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1.
Studies were made on the thermally stimulated discharge currents (TSDCs) in pure (undoped) and Fe-doped polystyrene films as a function of polarizing field, polarizing temperature and dopant concentration. While undoped films exhibited a single peak, doped films showed two peaks one at low temperatures and another at high temperatures. The low temperature peak, which exhibits a shift towards lower temperatures with increasing dopant concentration, is attributed to the relaxation of the main chain, while the high temperature peak, which shows a tendency to shift towards higher temperatures with dopant concentration, is due to space charge polarization. The TSDCs were higher for low dopant concentrations than their undoped counterparts, while for high concentrations of the dopant, the TSDCs decreased. Formation of charge transfer complexes at low dopant concentrations and molecular aggregates at higher dopant concentrations are suggested as the possible reasons for this behaviour. 相似文献
2.
Instrumental characterization of clay by XRF,XRD and FTIR 总被引:2,自引:0,他引:2
Instrumental characterizations of the clay were performed by different techniques such as XRF, XRD and FTIR. XRF shows the
chemical compositions of the clay where Al-oxide and silica oxide are present in major quantity whereas XRD confirms the presence
of these minerals in clay. FTIR studies show the presence of quartz, alumina, haematite and different mineral matters. 相似文献
3.
Yassine Slimani Sagar E. Shirsath Essia Hannachi Munirah A. Almessiere Moustafa M. Aouna Nouf E. Aldossary Ghulam Yasin Abdulhadi Baykal Bekir Ozçelik Ismail Ercan 《Journal of the American Ceramic Society》2021,104(11):5648-5658
Two phase-based nanocomposites consisting of dielectric barium titanate (BaTiO3 or BTO) and magnetic spinel ferrite Co0.5Ni0.5Nb0.06Fe1.94O4 (CNNFO) have been synthesized through solid state route. Series of (BaTiO3)1-x + (Co0.5Ni0.5Nb0.06Fe1.94O4)x nanocomposites with x content of 0.00, 0.25, 0.50, 0.75, and 1.00 were considered. The structure has been examined via X-rays diffraction (XRD) and indicated the occurrence of both perovskite BTO and spinel CNNFO phases in various nanocomposites. A phase transition from tetragonal BTO structure to cubic structure occurs with inclusion of CNNFO phase. The average crystallites size of BTO phase decreases, whereas that for the CNNFO phase increases with increasing x in various nanocomposites. The morphological observations revealed that the porosity is highly reduced, and the connectivity between grains is enhanced with increasing x content. The optical properties have been investigated by UV−vis diffuse reflectance spectroscopy. The deduced band gap energy (Eg) value is found to reduce with increasing the content of spinel ferrite phase. The magnetic as well as the dielectric properties were also investigated. The analysis showed that CNNFO ferrite phase greatly affects the magnetic properties and dielectric response of BTO material. The obtained findings can be useful to enhance the performances of magneto-dielectric composite-based systems. 相似文献
4.
Hot-corrosion attack on gas-turbine components has been a problem of practical importance for over two decades. The nature and the extent of corrosion are influenced by the type of contaminants, the alloy constituents, and temperature. The hot-corrosion process is quite complex. There is controversy regarding the role of alloying elements, and whether the process is chemical or electrochemical in nature. In this investigation, an attempt has been made to investigate the role of Al and Ti in influencing the hot-corrosion attack of Ni-20 wt. % Cr alloys in molten Na2SO4-NaCl mixtures. It was found that Ni-Cr-Al alloys undergo a localized, heavy-blister attack under certain experimental conditions which is electrochemical in nature. An electrochemical model has been proposed which can satisfatorily explain the nature and kinetics of the localized blister corrosion. 相似文献
5.
Sagar Chaki Edmund Clarke Natasha Sharygina Nishant Sinha 《Formal Methods in System Design》2008,32(3):235-266
This paper presents an automated and compositional procedure to solve the substitutability problem in the context of evolving software systems. Our solution contributes two
techniques for checking correctness of software upgrades: (1) a technique based on simultaneous use of over-and under-approximations
obtained via existential and universal abstractions; (2) a dynamic assume-guarantee reasoning algorithm—previously generated component assumptions are reused and altered on-the-fly to prove
or disprove the global safety properties on the updated system. When upgrades are found to be non-substitutable, our solution
generates constructive feedback to developers showing how to improve the components. The substitutability approach has been
implemented and validated in the ComFoRT reasoning framework, and we report encouraging results on an industrial benchmark.
This is an extended version of a paper, Dynamic Component Substitutability Analysis, published in the Proceedings of the Formal Methods 2005 Conference, Lecture Notes in Computer Science, vol. 3582, by the
same authors. This research was sponsored by the National Science Foundation under grant nos. CNS-0411152, CCF-0429120, CCR-0121547,
and CCR-0098072, the Semiconductor Research Corporation under grant no. TJ-1366, the US Army Research Office under grant no.
DAAD19-01-1-0485, the Office of Naval Research under grant no. N00014-01-1-0796, the ICAST project and the Predictable Assembly
from Certifiable Components (PACC) initiative at the Software Engineering Institute, Carnegie Mellon University. The views
and conclusions contained in this document are those of the authors and should not be interpreted as representing the official
policies, either expressed or implied, of any sponsoring institution, the US government or any other entity. 相似文献
6.
Prasant Ku. Dash Lopamudra Hota Madhumita Panda N. Z. Jhanjhi Kshira Sagar Sahoo Mehedi Masud 《计算机系统科学与工程》2023,44(3):2225-2242
The 3D Underwater Sensor Network (USNs) has become the most optimistic medium for tracking and monitoring underwater environment. Energy and collision are two most critical factors in USNs for both sparse and dense regions. Due to harsh ocean environment, it is a challenge to design a reliable energy efficient with collision free protocol. Diversity in link qualities may cause collision and frequent communication lead to energy loss; that effects the network performance. To overcome these challenges a novel protocol Forwarder Selection Energy Efficient Routing (FSE2R) is proposed. Our proposal’s key idea is based on computation of node distance from the sink, Residual Energy (RE) of each node and Signal to Interference Noise Ratio (SINR). The node distance from sink and RE is computed for reliable forwarder node selection and SINR is used for analysis of collision. The novel proposal compares with existing protocols like H2AB, DEEP, and E2LR to achieve Quality of Service (QoS) in terms of throughput, packet delivery ratio and energy consumption. The comparative analysis shows that FSE2R gives on an average 30% less energy consumption, 24.62% better PDR and 48.31% less end-to-end delay compared to other protocols. 相似文献
7.
Kuldeep Chouhan Mukesh Yadav Ranjeet Kumar Rout Kshira Sagar Sahoo NZ Jhanjhi Mehedi Masud Sultan Aljahdali 《计算机系统科学与工程》2023,45(2):1113-1128
Twitter is a radiant platform with a quick and effective technique to analyze users’ perceptions of activities on social media. Many researchers and industry experts show their attention to Twitter sentiment analysis to recognize the stakeholder group. The sentiment analysis needs an advanced level of approaches including adoption to encompass data sentiment analysis and various machine learning tools. An assessment of sentiment analysis in multiple fields that affect their elevations among the people in real-time by using Naive Bayes and Support Vector Machine (SVM). This paper focused on analysing the distinguished sentiment techniques in tweets behaviour datasets for various spheres such as healthcare, behaviour estimation, etc. In addition, the results in this work explore and validate the statistical machine learning classifiers that provide the accuracy percentages attained in terms of positive, negative and neutral tweets. In this work, we obligated Twitter Application Programming Interface (API) account and programmed in python for sentiment analysis approach for the computational measure of user’s perceptions that extract a massive number of tweets and provide market value to the Twitter account proprietor. To distinguish the results in terms of the performance evaluation, an error analysis investigates the features of various stakeholders comprising social media analytics researchers, Natural Language Processing (NLP) developers, engineering managers and experts involved to have a decision-making approach. 相似文献
8.
Yuan Chenxi Li Guoyan Kamarthi Sagar Jin Xiaoning Moghaddam Mohsen 《Journal of Intelligent Manufacturing》2022,33(2):425-439
Journal of Intelligent Manufacturing - In recent years, driven by Industry 4.0 wave, academic research has focused on the science, engineering, and enabling technologies for intelligent and cyber... 相似文献
9.
Kwang-Jun Oh Young-Bong Ko Sagar Jaiswal In-Cheul Whang 《Journal of materials science. Materials in medicine》2016,27(12):179
The purpose of this study was to compare the osteoconductivity, and absorbability of hydroxyapatite or beta-tricalcium phosphate in clinical scenario of opening wedge high tibial osteotomy Total 41 knees of 40 patients with follow up period of more than 1 year were enrolled. These patients were divided into two groups, Group I (22 knees, 21 patients) used hydroxyapatite and Group II (19 knees, 19 patients) used beta-tricalcium phosphate as a substitute in the opening gap. According to proven method, the osteoconductivity was assessed radiographically by the extent of new bone formation at osteotomy space and absorbability was evaluated by measuring the area occupied by substitute at immediate postoperative, postoperative 6 months and 1 year. Regarding preoperative demographic data, no significant differences were found between two groups. No statistically significant differences were found between two groups regarding lower limb alignment (mechanical femorotibial angle, weight-bearing line%) and posterior tibial slope at postoperative and final follow up radiographs. Concerning the osteoconductivity, there were no significant differences between two groups in any zone. However, the absorption rate was significantly greater in the Group II than in Group I at 6 months (Group I: 13.7?±?6.8, group II: 35.3?±?15.8, P?=?0.001) and 1 year (Group I: 24.2?±?6.3, Group II: 49.6?±?14.3, P?<?0.0001). The complications related to bone substitutes were not observed. Both hydroxyapatite and beta-tricalcium phosphate showed satisfactory gap healing without complications and can be successfully used as alternative healing materials in opening wedge high tibial osteotomy. Our study showed that beta-tricalcium phosphate has superior absorbability than hydroxyapatite. But osteoconductivity showed no significant difference. 相似文献
10.
We present a framework, called air, for verifying safety properties of assembly language programs via software model checking. air extends the applicability of predicate abstraction and counterexample guided abstraction refinement to the automated verification
of low-level software. By working at the assembly level, air allows verification of programs for which source code is unavailable—such as legacy and COTS software—and programs that use
features—such as pointers, structures, and object-orientation—that are problematic for source-level software verification
tools. In addition, air makes no assumptions about the underlying compiler technology. We have implemented a prototype of air and present encouraging results on several non-trivial examples. 相似文献