The key feature of thermosensitive polymers is the reversible transition between the hydrophilic and hydrophopic forms depending on the temperature. Although the main research efforts are focused on their application in different kinds of drug delivery systems, this phenomenon also allows one to precisely control the stability of solid-liquid dispersions. In this paper research on the application of poly(N-isopropylacrylamide) copolymers in processing of minerals is presented. In the experiments tailings from flotation plant of one of the coal mines of Jastrzębska Spółka Węglowa S.A. (Poland) were used. A laser particle sizer Fritsch Analysette 22 was used in order to determine the Particle Size Distribution (PSD). It was proved that there are some substantial issues associated with the application of thermosensitive polymers in industrial practice which may exclude them from the common application. High salinity of suspension altered the value of Lower Critical Solution Temperature (LCST). Moreover, the co-polymers used in research proved to be efficient flocculating agents without any temperature rise. Finally, the dosage needed to achieve steric stabilization of suspension was greatly beyond economic justification.
The data aggregation process of wireless sensor networks faces serious security problems. In order to defend the internal attacks launched by captured nodes and ensure the reliability of data aggregation, a secure data aggregation mechanism based on constrained supervision is proposed for wireless sensor network, which uses the advanced LEACH clustering method to select cluster heads. Then the cluster heads supervise the behaviors of cluster members and evaluate the trust values of nodes according to the communication behavior, data quality and residual energy. Then the node with the highest trust value is selected as the supervisor node to audit the cluster head and reject nodes with low trust values. Results show that the proposed mechanism can effectively identify the unreliable nodes, guarantee the system security and prolong the network lifetime.
Queuing regime is one outstanding approach in improving channel aggregation. If well designed and incorporated with carefully selected parameters, it enhances the smooth rollout of fifth/next generation wireless networks. While channel aggregation is the merging of scattered TV white space (spectrum holes) into one usable chunk for secondary users (SU). The queuing regime ensures that these unlicensed users (SUs) traffic/ services are not interrupted permanently (blocked/dropped or forced to terminate) in the event of the licensed users (primary user) arrival. However, SUs are not identical in terms of traffic class and bandwidth consumption hence, they are classified as real time and non-real time SU respectively. Several of these strategies have been studied considering queuing regime with a single feedback queuing discipline. In furtherance to previous proposed work with single feedback queuing regime, this paper proposes, develops and compares channel aggregation policies with two feedback queuing regimes for the different classes of SUs. The investigation aims at identifying the impacts of the twofeedback queuing regime on the performance of the secondary network such that any SU that has not completed its ongoing service are queued in their respective buffers. The performance is evaluated through a simulation framework. The results validate that with a well-designed queuing regime, capacity, access and other indices are improved with significant decrease in blocking and forced termination probabilities respectively.
The paper presents Gupta's relational decomposition technique expanded on linguistic level. It allows to reduce the hardware cost of the fuzzy system or the computing time of the final result, especially when referring to First Aggregation Then Inference (FATI) relational systems or First Inference Then Aggregation (FITA) rule systems. The inference result of the hierarchical system using decomposition technique is more fuzzy than of the classical system. The paper describes a linguistic decomposition technique based on partitioning the knowledge base of the fuzzy inference system. It allows to decrease or even totally remove a redundant fuzziness of the inference result.
Geographical Information Systems have become essential tools for land analysis and the subsequent decision making in many fields of human activity. In the field of mining, GIS applications have appeared in ore deposit modelling, environmental pollution, or planning of mining spaces. In this research, the powerful multicriteria tools of GIS platforms have been applied for the determination of an index that has been called “Exploitability Index”. This index allows analyzing a series of outcrops of industrial aggregates, to help in the selection of the most adequate one to be enhanced from a mining approach. The multicriteria analysis has been applied for its determination, and as a result of this research, a model is proposed. The main criteria that condition the decision have been established in this model, along with their subsequent hierarchization and their weighting. The proposed model is applied to a specific case: the analysis of a series of outcrops of industrial aggregates (ophites) in Cantabria, Spain. After defining the Exploitability Index for those ophitic outcrops, it has been observed that the only deposit that has been classified as very suitable for its exploitation is the only one that has been really exploited, supporting the proposed methodology.
Proper values of physical and mechanical properties and their homogeneity are one of major requirements deciding about technological suitability of the rocks quarried to manufacturing aggregates. These properties depend on the natural features of a rock, its mineral composition, texture and structure. The characteristic of aggregates and the technical requirements they must meet are normalized in adequate standards that describe the procedures of conducting particular determinations and the methods of interpreting their results. In the basaltoids (usually called basalts) of selected deposits of Lower Silesia that represent different intrusive forms, five textural varieties have been distinguished: aphanitic, aphanitic-porphyritic, porphyritic-aphanitic, porphyritic-nodular and nodular-porphyritic. The petrography and essential physical and mechanical properties of these varieties have been described in Tables 1 and 2, respectively. The highest technical parameters have the aphanitic and aphanitic-porphyritic rock varieties. They result mainly from the textures of these rocks and their insignificant weathering, and to a lesser degree from their mineral composition. The resistance to wear (micro-Deval) and the resistance to fragmentation (Los Angeles) of the aggregates that represent the grain fraction 10-14 mm of the five varieties of basaltoids and the rock composites were determined according to the standards PN-EN 12620: 2008 and PN-EN 13043: 2004. Of the aggregates produced from the five major varieties, only those made of the nodular-porphyritic basaltoids have the properties of lower categories, whereas the remaining four are the materials of very high quality. Additionally, it has been shown that by combining various basaltoid types it is possible to produce composite aggregates with the variable qualities belonging to the categories LA and MDE (Tab. 3). The effect of rock petrography on the differentiation of the parameters of aggregates depending on the grain fraction of the products (Fig. 1, Tab. 4) is the lowest in the case of the aggregates produced from the homogenous and not weathered rock. In contrast, the range of variability of the parameters is higher if the starting material to produce aggregates is composed of several textural varieties and shows signs of weathering as well. The possibility of delineation of the areas occupied in the deposit by basaltoids with specific textural varieties creates the conditions of determining the rock zones, from which the aggregates of the predicted quality may be produced. This quality may be controlled and partly changed to the user needs by producing aggregates from the specially prepared rock mixtures (i.e. the charge to crushers) with specified proportions of the basaltoid varieties.
In this paper, a new set of intuitionistic fuzzy aggregation operators have been introduced under the environment of intuitionistic fuzzy sets (IFSs). For this, firstly focused on some existing aggregation operators and then new operational rules known as Dombi operation have been pro- posed which make the advancement of flexibility behavior with the parameter. Based on Dombi operation laws, some new averaging and geometric aggregation operators namely, intuitionistic fuzzy Dombi weighted averaging, ordered weighted averaging and hybrid weighted averaging operator, classified as IFDWA, IFDOWA and IFDHWA operators respectively and intuitionistic fuzzy Dombi geometric, ordered weighted geometric and hybrid weighted geometric operators, labeled as IFDWG, IFDOWG and IFDHWG operators respectively have been proposed. Further, some properties such as idempotency, boundedness, monotonicity and commutative are investigated. Finally, a multi-attribute decision-making model has been developed for the proposed operators to select the best mutual fund for investment. The execution of the comparative study has been examined with the existing operators in this environment.
Arid areas are particularly susceptible to soil erosion due to long dry periods and sudden heavy downpours. This study investigates the aggregate size distribution and aggregate stability of twelve tilled fallow areas of Hyderabad district, Sindh, Pakistan. This study determined aggregate size distribution by dry sieving to evaluate the seedbed condition and aggregate stability using wet sieving to assess the susceptibility of tilled fallow areas to soil erosion. The aggregate size distribution of the soils of the selected areas was highly variable. Gulistan-e-Sarmast had the largest number of clods (51.0%) followed by Kohsar (49.0%), Latifabad # 10 (41.10%) and Daman-e-Kohsar (39.0%). Fazal Sun City, the left side of the Indus River, the Village Nooral Detha and the left side of the Abdullah Sports city had a greater number of large (>8.0 mm) and small aggregates (<0.5 mm). The optimum aggregate size distribution was found in the left side of the channel, which had the largest number of aggregates (50.50%) in the 0.5–8.0 mm sieve size range. Maximum aggregate stability (AS) was found in Gulistan-e-Sarmast (46%), Kohsar (42%) and Latifabad # 10 (34%), while all other soils had minimum aggregate stability (<14%). The minimum aggregate stabilities demonstrate that the tilled fallow areas of Hyderabad district are highly susceptible to erosion. Therefore, the present study suggests investigating potential ways to enhance the aggregate stabilities of soils.
Providing Privacy and security for aggregated data in wireless sensor networks has drawn the attention of practicing engineers and researchers globally. Several cryptographic methods have been already proposed to solve security and data integrity problems for aggregated data. Matrix cryptography is a better option for creating secure encryption/decryption algorithms to counter quantum attack. However, these algorithms have higher computational cost and increased communication overhead. Hence, a new technique of loss-less secure data aggregation in Clustered Wireless Sensor Networks is presented. The proposed method uses integer matrices as keys for data security and data integrity. Matrix operations are carried out in finite field Zp. Loss-less secure data aggregation is extended for homomorphic summation while the cipher text expansion ratio is kept substantially low. The proposed algorithm has inbuilt fast and efficient signature verification facility. The execution time of our signature verification mechanism is found to be approximately 50 percent less compared to a couple of standard existing signature verification schemes.
The basic tests that allow the mechanical properties of grained material to be evaluated are tests of an aggregate’s resistance to crushing - the Los Angeles coefficient, and resistance to abrasion - the micro-Deval coefficient. These parameters primarily depend on the physical and mechanical properties of the raw material from which they are produced. The available literature widely describes the relationship between these parameters and bulk density, porosity, ultrasonic wave velocity, compression strength, tensile strength and point strength. This paper presents the relationship between the mechanical properties of aggregates and their geometrical properties. The analysis was carried out for the relationship between the Los Angeles and micro- Deval coefficients and the flatness and shape indices. As a result of the conducted considerations, the influence of the aggregate assortment on the analysed coefficients was also noted. All of the tests were carried out for aggregates (arch stones and mixtures) produced from sandstones from the Magura, Cergo and Krosno layers.
The purpose of this article is to develop a multicriteria group decision making (MCGDM) method in dual hesitant fuzzy (DHF) environment by evaluating the weights of the decision makers from the decision matrices using two newly defined prioritized aggregation operators based on score function to remove the inconsistencies in choosing the best alternative. Prioritized weighted averaging operator and prioritized weighted geometric operator based on Einstein operations are described first for aggregating DHF information. Some of their desirable properties are also investigated in details. A method for finding the rank of alternatives in MCGDM problems with DHF information based on priority levels of decision makers is developed. An illustrative example concerning MCGDM problem is considered to establish the application potentiality of the proposed approach. The method is efficient enough to solve different real life MCGDM problems having DHF information.
The growth of the global population, urbanization as well as economic and industrial development, affect the continuously increasing demand for mineral aggregates. The current assessed global production of mineral aggregates amounts to 50 billion Mg/year, which statistically approximates 6.5 Mg per an inhabitant of the globe. In terms of consumption volume, water is the only raw material ahead of aggregates. Despite such a great scale, in many countries and regions the extraction and production of aggregates belong to the least regulated sector of human activity. This refers particularly to the countries of A sia, A frica, and North A merica, where both the resources and the extraction of aggregates, particularly of sand and gravels, are either not monitored and registered. It significantly increases the negative impact on the natural environment, due to the destruction of riverbeds and oxbows, coastal erosion, drying up cultivation areas, etc. In the reports, local terminology of aggregates often functions, which makes it difficult to compare them and prepare appropriate balances. In order to regulate the unfavorable situation, one of the main conclusions of the Report (UNEP 2019) is the need of implementing a common requirement to plan and monitor the process of extraction of natural resources. The paper presents the possibility of forecasting the extraction and producing aggregates based on the consumption of cement, i.e. the basic building material. A lthough the analyzed coefficient of mineral aggregate production per unit of cement consumption (production) varies, its advantage is the fact that the production of cement is identified and taken into account in balances of industrial production of the majority of countries, whereas such identification for mineral aggregate production are still lacking.
In the construction industry carbonate aggregates are commonly used in processes such as concrete production. Aggregates which contain (in their mineral composition) dolomite and an admixture of clay minerals and amorphous silica , can react with alkalis. These reactions can lead to a destructive expansion in concrete. This article explains the mechanisms and the essence of this phenomenon. What is more, some effective and fast methods of the estimation and evaluation of Polish aggregates consisting of carbonate rocks suggests effective methods to determine the usefulness of Polish carbonate aggregates in concrete production are discussed in the paper. Underneath the quality criteria to determine the reactivity of the aggregates will be given. It has been agreed that alkaline reaction and expansion are two separate phenomena related to each other genetically. The aggregates in which reactions caused by clay-siliceous admixtures occur are subjected to expansion. Mineral composition of expansive aggregates as well as their texture indicate that epigenetic dolomites with a distinctive texture are the most reactive. The phase transformations do not end with a complete disintegration of dolomite. They have a cyclical character. They consist of interchangeable reactions of dedolomitization and dolomitization of secondary calcite formed as a result of dolomite's disintegration. The secondary calcite can be effected by Mg+2 ions from pores' solutions and it can form a secondary dolomite. The Mg2+ ions originate from brucite [Mg(OH)2], created in dolomitization process. As a consequence of its reaction with silica, brucite can dissolve and enrich secondary calcite with magnesium. Therefore the reactions which take place in reactive carbonate aggregates and concrete that ismade of it are in fact ongoing processes which consist of dolomite's changes into calcite and vice versa. They are reactions between dedolomitization products (brucite, silica) and products from outside (water, alkalis). The described dedolomitization reactions are a phase of the process that enables expansion due to formation of pressure in inter-granular cracks, with pressure being a result of dry clay-minerals' expansion under the influence of water solutions. Loosening of the aggregate's structure as an effect of dedolomitization reaction makes it easier for water solutions to migrate far into the aggregate's grains followed by their contact with clay minerals.