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1 – 10 of over 2000
Article
Publication date: 15 October 2020

Vicente Jara-Vera and Carmen Sánchez-Ávila

The distribution of natural numbers in the Ulam spiral manifests a series of unexpected regularities of the elusive prime numbers. Their sequencing remains a topic of research…

Abstract

Purpose

The distribution of natural numbers in the Ulam spiral manifests a series of unexpected regularities of the elusive prime numbers. Their sequencing remains a topic of research interest, with many ramifications in different branches of Mathematics, especially in number theory and the prime factorisation problem. Accordingly, the focus of the research is on the most known and widespread asymmetric cryptographic system, that is, the RSA encryption.

Design/methodology/approach

This paper presents the presence of one, two, three or four adjacencies for the diverse primes that appear in a spiral, considering the Hardy–Littlewood twin prime conjecture and the constellations of primes.

Findings

Through equations, the calculation formulas of primes inside a spiral that have one to four primes in their adjacent places is offered, with approximate expressions that facilitate the operations, showing that the adjacencies decrease very rapidly as the spiral progresses, although without disappearing.

Originality/value

A generalisation to cases in which the distances to the prime values change in an ascending way in accordance with the step of the Ulam spiral is offered.

Details

Engineering Computations, vol. 38 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 11 March 2016

Jabbar P, Hariharan N.M, Palani Sivashanmugam and S. Kasthurirengan

The present investigation deals with the analysis of the performance of twin thermoacoustic prime mover (TAPM) which are measured in terms of frequency and pressure amplitude by…

Abstract

Purpose

The present investigation deals with the analysis of the performance of twin thermoacoustic prime mover (TAPM) which are measured in terms of frequency and pressure amplitude by varying the parameters such as temperature gradient along the length of stack and the operating pressures of fluid medium argon using CFD simulation. With the help of CFD researchers and Engineers can evaluate the performance of a wide range of thermoacoustic systems on the computer without the time, expense, and disruption required to make actual changes onsite (stack) which is tedious to fabricate.

Design/methodology/approach

For the present simulation, the operating pressures of argon such as 1bar, 3bar and 5bar, and the temperature gradient is varied from 600K to 1400K with the regular intervals of each 200K. The geometry of twin TAPM is created using GAMBIT processor, and the simulation is carried out using FLUENT. The geometrical parameters of twin TAPM are kept constant throughout the simulation. The results for frequency and pressure amplitude obtained from the CFD simulation of twin TAPM for various temperature gradient and operating pressures are analysed and reported.

Findings

The computational results of twin thermoacoustic prime mover shows an increase in pressure amplitude with an increase in the temperature gradient and also it increases with an increase in operating pressures of the fluid medium. The parameter operating pressures of the working fluid medium and the stack hot end temperature has no significant effect on the output, frequency.

Originality/value

Though several experimental works had been published based on the twin thermoacoustic prime mover, an attempt has been made in the present investigation for the first time to estimate the performance of twin thermoacoustic prime mover using CFD package (ANSYS-FLUENT) by varying temperature gradient. The temperature gradient and operating pressures were varied and the performance of twin thermoacoustic prime mover was measured in terms of frequency and pressure amplitude.

Details

Engineering Computations, vol. 33 no. 3
Type: Research Article
ISSN: 0264-4401

Article
Publication date: 1 August 1984

Saad Amin Fam and Fawzia F. Abdel‐Mohsen

A petroleum fraction having a boiling range 200–250°C (kerosene), free from aromatic and n‐paraffin hydrocarbons was oxidised by bubbling air at 130–150°C, at normal pressure, in…

Abstract

A petroleum fraction having a boiling range 200–250°C (kerosene), free from aromatic and n‐paraffin hydrocarbons was oxidised by bubbling air at 130–150°C, at normal pressure, in the presence of cobalt naphthenate as a catalyst. Optimum yield of oxynaphthenic acid was obtained after sixteen hours and thirty minutes oxidation at 140°C. Two layers were formed, the bottom product was a viscous liquid insoluble in petroleum ether and alcohols. Oxyacids, mainly hydroxy naphthenic acids, were obtained after treatment and purification of the viscous liquid.

Details

Pigment & Resin Technology, vol. 13 no. 8
Type: Research Article
ISSN: 0369-9420

Case study
Publication date: 18 October 2021

Pravat Surya Kar, V. Padhmanabhan, Akshay Bhat and Amit Satija

Teaching objectives: to help students review entertainment service and its ecosystem; to discuss leadership anxiety during change management and organizational development; to…

Abstract

Learning outcomes

Teaching objectives: to help students review entertainment service and its ecosystem; to discuss leadership anxiety during change management and organizational development; to understand organizational diagnosis while initiating change management exercise; and to compare various strategic alternatives and the implications of selecting an option.

Case overview/synopsis

This case narrates dilemma of Krishna Goenkar, a management consultant entrusted to revisit strategic orientations of Mahem Entertainment Society (MES). Mahem is a fictitious state in the west coast of India. MES had been created by the Government of Mahem as a regulatory body to promote the state as a world class destination for entertainment. Public interest guided the organization, as it was a government instituted body. Hence, Goenkar had twin challenges. Firstly, what strategic initiatives should he propose to scale up the operations in spite of the given organizational constraints? Secondly, how to scale up and diversify if required, with minimal resistance? The case would help students get familiarized with entertainment domain, service ecosystem and challenges of driving strategic change in public utilities, especially in Indian and emerging market context.

Complexity academic level

This case is suitable for graduate-level programme in marketing management.

Supplementary materials

Teaching notes are available for educators only. Please contact your library to gain login details or email support@emeraldinsight.com to request teaching notes.

Subject code

CSS 8: Marketing.

Details

Emerald Emerging Markets Case Studies, vol. 11 no. 3
Type: Case Study
ISSN: 2045-0621

Keywords

Book part
Publication date: 11 August 2014

Kenneth A. Couch, Gayle L. Reznik, Christopher R. Tamborini and Howard M. Iams

Data from the 1984 Survey of Income and Program Participation are linked to longitudinal records from the Social Security Administration to examine the relationship between the…

Abstract

Data from the 1984 Survey of Income and Program Participation are linked to longitudinal records from the Social Security Administration to examine the relationship between the long-term unemployment that prime-aged (ages 25–55) male workers experienced around the time of the 1980–1982 twin recessions with earnings, receipt of either Disability Insurance or Supplemental Security Income (DI-SSI) benefits, and mortality. Separate estimations are made for those who voluntarily and involuntarily left employment and the combined sample of these two groups. We find that 20 years later, long-term joblessness was associated with significantly lower earnings and higher likelihoods of the receipt of DI-SSI benefits as well as mortality.

Executive summary
Publication date: 28 September 2022

JAPAN: Kishida may recover from twin controversies

Details

DOI: 10.1108/OXAN-ES273023

ISSN: 2633-304X

Keywords

Geographic
Topical
Content available
Article
Publication date: 1 May 2002

1310

Abstract

Details

Disaster Prevention and Management: An International Journal, vol. 11 no. 2
Type: Research Article
ISSN: 0965-3562

Article
Publication date: 1 June 2002

George K. Chacko

Develops an original 12‐step management of technology protocol and applies it to 51 applications which range from Du Pont’s failure in Nylon to the Single Online Trade Exchange…

3616

Abstract

Develops an original 12‐step management of technology protocol and applies it to 51 applications which range from Du Pont’s failure in Nylon to the Single Online Trade Exchange for Auto Parts procurement by GM, Ford, Daimler‐Chrysler and Renault‐Nissan. Provides many case studies with regards to the adoption of technology and describes seven chief technology officer characteristics. Discusses common errors when companies invest in technology and considers the probabilities of success. Provides 175 questions and answers to reinforce the concepts introduced. States that this substantial journal is aimed primarily at the present and potential chief technology officer to assist their survival and success in national and international markets.

Details

Asia Pacific Journal of Marketing and Logistics, vol. 14 no. 2/3
Type: Research Article
ISSN: 1355-5855

Keywords

Case study
Publication date: 15 November 2023

Parameswaran Iyer, Ajay Pandey, Mahima Vashisht and Daniel W. Smith

This case is the second of a three-part series that follows the managerial, strategic, and communications decisions of the Swachh Bharat Mission (SBM) or Clean India Mission, the…

Abstract

This case is the second of a three-part series that follows the managerial, strategic, and communications decisions of the Swachh Bharat Mission (SBM) or Clean India Mission, the flagship programme of the Government of India to eliminate the practice of open defecation (i.e., not using a toilet) from 2014 to 2019. As of 2014, 550 million people in India practiced open defecation. This problem posed a massive public health hazard and economic drag for the country as well as a threat to global health. Written from an insider's perspective, the cases centre on the decisions made by a new Secretary of India's Ministry of Drinking Water and Sanitation, who was hired to manage SBM, and the team he assembled. Case B discusses the start-up challenges for SBM, including implementation in India's complex federal system, workplace culture, and the deep-rooted behaviour of open defecation in rural India and the managerial and communication strategies formulated to address them. The case concludes by framing the difficulties with slow-moving states and monitoring rigour that the leadership SBM, with a new team, strategic focus, and early momentum, faced as the mission entered its final two years.

Details

Indian Institute of Management Ahmedabad, vol. no.
Type: Case Study
ISSN: 2633-3260
Published by: Indian Institute of Management Ahmedabad

Keywords

Book part
Publication date: 11 December 2006

Patricia A. McGraw, Kamphol Panyagometh and Gordon S. Roberts

We extend Diamond's (1989, 1991) life-cycle hypothesis to posit that, once they reach the stage of bank borrowing, firms begin with prime loans and evolve toward borrowing more…

Abstract

We extend Diamond's (1989, 1991) life-cycle hypothesis to posit that, once they reach the stage of bank borrowing, firms begin with prime loans and evolve toward borrowing more cheaply at LIBOR as they grow larger, less risky and less characterized by asymmetric information. We conduct multinomial logit regressions to explain firms’ membership in one of three groups: prime only, prime and LIBOR, and LIBOR. We also examine spreads over prime and LIBOR and find that loans set up to allow borrowing at prime carry higher spreads than those allowing borrowing at LIBOR. Both sets of tests support the life-cycle hypothesis.

Details

Research in Finance
Type: Book
ISBN: 978-1-84950-441-6

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