bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of Gunungrowo Reservoir operation
Authors: Ari Wulandari Dyah , Darsono Suseno , Kurniani Dwi
Published: February 2019

Inaccurate water release has occurred from Gunungrowo Reservoir. In May–June, there is excess water release from Gunungrowo Reservoir while in the period from July to August there is a shortage of water release. Therefore the reservoir operation should be evaluated and updated in order to obtain optimal results and to adjust the changes. The purpose of this study was to evaluate the existing reservoir operation and to carry out an optimization to find the optimal reservoir operation. The objective is to conduct hydrological analysis, evaluate the reservoir operation, formulate a model of reservoir operation, optimize the reservoir operation, and analyse the results of reservoir operation optimization. Optimization of reservoir operation generates the water level of reservoirs and the release of water in each period as well as the objective function value under each scenario of reservoir operation. The existing reservoir operation is not optimal and has a reliability of only 24%. In the operation of the existing reservoir, emptying of the reservoir storage always happens and inaccuracies in the release of water have occurred. The optimal reservoir operation is scenario I, with a reliability of 75%, in which water is released in Planting Season II and Planting Season III.
Prediction of shoreline change using a numerical model: case of the Kulon Progo Coast, Central Java
Authors: Chrysanti Asrini , Bagus Adityawan Mohammad , Widyaningtyas  , Pramono Yakti Bagus , Nugroho Joko , Zain Khilmi , Haryanto Iman , Sulaiman Muhammad , Kurniawan Adhy , Tanaka Hitoshi
Published: February 2019

Kulon Progo Airport is an airport development project located in the coastal area near Yogyakarta, Indonesia, which is expected to complete in 2019. With the increase in population, huge land acquisition will be difficult, so the development of coastal areas for the airport became inevitable. Kulon Progo is located in the disaster-prone zone area of the earthquake and tsunami, the airport design must consider the risk management and mitigation from tsunami and earthquake disaster. Although the airport is already calculated the danger of earthquake and tsunami, the development of the coastal area also needs to consider the danger of the natural coastal process itself such as sedimentation and erosion. Shoreline changes due to the new infrastructure in the coastal area can disrupt the equilibrium of coastal process especially the longshore sediment transport. A satellite image shows that Kulon Progo shoreline retreats over 60 meters due to the heavy sediment longshore transport in the past 10 years. Breakwaters in Tanjung Adikarto fishing port also made a great contribution in huge sedimentation behind the infrastructure up to 90 meters. This research will conduct an analysis trough satellite and numerical model to observe the shoreline changes along Kulon Progo Coast. A numerical model shows a high erosion rate along the coast. High sedimentation also observed at the river mouth of Bogowonto and Serang Rivers.
The risks of construction grant support in toll road investment faced by Indonesia's government
Authors: Mahani Iris , Tamin Rizal Z. , Pribadi Krishna S. , Wibowo Andreas
Published: February 2019

In order to increase the role of private sector in infrastructure implementation in Indonesia, the Indonesia government facilitates Public-Private Partnership (PPP), such as by providing Viability Gap Funding (VGF) in the form of construction grants. Some projects get a construction grant but in toll road investment, the support is provided in another form. If the government provides construction grant on toll road investment, there would be risks that government need to face. This study aims to identify the said risks and analyse them so that the government could mitigate the risks. It is also could be used for devising public policy. This study is conducted qualitatively based on interviews with government officials, businessmen, and members of society. Based on the risk identification at each stage of the given support, there are 9 (nine) risks. After preliminary screening, the qualitative analysis and validation indicate that there are 4 (four) risks that must be mitigated by the government. These risks include: the possibility of being disapproved by the finance ministry, the approval process at the finance ministry takes a long time, it is too costly the state budget could not provide it and lastly, the difficulty of obtaining approval from the legislative.
Readiness of local government in PPP project development - case of LRT Bandung
Authors: Putri Revana , Wirahadikusumah Reini D.
Published: February 2019

Infrastructure development with PPP (Public Private Partnership) scheme is a relatively new concept applied by the Indonesian construction industry as an alternative to overcome delays and the low absorption of the Indonesian Government Budget (APBN) and Regional Government Budget (APBD) in the procurement of basic infrastructure. However, in practice, the failure rate of the government in carrying out infrastructure projects with PPP scheme is high. The failure of PPP project is generally caused by the way the government works in preparing projects that are not adjusted to the needs of PPP, the constraints of land acquisition, poor coordination between central and local government, participation, and overlapping regulations. This raises the question of how to know the condition of government readiness in implementing projects under PPP scheme and identify the constraints affecting government readiness. This study develops an assessment that can be used to measure government readiness in implementing projects under PPP scheme. Factors used in the system were developed based on three studies on the readiness assessment systems in various countries, namely: Public-Private Partnerships for Transport Infrastructure Toolkit from PPPIRC World Bank, United Nations Economic and Social Commission for Asia and the Pacific (ESCAP) and United Nations Economic Commission for Europe (UNECE). The assessment will be used to assess the level of readiness and constraints faced by the government of Bandung in implementing the project LRT Bandung.
Construction cost optimization of shallow foundation for sand soil in Indonesia
Authors: Azhim Abdul , Prakoso Widjojo A.
Published: February 2019

In designing foundation, there are three fundamental requirements namely: ultimate limit state (ULS), serviceability limit state (SLS), and economics. Generally, the ULS and SLS are the focus of the design process, while the cost factors are not explicitly considered. This paper deals with the three requirements with the minimum construction cost as the controlling objective. A wide range of sand density conditions are considered, while the typical ULS and SLS design checks available in the literature are employed. The optimization tool used is the Solver add-in function available in MS-Excel™. The effects of different construction cost structures in four Indonesia's provinces are examined in this paper. The purpose of this research is to be able in designing the shallow foundation with 3 aspects consideration at once, namely ULS, SLS and economic. On the other hand, this research is to analyse the sensitivity's factor which influence the design, namely work unit price, soil properties and design's requirements.
The cost of implementing OHSMS regulation on high-rise building projects
Authors: Wirahadikusumah Reini D. , Adhiwira Felix
Published: February 2019

In 2014, the Ministry of Public Works and Housing have published regulation that require the full implementation of Occupational Safety and Health Management System or short as OHSMS (known as SMK3 in Indonesia) in all phases of construction projects. The so called PerMenPUPR 5/2014 imposed an allocation of cost specific for OHSMS in the owner’s estimate, which was later updated as PerMenPUPR 2/2018 for minor adjustments in the regulation. This regulation was supported with guidelines for project managers on estimating the cost allocation for OHSMS. However, the initiative to address safety issues more comprehensively has been ineffective. The directive has not been seriously implemented by stakeholders on public projects. Thus, to help convince all stakeholders, more quantitative evidence on the costs for implementing OHSMS is pursued. This study is to determine the percentage of costs allocated by contractors for the procurement of OHSMS components. Data were collected from surveys to eight construction sites of high-rise building projects in Jakarta and Bandung. Based on interviews, questionnaires, and supporting documents from each case study, the cost of implementing the regulation was simulated and estimated. The cost allocation ranges from 2.01% to 3.70% of the contract value. The most significant components of the costs were related to OSH personnel (44.10%), insurance and licensing (35.2%), and OSH induction and promotion (5.82%).
Composite girder to fulfill the needs of 60 up to 80 m span bridge for toll road projects in Indonesia
Authors: Trisaputra Zuna Herry , Budi Astuti Zulaikha
Published: February 2019

Ministry of Public Works and Housing of Indonesia is targeting to complete the construction of 1.000 km of new toll road projects by the end of 2019. In 2015 until August 2018, 443 km new toll roads have been operated and 1.400 km are under construction. Various types of structure for elevated toll road constructions are applied to meet the geometry and safety requirements such as cast in-situ balanced cantilever, steel I-girder, and steel box are becoming type of elevated toll construction to be applied. To meet the requirements of construction methods, construction time completion, and material volume efficiency, Indonesia Toll Road Authority on behalf Ministry of Public Works and Housing gives opportunities to toll road investors to apply the new technology as the proper selection. Composite Girder technology named Sbarch is proposed for Krian Legundi Bunder Manyar toll road project to cross at SUMO Junction. Compares Sbarch among cast in situ balanced cantilever, steel I-girder and steel box, Sbarch can comply for all requirement that cannot be fulfilled by others method such as with finish grade requirement, to road geometry alignment, accessibility, workability, and steel tonnage reducing.
Impacts of infrastructure development in the villages of Batang Regency in terms of social, economy, education, and health
Authors: Fajri Muhammad , Rarasati Ayomi
Published: February 2019

The increase of village fund since 2015 led to the Indonesian government’s expectation for economic growth and more infrastructure development in villages, with the hope that the villagers’ quality of life will improve. This research aimed at analyzing the impacts of infrastructure development in Batang Regency, Central Java in terms of social, economy, education, and health aspects. Data was collected via structured interviews. The focus of the research is to identify the differences of impacts on infrastructure development based on 2 categories. The first category is the 3 geographical zones: the borders of the north coast Trans Java highway network (Pantura), mountainous area and coast area. The second category is based on the villagers’ duration of stay in their village: more than 10 years and less than 10 years. Based on the geographical zone research results, there were differences found in the impacts on social aspects, but none in the economy, education, health and education aspects. In the length of stay category, there were no differences in the impacts resulted from the infrastructure development on either the social, economy, education, or health aspects.
Criteria to consider in selecting and prioritizing infrastructure projects
Authors: Hansen Seng , Too Eric , Le Tiendung
Published: February 2019

Infrastructure project selection and prioritization is a challenging decision-making problem. Thus, decision makers are required to develop and use a decision-making framework to evaluate the proposals. The first step in developing such framework is to establish the decision criteria. This research aims to identify these criteria based on a systematic review of literature. A total of 34 decision criteria for infrastructure project selection was identified. In addition, this research has also identified three major facts related to decision criteria and presented a structured model to integrate these decision criteria into a Decision-Making Framework. As a preliminary study, the findings from this research are expected to assist further research on developing a Decision-Making Framework for infrastructure project selection.
Advancing Safety in Organisations: Application via the Luton Safety Stack
Authors: Smeltink Job , Stroeve Sybert , Kirwan Barry
Published: February 2019

Controlling and improving safety in organisations is achieved using a Safety Management System (SMS). Notwithstanding the variety of components considered in SMS standards, including human factors and safety culture, safety management systems are sometimes observed by those at the ‘sharp end’ as being bureaucratic, distinct from actual operations, and being too focused on the prevention of deviations from procedures, rather than on the effective support of safety in the real operational context. The soft parts of advancing safety in organisations, such as the multitude of interrelations and the informal aspects in an organisation that influence safety, are only considered to a limited extent in traditional safety management systems. The research in Future Sky Safety Project 5 (FSS P5) focused on improving these human-related, informal organisational aspects. Since every organisation is unique, in the operations it conducts, its history, and its organisational culture, there cannot be a one-size-fits-all standard for advancing safety in organisations. Rather, this needs to be based on the organisation at hand, leading to tailored solutions. This has been applied to a safety culture assessment and enhancement approach applied for six key organisations at London Luton Airport, and the approach has become known as the Luton Safety Stack. The six organisations decided to share the detailed results of their individual safety culture assessments. They formed a group that holds quarterly meetings, which always include a workshop element. From this approach, the organisations were stimulated to develop harmonised procedures for all ground-handling operators at Luton, and for each operation, creating a simple one-page procedure with diagrams, to keep it simple and safe. The Luton Safety Stack shows that when organisations share a place, such as at an airport, they need the opportunity to meet to discuss both potential safety threats, and opportunities to advance safety, because even through organisations are interdependent, safety issues in one organisation often have implications for others.
Design, Implementation and Perceptions of Safety Culture Prerequisites
Authors: Karanikas Nektarios , Roelen Alfred , Vardy Alistair
Published: February 2019

In the frame of an on-going 4-years research project, the Aviation Academy Safety Culture Prerequisites (AVAC-SCP) metric was developed to assess whether an organisation plans and implements activities that correspond to prerequisites for fostering a positive safety culture. The metric was designed based on an inclusive theoretical framework stemmed from academic and professional literature and in cooperation with knowledge experts and aviation companies. The goal of the AVAC-SCP is to evaluate three aspects, namely (1) the extent to which the prerequisites are designed/documented, (2) the degree of the prerequisites’ implementation, and (3) the perceptions of the employees regarding the organizational safety culture as a proxy for the effectiveness of the prerequisites’ implementation. The prerequisites have been grouped into six categories (common prerequisites and just, flexible, reporting, information and learning cultures) and the metric concludes with scores per aspect and category. The results from surveys at 16 aviation companies showed that these companies had adequately included most of the Safety Culture Prerequisites (SCP) in their documentation where Just culture plans scored the lowest and Reporting culture plans were found with the highest percentage of planning. The level of SCP implementation was the same high as the organisational plans and quite uniform across the companies and sub-cultures. The perceptions were at the same overall level with implementation, but employees perceived the organisational environment as less fair and more flexible than managers claimed. Although the study described in this report was exploratory and not explanatory, we believe that the results presented in combination with the ones communicated to the participating companies can trigger the latter to investigate further their weaker areas and foster their activities related to Safety Culture Prerequisites. Also, the AVAC-SCP metric is deemed useful to organisations that want to self-assess their SCP levels and proceed to comparisons amongst various functions and levels and/or over time.
Paradigm of Safety by Design
Authors: Rajabalinejad Mohammad
Published: February 2019

Safety by design is a challenge not because designers are unwilling to design safe products or systems but because they focus on the creation of products that fulfil customer wishes as much as possible, and it is hard to focus on intended functions for a product and unintended functions or malfunctions at the same time. The paper highlights the ever-increasing safety challenges for designers, and it argues that safety must be an integral part of the design process.
When Compliance Checks are Just the Start of the Journey: an Aviation Case
Authors: De Vré Mart , Richardson Delia A.
Published: February 2019

Compliance with standards is assessed through internal and external audits, the findings of which are viewed as imperfections to be quickly repaired. A zero-findings mentality underlies companies that want to excel before the eyes of the authorities, customers, insurance companies and competitors. However, scholars and professionals over the last decades agree that compliance is a necessary but not sufficient condition for optimum system performance. The current study was initiated by a Ground Service Provider that in 2017 underwent an IATA Safety Audit for Ground Operations and revealed several findings, especially in the documentation, such as missing parts, non-compliant material and lack of detail. Their goal was to pass the next audit without any findings within the documented procedures of six operational departments. To assess the audit documentation criteria, the researchers visited the operational departments, analysed 186 procedures, and conducted six semi-structured interviews with managers/supervisors and nine interviews with operational personnel. The analysis showed that all documents were properly controlled, but four departments had duplicated generic guidance material from 6% to 83% of the text checked. The interviewees claimed that understandability was not optimum due to language barriers and the non-tailoring of the content to their needs, leading to some staff disregarding manuals and consulting their supervisor instead. Other remarks included the long length of the documents, lack of knowledge of how to access online material, ignorance of the existence of documentation access points, and low technical accuracy. Overall, the results suggested room for improvement. Most importantly, through this research, the specific Ground Service Provider gained a better understanding behind non-compliance and had the opportunity to improve the quality and communication of its procedures. This study showed that even when compliance is the target, substantial improvement moves beyond box-ticking and engages employees in the revelation and mitigation of system imperfections.
The Importance of Assuring Algorithm-based Verification Agents
Authors: Haugen Odd Ivar
Published: February 2019

Safety verification is about creating trust and building confidence that a system is safe and conforms to the specified requirements. The term confidence means the assurance level which is built by generating objective evidence through activities such as testing. In the maritime industry, classification societies (a.k.a. class) are instrumental in the assurance process of maritime safety-critical systems. These systems become more and more software-intensive, enabling a high degree of complexity and even autonomy. Automatization in the verification effort emerges as system complexity increases and cost-pressure rises. An automatic condition-based survey scheme, utilizing data from sensors and algorithms is seen as more efficient and effective than the traditional calendar-based survey scheme performed by trained class surveyors (people) today. In the assurance of self-learning adaptive systems such as autonomous navigation systems, possibly based upon Machine Learning (ML), online safety monitors may become instrumental in creating relevant safety evidence. These monitors may also be based on ML and may be adaptive, resulting in one adaptive ML-algorithm verifying another adaptive ML-based target system. Class surveyors are test engineers who are verification agents and generate evidence about the system safety level. The verification algorithms, such as a Condition Monitoring system should also be categorized as a verification agent; an Algorithm-based Verification Agent (AVA). Moreover, class surveyors represent an independent Verification Organization. Independence in the verification effort increases the assurance level because the level of evidence objectiveness increases. If the AVA is developed by the target system developer, it decreases the evidence objectiveness and affects the agency of humans in the verification. This paper argues that AVAs must be assured at a level reflecting their agency within the verification effort, and the target system criticality. The same cognitive and societal biases infecting the target system may also affect the AVA if it is developed by the same organization as the developer, possibly masking critical defects, and making the generated evidence less trustworthy.
The Concept Towards a Standard Safety Model (STASAM v.0)
Authors: Karanikas Nektarios , Roelen Alfred
Published: February 2019

In safety science and practice, there have been various safety models, each of them reflecting a particular approach to safety management and accident causality. The large variety of models suggested in literature and applied in practice serve the communication of diverse perspectives towards safety and the need to consider contextual factors, but it does not allow the establishment of a common language within and across organisations and industry sectors. Considering the potential benefits of talking a lingua franca when it comes to safety and inspired by the Standard Model used in particle physics and recent suggestions from relevant studies, we thought of exploring the possibility to introduce a Standard Safety Model (STASAM). As a first step, we focused on four representative safety and accident models widely used, discussed and debated: the Swiss Cheese Model, AcciMap, Functional Resonance Analysis Method (FRAM) and Systems-Theoretic Accident Model and Processes (STAMP). We reviewed literature which compares the particular models, and we listed the strengths and weaknesses of each as a means to set the grounds for the STASAM. The combinations of these models with a focus to host their advantages and avoiding their disadvantages led to a three-level STASAM. The concept STASAM was used in two random incident investigation reports to assess its applicability and visualisation against the original models. The results of the application along with the STASAM concept were reviewed by three safety professionals and three safety researchers. The comments received were in the positive direction and indicated the potential of establishing an inclusive and commonly accepted safety/accident model. The next research phase will be the additional review of the STASAM and its pilot application to a variety of safety events and systems as a means to test its reliability and strengthen its validity.
Safety Verification for Autonomous Ships
Authors: Rokseth Børge , Haugen Odd Ivar , Utne Ingrid Bouwer
Published: February 2019

Autonomous and unmanned ships are approaching reality. One of several unsolved challenges related to these systems is how to perform safety verification. Although this challenge represents a many-faceted problem, which must be addressed at several levels, it seems likely that simulatorbased testing of high-level computer control systems will be an important technique. In the field of reliability verification and testing, design verification refers to the process of verifying that specified functions are satisfied over the life of a system. A basic requirement for any autonomous ship is that it has to be safe. In this paper, we propose to use the Systems-Theoretic Process Analysis (STPA) to (i) derive potential loss scenarios for autonomous ships and safety requirements to prevent them from occurring, and (ii) to develop a safety verification program, including test cases, intended to verify safety. Loss scenarios and associated safety requirements are derived using STPA. To derive a safety verification program, these unsafe scenarios and safety requirements are used to identify key variables, verification objectives, acceptance criteria and a set of suitable verification activities related to each scenario. The paper describes the proposed methodology and demonstrates it in a case study. Test cases for simulator-based testing and practical sea-trials are derived for autonomous ships. The case study shows that the proposed method is feasible as a way of generating a holistic safety verification program for autonomous ships.
Use of STAMP/STPA to Model Organizational Risk and Safety Management at Cruise and Ferry Companies
Authors: Williams Stuart
Published: February 2019

Recent well-publicized cruise and ferry ship accidents have been a wake-up call to the shipping industry. These events raise the need for ship owners to use more advanced risk management approaches. Enterprise Risk Management (ERM) has become an integral part of modern corporations, especially in safety critical industries where unsafe operations can lead to catastrophic accidents that result in loss of life, huge financial losses and the potential demise of the corporation. This paper presents the current findings of an on-going research to determine the best implementation of a Risk Management System (RMS) integrated with the Safety Management System (SMS) at cruise and ferry operating companies. The hypothesis is that ship management companies with better enterprise risk management will have better safety records and stronger financial performance. The paper presents the results of the application of Systems-Theoretic Accident Model and Processes (STAMP)/Systems Theoretic Process and Analysis (STPA) to a ferry operator to analyse the organizational performance of their risk and safety management systems. Initial results from the analysis showed gaps in communication paths, lack of tracking of risks and limited involvement of senior management in the risk process. A preliminary approach to deriving key indicators is presented.
Institutionalisation, Capability and Effectiveness of Aviation Safety Management Systems
Authors: Karanikas Nektarios , Roelen Alfred , Vardy Alistair , Kaspers Steffen
Published: February 2019

In the frame of an on-going 4-years research project, the Aviation Academy Safety Management Systems (AVAC-SMS) metric for the self-assessment of aviation Safety Management Systems (SMS) was designed based on the Safety Management Manual of the International Civil Aviation Organization and in cooperation with knowledge experts and aviation companies. The particular metric evaluates three areas, namely (1) the degree of institutionalisation of SMS (design and implementation of processes), (2) the extent of managers' capability to deliver the SMS processes, and (3) the employees' perceived effectiveness of the SMS-related deliverables. The metric concludes with a score per area and per SMS component/element assessed, and it is scalable to the size and complexity of each organisation. Results of a survey at 18 aviation companies did not show statistically significant differences in their SMS scores across all three assessment areas but revealed a distance between the area of Institutionalization and the areas of Capability and Effectiveness. Also, differences were detected regarding the scores per SMS component and element within and across companies and assessment areas. The various assessment options offered for the AVAC-SMS metric accommodates the resources each SME and large company can invest in the application of the metric. Even the lowest level of resolution of the SMS metric can trigger companies to investigate further their weaker areas and foster their SMS-related activities. Therefore, the AVAC-SMS metric is deemed useful to organisations that want to self-assess their SMS and proceed to comparisons amongst various functions and levels and/or over time.
Comparison of STPA and Bow-tie Method Outcomes in the Development and Testing of an Automated Water Quality Management System
Authors: Merrett Hew Cameron , Horng Jao Jia , Piggot Andrew , Qandour Amro , Tong Chen Wei
Published: February 2019

The technology available to water quality management applications needs to be advanced due to greater use of automation to increase ease of operation, support remote operation and reduce risks due to operator error. In this case study, a comparison is made between System-Theoretic Process Analysis (STPA) and the Bow-tie methodology for identifying process hazards and countermeasures which can be used to guide the design and testing of an automated water quality management system (AWQMS). For this study, the application considered is a small hydroponics installation where water quality management has been automated. The STPA methodology uses a system theory-based approach to identify hazards, which include operational failures, human errors, and component interactions. The Bow-tie diagram focuses on individual barriers for a given threat which can prevent the realisation of a hazardous event and unwanted consequences. Thus, the 22 preventative barriers and seven recovery barriers identified through the Bow-tie diagram provide the design process with broad requirements for reducing the risks of user error as well as the ones associated with ongoing operations. The STPA method identified many Causal Factors (CF) generated from the Unsafe Control Actions after considering all the feasible scenarios. For design input, the STPA provided the design process with 204 specific CFs which were used to create 94 countermeasures to be included in software and hardware design as well as user information material. Both methods identified useful measures to control the hazards associated with human interaction with the AWQMS. However, the measures differed in the level of detail and the involvement in the evolution in the final system losses. In this study, the STPA process was able to identify several hazards which did not visibly relate to the Bow-tie barriers. However, the Bow-tie diagram illustrates a distinction between preventative and recovery hazard controls.
A CAST Analysis of an Accident of Software Project
Authors: Kusakabe Shigeru , Miwa Azuma
Published: February 2019

We report a CAST analysis of a software project by a team across the primary and subcontractor companies focusing on a kind of safety, psychological safety. By using CAST, we can understand the context of the behaviours leading to the unintended event and avoid personal blames to keep psychological safety. The project was a software maintenance project, in which an online trading system went down in the production migration, the final phase before the system release. The end users had no damages in this case, but some members were going to lose respects from other members and stakeholders. The system down was caused by a defect, and the first investigation report simply blamed the subcontractor members related to the defect injection and leakage. The senior manager, who cares to build and maintain psychological safety in the team, wanted to conduct a deeper analysis to avoid personal blames. The CAST helped to uncover that process changes over time from the originally defined one contributed the injection and leakage of the defect. It turned out the process owner and manager at the primary contractor side had a part of the responsibility for the defect leakage. The senior manager made this conclusion shared among team members and succeeded to avoid losing psychological safety. We conclude the CAST based on STAMP is useful in analyzing issues of software project management such as psychological safety.
Utilization of sulphidic mine tailings in alkali-activated materials
Authors: Kiventerä Jenni , Yliniemi Juho , Golek Lukasz , Deja Jan , Ferreira Victor , Illikainen Mirja
Published: February 2019

Disposal of mine tailings is one of the most important environmental issues during the mining lifetime. Especially sulphidic tailings can cause environmental and ecological risks because of their tendency to oxidize in the presence of water or air. Because of small particle size and harmful chemical properties, utilization possibilities of sulphidic mine tailings are limited. The aim of the present study was to develop technologies to utilize sulphidic mine tailings in alkali activated materials. Alkali-activated materials also known as geopolymers are nanosized zeolite type or slightly amorphous materials comparable to traditional Portland cement concrete, which can physically encapsulate or chemically stabilize the hazardous elements such as heavy metals into the 3D structure. Mine tailing based geopolymer aggregates were successfully produced from sulphidic mine tailings with good physical properties. The geopolymer aggregates performed as a concrete aggregate comparable to commercial lightweight aggregates. In addition, geopolymer mortars were prepared from mine tailings. In mortar application, there is a need to add some co-binder such as blast furnace slag in order to achieve high strength for the material. The mine tailing based geopolymer structure has an ability to stabilize a large number of cationic species into the structure while some anionic species were not able to immobilize by alkaline activation.
Effects of EAF-Slag on alkali-activation of tungsten mining waste: mechanical properties
Authors: Sedira Naim , Castro-Gomes João
Published: February 2019

The mechanical properties of alkali-activated binders based on blends of tungsten mining waste mud (TMWM) and electric arc furnace slag (EAF-S) were investigated. The synthesis of alkali-activated binders was conducted at 60°C for 24 h with different TMWM/EAF-Slag ratios (90:10, 80:20, 70:30, 60:40, and 50:50 vt.%). Using sodium hydroxide (SH) and sodium silicate (SS) solutions as alkaline activators with ratio solid/liquid 4 by unit of volume, and the sodium silicate to NaOH (SS:SH) ratio of 2:1. The X-ray Diffraction (XRD), mercury intrusion porosimetry (MIP) were determined. The different percentages of the precursors and the alkaline activators were optimised to produce paste samples. The compressive strength of samples with 10 vt.% EAF-Slag was close to 20.7 MPa after 90 curing days. The mechanical properties were further increased up to 30 MPa by increasing the percentage of EAF-Slag to 50 vt.%. This demonstrates a new potential for re-using waste material for various constructional applications.
Viability of lateritic soil as alkaline activated precursor
Authors: Pereira-De-Oliveira Luiz , Macedo Lucio , Neto José , Santos Dellane , Silva Hugo
Published: February 2019

This study investigates the disposal of lateritic soil available in the state of Maranhao, Brazil, to be used as a natural precursor of alkaline activated material. Lateritic soils are formed in the tropics through weathering processes that favour the formation of iron, aluminium and may contain a large amount of quartz and kaolinite. The quality of laterite for this application may vary significantly depending on both geographic location and depth of a quarry. The identification of quarry locals was carried out in this work, together with a disposal volume estimation considering economic issues about exploration techniques. A comparison of the chemical composition of the lateritic soil of the state of Maranhao with those related in the literature is used to outline the feasibility of using this natural material as precursor of alkaline activated cements. It is concluded that the lateritic soil availability, as well as their characteristics, can enable the development of alkaline activated materials as a future local building material and environmentally friendly.
Leaching of alkali-activated tungsten mining waste materials by electrical conductivity and DRX
Authors: Fernandes Ana , Magrinho Manuel , Castro-Gomes João
Published: February 2019

The production of Portland cement leads to high energy and natural resource consumption, as well as relevant emission of CO2 into the atmosphere. Thus, this research work intends to contribute to the study of Portland cement alternative alkali activated binders, which utilization can contribute to counteract to this status. Different samples of alkaline activated binders using different combinations of tungsten mining waste from Panasqueira Mines, milled glass and metakaolin were made. Compression tests were performed at 3, 7, 14 and 28 days of curing. For evaluating reactivity chemical leaching was measured. For such, conductivity tests were carried out simultaneously with pH measurement, SEM-BSE and ATR-FTIR analysis. Electrical conductivity tests enabled to preliminary identify the chemical leaching for different precursors. Additionally, by SEM-BSE it was possible to observed reacted and nonreacted particles, and the reactivity extend was confirmed by ATR-FTIR.
New casting glass technique through the use of geopolymers
Authors: Duran-Suarez Jorge , Villegas Maria-Angeles , Peralbo-Cano Rafael , Castro Gomes Joâo
Published: February 2019

By using silicate inorganic binders and glass waste (colourless or coloured) it is possible to mould technical and artistic elements, which later can be hardened by means of high temperature processing. This procedure is controlled by both the glass transition temperature of binder and of glass waste used as aggregate. "water glass", catalysed with sodium hydroxide was used as a binder of glass shards from common industrial bottles, classified to a grain size distribution below 2 mm. Chemical analysis shows similarity of silica content between binder and aggregates of recycled glass, establishing as main differences in the percentages of chromophore oxides. In addition dilatometry curves of the two materials show close glass transition temperature values (575 and 598 °C, respectively), fact that facilitates sintering between binder and aggregates. The non-heat-treated samples present good compactness and mechanical resistance values, improved with heat-treatment at 700 °C. The high compactness of heated samples, showing rounded aggregate grains and softening of binder could let a good way for obtaining well-consolidated technical elements, made of recycled glass. From this test, it would be possible to use thermal ranges between 550 and 600 °C, as well as shorter exposure times for a proper hardening.
Application of Mining Waste Powder as filler in Hot Mix Asphalt
Authors: Cesare Sangiorgi , Piergiorgio Tataranni , Claudio Lantieri , Francesco Mazzotta
Published: February 2019

Asphalt concrete mixtures are composed of two main components: aggregates and binder. The fraction of aggregates passing through the 63μm sieve is traditionally considered as filler. During years, several researches have shown the importance and the influence of filler in controlling the physical and mechanical properties of Hot Mix Asphalts (HMAs). The main objective of this research is to investigate and to assess the effects given by the use of Mining Waste Powder (MWP) within HMAs in total substitution of traditional limestone filler. The MWP used in this study is a residual of the tungsten extraction process in Panasqueira (Portugal) mine. The evaluation of properties conferred by the presence of the MWP filler within asphalt mixtures is based on a physical and mechanical laboratory characterization. For this purpose, tests have been performed both on bituminous mastics and on HMAs. Results indicate that the use of MWP in total substitution of limestone filler does not negatively affect the performances of HMAs and their bituminous mastics.
Modification of Alkali Activated Blast Furnace Slag for Pothole Repairs
Authors: Sarkkinen Minna , Kujala Kauko , Gehör Seppo
Published: February 2019

Potholes denote small, typically sharp edged holes in the pavement. The aim of this research was to study the usability of alkali activated (AA) blast furnace slag based material in the repair of paved roads, especially during the cold winter and spring seasons when such repairs are needed most and the use of hot asphalt is not possible. The objective was to a find material which is both more cost-efficient and durable than plain cold asphalt. Properties like rapid strength development, good bonding with old paving material, weather resistance, abrasion resistance, and low shrinkage were required. The influence of the chosen factors on the performance of the material was studied applying the multi-attribute optimization method. The impact of different additives, such as Portland cement, fibers and crushed tire rubber were studied. The results indicated that the AA slag based materials studied can be improved by suitable additives to make them reach desired performance. According to the tests, adding Portland cement increased compressive strength threefold after 3 hours and reduced shrinkage by 34% but should be a negative impact on higher levels related to freeze-thaw resistance. In addition, crushed rubber was indicated to have a positive impact related to all the studied performance properties.
Geopolymers from mining tailings for more sustainable raw material supply
Authors: Obenaus-Emler Robert , Illikainen Mirja , Falah Mahroo , Kinnunen Päivi , Heiskanen Kari
Published: February 2019

For ecologic and economic reasons tailings, waste rock and water management become progressively important factors in the mining industry. The European Union funded project ‘Integrated mineral technologies for more sustainable raw material supply’ (ITERAMS) aims to (1) close the water cycle of the mineral processing plant (i.e. minimizing the release of wastewater to the adjacent environment), and (2) to use tailings (and waste rock) as raw materials for geopolymers. This will (1) enable significantly more efficient water recycling at the mining sites, (2) deliver cost savings and added income due to the valorisation of solid waste residues, and (3) minimize the overall environmental footprint of the mining industry and will therefore help improving its performance and as a consequence its social position. The developed solutions influence the total lifecycle of the mining operation, as they provide input to project planning and operational phases as well as to the closure and recultivation. In this paper, the valorisation of the tailings and the waste rock is discussed. The main applications of the geopolymer products are (1) backfill material to fill open cavities from the mining operation and (2) a cover for surface deposits of tailings to store them environmentally safe – i.e. seal them off from surface water streams and oxidising conditions.
Modelling and Experimentation on Mechanical Properties of Graphene-Oxide Cement
Authors: Lin Zhiyuan , Fan Ding , Yang Shangtong
Published: February 2019

Cementitious nano-composites have recently attracted considerable research interest in order to improve their properties such as strength and durability. Graphene oxide (GO) is being considered as an ideal candidate for enhancing the mechanical properties of the cement due to its good dispersion property and high surface area. Much of work has been done on experimentally investigating the mechanical properties of GO-cementitious composites; but there are currently no models for accurate estimation of their mechanical properties, making proper analysis and design of GO-cement based materials a major challenge. This paper attempts to develop a novel multi-scale analytical model for predicting the elastic modulus of GO-cement taking into account the GO/cement ratio, porosity and mechanical properties of different phases. This model employs Eshelby tensor and Mori-Tanaka solution in the process of upscaling the elastic properties of GO-cement through different length scales. In-situ micro bending tests were conducted to elucidate the behavior of the GO-cement composites and verify the proposed model. The obtained results showed that the addition of GO can change the morphology and enhance the mechanical properties of the cement. The developed model can be used as a tool to determine the elastic properties of GO-cement through different length scales.
Einsatz der spinalen Navigation in der Wirbelsäulenchirurgie – Pro
Authors: Vajkoczy Peter
Published: February 2019

Computer-asssistierte Navigation wird zunehmend populärer und akzeptierter in der Wirbelsäulenchirurgie. Die liegt vor allem an verbesserten bildgebenden Verfahren und intraoperativen Abläufen. Ziel dieser Übersichtsarbeit ist es, die Hauptvorteile der spinalen Navigation zusammenzufassen. Zum Ersten verbessert die spinale Navigation the Präzision der Pedikelschraubenplatzierung signifikant. Zum Zweiten schafft die spinale Navigation die Notwendigkeit für eine Strahlenexposition des chirurgischen Teams nahezu vollständig ab. Dies trägt zur Erhöhung der Sicherheit und des Komforts der Behandler in der Wirbelsäulenchirurgie relevant bei. Zum Dritten ist die spinale Navigation der Schlüssel, die Minimal-Invasiven Techniken voranzutreiben da sie bei der anatomischen Orientierung bei gewebeschonenden Zugängen von Hilfe ist. Zum Vierten spielt die spinale Navigation ihre Stärke in spinalen Problemzonen aus, wie am craniocervikalen und cervicothorakalen Übergang, oder am Becken. Hier bereiten die anatomische Orientierung und die Bildgebung mit dem konventionellen Bildwandler häufig Schwierigkeiten für den Operateur. Und schließlich hilft die spinale Navigation bei komplexen onkologischen Fällen, zum Beispiel bei en bloc Resektionen von sakralen Knochentumoren. Zusammengefasst überwiegen die Vorteile der spinalen Navigation die steigenden Kosten und infrastrukturellen Herausforderungen, vor allem in Zentren mit einem Fokus auf komplexe Wirbelsäulenpathologien.