Showing papers in "Procedia Engineering in 2017"

Synthesis of Graphene Oxide using Modified Hummers Method: Solvent Influence

Abstract: The aim of this study is to study the influence of different solvents on the structure and electrical properties of graphene oxide. GO was obtained from graphite flakes by using modified hummers method in which different from conventional hummer's method. In this method, the experiment was synthesized without sodium nitrate (NaNO3) and ice bath, but carried out at room temperature. Prepared GO powders were then dissolved into different solvents, namely acetone and ethanol. Then spin-coated onto silicon wafer and IDE to produce acetone-GO (A-GO) and ethanol-GO (E-GO). SEM result shows that several square micron GO were obtained. In addition, due to the large agglomerates and contact between the flakes in E-GO sample, current-voltage pattern indicated the E-GO produced higher current flow than A-GO. Meanwhile, GO characterized using FTiR shows that both samples contain several functional groups such as hydroxyl, epoxy, carboxyl and carbonyl. Besides that, due to the lower diffraction peak of A-GO, XRD result shows the interlayer spacing of A-GO sample is slightly higher than E-GO sample.

Internet of Things, Big Data, Industry 4.0 – Innovative Solutions in Logistics and Supply Chains Management ☆

Abstract: The aim of this article is to present some ‘smart’ solutions which could be recognised as innovative solutions in both areas: technology and organisation. The above mentioned solutions could be implemented by logistics which, in the era of globalization, plays a very important role. This applies not only to functioning of individual companies, but also to national economies and even the world economy. The phenomenon of competition can now be observed not just in individual companies but in entire supply chains. The pace of development of the modern economy means that companies are forced to constantly introduce more and more new solutions, resulting in innovation driving the progress of the market. This article is a part of research, which considers the problem of implementation of IT solutions logistics.

Towards Lean Production in Industry 4.0

Abstract: Lean Production is widely recognized and accepted in the industrial setting. It concerns the strict integration of humans in the manufacturing process, a continuous improvement and focus on value-adding activities by avoiding waste. However, a new paradigm called Industry 4.0 or the fourth industrial revolution has recently emerged in the manufacturing sector. It allows creating a smart network of machines, products, components, properties, individuals and ICT systems in the entire value chain to have an intelligent factory. So, now a question arises if, and how these two approaches can coexist and support each other.

Potentials of Blockchain Technology for Construction Management

Abstract: Blockchain technology enables distributed, encrypted and secure logging of digital transactions. It is the underlying technology of Bitcoin and other cryptocurrencies. Blockchain is expected to revolutionize computing in several areas, particularly where centralization was unnatural and privacy was important. In the paper, we present research on where and how this technology could be useful in the construction industry. The work is based on the study of literature on open issues that exist in construction process management. These are than matched to the capabilities of blockchain. We are motivated by the fact that construction projects involve a dynamic grouping of several companies. We study the degree to which the relationships among them are hierarchical or peer-to-peer and note that particularly in information intensive phases, centralization of information management was necessary because of technology. When using un-constraining technology, communication patterns among participants show a peer-to-peer nature of the relationships. In such environment, blockchain can provide a trustworthy infrastructure for information management during all building life-cycle stages. Even if building information modelling (BIM) is used, which assumes a centralized building information model, there is a role for blockchain to manage information on who did what and when and thus provide a basis for any legal arguments that might occur. On the construction site blockchain can improve the reliability and trustworthiness of construction logbooks, works performed and material quantities recorded. In the facility maintenance phase, blockchain's main potential is the secure storage of sensor data which are sensitive to privacy. We conclude that blockchain provides solutions to many current problems in construction information management. However, it is more likely that it will be built into generic IT infrastructure on top of which construction applications are built, rather than used directly by authors of construction related software. It has a potential to make construction processes less centralized which opens needs for research in that direction.

The Smart City Concept in the 21st Century

Abstract: The quality of life was significantly improved in the last century mainly as regards the access to services. However, the heavy industrialization and the increasing population in the urban areas has been a big challenge for administrators, architects and urban planners. This paper provides a brief presentation of the evolution of the “smart city” term and the most representative characteristics of it. Furthermore, various alternative terms that were proposed to describe the multiple characteristics of the future cities are analyzed. A connection between smart city and smart grid is also presented.

Biopolymers in Medical Implants: A Brief Review

Abstract: Biopolymers have been established as a promising class of materials with a wide range of applications, of which medicine stands out. Characteristics such as biocompatibility, biodegradation and non-cytotoxicity make these material excellent candidates to be used in implantable materials. This review examines the main properties of biopolymers, as well as the potential of different biopolymers, including polylactic acid (PLA), silk and chitosan, for application in implantable medical devices.

Technical, Economic and Environmental Review of the Lubrication/Cooling Systems Used in Machining Processes☆

Abstract: The use of cutting fluids in machining processes is a serious concern because their cost, and environmental and health effects. In the last decades, efforts have been developed to come up with alternatives to overcome their main drawbacks. The ultimate goal is the complete suppression of cutting fluids. However, because of the demanding requirements of the machining processes, in some cases it is not possible to use dry machining conditions. Reasons can be found in the excessive heat generated in the process, the increase of the friction between the tool and the workpiece or the need to evacuate the chips generated. The pull for sustainable products is also encouraging the developing of new cutting fluid formulations. In the present paper, a comprehensive analysis of the use of cutting fluids and main alternatives in machining is carried out. Particularly, the analysis was done focusing on the economic, environmental and technical points.

The Effect of Layer Thickness at Selective Laser Melting

Abstract: Selective laser melting technology involves various parameters which may influence properties of the resulting part. This study presents the correlation between powder layer thickness and relative density, microstructure and mechanical properties of nickel-based superalloy produced by selective laser melting. It is shown that the microstructure of the bulk material consists of columnar dendritic cells. The size of these cells depends on the layer thickness used during SLM. Tensile strength and elongation at break also depend on the powder layer thickness during SLM. Samples build with 30 μm layer thickness demonstrate higher strength and lower elongation at break than those build with 50 μm layer thickness. It is also established that the horizontally build samples show higher strength properties and lower plasticity compared to the vertically build samples.

Traffic Flow Prediction using Kalman Filtering Technique

Abstract: Traffic flow prediction is an important research problem in many of the Intelligent Transportation Systems (ITS) applications. The use of Autoregressive Integrated Moving average (ARIMA) or seasonal ARIMA (SARIMA) for traffic flow prediction requires huge flow data for model development and hence it may not be possible to use ARIMA in cases where sufficient data are unavailable. To overcome this problem, a prediction scheme based on Kalman filtering technique (KFT) was proposed and evaluated which requires only limited input data. Only previous two days flow observations has been used in the prediction scheme developed using KFT for predicting the next day flow values with a desired accuracy. Traffic flow prediction using both historic (previous two days flow data) and real time data on the day of interest was also attempted. Promising results were obtained with mean absolute percentage error (MAPE) of 10 between observed and predicted flows and this indicates the suitability of the proposed prediction scheme for traffic flow forecasting in ITS applications.

Smart City, Safety and Security

Abstract: Nowadays, cities across the world are one after another trying to become so called Smart Cities. In this paper we propose several ideas on how to define the concept of Smart City, including our own. However, our main focus will be on the question of the safety and security in such cities in the future. Our study of the Smart City program shows the lack of importance which is being given to this topic. Because of that, we are inspired to introduce our definition of a Safe City. Along with the topics of safety and security, we also provide the reader with an insight into the importance and use of the modelling and simulations in a Safe City.

Integrated Application of BIM and GIS: An Overview

Abstract: With the concepts of Smart City attracting the industry, the method of managing spatial information has become a hot research topic. Relating to this topic, GIS and BIM are two critical technologies. Although the application of GIS has a long history and BIM has also developed for over 10 years, their integrated application starts a new direction and is still at the early exploration stage. To better understand this newly expanded field, we review previous works in the field from the perspective of research and relevant application platform. Based on that, directions of future research are discussed.

Decision Making in Construction Management: AHP and Expert Choice Approach

Abstract: The term and content of construction project management are outlined in this article. The main problems of construction management were identified and possibilities to solve them are discussed. The model for decision making in construction management by using multi-criteria methods was created and applied to real case study. AHP method and “Expert Choice” computer program was employed for calculations.

CNN Design for Real-Time Traffic Sign Recognition

Abstract: Nowadays, more and more object recognition tasks are being solved with Convolutional Neural Networks (CNN). Due to its high recognition rate and fast execution, the convolutional neural networks have enhanced most of computer vision tasks, both existing and new ones. In this article, we propose an implementation of traffic signs recognition algorithm using a convolution neural network. The paper also shows several CNN architectures, which are compared to each other. Training of the neural network is implemented using the TensorFlow library and massively parallel architecture for multithreaded programming CUDA. The entire procedure for traffic sign detection and recognition is executed in real time on a mobile GPU. The experimental results confirmed high efficiency of the developed computer vision system.

Project Management Success Factors

Abstract: Project management success is extremely interesting topic from scientific, as well as practical point of view. Namely, different models of project management success emerged through history, indicating the level of thoughts considering management of project successful. This article differs project management from project success, gives definitions of project management success, aims to review different models of project management success, differs success of managing public and private projects and gives a special accent on present situation in context of project management in Croatia. Comprehensive literature review is given, analysis and synthesis of most interesting material is made, and applicable practical guidelines are defined.

Delay and Cost Overrun in Infrastructure Projects in Jordan

Abstract: The aim of this study is to investigate the factors that may cause overrun of the planned cost, allocated resources and scheduled time of infrastructure engineering projects in Jordan. To achieve the goal of this study, final reports of a sample of 40 public infrastructure projects implemented during the period from 2000 to 2008 were collected and analysed. The final reports were collected from the Ministry of Public Works and Housing (MPWH) of Jordan, which administers the public infrastructure projects in the capital Amman. The analysis showed that delay and cost overrun of infrastructure projects were caused by 20 factors according to the records in the collected final reports of projects. The results showed that Terrain and Weather conditions are the top factors causing completion delay and cost overrun in infrastructure projects in Jordan.

Analysis of Delay Impact on Construction Project Based on RII and Correlation Coefficient: Empirical Study

Abstract: The occurrence of a delay in the construction projects is common and significantly affects by enormous ways. This study investigates the typical causes of delay at different stages of construction and its effect in the Ethiopian construction projects. Using a questionnaire with 52 causes and 5 effects of delay, data were collected from 77 participants’ selected based on purposive sampling from the different contracting organizations. The methodologies used in this research are relative important index (RII) and correlation coefficient. Based on the comparison, the impact of delay is found as, construction stage, pre-construction stage, and post-construction stage sequentially. The analysis of the relation in construction process shows; the average/overall is highly related, construction stage is the second related, post-construction stage is the third related and pre-construction stage is far part of all stages. As far as, overall/average causes of delay are comparable to all stages. So from the overall, the influential causes of delay investigated are corruption, unavailability of utilities at site, inflation/price increases in materials, lack of quality materials, late design and design documents, slow delivery of materials, late in approving and receiving of complete project work, poor site management and performance, late release budget/funds, and ineffective project planning and scheduling successively as unique to the Ethiopian construction project. The critical effects of delay investigated are cost overruns, time overrun, termination of contract, arbitration, and litigation sequentially. Although, the research is conducted on the Ethiopian construction projects, but it can also apply to other countries and further study.

Comparing Ridge and LASSO estimators for data analysis

Abstract: This paper is devoted to the comparison of Ridge and LASSO estimators Test data is used to analyze advantages of each of the two regression analysis methods All the required calculations are performed using the R software for statistical computing

Effects of Fibre Configuration on Mechanical Properties of Banana Fibre/PP/MAPP Natural Fibre Reinforced Polymer Composite ☆

Abstract: Natural fibre reinforced polymer matrix composite (PMC) is one of the advanced technologies developed in the materials engineering industry. Amongst the advantages of natural fibre reinforced PMC are biodegradable, recyclable, lightweight, low production cost, and readily available. Therefore, natural fibre reinforced polymer composites have been used for many applications such as automotive components, aerospace parts, sporting goods and building industry. In this research, high performance polypropylene (PP) composites, using continuous banana fibre as reinforcement with polymer to fibre by weight percent ratio of 70:30, were developed. This research aims to investigate the effects of different configurations of continuous banana fibre reinforcement on mechanical properties of the composite materials. Coupling agent, which is maleic anhydride grafted polypropylene (MAPP) is added to the composites to improve bonding between the polymer matrix and the natural fibre. To further improve the PMC's mechanical properties, banana fibre's configurations are varied, in which their performance are tested. The banana fibre is varied by three different configurations; raw banana fibre, banana fibre yarn, and banana fibre mat. Mechanical properties of the composite samples were assessed using tensile and flexural testing in accordance to ASTM D638 and ASTM D790, respectively. Microstructural analysis was performed by using scanning electron microscope to explain the failure mechanisms and behavior of the composites. This study has enabled ranking of different banana fibre configurations towards mechanical properties of the natural fibre reinforced thermoplastic-based composites. Morphology examination of the fracture surfaces confirmed failure mechanisms and explained why one fibre configuration is superior to the others.

Analysis of the Adoption Rate of Building Information Modeling [BIM] and its Return on Investment [ROI]

Abstract: In an effort to remedy the issue of stagnant labor productivity in the construction industry, Building Information Modeling was proposed in the late 80's as a new solution for streamlining the design and delivery process of construction projects. BIM is a digital representation of a building meant to serve all project participants as a repository of all relevant data throughout the project's lifecycle. Management of this data along with the collaborative nature of BIM has been shown to offer many potential benefits to those involved in the project. Despite the huge potential for increasing productivity as well as the overall efficiency of construction projects, the adoption of BIM throughout the industry has been observed as slower than expected. This paper explores and analyzes the various barriers hindering the widespread adoption of BIM throughout the industry as well as proposes methods for addressing them. The author then answers the question of who should be responsible for driving the adoption of BIM and how to effectively do it. Finally the author proposes areas of further research and development which will assist in achieving a more widespread adoption of BIM throughout the industry.

Significant Factors Causing Cost Overruns in the Construction Industry in Afghanistan

Abstract: It is generally acknowledged that one criterion for judging the success of a construction project is whether it is completed within budget. Due to various factors, this is often more of a challenge in developing countries where budget problems are just one factor in often poor project performance. In Afghanistan, construction cost overruns are the most substantial problem (facing all parties to a project; suppliers, subcontractors, main contractors and clients). This research aims to identify the significant factors that lead to construction cost overruns in Afghanistan. The finding of the research is that the key critical causes that potentially result in construction cost overruns in Afghanistan are: corruption, delay in progress payment by owner, difficulties in financing project by contractors, security, change the order by the owner during construction and market inflation.

Construction and Demolition Waste Recycling Plants Revisited: Management Issues☆

Abstract: Today, recycling of construction and demolition waste (C&DW) by plants is a reasonable alternative to the existing unsustainable disposal methods such as landfilling and fly tipping. Therefore, this study aims to report current management issues of these plants in the literature. As a result, it was seen that these management issues investigated in past researches can be classified under four main groups such as economics, environment, location, and administration. Their pros and cons were also revealed in a covering manner. As these issues have not been addressed together up to date and each one of them has been investigated separately, the present study is the first attempt to give a full picture of management issues of the recycling plants. Thus, it can fill the gap in the literature. As a research implication, this study may help researchers who will investigate C&DW recycling plants from different perspectives. In terms of the practical implication, it may attract attention of industrial practitioners and entrepreneurs in public authorities and the private sector to benefit from such wastes through plants. Finally, as a social implication, better management of C&DW recycling plants can save and enhance the sustainability of the overall environment and affect society positively.

Big Data in Building Energy Efficiency: Understanding of Big Data and Main Challenges

Abstract: Data generation has increased drastically over the past few years. Data management has also grown in importance because extracting the significant value out of a huge pile of raw data is of prime important thing to make different decisions. One of the important sectors nowadays is construction sector, especially building energy efficiency field. Collecting big amount of data, using different kinds of big data analysis can help to improve construction process from the energy efficiency perspective. This article reviews the understanding of Big Data, methods used for Big Data analysis and the main problems with Big Data in the field of energy.

Assessment of Urban Energy Performance through Integration of BIM and GIS for Smart City Planning

Abstract: Smart city has been becoming nowadays a very popular topic that not only in developed countries but also in developing countries. There are variety of definitions for smart city in different fields and regions. Generally, it aims for a sustainable city development through the optimal management of the resources and potential, offering a comprehensively higher quality life to the citizens. The planning of area energy system is one of the most important issues, which is related to the energy generation, the energy consumption by facilities, transportation system, and any other city infrastructures. Especially for Japan, one of the countries facing the complex issues of an aging society, disaster management and energy dependency need a new methodologies for optimal urban energy planning that integrates all information from these sectors. Smart city with highly developed information and communications technology (ICT) is considered as such an important approach. To encourage the smart city concept in Japan, this paper proposes a “GIS-BIM” based urban energy planning system to access the optimal technical and policy solution for readjust city infrastructure beyond the integrated analysis. Firstly, it introduces the concept of Japanese smart city which covers from urban planning to infrastructure. Secondly, the research proposes a GIS-BIM based urban energy planning system including the database construction and analysis by GIS, the optimal energy system design aided by BIM and 3D visualization with user-friendly interface. Finally, center of Tokyo is adopted as a case study, suggesting the potential to access the optimal technical and policy solution.

The carbon footprint of Australia's construction sector

Abstract: Australia accounts for just 0.33% of the world's population yet it is one of the highest emitters of greenhouse gas (GHG) emissions per capita in the world. The construction sector is a substantial area for mitigation efforts in Australia because of its economic importance and its involvement with indirect GHG emissions, i.e. those embodied in construction supply chains, including construction materials and electricity use. While the majority of policies and regulations focus on reducing direct emissions from buildings, more attention needs to be paid to the embodied emissions of the whole sector as these can take up anywhere between 10% and 97% of the whole life-cycle carbon emissions. This study aims at unravelling the total carbon footprint of the construction sector in Australia from 2009 to 2013, identifying the key contributing supply chains, industries and products. An economy wide input-output (IO) analysis is performed using a collaborative, cloud-based data platform – the Industrial Ecology Virtual Laboratory (IELab). This allows for a detailed disaggregation of sectors and permits more refined analysis as well as benchmarking against other sectors in the economy. Results for CO 2 e emissions by final demand show the construction sector makes up 18.1% of Australia's carbon footprint, compared to only 1.9% of direct emissions in 2013. The largest contributors to these embodied emissions are electricity, water & waste and materials throughout the years. Results are also broken down by detailed construction activities in residential / non-residential, road & bridge, other heavy and civil engineering and construction services. Mitigation options for electricity supply and materials use in the Australian construction sector are suggested.

The Use of UAV's for Search and Rescue Operations

Abstract: Modern public services are nowadays capable of conducting complex operations in case of various natural or man-made hazards. In last decades, the responsibilities of the fire services have been significantly extended from ‘ordinary’ fire-fighting to complex operations including technical rescue, but also chemical, biological, radiological, nuclear rescue. Therefore this crucial public service is being constantly equipped with the newest and the most efficient solutions aiming at optimization of their primary activity, which saves victims lives. Thanks to INSARAG guidelines, activities of certified heavy urban search and rescue groups (HUSAR) are based on solid foundations: knowledge and experience gained during historical events in last decades. However, rapid technological progress might be beneficial. The article describes the MOBNET system, that is currently under development. There was a research work conducted to gather end-user requirements in purpose to create a tailor-made solution supporting traditional activities of USAR teams. The target group of the system has been extended, as other public services might benefit from the system implementation as well. The system will use combined DCT – EGNSS technology to track victims.

Selected Mechanical Properties of PETG 3-D Prints ☆

Abstract: The 3D printing is a way of additive manufacturing that allows the creation of sophisticatedly shaped bodies at relatively low cost and in short time span. It is especially useful for rapid manufacturing, including engineering applications such as rapid prototyping. The commonly used fused deposition modelling (FDM) method dispenses filament from heated nozzle positioned in three axes that hardens after exiting the nozzle. This article presents the research focused on the mechanical properties (mainly the basic tensile strength and elastic modulus) of elements printed using the FDM method, made of two distinctive materials: polyethylene terephthalate glycol (PETG) without additions and glass-fiber reinforced PETG. The paper outlines strengths and weaknesses of the materials described and compares the properties of PETG with and without the addition of glass fiber. The gathered data helps to quantify the mechanical properties of parts made of PETG and may also be used for modelling the properties of 3D printed elements.

The Development of a Waste Management System in Kerbala during Major Pilgrimage Events: Determination of Solid Waste Composition

Abstract: Several religious events take place annually in Kerbala, Iraq, attracting approximately 20 million pilgrims. Consequently, huge amounts of solid waste are generated which have a direct effect on both the environment and human health. The management of such waste poses a serious and complex problem for the city authorities. Therefore, establishing accurate and reliable information about this issue is valuable in terms of waste management planning and resource recovery application. The aim of this study is to analyze the composition of said solid waste during these religious events. To achieve this goal, a field investigation was conducted at three temporary transfer stations, over 10 days, during one event in Kerbala. Sampling and data analysis were carried out based on the ASTM D5231-92 (2003) standard method. Sixty samples of unprocessed solid waste were collected and manually sorted into six different categories: organics, plastics, paper, metals, glass and miscellaneous wastes. The results show that organic waste constituted the main waste category (57%) with paper, plastics and miscellaneous at 15%, 14.6% and 6.5%, respectively. These findings indicate that because of the high percentage of food waste, there exists a strong potential for energy generation or composting. In addition, plastics, papers, metals and glass have the potential to be separated and collected for recycling purposes. These results can be taken as a baseline for developing a successful waste management system in Kerbala city and other cities that have similar major pilgrimage events.

Machinability of Hybrid Metal Matrix Composite - A Review

Abstract: Aerospace and automotive industries are eager on introducing hybrid metal matrix composites in their components due to their excellent mechanical and physical properties, leading to reduction in the weight of structural components and energy requirement for propelling. Components made by hybrid metal matrix composite (based on Aluminum alloy reinforced with single wall and multi wall carbon nanotubes, Graphene and ceramic particles) required secondary operations to enhance the dimensional tolerance and surface finish. Machining operations generally requires minimum tool wear rate and good surface finish with lowest energy requirement. Hard metal, ceramic and oxide reinforcements in the composite increase the tool wear and machining cost. To improve tool life and increase the metal removal rate significant care is needed for the selection of optimum cutting parameters and cutting conditions. This review focuses on the influence of reinforcement particle's types, shape, size and volume fractions on the machinability issues like the cutting force, tool wear, chip formation and surface roughness. Further, the role of various cutting parameters like cutting speed, feed, depth of cut and tool material, tool geometry and cutting conditions during turning of hybrid metal matrix composites are critically reviewed.

Life Cycle Costing as an Important Contribution to Feasibility Study in Construction Projects

Abstract: The purpose of this paper is to highlight the role of life cycle cost (LCC) analysis in the feasibility study of construction projects, especially in the public sector. Feasibility study is usually conducted in the early phase of construction projects when the greatest benefit of LCC can be obtained. The commonly used construction cost minimization approach should be replaced with LCC optimization. In order to achieve the maximum value for money, all costs incurred over the whole life span must be evaluated. Life cycle costing is a method of economic analysis directed at all costs related to constructing, operating, and maintaining a construction project over a defined period of time. The optimization of the LCC of a project, construction or equipment, is essential for the complex decision-making process. It is then at this point that the solution with the minimum value of LCC can be chosen. The public sector in the Czech Republic is now beginning to require quantification of LCC when deciding on construction. In addition, LCC has become a criterion in public tenders. This paper summarizes the experience of assessing building designs in terms of LCC. Not only public sector benefits are identified and summarized but also some significant difficulties. Case studies are provided.

Sensitivity Analysis of the Micro-Parameters Used in a PFC Analysis Towards the Mechanical Properties of Rocks

Abstract: Reproduction on complex behavior of rocks in actual case studies is undoubtedly the main aim of numerical modelling applied to rock mechanics. However, to achieve a reliably realistic simulation process a good knowledge of rock behavior is needed together with calibration or matching processes of actual and controlled tests on rock. Within this framework, in a previous approach, the authors calibrated PFC (Particle Flow Code) micromechanical parameters to reproduce in a reasonably accurate way the complete stress-strain response of granite samples under triaxial conditions in the lab. In this previous study, it was found that the number of different micro-parameters needed to define a PFC model was large, and that the influence of some of these parameters on rock response was not clear. In this new study, a sensitivity program is carried out in order to assess the influence of micro-mechanic parameters on the macroscopic response of the numerical simulation of rock samples. The sensitivity approach carried out shows that there is a direct connection between some parameters, for example, the bond cohesion and the bond tensile strength influences the peak strength and tensile strength of the rock, respectively. However, it is not clear how these parameters may influence other geomechanical macro properties, neither the exact influence of other parameters as the friction coefficient or the stiffness ratio. The present study addresses some of these issues, and it sheds light on which are most relevant parameters and how they control the main macro-properties of the simulated rocks.