scholarly journals The Effect of Microparticles on the Storage Modulus and Durability Behavior of Magnetorheological Elastomer

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 948
Author(s):  
Mohd Aidy Faizal Johari ◽  
Saiful Amri Mazlan ◽  
Nur Azmah Nordin ◽  
U. Ubaidillah ◽  
Siti Aishah Abdul Aziz ◽  
...  
Keyword(s):  
Storage Modulus ◽  
Magnetic Stimulation ◽  
Extended Period ◽  
Iron Particle ◽  
Weight Percent ◽  
Rubber Matrix ◽  
Practical Implementation ◽  
Second Phase ◽  
Durability Test ◽  
Application Systems

This paper presents the effect of the micro-sized particles on the storage modulus and durability characteristics of magnetorheological elastomers (MREs). The initial phase of the investigation is to determine any associations among the microparticles’ weight percent fraction (wt%), structure arrangement, and the storage modulus of MRE samples. In order to carry out this, both isotropic and anisotropic types of MRE samples consisting of the silicone rubber matrix and 50, 60, 70, 75, and 80 wt% microparticles of carbonyl iron fractions are prepared. It is identified from the magneto-rheometer that the increase in storage modulus and decrease in linear viscoelastic region limit are observed in varying consistency depending on wt% and particle arrangement. The consistency of this dependency feature is highlighted by superimposing all of the graphs plotted to create the proposed the samples’ behavior model. In response to increasing magnetic stimulation, a sample of 70 wt% microparticles with an isotropic arrangement is found to be significant and stable. The experimentally defined fraction is then used for the durability test as the second phase of the investigation. During this phase, the durability evaluation is subjected to stress relaxation for an extended period of time. After undergoing durability testing, storage modulus performance is decreased by 0.7–13% at various magnetic stimulation levels. This result directly indicates that the storage modulus characteristics of different forms of MRE are sensitive to the different iron particle fractions’ and microparticles’ alignment. Therefore, important treatments to alter the storage modulus can be undertaken before the practical implementation to accommodate any desired performance of MRE itself and MRE application systems.

Modelling and experimental characterisation of a compressional adaptive magnetorheological elastomer isolator

2021 ◽  
pp. 107754632110253
Author(s):  
Emiliano Rustighi ◽  
Diego F Ledezma-Ramirez ◽  
Pablo E Tapia-Gonzalez ◽  
Neil Ferguson ◽  
Azrul Zakaria
Keyword(s):  
Magnetic Field ◽  
Silicone Rubber ◽  
Magnetic Interaction ◽  
Iron Particle ◽  
Material Model ◽  
Rubber Matrix ◽  
Magnetorheological Elastomer ◽  
Volume Percentage ◽  
Shock Absorbers ◽  
Percent Concentration

This article proposes a simple physical-based model to describe and predict the performance of axially compressed magnetorheological elastomer cylinders used as vibration and shock absorbers. The model describes the magnetorheological elastomer macroscopic stiffness changes because of an externally applied magnetic field from a microscopic composite cell of silicone rubber and carbonyl iron particle. Despite neglecting the material hyperelasticity, anisotropy and adjacent magnetic interaction, the model describes effectively the effect of the magnetic field on the macroscopic modulus of elasticity. The changes in the mechanical properties with the induced magnetic field are measured on samples of different particle concentration based on volume percentage, that is, 10 and 30 percent concentration of iron particles in a silicone rubber matrix. The manufacturing process of the samples is detailed, as well as the experimental validation of the effective stiffness change under a magnetic field in terms of transmissibility and mobility testing. However, the prediction seems to be limited by the linear elastic material model. Predictions and measurements are compared, showing that the model is capable of predicting the tunability of the dynamic/shock absorber and that the proposed devices have a possible application in the reduction of mechanical vibrations.

scholarly journals TWO-PHASE MIXING IN A TRACTOR DIESEL: THE CONCEPT OF TECHNICAL SOLUTION

2020 ◽  
Author(s):  
А.П. Уханов ◽  
М.Д. Дубин ◽  
М.В. Рыблов
Keyword(s):  
Combustion Chamber ◽  
Functional Model ◽  
Environmental Indicators ◽  
Injection System ◽  
Practical Implementation ◽  
Second Phase ◽  
Technical Solution ◽  
Two Phase ◽  
Phase Mixing ◽  
Diesel Cylinder

Статья посвящена проблеме улучшения эффективных и экологических показателей автотракторной техники путем двухфазного смесеобразования в дизелях, оснащенных системой питания с непосредственным впрыском топлива в камеру сгорания. При данном способе смесеобразования первая фаза осуществляется путем впрыска определенной дозы (10-20 %) жидкого активатора (бензина, керосина, дизельного топлива и др.) в такте впуска во впускной тракт дизеля с образованием активаторно-воздушной смеси в цилиндре дизеля. Во второй фазе смесеобразования впрыск основной дозы топлива в цилиндр дизеля осуществляется штатной топливной аппаратурой в конце такта сжатия в сжатую активаторно-воздушную смесь с образованием рабочей смеси, подготовленной для активного воспламенения по всему объему камеры сгорания. Для практической реализации первой фазы двухфазного смесеобразования дизель необходимо дополнительно оснастить системой многоточечного впрыска активатора электромагнитными форсунками, управляемыми электронным блоком. Данная система должна обеспечивать высокую точность дозирования активатора, его своевременную подачу в такте впуска и равномерное распределение по цилиндрам дизеля. Выполненные НИОКР включали разработку функциональной модели системы, а также методик по обоснованию длительности и алгоритма управляющих импульсов, подаваемых на электромагнитные форсунки. Система содержит бак для активатора, фильтр, электронасос, модернизированный впускной трубопровод, электромагнитные форсунки, датчики и электронный блок управления, выполненный на базе программируемого микроконтроллера. The article is devoted to the problem of improving the effective and environmental indicators of automotive equipment by two-phase mixing in diesels equipped with a power system with direct fuel injection into the combustion chamber. In this method of mixing, the first phase is carried out by injecting a certain dose (10-20 %) of a liquid activator (gasoline, kerosene, diesel fuel, etc.) in the instroke into the diesel intake tract to form an activator-air mixture in the diesel cylinder. In the second phase of mixing, the injection of the main fuel dose into the diesel cylinder is carried out by normal fuel equipment at the end of the instroke into a compressed activator-air mixture with the formation of a working mixture prepared for active ignition throughout the entire volume of the combustion chamber. For the practical implementation of the first phase of two-phase mixing, the diesel engine must be additionally equipped with a multi-point activator injection system with electromagnetic nozzles controlled by an electronic unit. This system should ensure high accuracy of activator dosing, its timely delivery in the instroke and equable distribution across the diesel cylinders. The performed research and development works included the development of a functional model of the system, as well as methods to justify the duration and algorithm of control pulses applied to electromagnetic nozzles. The system contains an activator tank, filter, electric pump, upgraded intake pipeline, electromagnetic nozzles, sensors and an electronic control unit based on a programmable microcontroller.

scholarly journals Effect of Niobium and Titanium Addition on Formation of Second Phase Particles in CHQ Steel Using Transmission Electron Microscope

2021 ◽  
Vol 40 (1) ◽  
pp. 31-37
Author(s):  
Shahid Hussain Abro
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Percent ◽  
Holding Time ◽  
Second Phase ◽  
Steel Matrix ◽  
Ehlers Danlos Syndrome ◽  
Transmission Electron ◽  
Second Phase Particles

It is common practice that formation of second phase particles such as nitrides or carbides in the steel matrix has significant role to control the grain size of steel. An attempt is made in the present research work to find out the role of nitrogen to form the nitride particles either with Al, Ti, B, Cr or Si. Two steel samples Steel-A and Steel-B with same titanium and aluminum weight percent in the chemical composition were obtained in hot rolled conditions from international market with only the difference of presence of Niobium in Steel-A. Solution heat treatment was performed at 1350°C with 60 minutes holding time in protherm heat treatment furnace available locally was used to dissolve the particles and then steel samples were reheat treated at 800°C with holding time of 60 minutes and water quenched and microstructure was revealed. Transmission electron microscope connected with Ehlers-Danlos Syndrome (EDS) was used to reveal the morphology of second phase particles. Both samples for a high resolution power Transmission Electron Microscopy (TEM) (Jeol JEM 3010) analysis were prepared by using carbon extraction replica method in 5% Nital solution as an etching technique. Both samples were then caught in copper grid of 3mm for using TEM analysis. TEM micrographs clearly revealed the second phase particles in the matrix of steel. The EDS peaks were studied and it was found that the peaks showed the titanium peaks in both the samples A and B and surprisingly there was no any peak found for aluminum. Stoichiometric calculations were carried out and it was found that weight percent nitrogen required for forming TiN is 0.0073, however the total nitrogen present in both the steels A and B is 0.0058 and 0.0061 respectively. That means that all the nitrogen present in the steel matrix was consumed by titanium to form the Titanium Nitride (TiN) so there was no nitrogen remain to fulfil the requirement of aluminum to form the Aluminum Nitride (AlN) particles.

Why Should we Use Inclined Tables in Engineering Drawing Works?

2021 ◽  
Vol 10 (5) ◽  
pp. 90-95
Author(s):  
Abdelaty E. Abdelgawad ◽  
Ahmed T. Soliman ◽  
Mohamed Z. Ramadan
Keyword(s):  
Human Factors ◽  
Extended Period ◽  
Second Phase ◽  
Engineering Drawing ◽  
Body Postures ◽  
Simple Tool ◽  
Proposed Model ◽  
Engineering Designs ◽  
Two Stages

One of the primary purposes of studying human Factors is to relieve work stresses imposed on the workers during their jobs. The current study consisted of two stages. The first phase aimed to develop a microcomputer biomechanically based to analyze clerk body postures. The second phase was to test that developed model on studying table tapes (i.g., adjustable inclined versus table vs. fixed horizontal table) during drawing engineering designs. The results showed the capability of the proposed model for analyzing the clerks’ jobs. In addition, the inclined furniture was superior in reducing the stresses associated with doing jobs using furniture compared with fixed horizontal tables. Finally, it would be better to use a simple tool such as the developed one to analyze complicated tasks that force workers to take awkward postures and sustained that posture for an extended period.

scholarly journals Master data management: its importance and reasons for failed implementations

2020 ◽  
Author(s):  
◽  
Panagiotis Lepeniotis
Keyword(s):  
Data Quality ◽  
Data Management ◽  
Business Processes ◽  
Second Phase ◽  
Successful Implementation ◽  
The Third ◽  
Application Systems ◽  
Master Data ◽  
Master Data Management

This research aims to identify the useful impact of Master Data Management (MDM) on a Business Transformation Programme (BTP). A BTP consists of three distinct phases. The first phase is the selection of the appropriate set of application systems as well as the introduction of new business processes across multiple lines of business and different channels. The second phase is the implementation of the new application systems and the data migration process. The third and final phase is the transition from the legacy application systems and business processes to the newly defined framework of processes and technologies that ensure the business and data continuity. MDM encompasses a pivotal role during the second and the third phase of a BTP and is defined as the process that runs in parallel with any other business process; assigning responsibility to people and technology on processing, capturing, maintaining and defining data accuracy based on a defined set of rules. Multiple parameters relevant to MDM such as change management, no practical commitment from senior management, no compliance with any data governance policies, implementing new integrations or any pre-existing data quality challenges along with multiple others, can jeopardise the successful completion of a BTP. As MDM becomes significant in the second phase, the research focuses on how the invasive circumstances arising from such parameters during this BTP phase and beyond may be addressed by the BTP’s programme directorate to enhance decision-making through the appropriate impact on MDM. The programme committee of a BTP would thus become aware of how to: a) manage master data, b) reinforce enterprise data quality and c) govern the overall BTP lifecycle by safeguarding data practices. Alongside an extensive learned literature review and industry resources to establish the research aims from the outset, the research appropriated a deductive and interpretive research methodology to two Data audits as case studies plus a series of semi-structured interviews and subjected to a comprehensive qualitative analysis. Each BTP either faced challenges or was about to face challenges. The different roles of the participants and the different phases of each BTP in which the audits took place allowed the research to employ these multiple methods to reflect different aspects of the same issue. Referring to the Data Audit Framework for added structure, the two data audits took place in two different companies. The first company was performing the audit after a failed BTP, and they had already an MDM function within the organisation. The audit focused on the performance of its already existing function. The second company had initiated a BTP and wanted to ensure that the required controls were in place for a successful delivery. These two audits provided valuable case study evidence for the evaluation of the decisions made during the BTP with regards to a) master data, b) what led the programme directorate to these decisions and c) how the decisions affected the outcome of the BTP as well as the organisation itself. The interviews consisted of twenty-eight semi-structured questions and involved eighteen people with diverse backgrounds and from divergent functions of the business. All the interviewees were participating in a BTP with an underlying MDM process. The interviews provided evidence on a) how different roles within the programme reflect and react under specific circumstances and b) how each workstream prioritised data-related activities in conjunction with the overall programme. From the case study audits and the interviews, the research identified an enhanced understanding of the reasons behind the decisions during a BTP concerning MDM, and how these decisions consequently affect the successful implementation of a BTP. From these findings, the research proposes a novel MDM-impacted BTP decision model that brings together its contributions to knowledge, and the basis for future work.

scholarly journals Methods and tools of the rehabilitation process in a case of acute disseminated encephalomyelitis (ADEM) in the evolutionary age: continuity hospital - territory

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
G. Grippo ◽  
T. Bolgeo ◽  
G. Carpanese ◽  
C. Florio ◽  
A. Prosperi ◽  
...  
Keyword(s):  
Continuity Of Care ◽  
Acute Disseminated Encephalomyelitis ◽  
Positive Outcome ◽  
Practical Implementation ◽  
Second Phase ◽  
Care Hospital ◽  
Web Page ◽  
Organizational Models ◽  
Study Results ◽  
Good Individual

Background: An analysis of the situation of the Piedmont Region and Italy shows a lack of continuity of care due to the difficulties of communication, the fragmentation and incorrect timing of the interventions, the development of ultraspecialized skills and a lack of organizational models. However, program sharing and coordination of interventions are essential for the practical implementation of the rehabilitation, especially in pediatric physiotherapy. Purpose and Objective: Aim of the study is the continuity of care (hospital-territory) for children with acute disseminated encephalomyelitis, in order to achieve a good individual and family compliance in the rehabilitation programme and greater levels of autonomy. This study uses a figure to link the two realities and telerehabilitation. Methods: The project was divided into a first phase, the intensive hospitalization and a second phase, the return to the home withrehabilitation, trainingeducational and organizational interventions. The graduand student has been identified as a point of reference and a “bridge” between the two realities. A web page with “Google Forms” customized for children was created in order to increase compliance and motivation of patients and family. Questionnaires were administered to families, children and healthcare to check the methods and tools used in the study. Results: At the end of the study the rehabilitative intervention was assessed by scales and test scores, and improvements have been achieved. The organizational intervention (web page and hospital and communuty continuity mode), evaluated through questionnaires, has been postively assessed by those who took part in this project. Hospital-Territory continuity is a crucial and important moment for patients: having a physiotherapist who acts as a trait d’union is essential as is the use of telerehabilitation for monitoring and maintaining the autonomy of these children. Conclusions: Continuity of care is still operator-dependent; in rehabilitation this is a crucial and important time, as evidenced by the project. In order to support patients and their families and facilitate positive outcome it would be really important to have a reference organizational model and a referent physiotherapist who represents an interface between the various players in the socio-medical system The problem remains open and each route has its own story.

Dynamic mechanical behavior of composite materials reinforced by graphene and huntite minerals

2021 ◽  
Vol 63 (12) ◽  
pp. 1090-1096
Author(s):  
Dilek Atilla ◽  
Binnur Gören
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Damping Ratio ◽  
Weight Percent ◽  
Dynamic Mechanical Properties ◽  
Grain Structure ◽  
Dynamic Mechanical ◽  
Pure Resin

Abstract The aim of this study is to investigate the dynamic mechanical properties of composite materials reinforced by mineral experimentally. Graphene and huntite minerals were added to epoxy resin at different weight ratios (wt.-%) as 0.5 weight percent, 1 weight percent and 3 weight percent, to examine the effect of mineral types and percentages on the resulting dynamic mechanical properties. In addition, the effect of non-layered huntite unlike graphene, with a nano-sized grain structure, was investigated. Thus, glass transition temperature (Tg), storage modulus (E’), loss modulus (E”) and damping ratio (tan δ) values were determined and compared. Moreover, a tensile test was performed in order to explain the relation between stress and strain. It was seen that adding different minerals caused different results according to types and proportions. In general, adding minerals to the pure resin increased the storage modulus and loss modulus, whereas the damping ratio (tan δ) decreased compared to the pure resin.

Optimization of Aging Cycle of Stainless Maraging Steel Using Dilatometric and Differential Scanning Calorimetric Analysis to Improve its Strength

2015 ◽  
Vol 830-831 ◽  
pp. 147-150
Author(s):  
Ankit Sharma ◽  
Alok Agarwal ◽  
Mayukh Acharya ◽  
Govind ◽  
S.C. Sharma
Keyword(s):  
Heat Treatment ◽  
Maraging Steel ◽  
Aging Temperature ◽  
Extended Period ◽  
Subzero Temperature ◽  
Differential Scanning Calorimetric ◽  
Second Phase ◽  
Calorimetric Analysis ◽  
Stainless Maraging Steel ◽  
Dilatometric Studies

04X13H5M5К9Л is a stainless maraging steel with high strength and excellent toughness. This alloy has been selected for making Impeller casting which is subjected to localized stresses reaching as high as 700 MPa at the tip of its vanes. The impeller rotates at 19000 RPM for 253 seconds.This alloy comprises of austenitic – martensitic dual phase at room temperature, in which martensite exhibits Body Centered Cubic (BCC) structure with moderate hardness (HRC 30) and high toughness. The required strength is achieved by precipitation of second phase particles in soft martensite matrix at suitable aging temperature. There is always a chance of reversion of martensite to austenite on heating either for extended period or at higher temperature. Thus optimization of aging temperature and time becomes highly critical keeping in mind the functional stress requirements of the component. The optimization has been done using Differential Scanning Calorimetric (DSC) analysis, dilatometric studies and experimental iterations of heat treatment temperatures and aging time.Different combination of strength and ductility could be achieved by varying heat treatment parameters. Martensite start and finish temperatures and austenitic reversion temperatures were established through DSC and dilatometric studies. Effect of subzero temperature on properties and microstructure of this steel is also presented here. Scanning Electron Microscopy and Energy Dispersive Spectroscopy were also carried out to analyze phases in different heat treatment conditions.

Acquisition of Complex Assembly Skills through the Use of Systematic Training Procedures: Involving Profoundly Retarded Adults

AAESPH Review ◽  
1976 ◽  
Vol 1 (7) ◽  
pp. 14-25 ◽  
Author(s):  
Fred Spooner ◽  
Bob Hendrickson
Keyword(s):  
Skill Acquisition ◽  
Extended Period ◽  
The United States ◽  
Learning Ability ◽  
Second Phase ◽  
Training Procedure ◽  
Work Activity ◽  
Group Settings ◽  
Systematic Training ◽  
Three Phases

Work Activity Centers in the United States have been very prone to let their clientele attempt to learn basic industrial tasks in group settings without the use of a controlled training procedure. The usual effects have been: (a) excessively long periods of skill acquisition, (b) high variability in production techniques, (c) substantial fluctuations in product quality, and (d) preferential opportunities for those whose learning ability was least severely impaired. This report is concerned with the acquisition of skills to perform a complex industrial task by seven profoundly retarded adults using a systematic training procedure. The task consisted of inserting six different colored game pawns into a poly-bag and placing the loaded bag in a finish bin. The method described was adopted after an extended period of observation during which substantial numbers of clients were found to be unable to acquire the requisite skills through any of the various non-systematized methods of presentation. The training procedure employed three phases. The first was based on a backward chaining format and took place in a designated training area with only the trainer and a single trainee present. The second phase was based on a total task presentation in the same setting; and the third continued the total task format in the production area of the Center. Each of the five individuals who completed the training has reached the established criterion for all three phases.

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