty male Wistar rats weighing (100-140 g) were used in the experiment. They were grouping into five groups, Group 1: Normal group= Administered only distilled water. Then 10 mg/kg Propylthiouracil was added to the drinking water of all other groups to induce hypothyroidism. Group 2: Negative control without any treatment; Group 3: Test group= treated with oral administration of 500mg/kg extract; Group 4: treated with oral administration of 250mg/kg of the extract; Group 5: Standard group (positive control) = treated with intraperitoneal Levothyroxine. All rats were incubated for 20 days at animal house with room temperature of proper ventilation provided with standard diet. The result show that the Lepidium sativum extract was found to increases the T3 and T4 in the propylthiouracil induced rats with values (0.29 ng/dl T3 and 0.57 U T4) for the 500mg/kg and (0.27 ng/dl T3 and 0.517 U T4) for the 250mg/kg in comparison with standard with values (0.241 ng/dl T3 and 0.516 U T4) so that Lepidium sativum can be stimulatory to thyroid function and possess significant anti-hypothyroidism effect with p-values ranges from (0.000006*-0.893472). In conclusion, from results obtained, Lepidium sativum plant extract was found to posses anti-hypothyroidism effects so its act as an agent that stimulates thyroid hormone secretion.

Keywords: anti-hypothyroidism, extract, lepidium, sativum

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Authors: Vicente A. Hernandez, Felipe Galleguillos, Rene Thibaut, Alejandro Muller

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Natural pigments have been proposed as an eco-friendly alternative to artificial pigments. Among the diverse organisms able to synthesize natural pigments, several wood colonizing fungi produce extracellular pigments which have been tested to dye fabrics at laboratory conditions with good results. However, the dyeing conditions used at laboratory level not necessary meet the real conditions in which dyeing of fabrics is conducted at industrial level. In this work, yellow and red pigments from the fungi Penicillium murcianum and Talaromyces australis, respectively, were used to dye yarn and linen fabrics using dyeing processes optimized according to the standard conditions used at industrial level. After dyeing treatments, fabrics were tested for color fastness to wash and to wet and dry rubbing, but also to tensile strength tests. Satisfactory result was obtained with both yellow and red pigments in yarn and linen, when used alone or mixed to different proportions. According to these results, natural pigments synthesized by both wood colonizing fungi have a great potential to be used in dyeing processes at industrial level.

Keywords: natural pigments, fungal pigments, yarn, linen

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Authors: Johana Jaramillo, Robin Kalfat, Dmitriy A. Dikin

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The cement production process is one of the major sources of carbon dioxide (CO₂), a potent greenhouse gas. Indeed, as a result of its cement manufacturing process, concrete contributes approximately 8% of global greenhouse gas emissions. In addition to environmental concerns, concrete also has a low tensile and ductility strength, which can lead to cracks. Graphene nanoplatelets (GNPs) have proven to be an eco-friendly solution for improving the mechanical and durability properties of concrete. The current research investigates the effects of preparing concrete enhanced with GNPs by using different wet dispersions techniques and mixing methods on its mechanical properties. Concrete specimens were prepared with 0.00 wt%, 0.10 wt%, 0.20 wt%, 0.30 wt% and wt% GNPs. Compressive and flexural strength of concrete at age 7 days were determined. The results showed that the maximum improvement in mechanical properties was observed when GNPs content was 0.20 wt%. The compressive and flexural were improved by up to 17.5% and 8.6%, respectively. When GNP dispersions were prepared by the combination of a drill and an ultrasonic probe, mechanical properties experienced maximum improvement.

Keywords: concrete, dispersion techniques, graphene nanoplatelets, mechanical properties, mixing methods

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Authors: Sabina Huč, Staffan Svensson, Tomaž Hozjan

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Timber structures may be exposed to various environmental conditions during their service life. Often, the structures have to resist extreme changes in the relative humidity of surrounding air, with simultaneously carrying the loads. Wood material response for this load case is seen as increasing deformation of the timber structure. Relative humidity variations cause moisture changes in timber and consequently shrinkage and swelling of the material. Moisture changes and loads acting together result in mechano-sorptive creep, while sustained load gives viscoelastic creep. In some cases, magnitude of the mechano-sorptive strain can be about five times the elastic strain already at low stress levels. Therefore, analyzing mechano-sorptive creep and its influence on timber structures’ long-term behavior is of high importance. Relatively many one-dimensional rheological models for rheological behavior of wood can be found in literature, while a number of models coupling creep response in each material direction is limited. In this study, mathematical formulation of a coupled two-dimensional mechano-sorptive model and its application to the experimental results are presented. The mechano-sorptive model constitutes of a moisture transport model and a mechanical model. Variation of the moisture content in wood is modelled by multi-Fickian moisture transport model. The model accounts for processes of the bound-water and water-vapor diffusion in wood, that are coupled through sorption hysteresis. Sorption defines a nonlinear relation between moisture content and relative humidity. Multi-Fickian moisture transport model is able to accurately predict unique, non-uniform moisture content field within the timber member over time. Calculated moisture content in timber members is used as an input to the mechanical analysis. In the mechanical analysis, the total strain is assumed to be a sum of the elastic strain, viscoelastic strain, mechano-sorptive strain, and strain due to shrinkage and swelling. Mechano-sorptive response is modelled by so-called spring-dashpot type of a model, that proved to be suitable for describing creep of wood. Mechano-sorptive strain is dependent on change of moisture content. The model includes mechano-sorptive material parameters that have to be calibrated to the experimental results. The calibration is made to the experiments carried out on wooden blocks subjected to uniaxial compressive loaded in tangential direction and varying humidity conditions. The moisture and the mechanical model are implemented in a finite element software. The calibration procedure gives the required, distinctive set of mechano-sorptive material parameters. The analysis shows that mechano-sorptive strain in transverse direction is present, though its magnitude and variation are substantially lower than the mechano-sorptive strain in the direction of loading. The presented mechano-sorptive model enables observing real temporal and spatial distribution of the moisture-induced strains and stresses in timber members. Since the model’s suitability for predicting mechano-sorptive strains is shown and the required material parameters are obtained, a comprehensive advanced analysis of the stress-strain state in timber structures, including connections subjected to constant load and varying humidity is possible.

Keywords: mechanical analysis, mechano-sorptive creep, moisture transport model, timber

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Authors: Rajesh Karki, Safal Bhattarai, Saket Adhikari

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Reliable and economic operation of power systems are becoming extremely challenging with large scale integration of renewable energy sources due to the intermittency and uncertainty associated with renewable power generation. It is, therefore, important to make a quantitative risk assessment and explore the potential resources to mitigate such risks. Probabilistic models for different energy storage systems (ESS), such as the flywheel energy storage system (FESS) and the compressed air energy storage (CAES) incorporating specific charge/discharge performance and failure characteristics suitable for probabilistic risk assessment in power system operation and planning are presented in this paper. The proposed methodology used in FESS modelling offers flexibility to accommodate different configurations of plant topology. It is perceived that CAES has a high potential for grid-scale application, and a hybrid approach is proposed, which embeds a Monte-Carlo simulation (MCS) method in an analytical technique to develop a suitable reliability model of the CAES. The proposed ESS models are applied to a test system to investigate the economic and reliability benefits of the energy storage technologies in system operation and planning, as well as to assess their contributions in facilitating wind integration during different operating scenarios. A comparative study considering various storage system topologies are also presented. The impacts of failure rates of the critical components of ESS on the expected state of charge (SOC) and the performance of the different types of ESS during operation are illustrated with selected studies on the test system. The paper also applies the proposed models on the test system to investigate the economic and reliability benefits of the different ESS technologies and to evaluate their contributions in facilitating wind integration during different operating scenarios and system configurations. The conclusions drawn from the study results provide valuable information to help policymakers, system planners, and operators in arriving at effective and efficient policies, investment decisions, and operating strategies for planning and operation of power systems with large penetrations of renewable energy sources.

Keywords: flywheel energy storage, compressed air energy storage, power system reliability, renewable energy, system planning, system operation

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Authors: M. Aruna

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Emphasis on the advancement of new materials and technology has been there for the past few decades. The global development towards using cheap and durable materials from renewable resources contributes to sustainable development. An experimental investigation of mechanical behaviour of sisal fiber-reinforced concrete is reported for making a suitable building material in terms of reinforcement. Fibre reinforced composite is one such material, which has reformed the concept of high strength. Sisal fibres are abundantly available in the hot areas. The sisal fiber has emerged as a reinforcing material for concretes, used in civil structures. In this work, properties such as hardness and tensile strength of sisal fibre reinforced cement composites with 6, 12, 18, and 24% by weight of sisal fibres were assessed. Sisal fiber reinforced cement composite slabs with long sisal fibers were manufactured using a cast hand layup technique. Mechanical response was measured under tension. The high energy absorption capacity of the developed composite system was reflected in high toughness values under tension respectively.

Keywords: sisal fibre, fiber-reinforced concrete, mechanical behaviour, composite materials

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Authors: A. A. Salisu, M. Y. Yakasai, K. M. Aujara

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Sisal leaves were subjected to enzymatic retting method to extract the sisal fibre. A portion of the fibre was pretreated with alkali (NaOH), and further treated with benzoyl chloride and silane treatment reagents. Both the treated and untreated Sisal fibre composites were used to fabricate the composite by hand lay-up technique using unsaturated polyester resin. Tensile, flexural, water absorption, density, thickness swelling and chemical resistant tests were conducted and evaluated on the composites. Results obtained for all the parameters showed an increase in the treated fibre compared to untreated fibre. FT-IR spectra results ascertained the inclusion of benzoyl and silane groups on the fibre surface. Scanning electron microscopy (SEM) result obtained showed variation in the morphology of the treated and untreated fibre. Chemical modification was found to improve adhesion of the fibre to the matrix, as well as physico-mechanical properties of the composites.

Keywords: chemical resistance, density test, polymer matrix sisal fibre, thickness swelling

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Authors: Esabelle Lo Yan Yam, Pheak Chhoun, Sovannary Tuot, Emily Lancsar, Siyan Yi

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Persons living with HIV (PLHIV) need lifelong antiretroviral treatment (ART) to keep their viral load suppressed to an undetectable level, maintain a healthy immune system, and reduce the risk of transmitting HIV to others. However, many factors affect PLHIV's adherence to ART, including access to antiretrovirals (ARV), stigma, lack of social support, and the burden of seeking lifelong care. Community-based care has been shown to be instrumental in the experience of PLHIV in many countries, including Cambodia. In this study based in Cambodia, a community-based ART delivery (CAD) intervention involving community action workers (CAWs) who are PLHIVs was introduced. These workers collect pre-packaged ARVs from the ART clinics and dispense them to PLHIVs in the communities. The quasi-experimental study involved approximately 2000 stable PLHIV in the intervention arm and another 2000 PLHIV in the control arm (receiving usual care). A cost-effectiveness analysis is currently conducted to complement the clinical effectiveness of the CAD intervention on the care continuum and treatment outcomes for stable PLHIV, as well as the operational effectiveness in increasing the efficiency of the ART clinics and the health system. The analysis will consider health system and societal perspectives based on primary outcomes, including retention in care, viral load suppression, and adherence to ART. Additionally, a consultation with the National Centre for HIV/AIDS, Dermatology, and STD under the Cambodia Ministry of Health will be done to discuss the conduct of a budget impact analysis that can quantify the financial impact on the government's budget when adopting the CAD intervention at the provincial and national levels. The budget impact analysis will take into consideration various scaling-up scenarios for the interventions in the country. The research will assess the cost-effectiveness of the CAD intervention to support national stakeholders in Cambodia to make an informed decision on the adoption and scaling up of the intervention in Cambodia. The results are currently being analyzed and will be available at the time of the conference.

Keywords: Cambodia, community intervention, economic evaluation, global health, HIV/AIDs, implementation research

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Authors: Yemane Hailu Fissuh, Zhongzhan Zhang

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a systematic observation from a defined time of origin up to certain failure or censor is known as survival data. Survival analysis is a major area of interest in biostatistics and biomedical researches. At the heart of understanding, the most scientific and medical research inquiries lie for a causality analysis. Thus, the main concern of this study is to investigate the causal effect of treatment on survival time conditional to the possibly time-varying covariates. The theory of causality often differs from the simple association between the response variable and predictors. A causal estimation is a scientific concept to compare a pragmatic effect between two or more experimental arms. To evaluate an average treatment effect on survival outcome, the estimating equation was adjusted for time-varying covariates under the semi-parametric transformation models. The proposed model intuitively obtained the consistent estimators for unknown parameters and unspecified monotone transformation functions. In this article, the proposed method estimated an unbiased average causal effect of treatment on survival time of interest. The modified estimating equations of semiparametric transformation models have the advantage to include the time-varying effect in the model. Finally, the finite sample performance characteristics of the estimators proved through the simulation and Stanford heart transplant real data. To this end, the average effect of a treatment on survival time estimated after adjusting for biases raised due to the high correlation of the left-truncation and possibly time-varying covariates. The bias in covariates was restored, by estimating density function for left-truncation. Besides, to relax the independence assumption between failure time and truncation time, the model incorporated the left-truncation variable as a covariate. Moreover, the expectation-maximization (EM) algorithm iteratively obtained unknown parameters and unspecified monotone transformation functions. To summarize idea, the ratio of cumulative hazards functions between the treated and untreated experimental group has a sense of the average causal effect for the entire population.

Keywords: a modified estimation equation, causal effect, semiparametric transformation models, survival analysis, time-varying covariate

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Authors: Gürkan Şakar, Akgün Alsaran, Emrah E. Özbaldan

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In this study, lateral buckling analysis of composite beams with particle additive was carried out experimentally and numerically. The effects of particle type, particle addition ratio on buckling loads of composite beams were determined. The numerical studies were performed with ANSYS package. In the analyses, clamped-free boundary condition was assumed. The load carrying capabilities of composite beams were influenced by different particle types and particle addition ratios.

Keywords: lateral buckling, nanoparticle, composite beam, numeric analysis

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Authors: Vishwajit Ghatge, David Looper

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Over the last few decades, oilfield service rolling equipment has significantly increased in weight, primarily because of emissions regulations, which require larger/heavier engines, larger cooling systems, and emissions after-treatment systems, in some cases, etc. Larger engines cause more vibration and shock loads, leading to failure of electronics and control systems. If the vibrating frequency of the engine matches the system frequency, high resonance is observed on structural parts and mounts. One such existing automated control equipment system comprising wire rope mounts used for mounting computers was designed approximately 12 years ago. This includes the use of an industrial- grade computer to control the system operation. The original computer had a smaller, lighter enclosure. After a few years, a newer computer version was introduced, which was 10 lbm heavier. Some failures of internal computer parts have been documented for cases in which the old mounts were used. Because of the added weight, there is a possibility of having the two brackets impact each other under off-road conditions, which causes a high shock input to the computer parts. This added failure mode requires validating the existing mount design to suit the new heavy-weight computer. This paper discusses the modal finite element method (FEM) analysis and experimental modal analysis conducted to study the effects of vibration on the wire rope mounts and the computer. The existing mount was modelled in ANSYS software, and resultant mode shapes and frequencies were obtained. The experimental modal analysis was conducted, and actual frequency responses were observed and recorded. Results clearly revealed that at resonance frequency, the brackets were colliding and potentially causing damage to computer parts. To solve this issue, spring mounts of different stiffness were modeled in ANSYS software, and the resonant frequency was determined. Increasing the stiffness of the system increased the resonant frequency zone away from the frequency window at which the engine showed heavy vibrations or resonance. After multiple iterations in ANSYS software, the stiffness of the spring mount was finalized, which was again experimentally validated.

Keywords: experimental modal analysis, FEM Modal Analysis, frequency, modal analysis, resonance, vibration

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Authors: Gevorgianiene Violeta, Sumskiene Egle

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Background. Child removal is a profound and life-altering measure that significantly impacts both children and their mothers. Unfortunately, mothers with intellectual disabilities are disproportionately affected by the removal of their children. This action is often taken due to concerns about the mother's perceived inability to care for the child, instances of abuse and neglect, or struggles with addiction. In many cases, the failure to meet society's standards of a "good mother" is seen as a deviation from conventional norms of femininity and motherhood. From an institutional perspective, separating a child from their mother is sometimes viewed as a step toward restoring justice or doing what is considered "right." In another light, this act of child removal can be seen as the removal of a mother from her child, an attempt to shield society from the complexities and fears associated with motherhood for women with disabilities. This separation can be likened to the Greek legend of the Minotaur, a fearsome beast confined within an impenetrable labyrinth. By reimagining this legend, we can see the social fears surrounding 'mothering with intellectual disability' as deeply sealed within an unreachable place. The Aim of this Presentation. Our goal with this presentation is to draw from our research and the metaphors found in the Greek legend to delve into the profound challenges faced by mothers with intellectual disabilities in raising their children. These challenges often become entangled within an insurmountable labyrinth, including navigating complex institutional bureaucracies, enduring persistent doubts cast upon their maternal competencies, battling unfavorable societal narratives, and struggling to retain custody of their children. Coupled with limited social support networks, these challenges frequently lead to situations resulting in maternal failure and, ultimately, child removal. On a broader scale, this separation of a child from their mother symbolizes society’s collective avoidance of confronting the issue of 'mothering with disability,' which can only be effectively addressed through united efforts. Conclusion. Just as in the labyrinth of the Minotaur legend, the struggles faced by mothers with disabilities in their pursuit of retaining their children reveal the need for a metaphorical 'string of Ariadne.' This string symbolizes the support offered by social service providers, communities, and the loved ones these women often dream of but rarely encounter in their lives.

Keywords: motherhood, disability, child removal, support.

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Authors: A. Raj Kumar, S. Bilaloglu

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Stroke is a leading cause of adult disability worldwide. We depend on our hands for our activities of daily living(ADL). Although many patients regain the ability to walk, they continue to experience long-term hand motor impairments. As the number of individuals with young stroke is increasing, there is a critical need for effective approaches for rehabilitation of hand function post-stroke. Motor relearning for dexterity requires task-specific kinesthetic, tactile and visual feedback. However, when a stroke results in both sensory and motor impairment, it becomes difficult to ascertain when and what type of sensory substitutions can facilitate motor relearning. In an ideal situation, real-time task-specific data on the ability to learn and data-driven feedback to assist such learning will greatly assist rehabilitation for dexterity. We have found that kinesthetic and tactile information from the unaffected hand can assist patients re-learn the use of optimal fingertip forces during a grasp and lift task. Measurement of fingertip grip force (GF), load forces (LF), their corresponding rates (GFR and LFR), and other metrics can be used to gauge the impairment level and progress during learning. Currently ATI mini force-torque sensors are used in research settings to measure and compute the LF, GF, and their rates while grasping objects of different weights and textures. Use of the ATI sensor is cost prohibitive for deployment in clinical or at-home rehabilitation. A cost effective mechatronic device is developed to quantify GF, LF, and their rates for stroke rehabilitation purposes using off-the-shelf components such as load cells, flexi-force sensors, and an Arduino UNO microcontroller. A salient feature of the device is its integration with an interactive gaming environment to render a highly engaging user experience. This paper elaborates the integration of kinesthetic and tactile sensing through computation of LF, GF and their corresponding rates in real time, information processing, and interactive interfacing through augmented reality for visual feedback.

Keywords: feedback, gaming, kinesthetic, rehabilitation, tactile

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Authors: Ali Bagherinia

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Efficient task scheduling method can meet users' requirements, and improve the resource utilization, then increase the overall performance of the cloud computing environment. Cloud computing has new features, such as flexibility, virtualization and etc., in this paper we propose a two levels task scheduling method based on load balancing in cloud computing. This task scheduling method meet user's requirements and get high resource utilization, that simulation results in CloudSim simulator prove this.

Keywords: cloud computing, task scheduling, virtualization, SLA

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Authors: Fatiha Teklal, Bachir Kacimi, Arezki Djebbar

Abstract:

The study and application of composite materials are a truly interdisciplinary endeavor that has been enriched by contributions from chemistry, physics, materials science, mechanics and manufacturing engineering. The understanding of the interface (or interphase) in composites is the central point of this interdisciplinary effort. From the early development of composite materials of various nature, the optimization of the interface has been of major importance. Even more important, the ideas linking the properties of composites to the interface structure are still emerging. In our study, we need a direct characterization of the interface; the micromechanical tests we are addressing seem to meet this objective and we chose to use two complementary tests simultaneously. The microindentation test that can be applied to real composites and the drop test, preferred to the pull-out because of the theoretical possibility of studying systems with high adhesion (which is a priori the case with our systems). These two tests are complementary because of the principle of the model specimen used for both the first "compression indentation" and the second whose fiber is subjected to tensile stress called the drop test. Comparing the results obtained by the two methods can therefore be rewarding.

Keywords: Fiber, Interface, Matrix, Micromechanics, Pull-out

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Authors: C. Lalitha, R. Sayee, D. Apoorva

Abstract:

Reproductive failure or infertility may be due to several factors that are not limited to one sex. It remains a common problem causing significant psychological distress to those affected individuals and who are increasingly seeking medical advice. Male infertility means inability to induce conception in normal woman within a year. The etiological factors associated with male infertility are anatomical, developmental, seminal, hormonal, immunological and environmental factors. The paper was aimed to highlight the environmental factors and its association to male infertility and seasonality of birth and its influence. The data was collected from the 75 male patients referred with infertility for karyotyping and counseling. Their age ranged from 21 to 45 years. It is opined that certain occupations are preferentially associated with male infertility.

Keywords: environmental, occupational, seasonal, male infertility

Procedia PDF Downloads 267

Authors: Kirill Filianin, Satu-Pia Reinikainen, Tuomo Sainio

Abstract:

Frequent measurements of product steam quality create a data overload that becomes more and more difficult to handle. In the current study, plant history data with multiple variables was successfully treated by principal component analysis to detect abnormal process behavior, particularly, in copper solvent extraction. The multivariate model is based on the concentration levels of main process metals recorded by the industrial on-stream x-ray fluorescence analyzer. After mean-centering and normalization of concentration data set, two-dimensional multivariate model under principal component analysis algorithm was constructed. Normal operating conditions were defined through control limits that were assigned to squared score values on x-axis and to residual values on y-axis. 80 percent of the data set were taken as the training set and the multivariate model was tested with the remaining 20 percent of data. Model testing showed successful application of control limits to detect abnormal behavior of copper solvent extraction process as early warnings. Compared to the conventional techniques of analyzing one variable at a time, the proposed model allows to detect on-line a process failure using information from all process variables simultaneously. Complex industrial equipment combined with advanced mathematical tools may be used for on-line monitoring both of process streams’ composition and final product quality. Defining normal operating conditions of the process supports reliable decision making in a process control room. Thus, industrial x-ray fluorescence analyzers equipped with integrated data processing toolbox allows more flexibility in copper plant operation. The additional multivariate process control and monitoring procedures are recommended to apply separately for the major components and for the impurities. Principal component analysis may be utilized not only in control of major elements’ content in process streams, but also for continuous monitoring of plant feed. The proposed approach has a potential in on-line instrumentation providing fast, robust and cheap application with automation abilities.

Keywords: abnormal process behavior, failure detection, principal component analysis, solvent extraction

Procedia PDF Downloads 310

Authors: K. Nirmalkumar

Abstract:

An acute water scarcity is prevailing in the dry season in and around Perundurai (Erode district, Tamil Nadu, India) where there are more number of tannery units. Hence an attempt was made to use the effluent from the tannery industry for construction purpose. The mechanical properties such as compressive strength, tensile strength, flexural strength and the special properties such as chloride attack, sulphate attack and chemical attack were studied by casting various concrete specimens in form of cube, cylinders and beams, etc. It was observed that the concrete had some reduction in strength while subjected to chloride attack, sulphate attack and chemical attack. So admixtures were selected and optimized in suitable proportion to counter act the adverse effects and the results were found to be satisfactory. In this research study the corrosion results of specimens prepared by using treated and untreated tannery effluent were compared with the concrete specimens prepared by using potable water. It was observed that by the addition of admixtures, the adverse effects due to the usage of the treated and untreated tannery effluent are counteracted.

Keywords: corrosion, calcium nitrite, concrete, fly ash

Procedia PDF Downloads 269

Authors: Ziad. Sh. Al Sarraf

Abstract:

Ultrasonic metal welding has been the subject of ongoing research and development, most recently concentrating on metal joining in miniature devices, for example to allow solder-free wire bonding. As well as at the small scale, there are also opportunities to research the joining of thicker sheet metals and to widen the range of similar and dissimilar materials that can be successfully joined using this technology. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal spot welding device. The ultrasonic metal spot welding horn is modelled using finite element analysis (FEA) and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered effectively to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. The results show how the weld strength is particularly sensitive to the combination of clamping force and ultrasonic vibration amplitude of the welding tip, but there are optimal combinations of these and also limits that must be clearly identified.

Keywords: ultrasonic welding, vibration amplitude, welding force, weld strength

Procedia PDF Downloads 368