Search

Noise is one of the problems that often occur in urban areas due to the traffic condition. Noise in a building design depends on the choice of materials as sound absorbers. The type of sound dampening material that already exists is a porous material, a resonator, and a panel. The material often used as an absorber is porous materials, because it is relatively cheaper and lighter, especially to reduce the noise in the narrow spaces such as housing and offices. Various substitutes are made from cheap materials, such as the use of recycled materials of egg tray paper with the size of 40 x 40 centimeters. This is a quantitative research that will measure the place of egg tray paper in reducing noise, using a Sound Level Meter. The use of the egg tray paper is able to show an adequate acoustic quality as noise absorbers, with the average value of NR 22-26 dB.

In recent years, there have been a number of interests on the Palm Oil (PO) and Coconut Oil (CO) as a potential alternative dielectric insulating fluid in transformers which stimulate different types of studies on these oils properties. Among the important studies is the lightning impulse properties. This paper presents the investigation on the lightning impulse breakdown voltage of PO and CO under non-uniform electric field. The PO used in this study is Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein type. The influence of the testing methods, rising-voltage and up-and-down are investigated at 2 gap distances for both oils. It was found that the lightning breakdown voltage performance for some of the RBDPO and CO are comparable to MO.

Nowadays, consumers are concern about the quality of water that being supplied in order to ensure the water supplied is free from any harmful substances for example like Humic Substances (HS). High concentration of HS in drinking water can cause disease for human such as stomach cancer. Thus, it is important to develop a new technique to improve the quality of drinking water. Therefore, the objective of this research is to investigate the potential of using coconut copra treated with citric acid as activated carbon in adsorbing HS contained in wastewater collected from Asajaya Treatment Plant situated in district of Samarahan, Sarawak. In this research, the optimum condition of adsorption process need to determined. As such, there are two types of parameters which are considered as constant; temperature and pH of activated carbon and variable; solid liquid ratio and residence time. As a result, this research has shown that coconut copra possess the capacity to adsorp 97.5% of HS contained in wastewater.

Advanced computational methods are needed both for the design of large systems and to compute high accuracy solutions. Such methods are efficient in computation, but the validation of results is very complex, and highly skilled auditors are needed to verify them. We investigate legal questions concerning obligations in the development phase, especially for technical systems developed using advanced methods. In particular, we consider methods of resilient and robust optimization. With these techniques, high performance solutions can be found, despite a high variety of input parameters. However, given the novelty of these methods, it is uncertain whether legal obligations are being met. The aim of this paper is to discuss if and how the choice of a specific computational method affects the developer’s product liability. The review of legal obligations in this paper is based on German law and focuses on the requirements that must be met during the design and development process.

Composite materials are created as a quite complex architecture which includes a fibre reinforcement structure and matrix material. Many material parameters play a role when composite structures are modelled, e.g. in finite element models. In addition to the properties of the raw fibre and matrix materials which are used, also geometrical parameters have a significant effect on structural characteristics. Fibre reinforcement geometry together with material properties of fibre and matrix determine homogenised material properties.The first part of the paper gives an overview of the most important processes which are used in composites processing industry. The factors which affect variability are also listed, and the effect of variability on material parameters is mentioned as well. The second part of the paper elaborates the identification of geometrical variability of the fibre reinforcement structure which is encountered with one particular type of composite material, namely a twill 2/2 carbon fibre weave with an epoxy matrix.

RETRACTED PAPER: Energy conversion from ocean waves has become the need of the hour in view of the renewable energy awakening occurring all over the world. Energy conversion by Oscillating Water Column (OWC) concept has become an established technology in converting mechanical energy of ocean waves to electrical energy. But the limitations of OWC concept calls for further research and developments to make the technology commercially an attractive one. In this context Boccotti, the Italian scientist advanced the double chamber concept and the implications of the concept still remains to be investigated through model studies. This paper presents the details of a generic study carried out in a physical model device under regular waves.

In the present paper, the Preisach model of hysteresis is extended to structural analysis of trusses damaged under cyclic loading in plastic range. Parameters for the Preisach model of cyclic plasticity are obtained from uniaxial loading experiment. Damage, as a consequence of micro cracks appearance due to alternating loading in plastic domain, is modeled using brittle elements according to Preisach procedure. Results of this research are compared with the already existing in the literature. In the paper examples of trusses under various cyclic loadings are presented. Applied Mechanics and Materials

To provide fast digital communications systems, energy efficient, high-performance, low power is critical for decoding mobile receiver device. This paper proposes a low power optimization techniques in the Add Compare Select (ACS) unit for Space Time trellis codes (STTC) Viterbi decoder. STTC Viterbi decoder is used as a reference case. This paper discusses about how to lower the power in the ACS architecture, to optimize the Viterbi decoder STTC in reducing the total power consumption. Based on the results of design and analysis, power consumption Viterbi decoder modeling, low power system for STTC Viterbi decoder is proposed. Design and optimization of ACS unit in STTC Viterbi decoding is done using Verilog HDL language. Power analysis tools in the software Altera Quartus 2 is used for the synthesis of total system power consumption. Optimization strategy showed an increase of 83% power reduction compared to previous studies.

Green building has become an important issue among architects and urban planners due to the increment in global warming risks and climatic changes which influenced negatively on natural resources. It is also one of measures been put forward to alleviate the significant impacts of the influence of buildings on the environment, society and economy. There have been extensive studies on green buildings, as evidenced in the rapid growing number of papers been published in last decades. These studies have been conducted in both developed countries and developing countries, indicating this is a global issue. However, there is lack of extensive researches on the green buildings in Iraq that is crucial for the future exerts. This paper reports the definition of green building, the environmental, social and economical aspects of green building, and application of green building's principles in traditional housing in Iraq.

Human welfare is increasingly affected by the climate change impacts where more scientific evidence has pointed to a significant human contribution as the most contributing factors. Lately, the concept of ‘carbon-capability’ has been proposed recently to get the relative meanings related to carbon and individual power and enthusiasm to cut emissions. Thus, this paper aims to present a review ofthe theoretical framework and identifies the need for more specific components underlying the community carbon-capability. This study analyzes by using content analysis and based in part on related earlier study. The paper concludes thatcommunity carbon-capability framework's ability to help in reducing climate change impactsand highlighted the vital to understanding community engagement with overall climate change issues in Malaysia.

The development of architecture in early housing in Malaysia existed in the form of shop house and terrace house which were being introduced and popularized by Chinese migrants who settled in Malaysia before the Colonization by British Empire.This paper will discuss briefly the development of modern terrace house in Malaysia. Terrace house is define as a typology of one storey middle class terrace house in this country based on the existing literature review and our research. Those typologies will be used later for the process of typological assessment of terrace house from the cultural perspective at the end of the research. Thus, this paper is important as a step to understand the early development of terrace houses and to see how far the evolution of terrace houses happened until today.

Malaysia is one of the classic examples of a multi-ethnic society. The country is proud of its multiracial culture which makes it a model for other countries. The ubiquitous community hall in the Malaysian landscape, as it stands now, has long passed its time of usefulness. These halls are labelled with names like dewan serbaguna, dewan orang ramai or even balai raya. But as it stands today, the community hall in our midst is nothing more than a large empty space used for games like badminton or ping pong and the occa-sional event. The changing modern Malaysian society demands more of this simple out-dated facility; there must be a place for the various ethnic groups to meet and fulfil modern needs such as family days, health checks, child’s play, music lessons and many more important uses This paper strives to identify and analyse some of the architectural problems in current community centres in Malaysia with the focus on the spatial aspects and space usage. It is expected that this paper can give a clear picture of the problems faced by Malaysian community centres with some considerations and a framework to develop a new scheme for community centre development in the future.

There is increasing awareness of life cycle costing (LCC) by the management who has lengthy experience in the operation and maintenance of the building. Maintenance of buildings includes a replacement, updating, and repair building components by predetermined standards. This paper aim at developing a prototype of building maintenance system for a campus in Yogyakarta. The prototype is referred to ISO 15686 as well as Regulation of Minister of Public Works. The system complements the service life of the building components that can be up dated regularly. The system accommodates the 25-years life cycle cost plan to assist campus management office. Research data obtained by Building Maintenance personals, the users of the building as well as previous studies for similar ones. From the results of life cycle costing, the study shows its detail life cycle cost plan.. Finally, a prototype for the operation and maintenance of the building is developed. Keywords: operation and maintenance, campus building, ISO 15686, life cycle costing

Retinal microsurgery is one of the most technically demanding surgeries, during which the surgical tool needs to be inserted into the eyeball and is constantly constrained by the sclerotomy port. During the surgery, any unexpected manipulation could cause extreme tool-sclera contact force leading to sclera damage. Although, a robot assistant could reduce hand tremor and improve the tool positioning accuracy, it cannot prevent or alarm the surgeon about the upcoming danger caused by surgeon’s misoperations, i.e., applying excessive force on the sclera. In this paper, we present a new method based on a Long Short Term Memory recurrent neural network for predicting the user behavior, i.e., the contact force between the tool and sclera (sclera force) and the insertion depth of the tool from sclera contact point (insertion depth) in real time (40Hz). The predicted force information is provided to the user through auditory feedback to alarm any unexpected sclera force. The user behavior data is collected in a mock retinal surgical operation on a dry eye phantom with Steady Hand Eye Robot and a novel multi-function sensing tool. The Long Short Term Memory recurrent neural network is trained on the collected time series of sclera force and insertion depth. The network can predict the sclera force and insertion depth 100 milliseconds in the future with 95.29% and 96.57% accuracy, respectively, and can help reduce the fraction of unsafe sclera forces from 40.19% to 15.43%.

Face detection is the primary task in building a vision-based human-computer interaction system and in special applications such as face recognition, face tracking, face identification, expression recognition and also content-based image retrieval. A potent face detection system must be able to detect faces irrespective of illuminations, shadows, cluttered backgrounds, orientation and facial expressions. In previous literature, many approaches for face detection had been proposed. However, face detection in outdoor images with uncontrolled illumination and images with complex background are still a serious problem. Hence, in this paper, we had proposed a Geometric Skin Colour (GSC) method for detecting faces accurately in real world image, under capturing conditions of both indoor and outdoor, and with a variety of illuminations and also in cluttered backgrounds. The selected method was evaluated on two different face video smartphone databases and the obtained results proved the outperformance of the proposed method under the unconstrained environment of these databases.

End users and consumers of halal industry are facing difficulties in finding verified halal information. This occurred due to information that is stored in silos at every point of activity for every process chain, employing different structures and models, creating an issue of information verification. Integration of multiple information systems generally aims at combining selected systems so that information can be easily retrieved and manage by users. A proposed five components metadata representation development methodology is presented in this paper so that they form a unified new whole and give users the illusion of interacting with one single information system, therefore, data can be represented using the same abstraction principles (unified global data model and unified semantics) without any physical restructuring.

This paper presents the review of available visual water quality monitoring and proposes a conceptual sonification model of audiovisual analytics for precision aquaculture. This study reviews the current practice of the visual water quality monitoring system used to interpret the complex fish farming data. This study also explores the possibility of using an auditory display, by using sound as complementary elements to communicate information from the system to the user.

This paper presents the fun and engagement elements, and the assessment methods of these two elements for children. Fun to children is something they do that is amusing or enjoyable. Engagement refers to how a child shares a positive connection to peers or activities. Both of these elements could be an important factor to support and strengthen learning among children. We employed the Again-again table and the Adaptive Behaviour Scale [24] from Bayley-III to measure and to assess fun and engagement, particularly in educational mobile apps for children with speech delay. A local prototype of speech therapy mobile application was used in the experiment, and the results have shown that both fun and engagement are correlated.

In the environmental analysis of buildings, Life Cycle Assessment (LCA) is gaining more and more interest. It is due to the fact, that LCA is very comprehensive in considering many impacts in all life-cycle phases of the examined building. Since buildings have a complicated geometry that is built up with numerous constructions that consist of many materials, and the life-cycle includes many phases, the results of an assessment are likely to be difficult to analyze in detail. In this paper we introduce a visual method to help architects and analysts to quickly understand the results of an environmental assessment. It includes the hierarchic visualization of the performance of the individual elements of the building. Both energy use and environmental impacts can be presented. Also the contribution of the different life-cycle phases in the overall impact is visualized.There are increasing efforts nowadays to find the most efficient way to improve the environmental performance of buildings. This can be supported with a detailed analysis of the results. The method is presented through a case study of a realized energy efficient one-family house.

[EN] Construction sector has consumed an important percentage of natural resources and generated much of the waste discharged into the environment in the last decades. This is the reason why the social consciousness has strongly grown towards sustainable development. Concepts such as recycle, reuse, reduce and energy saving are gaining importance in obtaining products under a clearly defined objective of a sustainable development. The revaluation of agroforestry waste has established itself as a solution to the problems associated with these wastes and, increasingly, is being incorporated into the manufacture of new materials. The Wood Plastic Composites (WPC¿s) are an important group within these new sustainable building materials. WPC¿s are obtained from recycled plastics and natural fibres waste. This kind of materials reduces the consumption of resources and the amount of waste. These materials have emerged to replace natural wood in some exterior applications, where the durability of natural wood is most damaged. Natural wood, in addition to the loss of color that suffers in exterior, has other disadvantages such as anisotropy and hygroscopicity. WPC's do not have these drawbacks. In this way, the WPC¿s try to imitate the appearance of natural wood, with a good durability outdoors. Because of this, there are numerous companies that develop WPC products with different plastics and natural waste, with the aim of obtaining the best appearance and durability. In this paper, the color degradation of various WPC materials when exposed to ultraviolet (UV) radiation is evaluated. An artificial aging chamber with a fluorescent UV lamp and a colorimeter have been used to quantify the color parameters. Thus, conclusions are drawn on which plastics and residues achieve a minor alteration of color, an aspect highly appreciated in outdoor applications.

This paper shows how a databased approach towards production optimization was realized with the help of cloud-technologies. Several uncertainties, either in the manufacturing of the producing machines or in the production on these machines can be systematically reduced. In this way a significant improvement in production amount, but also in produced quality can be reached.

Fine machining processes are of great importance in automotive series production, e.g. the machining of valve guide and seat in the cylinder head of a combustion engine. In industrial manufacturing processes, disturbances are inevitable and provide a measure of uncertainty in each production step. Increasingly, the influence of such uncertainties is being evaluated using simulation models. In this paper, a modeling approach for simulation of multi-stage fine machining processes with step tools is presented and investigations regarding influence of uncertainty caused by disturbances are performed.

In the field of autonomous systems, manufacturers still face a high level of uncertainty, especially in the development phase. These systems are characterized by their ability to adapt to new conditions without any further action by the developer. One of the future challenges will be that autonomous systems continue to evolve during the use phase. These changes are hard to predict because they are affected by the specific product environment. Nevertheless, manufacturers are exposed to liability claims if damage events occur. Uncertainty about the question of the specific conditions for liability results in an incalculable risk for the manufacturer. This paper takes an interdisciplinary approach. The first step is to identify the manufacturers' legal obligations for the entire product lifecycle. These obligations are then checked for their technical feasibility and evaluated in terms of efficiency. Manufacturers can only be obligated to take measures that are sustainable. The aim of the study is to translate the legal requirements for manufacturers of autonomous systems into concrete solutions that are both practical and manageable.

The stiffness of metal formed products strongly affects the dynamic behavior of structures in which they are integrated. Forming processes underlie short and long-term variations which cause the stiffness to be uncertain.In the application of resonant shunted piezoelectric transducers for vibration attenuation, uncertain stiffness may cause significant reduction in the vibration attenuation performance due to imprecise tuning. In the past, large efforts were made to control one or more geometrical feature of products while weightier features that cause uncertainty have not been addressed.In this paper, a single point incremental forming process of a membrane-like spring element on a servo press with a 3 degrees of freedom drive system is investigated. This spring element is used in a beam support for lateral vibration attenuation with resonant shunted transducers as well as axial buckling stabilization.To reduce uncertainty caused by process variations, an offline closed-loop control of product stiffness is presented. Different product and forming criteria are integrated into a control approach based on an optimization routine. By making use of a model-based prediction of the product properties, the approach shows how to realize a multi-objective control.

Efficient surrogate modelling of computer models (herein defined as simulators) becomes of increasing importance as more complex simulators and non-deterministic methods, such as Monte Carlo simulations, are utilised. This is especially true in large multidimensional design spaces. In order for these technologies to be feasible in an early design stage context, the surrogate model (oremulator) must create an accurate prediction of the simulator in the proposed design space. Gaussian Processes (GPs) are a powerful non-parametric Bayesian approach that can be used as emulators. The probabilistic framework means that predictive distributions are inferred, providing an understanding of the uncertainty introduced by replacing the simulator with an emulator, known as code uncertainty. An issue with GPs is that they have a computational complexity of O(N3) (where N is the number of data points), which can be reduced to O(NM2) by using various sparse approximations, calculated from a subset of inducing points (where M is the number of inducing points). This paper explores the use of sparse Gaussian process emulators as a computationally efficient method for creating surrogate models of structural dynamics simulators. Discussions on the performance of these methods are presented along with comments regarding key applications to the early design stage.

High-rise water supply systems provide water flow and suitable pressure in all levels of tall buildings. To design such state-of-the-art systems, the consideration of energy efficiency and the anticipation of component failures are mandatory. In this paper, we use Mixed-Integer Nonlinear Programming to compute an optimal placement of pipes and pumps, as well as an optimal control strategy.Moreover, we consider the resilience of the system to pump failures. A resilient system is able to fulfill a predefined minimum functionality even though components fail or are restricted in their normal usage. We present models to measure and optimize the resilience. To demonstrate our approach, we design and analyze an optimal resilient decentralized water supply system inspired by a real-life hotel building.

Ontologies represent inter-related semantic information. The automated integration of new knowledge helps to detect and reduce data-induced conflicts and model-based uncertainty in ontologies. However, automatic extension of an existing ontology from heterogeneous distributed sources can often lead to incomplete and contradictory entities. In order to resolve these conflicts and to complete entities, inductive inference mechanisms should be applied in addition to the deductive mechanisms already in use. This paper first describes various inductive inference mechanisms and compares these with each other according to pre-defined requirements and other criteria. Finally, the mechanisms’ suitability for an information model for the exchange and visualization of uncertainty in load-carrying systems and possible combinations of the individual mechanisms are discussed, also with respect to the necessity of further modifications of these mechanisms.

The reaming process normally takes place at the end of manufacturing processes when a lot of value has already been added. Therefore, reaming plays an important role for the quality of the finished product. To achieve this high quality, the occurring process errors caused by the machine tool and the reamer or incorrect workpiece handling have to be minimised. Measured data of the reaming process allow the prediction of occurring process errors without the need to evaluate the bore with a coordinate measuring machine. However, manufacturing is already completed at this stage and the correction of errors is either no longer possible or very costly. This paper presents an approach to detect axis offsets within the entry phase of the reamer by analysing the process forces. The calculated offset is then compensated by adjusting the nominal value of the motion control.

Jitter in an electronic signal is any deviation in, or displacement of, the signal in time. This paper investigates on decomposition of two types of jitter, namely, periodic and random jitter in noisy signals. Generally, an oscilloscope generates an eye diagram by overlaying sweeps of different segments of a long data stream driven by the reference clock signal. We use the fast Fourier transform with time lag correlation of the signal since we do not have a clock reference signal and apply this technique to simulated noisy signals. We separately injected a random jitter (of known amount), periodic jitter (with known frequency and amount), and both together to various modulation frequencies of sinusoidal signals. The approach is validated by several experiments with numerous values in jitter parameters. When we separately inject random jitter (5 ps) and periodic jitter (5 ps at 4.37 MHz) to the signal, we obtained the results (4.52±0.25 ps) and (4.93±0.04 ps at 4.40±0.04 MHz), respectively.

Implementing monitoring over construction process of old bridge’s reinforcement serves as an important measure to ensure construction quality and safety and realize the goal of reinforcement. This paper, with a case study of the maintenance and reinforcement project of Zhicheng Yangtze River Bridge (steel truss highway-railway combined bridge), adopted MIDAS to establish finite element analysis model, and with stress and deformation as monitoring parameters, completed the construction monitoring work, numerical simulation analysis and site test for the reinforcement project.

Uncertainty in manufacturing processes is as old as the manufacturing process itself. Simulationson the other hand are always certain in their outcome based on the chosen parameters. Nonethelessit makes sense to incorporate uncertainties in the simulation for validation and analysis of the realand simulated processes. This paper aims on highlighting the importance of an accurate understandingand measurement of uncertainty for simulation validation and thus to increase the significance andacceptance of simulation results in the working environment.

Rising energy costs and volatile energy prices are motivation to integrate energy consumption with planning processes in manufacturing. Since centralized approaches for Manufacturing Control (MC) tend to ignore local energy related information, it is necessary to examine the potential of decentralized MC approaches. For this purpose, a factory simulation tool has been implemented. This paper presents the underlying assumptions behind the simulation tool and how the MC algorithms it uses are implemented using an agent-based simulation approach.

Visualization of work surface topography through simulations is very challenging task in grinding process due to the complexity of wheel-work interactions with a very high number of cutting points (grits). Kinematic mapping of abrasive grits on a three-dimensional wheel topography enables the evaluation of ground surface topography through simulations. In this paper, a method for generating the ground surface topography based on wheel specifications is presented. Abrasive grits size, abrasives volume percentage and their nature of distribution on the wheel surface are considered in the modeling and visualization of wheel topography. The simulation results of ground surface topographies prove the feasibility of the developed method.

The wear behavior of cutting tools directly affects the quality of the machined part. The measurement and evaluation of wear is a time consuming and process and is subjective. Therefore, an image-based wear measure that can be computed automatically based on given image series of cutting tools and an objective way to review the resulting wear is presented in this paper. The presented method follows the industrial vision system pipeline where images of cutting tools are used as input which are then transformed through suitable image processing methods to prepare them for the computation of a novel image based wear measure. For multiple cutting tool settings a comparative visualization of the wear measure outputs is presented. The effectiveness of the presented approach is shown by applying the method to measure the wear of four different cutting tool shapes.

For decades, multiple lighting simulation software packages and plugins for commercial software have been developed in an effort to ease the usage and integration of simulation into the lighting design process. In this effort, one of the main challenges is to provide lighting designers with an easy and comprehensive access to simulation results. Visualization is used as a means to achieve this goal. In this paper, we explore two of the most used free lighting simulation packages towards the identification of visualization techniques that facilitate the access to the simulation results as well as the identification of opportunities for the enhancement of simulation-assisted lighting design processes. A test case of a metal workshop illustrates the output produced by both software packages. Based on this exploration, we identified an open gap regarding three main aspects: interactive exploration of simulation results, visualization of compliance with lighting standards, and visual comparison of lighting solutions. We provide a discussion on how approaches from other domains can be applied to close this gap.

Sustainable protection and expansion of the competitiveness of the industrial location Germany is an important topic of current research. How can manufacturing companies in high wage countries counter the challenges of market turbulences? Crucial for the competitiveness of these companies is the compensation of wage and salary costs through highly efficient processes. A promising approach is to increase the responsiveness of a company. Responsiveness means, to react as quickly as possible to events or changes of the market, which are not yet evident and can not be foreseen at the time of production system planning. An increase of responsiveness enables companies to react quickly and flexible to market turbulences. The question arises, which market information are relevant, to which a company has to react as quickly as possible in order to handle market turbulence. This paper addresses this issue and identifies relevant information, that are already known during the phase of product development, and the unknown information of the market, to which an existing production system has to react in order to compensate market turbulences. The interplay of known and unknown information enables a responsive production control. The origin and usage of this information, which enables reactive production control, are a part of this article and are explained therein.

The formation of chips in cutting processes is characterised by large deformations and large configurational changes and therefore challenges established modeling techniques. To overcome these difficulties, the particle finite element method (PFEM) combines the benefits of discrete modeling techniques with methods based on continuum mechanics. In this work an outline of the PFEM, as well as an explanation of the finite element formulation are provided. The impact of the boundary detection on the structural integrity is studied. The numerical examples include a tensile test as well as cutting simulations. The paper is concluded by a comparison of cutting forces with analytical results.

Many machine tool manufacturers offer services to support their customers over the lifetime of a product. This kind of integration of products and services is called Product-Service Systems (PSS). PSS offer advantages for the customers as well as for PSS providers because they fulfill customers’ requirements and ensure a long and successful customer relationship. Since sustainability is getting more and more important and customers are interested in sustainable solutions, PSS providers need to improve the environmental impact of their products and services continuously. Under this aspect, an approach is necessary that identifies the ecological potential of services for machine tools. In this paper, an approach to analyze the impact of Product-Service Systems on the energy efficiency of machine tools is presented.

Selective Laser Sintering (SLS) has recently become one of the fastest growing additive manufacturing processes due to its capability of fabricating metal parts with high dimensional accuracy and surface quality. Physical modeling of this process plays an important role in properly controlling the process parameters of the process. In this paper, we present a 3 dimensional, adaptive discrete element method for simulation of the SLS process on personal computers. The presented method models the laser-powder interaction at particle level, achieving high simulation accuracy while adaptively increasing the discrete element size as local temperatures drop inside the powder bed for improved efficiency. Numerical shape functions are developed for calculating individual particle temperatures at any point during the simulation. Results show that this physical model improves the runtime significantly in virtual simulation of SLS process without loss of simulation accuracy.

On the macrolevel metal matrix composites (MMCs) resemble a homogeneous material. However, on the microlevel they have an inhomogeneous microstructure. This paper will show how heterogeneities affect the effective macroscopic properties the material, i.e. the effective properties. This investigation is done using computational homogenization techniques. Finite element (FE) simulations were conducted in ABAQUS in combination with MATLAB, using material parameters for aluminum alloy AA2124 and silicon carbide SiC to develop a representative volume element (RVE) of the MMC AMC217xe.

Impulse facilities generate transient high-velocity gas flows for ground testing in aerodynamics. The expansion tube is the facility type with the highest performance capability in terms of total flow enthalpy and total pressure, and is particularly useful for studies of atmospheric re-entry, chemical kinetics, scramjet flight and supersonic combustion. In operation, a thin film diaphragm that initially partitions two tube sections is required to rupture under the force of a shock-wave. Fragmented pieces are accelerated with the flow and can damage test models and instrumentation, and the rupture process itself affects flow properties. It has been proposed to replace the diaphragm with a fast open valve that clears the tube prior to shock arrival. This paper investigates the effect of early valve opening on the test flow.An inviscid, axisymmetric model was created using Eilmer3, a compressible CFD solver developed at the University of Queensland. Early valve opening was simulated at varying times for instantaneous diaphragm removal. The result was the formation of a secondary shock and expansion wave. The primary shockwave reaches the test section at a higher velocity due to passing through the expansion wave, creating a faster, higher-pressure test flow, but also higher temperature, leading to substantially reduced Mach number. The interactions with the secondary waves were found to cause unsteadiness in test flow properties.

The assessment of the capacity of RC masonry infilled RC structures constitutes nowadays a still debated issue. Pushover based procedures for the evaluation of seismic performance, such as N2 method, are largely used in practice and in force in several technical codes. The latter has proved to be reliable for a large number of structural typologies, however in the case of infilled frames, the choices made on the modelling strategy may radically modify the outcomes observable from the capacity curves and the consequent performance levels achievable. In the paper, the extent of different modelling choices on the results of the application of N2 procedure is investigated by the deep analysis of a case study of a scholastic facility in Italy. Three modelling hypotheses are considered: neglecting of infills; equivalent strut macromodeling and equivalent strut macromodeling with prediction of additional shear demand arising because of the interaction with the infills. The impact of each on the capacity curves and then on the reliability of the overall N2 procedure is discussed pointing out the major criticalities.

The computational fluid dynamics solver Eilmer has proven useful to The University of Queensland’s Centre for Hypersonics for its ability to simulate high-speed compressible flows. In Eilmer, turbulence is modelled using Wilcox’s 2006 k-ω model. While the turbulence model implementation has been validated for two-dimensional and axisymmetric flows, validation is required for three-dimensional flows. The present paper describes the progress of the validation of the k-ω turbulence model for two three-dimensional test cases. A case featuring Mach 4.5 air flow over a flat plate produced results that correlated with previous numerical results within 4%. A second case featuring the injection of Mach 1 air into a Mach 4 air cross-flow produced results indicating that the code successfully captured the main flow features.

Magnetorheological elastomer (MRE) base isolator is a semi-active control device which has currently obtained increasing attention in the field of vibration control of civil structures. However, the inherent nonlinear and hysteretic response of the device is regarded as a challenge aspect for using the smart device to realize the high performance. Therefore, an accurate and robust model is essential to make full use of these unique features for its engineering applications. In this paper, to solve this issue, adaptive neuro-fuzzy inference system (ANFIS) is utilized to characterize the dynamic behavior of the device. In this proposed model, the inputs are historical displacements and applied current of the device while the output is the shear force generated. To validate its forecast performance, the ANFIS model is also compared with some conventional models. Finally, the result verifies that ANFIS has the best perfection ability among existing MRE-based device models.

In the developing world artisanal fishermen use kerosene lanterns for night fishing. Solar powered fishing lights became an ecologic and economic alternative to the kerosene lanterns due to the development of high efficiency LED light sources and low price solar cells. In the last years several solar fishing light systems were developed. The choice of the battery technology influences the reliability and the operating cost of the fishing light, because the battery has the lowest lifetime of all components of the fishing light.In this paper we describe the results of a battery simulation over 5 years time: The battery is daily charged by a solar module and discharged by night fishing. The meteorological irradiation data of Tanzania are used. Different battery technologies (Lead Acid, Lithium-Ion, Lithium-Iron-Phosphate) are tried out.The results of the simulation are the battery lifetime, cost and waste mass per year dependent on the battery technology. The study shows, that the Lithium-Iron-Phosphate technology is the best choice in terms of these factors and to the advantage of the poverty-stricken fishermen at the Victoria Lake in Tanzania and the environment.

Particle analysis methodology is presented, together with the morphology of the wear debris formed during rolling contact fatigue. Wear particles are characterised by their surface topography and in terms of wear mechanism. Rail-wheel materials are subjected to severe plastic deformation as the contact loading progresses, which contributes to a mechanism of major damage in head-hardened rail steel. Most of the current methodologies involve sectioning of the rail-wheel discs to trace material damage phenomena such as crack propagation and plastic strain accumulation. This paper proposes methodology to analyse the development of the plastically deformed layer by sectioning wear particles using the focussed ion beam (FIB) milling method. Moreover, it highlights the processes of oxidation and rail surface delamination during unlubricated rolling contact fatigue.

This paper aims to study the windmill Savonius with multi-deflector. Multi-deflector placed around the windmill, which aims to reduced negative torque to the returning blade and directing the flow of wind to the advancing blade . CFD analysis with ANSYS software. The initial conditions with variation wind speeds 3, 4, 5 and 6 m / s. The result indicated by velocity distribution at positions 00, 450, 900 and 1350. The largest static torque occurs at position 450 caused by the greater the Coand-like flow, dragging flow and overlap flow. The greater the static torque that occurs with increasing wind speeds.

In this paper, we first define the concept of bipolar single neutrosophic graphs as the generalization of bipolar fuzzy graphs, N-graphs, intuitionistic fuzzy graph, single valued neutrosophic graphs and bipolar intuitionistic fuzzy graphs.

This paper introduces a methodology for the type synthesis of two degree-of-freedom hybrid translational manipulators with identical legs. The type synthesis method is based upon the screw theory. Three types of two degree-of-freedom hybrid translational manipulators with identical legs are identified based upon their wrench decomposition. Each leg of the manipulators is composed of a proximal module and a distal module mounted in series. The assembly conditions and the validity of the actuation scheme are also defined. Eventually, some novel two degree-of-freedom hybrid translational manipulators are synthesized with the proposed procedure.

Finger clubbing, also known as drumstick finger, is the medical symptom that is indicated by the development of the sponginess or swelling in the nail beds of nails and toes. The higher grade of clubbing on the patients can be easily identified with the presence of drumstick finger. The existing available measurement device to identify the early stage of clubbing required much time which is impractical for a busy clinic practice. This paper explains the determination of the finger clubbing by using the Digital Index (DI) measurement, which was deployed by implementing and developing the Portable Finger Clubbing Meter hardware and the Microsoft Visual Basic (VB) Graphical User Interface (GUI). Finger circumference values of nail-fold (NF) and distal interphalangeal joint (DIP) of twenty participants were measured using the developed hardware. Data analysis was then performed using the GUI for DI computation, and the presence of finger clubbing could be determined.