Differences in Iron Removal from Carbon Nanoonions and Multiwall Carbon Nanotubes for Analytical Purpose

The paper describes the differences between wet iron removal from carbon nanoonions and from multiwall carbon nanotubes for analytical purpose. Nowadays, both carbon nanoonions and multiwall carbon nanotubes are one of the most interesting materials with applicability in electronics, medicine and biotechnology. Medical applications of those nanomaterials require not only recognition of their structure but also measurement of metal impurities concentration. Inductively coupled plasma optical emission spectrometry as a method for Fe-determination requires liquid samples. Hence, we propose various protocols for leaching of iron from studied materials. Our results proved that structure of nanomaterials have an impact on the efficiency of iron removal

Differences in Iron Removal from Carbon Nanoonions and Multiwall Carbon Nanotubes for Analytical Purpose

The paper describes the differences between wet iron removal from carbon nanoonions and from multiwall carbon nanotubes for analytical purpose. Nowadays, both carbon nanoonions and multiwall carbon nanotubes are one of the most interesting materials with applicability in electronics, medicine and biotechnology. Medical applications of those nanomaterials require not only recognition of their structure but also measurement of metal impurities concentration. Inductively coupled plasma optical emission spectrometry as a method for Fe-determination requires liquid samples. Hence, we propose various protocols for leaching of iron from studied materials. Our results proved that structure of nanomaterials have an impact on the efficiency of iron removal

A Cloud-aided Group RSA Scheme in Java 8 Environment and OpenStack Software

In this paper a RSA based security system enabling the group of users to upload the single masked message to the cloud environment is proposed. Data stored are encrypted using RSA algorithm. The data receiver is able to encrypt the message retrieved from the cloud environment using private key. Two different separate RSA systems are used. The presented approach is divided into three parts. First, an RSA key is generated for each sender. Then masking the message by newly chosen mask proposed individually by every member, additionally encrypted by individual RSA private key of each member is proceed. Next, encrypting the gathered message inside the cloud environment, using the public key of the receiver is executed. In the third step, the message is decrypted by the receiver using his private RSA key. The scheme reduces the computational load on users side and transfers calculations and storage effort to the cloud environment. The proposed algorithm was developed for storing and sending the data that originally are produced by a group of users, but the receiver of the data is single. It was implemented using Java 8 and OpenStack software. Numerical test of different key length for RSA are presented

Using Polymatrix Extensive Stackelberg Games in Security – Aware Resource Allocation and Task Scheduling in Computational Clouds

In this paper, the Stackelberg game models are used for supporting the decisions on task scheduling and resource utilization in computational clouds. Stackelberg games are asymmetric games, where a specific group of players’ acts first as leaders, and the rest of the players follow the leaders’ decisions and make their decisions based on the leader’s actions. In the proposed model, the optimal schedules are generated under the security criteria along with the generation of the optimal virtual machines set for the scheduled batch of tasks. The security criteria are defined as security requirements for mapping tasks onto virtual machines with specified trust level. The effectiveness of the proposed method has been verified in the realistic use cases with in the cloud environment with OpenStack and Amazon Cloud standards

Stackelberg Security Games: Models, Applications and Computational Aspects

Stackelberg games are non-symmetric games where one player or specified group of players have the privilege position and make decision before the other players. Such games are used in telecommunication and computational systems for supporting administrative decisions. Recently Stackleberg games became useful also in the systems where security issues are the crucial decision criteria. In this paper authors briefly survey the most popular Stackelberg security game models and provide the analysis of the model properties illustrated in the realistic use cases

Exploiting CloudSim in a multiformalism modeling approach for cloud based systems

Cloud based architectures present many challenges, ranging from poorly dimensioned hardware to lengthy wait times and resource balancing issues. Most of these problems can be mitigated by using proper performance evaluation techniques, depending on the accuracy of the model abstracting the real system. The adoption of a formalism over another to describe the considered infrastructure plays a crucial role in achieving this goal. In this sense, multiformalism proves itself to be a powerful modeling approach describing each system component according to the most suitable representation. This paper presents a novel modeling method oriented to the prediction of cloud architectures performance, suitable for joining the advantages of high level modeling abstractions and of the detail of a specialized simulator. Generalized Stochastic Petri Nets are used to describe the workload and the behavior of users and applications, while Cloudsim, a well known cloud infrastructure simulator, is adopted for the cloud part. A case study of a simplified Edge Computing application is presented to demonstrate the effectiveness of the proposed approach

Low energy utilization of mine saline water in the integrated membrane-evaporative system

Przedstawiono rozwiązanie, w którym woda zasolona poddawana jest wstępnemu uzdatnianiu metodą nanofiltracji (NF) a następnie zatężaniu metodą wyparną lub w zintegrowanym układzie elektrodializa – odwrócona osmoza i dalszemu odparowaniu z krystalizacją chlorku sodu. Na przykładzie solanki z KWK Budryk wykazano, że uzysk soli, dzięki samemu zastosowaniu nanofiltracji, można zwiększyć z obecnej wartości 72,01% do 87,35%, a po dalszym usprawnieniu, polegającym na oczyszczaniu chemicznym, do 91,11% a nawet 99,1%. Wstępne uzdatnianie solanki metodą nanofiltracji, prowadzone w sposób opracowany przez Autorów w warunkach dużego przesycenia siarczanem wapnia z częściową recyrkulacją retentatu i kontrolowaną krystalizacją gipsu, daje możliwość zastosowania mało energochłonnych rozwiązań zatężania solanki. Na przykładzie solanki Budryk wykazano, że zużycie energii w procesie jej utylizacji można zmniejszyć z obecnych 888,7 kWh/t soli do 433,7-451,2 kWh/t soli, w przypadku zatężania solanki mało energochłonną metodą wyparną lub do 396,8 kWh/t soli w przypadku zatężania solanki w zintegrowanym układzie: elektrodializa – odwrócona osmoza. Proponowane rozwiązanie ma zostać przebadane w instalacji pilotowej w ramach projektu NANOS, finansowanego w programie TANGO2.The paper presents an integrated system, in which saline water is pre-treated with nanofiltration (NF), then concentrated with thermal method or with electrodialysis-reverse osmosis, followed by further evaporation with sodium chloride crystallization. Based on water from KWK Budryk coal mine, it was proved that salt recovery, thanks to nanofiltration alone, can be increased from current value of 72.01% to 87.35%, or up to 91.11% or 99.1% after further enhancement. Following Authors’ developed procedure of nanofiltration pretreatment – operation at high calcium sulphate supersaturation with partial retentate recirculation and gypsum precipitation, makes the low energy consumption brine concentration possible. Based on Budryk brine, it was proved that energy consumption can be decreased from the current value of 888.7 kWh/t of salt to 433.7-451.2 kWh/t if the low energy consumption thermal method is applied or down to 396.8 kWh/t if the integrated electrodialysis-reverse osmosis system is applied. The proposed solution is to be verified in a pilot plant during the NANOS project funded in the TANGO2 programme

The distribution of rare earth elements (REE) during sequential chemical leaching of coal from seam 404, “Pniówek” Coal Mine (USCB)

Celem pracy było określenie dystrybucji pierwiastków ziem rzadkich (REE) w procesie sekwencyjnego chemicznego ługowania próbek węgla z pokładu 404 KWK Pniówek. Na potrzeby pracy wykorzystano pięciostopniową zmodyfikowaną procedurę ługowania opisaną w pracy D.A. Spears. Zawartość REE w uzyskanych roztworach oznaczono metodą ICP-MS). Analizowano oddzielnie udziały REE w próbkach bruzdowych węgla oraz w roztworach będących produktami sekwencyjnego ługowania substancji nieorganicznej i organicznej węgla. Stwierdzono zróżnicowany udział REE w analizowanych próbkach węgla. Normalizacja udziałów REE do chondrytów wykazała obecność małej anomalii ujemnej dla Eu i większej dodatniej dla Gd. Na wszystkich krzywych po znormalizowaniu widoczne jest wzbogacenie próbek węgla w LREE i odpowiednio niższy mało zróżnicowany udział HREE. Podobnym przebiegiem charakteryzują się krzywe po znormalizowaniu uzyskane dla produktów ługowania związanych z substancją organiczną węgla (etap IV-V) i krzemianami. Krzywe normalizacyjne uzyskane dla produktów ługowania związanych z substancją mineralną (etap I-III) dla poszczególnych próbek węgla są podobne. Wszystkie charakteryzują się dodatnimi anomaliami w zakresie Sm-Tb oraz wzbogaceniem udziałów MREE względem LREE.The aim of the study was to determine the distribution of REE in coal using during the sequential chemical leaching of four coal samples from 404 seam of Ruda beds of “Pniówek” coal mine. The five digestion steps were used to determine REE distribution. In this study adopted the leaching procedure described in work D.A. Spears.The content of REE in obtained solutions was determined by ICP-MS method.The contents of REE in the samples was analyzed in coal and separately in the solutions which were products of the sequential leaching of inorganic and organic substances of coal. It was found that the REE content in coal samples is varied. The contents of REE were normalized to chondrites. It showed a small negative anomaly for Eu and larger positive anomaly for Gd. The enrichment in LREE of coal samples and respectively lower and less diverse of HREE content are shown on all of the normalized curves. The normalized curves obtained for chondrites REE content in the leaching products connected with organic substance (stage IV-V) have a similar course.The normalized curves obtained for chondrites REE content of the leaching products connected with mineral substance (stage I-III) for the individual samples of coal were similar. All these curves are characterized by positive anomalies in the range of Sm-Tb and enrichment in MREE relative to LREE

Corrosion of Biocompatible Mg66+xZn30-xCa4 (x=0.2) Bulk Metallic Glasses

The aim of this paper was to investigate the corrosion resistance of Mg66Zn30Ca4 and Mg68Zn28Ca4 metallic glasses and evaluate the ability of this amorphous alloy use for medical applications as biodegradable medical implants. Taking into account the amount of Mg, Zn, Ca elements dissolved in multielectrolyte physiological fluid (MPF) from Mg66+xZn30-xCa4 (x=0.2) alloys the daily dose of evolved ions from alloys components was determined. Additional goal of the paper was determination of corrosion rate (Vcorr) and amount of hydrogen evolved from amorphous magnesium alloys in simulated environment of human body fluids during 24h immersion and during electrochemical tests. Corrosion studies were done in the multielectrolyte physiological fluid (MPF) at 37°C. The amount of hydrogen evolved [ml/cm2] and corrosion rate Vcorr [mm/year] of amorphous Mg66Zn30Ca4 and Mg68Zn28Ca4 alloys were compared. The work also presents characterization of Mg-based bulk metallic glasses structure in the form of 2 mm thickness plates. Samples structure was analyzed by means of X-ray diffraction. Fracture and surface morphology of magnesium alloy samples were identified using scanning electron microscopy

Corrosion of Biocompatible Mg66+xZn30-xCa4 (x=0.2) Bulk Metallic Glasses

The aim of this paper was to investigate the corrosion resistance of Mg66Zn30Ca4 and Mg68Zn28Ca4 metallic glasses and evaluate the ability of this amorphous alloy use for medical applications as biodegradable medical implants. Taking into account the amount of Mg, Zn, Ca elements dissolved in multielectrolyte physiological fluid (MPF) from Mg66+xZn30-xCa4 (x=0.2) alloys the daily dose of evolved ions from alloys components was determined. Additional goal of the paper was determination of corrosion rate (Vcorr) and amount of hydrogen evolved from amorphous magnesium alloys in simulated environment of human body fluids during 24h immersion and during electrochemical tests. Corrosion studies were done in the multielectrolyte physiological fluid (MPF) at 37°C. The amount of hydrogen evolved [ml/cm2] and corrosion rate Vcorr [mm/year] of amorphous Mg66Zn30Ca4 and Mg68Zn28Ca4 alloys were compared. The work also presents characterization of Mg-based bulk metallic glasses structure in the form of 2 mm thickness plates. Samples structure was analyzed by means of X-ray diffraction. Fracture and surface morphology of magnesium alloy samples were identified using scanning electron microscopy