• Kyungpook Mathematical Journal
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• 제46권3호
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• pp.389-397
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• 2006

A fixed point theorem of Singh and Singh [10] is generalized to locally convex spaces and the new result is applied to extend a result on invariant approximation of Jungck and Sessa [5].

• Advances in materials Research
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• 제9권2호
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• pp.115-131
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• 2020

Limit elastic speed analysis of Al/SiC-based functionally graded annular disk of uniform thickness has been carried out for two cases, namely: metal-rich and ceramic rich. In the present study, the unknown field variable for radial displacement is solved using variational method wherein the solution was obtained by Galerkin's error minimization principle. One of the objectives was to identify the variation of induced stress in a functionally graded disk of uniform thickness at limit elastic speed using modified rule of mixture by comparing the induced von-Mises stress with the yield stress along the disk radius, thereby locating the yield initiation. Furthermore, limit elastic speed has been reported for a combination of varying grading index (n) and aspect ratios (a/b).Results indicate, limit elastic speed increases with an increase in grading indices. In case of an increase in aspect ratio, limit elastic speed increases up to a critical value beyond which it recedes. Also, the objective was to look at the variation of yield stress corresponding to volume fraction variation within the disk which later helps in material tailoring. The study reveals the qualitative variation of yield stress for FG disk with volume fraction, resulting in the possibility of material tailoring from the processing standpoint, in practice.

• Steel and Composite Structures
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• 제42권3호
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• pp.375-388
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• 2022

In this work, limit elastic speed analysis of functionally graded porous rotating disks has been reported. The work proposes an effective approach for modeling the mechanical properties of a porous functionally graded rotating disk. Four different types of porosity models namely: uniform, symmetric, inner maximum, and outer maximum distribution are considered. The approach used is the variational principle, and the solution has been achieved using Galerkin's error minimization theory. The study aims to investigate the effect of grading indices, aspect ratio, porosity volume fraction, and porosity types on limit angular speed for uniform and variable disk geometries of constant mass. To validate the current study, finite element analysis has been used, and there is good agreement between the two methods. The study yielded a decrease in limit speed as grading indices and aspect ratio increase. The porosity volume fraction is found to be more significant than the aspect ratio effect. The research demonstrates a range of operable speeds for porous and non-porous disk profiles that can be used in industries as design data. The results show a significant increase in limit speed for an exponential disk when compared to other disk profiles, and thus, the study demonstrates a range of FG-based structures for applications in industries that will not only save material (lightweight structures) but also improve overall performance.

• 한국재료학회지
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• 제32권5호
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• pp.280-286
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• 2022

Corrosion is a natural, inevitable process, and is one of the world's most serious problems. Losses incurred due to corrosion are extremely expensive for society. Several technological strategies have been explored and implemented to address these losses. The use of inhibitors to prevent corrosion is a common and efficient method to reduce corrosion losses. This review covers Al and Al-composite corrosion inhibitors in chloride-containing solutions, because of their popularity in a broad array of industrial applications. A vast number of studies in the literature detail the common tendency of Al and Al-composites with reinforcements to deteriorate. Accordingly, it is worthwhile to employ inhibitors to protect them, as discussed in the present work. The emphasis is on selecting the smartest corrosion inhibitor and evaluating its performance. According to the study, the most commonly used corrosion inhibitors are 1,4-naphthoquinone (NQ), 1,5-naphthalene diol, 3-amino-1,2,4-triazole-5-thiol (ATAT), ammonium tetrathiotungstate, clotrimazole, amoxicillin, antimicrobial and antifungal drugs. Electrochemical impedance spectroscopy (EIS), potentiodynamic (PDP), and weight loss were among the most commonly used modern electrochemical technologies to test inhibitors' efficacy under environmental conditions.

• Asia pacific journal of information systems
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• 제30권1호
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• pp.21-30
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• 2020

Bitcoin (BTC) is a type of cryptocurrency that supports transaction/payment of virtual money between BTC users without the presence of a central authority or any third party like bank. It uses some cryptographic techniques namely public- and private-keys, digital signature and cryptographic-hash functions, and they are used for making secure transactions and maintaining distributed public ledger called blockchain. In BTC system, each transaction signed by sender is broadcasted over the P2P (Peer-to-Peer) Bitcoin network and a set of such transactions collected over a period is hashed together with the previous block/other values to form a block known as candidate block, where the first block known as genesis-block was created independently. Before a candidate block to be the part of existing blockchain (chaining of blocks), a computation-intensive hard problem needs to be solved. A number of miners try to solve it and a winner earns some BTCs as inspiration. The miners have high computing and hardware resources, and they play key roles in BTC for blockchain formation. This paper mainly analyses the underlying cryptographic techniques, identifies some weaknesses and proposes their enhancements. For these, two modifications of BTC are suggested ― (i) All BTC users must use digital certificates for their authentication and (ii) Winning miner must give signature on the compressed data of a block for authentication of public blocks/blockchain.

• 전기기술인
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• 통권338호
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• pp.16-18
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• 2010

두산중공업은 지난 2007년 5월 16일 세계 최대 규모의 인도 구자라트 지역에 있는 문드라(Mundra) 석탄화력발전 프로젝트를 수주했다. 문드라 석탄화력발전소는 인도정부가 전력난 해소와 전력요금 인하를 위해 2016년까지 9개의 초대형 화력발전소를 건설하는 프로젝트의 일환으로, 800MW급 초임계압 보일러 5기, 총 발전용량 4,000MW에 이르는 사상 최대 규모의 발전소다. 두산중공두산중공업은 인도 발전시장에는 이미 지난 1990년대말부터 진출한 이래 지난 2004년 인도 시파트 석탄화력발전소를 수주해 주목을 받은 바 있고, 올해 초에는 1,370MW (685MW 2기) 규모의 라이푸르-차티스가르(Raipur-Chhattisgarh) 석탄화력발전소를 수주해 인도발전시장에서 위상을 높이고 있다.

• Nonlinear Functional Analysis and Applications
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• 제28권1호
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• pp.107-121
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• 2023

In this work, we study generalized integral type F-contractions in partial metric spaces and establish some common fixed point theorems. Also, we give some consequences of the established result. Our results extend and generalize several results from the existing literature.

• 대한수학회보
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• 제37권4호
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• pp.729-741
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• 2000

In this paper, we study in Banach spaces the existence of fixed points of asymptotically regular mapping T satisfying: for each x, y in the domain and for n=1, 2,…, $$\parallelT^nx-T^ny\parallel\leq$\leq$a_n\parallelx-y\parallel+b_n (\parallelx-T^nx\parallel+\parallely-T^ny\parallely)$$ where $a_n,\; b_n,\; C_n$ are nonnegative constants satisfying certain conditions. We also establish some fixed point theorems for these mappings in a Hibert space, in L(sup)p spaces, in Hardy space H(sup)p, and in Soboleve space $H^{k,p} for 1<\rho<\infty \; and \; k\geq0$. We extend results from papers [10], [11], and others.

• Asia pacific journal of information systems
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• 제32권2호
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• pp.191-225
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• 2022

Based on its technological elements (distribution, encryption, immutability, tokenisation, decentralisation, and smart contracts), blockchain has drawn considerable attention in various industries and verticals. Still, the strategic adoption of blockchain is in its early stages because of the current barriers and challenges in the areas of 'customer experience', 'business models', and 'operational processes.' This work delivers a comprehensive synopsis of the fundamental challenges faced by blockchain adopters in their digital journey, based on a literature survey. The authors leveraged MAXQDA software and the theory, context, characteristics, and methodology (TCCM) framework to develop themes, findings, and evidence for adoption barriers. The research evaluates the literature on blockchain adoption challenges and offers research insights and managerial agendas for future inferences.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.6141-6145
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• 2013

Background: The objective of the study was to determine the knowledge, attitude and behaviors of the practicing dentists regarding tobacco cessation counseling (TCC) in Chhattisgarh state and also the barriers that prevent them from doing so. Materials and Methods: The study was conducted among dental practitioners of Raipur district, Chhattisgarh state (India). The sampling frame was registration with the State Dental Council and practicing in Raipur district. A questionnaire was personally administered and the practitioners were given explanations regarding how to complete it. Only descriptive statistics were calculated (SPSS version 16 for Windows). Results: Based on the responding dentists' self reports, 76% were not confident in TCC, 48% did not assume TCC to be their responsibility, 17% considered that it might have a negative impact on their clinical practice, whereas 24% considered it might take away precious time from their practice, 25% considered TCC by dentists to be effective to a considerable extent and 80% considered TCC activities are not effective due to lack of formal training, 69% considered dental clinics as an appropriate place for TCC but 82% thought there must be separate TCC centre and 100% of the dentists wanted TCC training to be a part of practice and that it should be included in dental curriculum. Some 95% of them were of the view that tobacco products should be banned in India and 86% responded that health professionals must refrain from tobacco habits so to act as role models for society. Conclusions: Dental professionals must expand their armamentarium to include TCC strategies in their clinical practice. The dental institutions should include TCC in the curriculum and the dental professionals at the primary and the community health care level should also be trained in TCC to treat tobacco dependence.