Geopolymerization is an innovative technology that can transform several solid aluminosilicate materials into useful products called geopolymers or inorganic polymers. Although the geopolymerization ...mechanism is not well understood, the most proposed mechanism includes four parallel stages: (a) dissolution of solid aluminosilicate materials in alkaline sodium silicate solution, (b) oligomerization of Si and/or Si–Al in aqueous phase, (c) polymerization of the oligomeric species, and (d) bonding of undissolved solid particles in the polymer. It is obvious that polymerization in sodium silicate solutions comprises a fundamental process in geopolymerization technology. Therefore, this article aims at studying experimentally the polymerization stage in synthetic pure sodium silicate solutions. The structure of sodium silicate gels as a function of the SiO
2
/Na
2
O molar ratio is examined and their hardness as well as hydrolytic stability are determined. In addition, the effect of aluminum incorporation in the hydrolytic stability of these gels is also examined. Finally, the structure of sodium silicate and aluminosilicate gels is correlated to the measured properties drawing very useful conclusions that could be applied on geopolymerization technology.
Red mud is a residue coming from the metallurgical treatment of bauxite with the Bayer process. Million of tons of red mud are produced annually worldwide and disposed of on land, degrading vast ...areas. Therefore, red mud utilization is a first-priority issue for any alumina plant. In the present work, the potential use of red mud for synthesis of inorganic polymeric materials through geopolymerization process was studied. The main focus was the production of inorganic polymeric materials that could be used in the construction sector as artificial structural elements such as massive bricks. The geopolymerization process involves a chemical reaction between red mud and alkali metal silicate solution under highly alkaline conditions. The product of this reaction is an amorphous to semi-crystalline polymeric structure, which binds the individual particles of red mud transforming the initial granular material to a compact and strong one. The effect of main synthesis parameters-like solid-to-liquid ratio, caustic soda as well as soluble silica concentrations, and metakaolin addition-on the properties of red mud-based inorganic polymeric materials was investigated. The results showed that the produced materials have high compressive strength, very low water absorption, satisfactory apparent density, and excellent fire resistance. Therefore, this work proved that the red mud-based inorganic polymeric materials have promising properties and have the potential to be used as artificial structural elements in the construction sector.
The realization of a wireless sensing system and its sensing performance evaluation, under laboratory conditions, for the monitoring of specific volatile organic compounds (VOCs) present in printed ...flexing packaging industries is demonstrated. Prior to the utilization of the wireless mote, we present the microfabrication of appropriate sensor array based on chemocapacitors and its integration with appropriate low power consumption read-out electronics meeting the requirements of the application. The sensing unit is an array of interdigitated chemocapacitors (IDCs). The wireless sensing system is tested upon exposure to VOCs, humidity and gaseous mixtures simulating the real industrial environment and the raw data are transmitted via a wireless network and monitored to a front-end software. Results showed that the sensing system is characterized by very good sensing performance with high repeatability and long-term stability. Further data processing with principal component analysis (PCA) highlights the sensing system's ability to discriminate between gaseous environments with different composition/concentration. Thus the particular wireless sensing system is suitable for remote real-time unattended industrial environment monitoring.
The sensing performance of a self-calibrated Wireless Sensing System (WSS) was evaluated under laboratory and real environment conditions. The Wireless Sensing Node consists of a sensor array based ...on chemocapacitors, which is integrated with appropriate low power consumption read-out electronics and is connected with appropriate wireless module. The sensing system was evaluated and calibrated under laboratory conditions with two different VOCs transfer methods: dynamic and static. The sensing unit calibration deals with changes of VOCs and/or humidity concentration and temperature variations, simulating the real industrial environment. Finally the WSS was placed in the workspace of a printed flexing packaging industrial installation and comparison with the already installed commercial detectors was performed. A very good agreement between the results of the two measurement systems is demonstrated. Additionally these results showed that the WSS is characterized by fast response with high repeatability and long-term stability. Concluding, this system is suitable for the targeted application.
Griya Arwana Lestari Housing Merauke Regency is one of the housing estates located in the area around the Merauke coast. The majority of residents of Griya Arwana Lestari housing use rainwater ...sources and buy water from water tanker trucks for their clean water needs. When the dry season arrives, the price of water from tanker trucks is quite expensive, making it difficult for residents of Griya Arwana Lestari housing to get clean water. So it is necessary to plan a clean water supply network system. The purpose of this study is to find out how much the discharge needs of clean water in Griya Arwana Lestari housing and find out what the diameter of the main pipe and secondary pipe are used. The method used is qualitative and quantitative based on field observations and counting the number of occupants in sustainable arowana housing then analyzing the need for clean water and then determining the diameter of the main pipe and secondary pipe. The results in this study are the required discharge in the housing is 3,973 l/s and for the main pipe diameter is 4 inches and for the secondary pipe 1 inch.
The associative memory (AM) system of fast tracker (FTK) processor has been designed for the tracking trigger upgrade to the ATLAS detector at the Conseil Europeen Pour La Recherche Nucleaire large ...hadron collider. The system performs pattern matching (PM) using the detector hits of particles in the ATLAS silicon tracker. The AM system is the main processing element of FTK and is mainly based on the use of application-specified integrated circuits (ASICs) (AM chips) designed to execute PM with a high degree of parallelism. It finds track candidates at low resolution which become seeds for a full resolution track fitting. The AM system implementation is based on a collection of large 9U Versa Module Europa (VME) boards, named "serial link processors" (AMBSLPs). On these boards, a huge traffic of data is implemented on a network of 900 2-Gb/s serial links. The complete AM-based processor consumes much less power (~50 kW) than its CPU equivalent and its size is much smaller. The AMBSLP has a power consumption of ~250 W and there will be 16 of them in a crate. This results in unusually large power consumption for a VME crate and the need for complex custom infrastructure in order to have sufficient cooling. This paper reports on the design and testing of the infrastructures needed to run and cool the system which will include 16 AMBSLPs in the same crate, the integration of the AMBSLP inside a first FTK slice, the performance of the produced prototypes (both hardware and firmware), as well as their tests in the global FTK integration. This is an important milestone to be satisfied before the FTK production.
Virtuality is noticeably present in organisations and influences the way people interact within teams. This study involved 104 organisational teams with some degree of virtuality and intends to ...analyze a moderated-mediation model in which virtuality moderates the indirect effect of team conflict on team effectiveness and innovation through team trust. First, results reveal that the negative association between conflict and team trust was significant for task conflict only in teams with low virtuality, and for relationship conflict was significant under low and moderate levels of virtuality. Finally, findings indicate that virtuality moderated the negative mediated relationship between both task and relationship team conflict and team effectiveness only through cognitive trust. Overall, the findings suggest that virtuality may protect team trust from the negative effects of conflict, and they point to the key role of cognitive trust as an antecedent of team effectiveness in hybrid teams.
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