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Article
Publication date: 21 September 2022

Wenliang Zhang, Heng Huang, Guogang Gao and Xiaopeng Xie

The purpose of this paper is to design the novel oil–air distributor (N-OAD). Its structure design, oil feeding reliability, service life and viscosity properties of air…

Abstract

Purpose

The purpose of this paper is to design the novel oil–air distributor (N-OAD). Its structure design, oil feeding reliability, service life and viscosity properties of air bubble (AB) oil were analyzed. Meanwhile, the formation mechanism of AB oil was established based on Kelvin–Helmholtz instability.

Design/methodology/approach

First, oil–air distributor (OAD) and N-OAD were randomly selected for testing when the air pressure was 0.25 MPa and oil feeding was 100 times per hour. Then, the bubbles were found in the lubricant during the experiment, and the void fraction and viscosity properties of AB oil were tested by image processing method and the MARS 40 rheometer, respectively.

Findings

N-OAD has longer service life and higher working reliability than OAD. The key factors of AB oil formation were air pressure and oil feeding. And the void fraction of AB oil has different results on the viscosity at high and low shear rates.

Originality/value

The outcome of this research paper gives an insight to improve the reliability of oil–air lubrication systems and the safety factor of machine tool spindle operation.

Details

Industrial Lubrication and Tribology, vol. 74 no. 10
Type: Research Article
ISSN: 0036-8792

Keywords

Abstract

Details

Dynamic Linkages and Volatility Spillover
Type: Book
ISBN: 978-1-78635-554-6

Book part
Publication date: 25 March 2010

Helen Xu

This study presents evidence of a statistically significant negative correlation between crude oil and equities over the past 20 years. Including proper proportions of…

Abstract

This study presents evidence of a statistically significant negative correlation between crude oil and equities over the past 20 years. Including proper proportions of negatively correlated assets in a diversified portfolio can improve the ratio of reward relative to risk, and therefore, adding crude oil with equities into a diversified portfolio can provide superior portfolio performance, compared with equities alone. Because crude oil prices held stable for nearly a century before the oil crisis of 1973, and oil derivatives did not begin trading actively on public markets until the 1980s, the diversification value of oil is a relatively new phenomenon. Also contributing to the phenomenon, the majority of oil reserves and the majority of crude oil production capacity worldwide are held by entities that are not traded in public equity markets, and therefore, the diversification benefits of oil cannot be fully realized by holding a portion of the global market portfolio of equities.

Details

Research in Finance
Type: Book
ISBN: 978-1-84950-726-4

Book part
Publication date: 12 February 2021

Munirah Khamarudin, Norkhazzaina Salahuddin and Normalisa Md Isa

The Malaysian oil palm has seen steady progress. Started in Malaysia as an ornamental plant, it has turned into a huge industry. Oil palm production has yielded unlimited…

Abstract

The Malaysian oil palm has seen steady progress. Started in Malaysia as an ornamental plant, it has turned into a huge industry. Oil palm production has yielded unlimited economic profits and is currently an emerging Malaysian economic sector. Malaysia currently accounts for an overwhelming contribution to the production and export of palm oil worldwide, which is 39% and 44%, respectively. From around 4.49 million hectares of land, a massive 17.73 million tons of palm oil and 2.13 tons of palm kernel oil were produced. It has been widely use as food products, cosmetics, livestock feed, as well as in bioenergy industry. This is in line with the fast-growing global demand for the palm oil products. Nevertheless, it is currently experiencing a period of slow or less growth in terms of contributing naturally to gross national productivity. Issues such as extreme weather, aging trees, and plant diseases are most prominent among the natural factors that are hindering the growth of the industry. The global pandemic of COVID-19 is also contributing to the current slow growth of palm oil sector. Malaysia has a crucial role to play in meeting the growing global need for oils and fats, as Malaysia is one of the palm oil and palm oil products' major producers and exporting countries.

Details

Modeling Economic Growth in Contemporary Malaysia
Type: Book
ISBN: 978-1-80043-806-4

Keywords

Book part
Publication date: 4 March 2008

T.J. O’Neill, J. Penm and R.D. Terrell

The primary aim of this chapter is to examine whether the recent increase in world oil prices has affected inflation expectations and stock market returns in major OECD…

Abstract

The primary aim of this chapter is to examine whether the recent increase in world oil prices has affected inflation expectations and stock market returns in major OECD countries. The key findings are as follows. First, we found no evidence to support the presence of a long term relationship between oil prices and inflation expectations – measured by the difference between yields of inflation indexed and non-inflation indexed government bonds – over the sample between early 2003 and late 2006. Second, higher oil prices are found to lead to expectations of higher inflation. This evidence is stronger over the period where oil prices had been higher and signs of capacity constraints in the economy were emerging. Third, the impact of higher oil prices on stock market returns differs among countries. While higher oil prices are found to adversely affect stock market returns in the United States, the United Kingdom and France, the effects are positive in Canada and Australia as these countries are significant exporters of energy resources.

Details

Research in Finance
Type: Book
ISBN: 978-1-84950-549-9

Article
Publication date: 1 July 2022

Xin Kuang, Bifeng Yin, Jian Wang, Hekun Jia and Bo Xu

The purpose of this paper is to evaluate the dispersion stability and the wear properties of lubricating oil blends added with modified nanometer cerium oxide (CeO2) at…

Abstract

Purpose

The purpose of this paper is to evaluate the dispersion stability and the wear properties of lubricating oil blends added with modified nanometer cerium oxide (CeO2) at high temperature.

Design/methodology/approach

In this paper, CeO2 was self-made and it was chemically modified. The dispersion stability of CeO2 in lubricating oil was studied. And the wear test of lubricating oil blends added with modified CeO2 was carried out at high temperature.

Findings

The results showed that CeO2 was successfully modified by oleic acid and stearic acid. The dispersion stability of modified CeO2 in lubricating oil was improved. Adding modified nano-CeO2 with the concentration less than 50 ppm into the lubricating oil can improve the wear properties of friction pairs in different extent. With the increase of the amount of CeO2, the wear properties increased first and then decreased. The lubricating oil blend added with 25 ppm CeO2 has the best wear properties.

Originality/value

The raw material CeO2 in this paper is self-made and its shape and size are well controlled. Research on the addition of nano-CeO2 to the engine low viscosity finished lubricants is lacking. It is of great significance to study the dispersion stability and tribological properties of nano-lubricants under the new background of low viscosity of lubricating oil and close to the real engine working conditions. It has certain significance to promote the development of nano-lubricants for engines.

Details

Industrial Lubrication and Tribology, vol. 74 no. 7
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 9 May 2022

Yanhong Yan, Xiaocui Yan, Chengwen Yang, Yanfei Zhou, Zhining Jia and Caizhe Hao

The purpose of this study is to improve the dispersion of nanoserpentine modified with OA, KH550 and KH550/oleic acid in lubricating oil. The main aims are to analyze the…

Abstract

Purpose

The purpose of this study is to improve the dispersion of nanoserpentine modified with OA, KH550 and KH550/oleic acid in lubricating oil. The main aims are to analyze the influence of the dispersion and stability of nanoserpentine modified by different modifiers on the friction properties of lubricating oil.

Design/methodology/approach

The nanoserpentine particles obtained by ball-milling were modified by silane coupling agent KH550, OA and KH550/OA, respectively. The dispersity and stability of nanoserpentine in base lubricating oil were characterized by the absorbance value method, centrifuge precipitation rate method and static observation method. The MMU-5G screen display friction and wear tester was used to evaluate the tribological properties of C45E4/C45E4 friction pairs in corresponding lubricating oils. The surface morphology of the friction pairs was observed by scanning electron microscopy and energy dispersive spectroscopy.

Findings

The results showed that the dispersity and stability of nanoserpentine particles in lubricating oil were best modified by OA, followed by the KH550/OA and finally, the KH550. Nanoserpentine particles modified with oleic acid showed optimum tribological properties as lubricant additives.

Originality/value

This study can improve the dispersion stability of nanoserpentine particles in lubricating oil, increasing the antiwear and antifriction performance of lubricating oil, which has great significance in economic and military aspects.

Details

Industrial Lubrication and Tribology, vol. 74 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 30 January 2023

Opeoluwa Adeniyi Adeosun, Richard O. Olayeni, Mosab I. Tabash and Suhaib Anagreh

This study investigates the nexus between the returns on oil prices (OP) and unemployment (UR) while taking into account the influences of two of the most representative…

Abstract

Purpose

This study investigates the nexus between the returns on oil prices (OP) and unemployment (UR) while taking into account the influences of two of the most representative measures of uncertainty, the Baker et al. (2016) and Caldara and Iacovello (2021) indexes of economic policy uncertainty (EP) and geopolitical risks (GP), in the relationship.

Design/methodology/approach

The authors use data on the US, Canada, France, Italy, Germany and Japan from January 2000 to February 2022 and the UK from January 2000 to December 2021. The authors then apply the continuous wavelet transform (CWT), wavelet coherence (WC), partial wavelet coherence (PWC) and multiple wavelet coherence (MWC) to examine the returns within a time and frequency framework.

Findings

The CWT tracks the movement and evolution of individual return series with evidence of high variances and heterogenous tendencies across frequencies that also align with critical events such as the GFC and COVID-19 pandemic. The WC reveals the presence of a bidirectional relationship between OP and UR across economies, showing that the two variables affect each other. The authors’ findings establish the predictive influence of oil price on unemployment in line with theory and also show that the variation in UR can impact the economy and alter the dynamics of OP. The authors employ the PWC and MWC to capture the impact of uncertainty indexes in the co-movement of oil price and unemployment in line with the theory of “investment under uncertainty”. Taking into account the common effects of EP and GP, PWC finds that uncertainty measures significantly drive the co-movement of oil prices and unemployment. This result is robust when the authors control for the influence of economic activity (proxied by the GDP) in the co-movement. Furthermore, the MWC reveals the combined intensity, strength and significance of both oil prices and the uncertainty measures in predicting unemployment across countries.

Originality/value

This study investigates the relationship between oil prices, uncertainty measures and unemployment under a time and frequency approach.

Highlights

  1. Wavelet approaches are used to examine the relationship between oil prices and unemployment in the G7.

  2. We account for uncertainty measures in the dynamics of oil prices and unemployment.

  3. We observe a bidirectional relationship between oil prices and unemployment.

  4. Uncertainty measures significantly drive oil prices and unemployment co-movement.

  5. Both oil prices and uncertainty measures significantly drive unemployment.

Wavelet approaches are used to examine the relationship between oil prices and unemployment in the G7.

We account for uncertainty measures in the dynamics of oil prices and unemployment.

We observe a bidirectional relationship between oil prices and unemployment.

Uncertainty measures significantly drive oil prices and unemployment co-movement.

Both oil prices and uncertainty measures significantly drive unemployment.

Details

China Finance Review International, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2044-1398

Keywords

Article
Publication date: 3 February 2023

Thuy Hang Duong

The purpose of this paper is to examine the effects of several structural shocks in oil prices on the Vietnamese economy and answer three key research questions: Is there…

Abstract

Purpose

The purpose of this paper is to examine the effects of several structural shocks in oil prices on the Vietnamese economy and answer three key research questions: Is there a relationship between oil price shocks and macroeconomic indicators in Vietnam? How do different types of oil price impulses affect Vietnamese inflation and economic performance? To what extent do structural shocks in oil prices explain variations in Vietnam’s macroeconomic indicators?

Design/methodology/approach

Lower triangular Cholesky decomposition is performed on a short-term impact matrix in a two-block structural vector autoregressive model. The data set is defined monthly, from January 2000 to December 2021. The contributions of structural shocks in oil prices to the domestic variances are analysed using variance decomposition methods. In this study, both forecast error variance decomposition and historical decomposition are used.

Findings

The consequences of oil price fluctuations on Vietnamese output and inflation depend on different sources of oil price shocks. In comparison, oil supply shocks have an insignificant effect on both domestic industrial output and consumer price index inflation; however, positive shocks in aggregate and precautionary oil demands increase these domestic indicators substantially and sustainably. An analysis of variance decompositions reveals that supply-side oil shocks have very limited explanatory power for variations in domestic variables. Nevertheless, the contributions of unanticipated demand-side booms to domestic variations in the past and projected forecasts are considerable.

Research limitations/implications

The findings from this research uncover potential risks for Vietnam’s economic prospects if the consequences of oil price shocks are not managed effectively.

Originality/value

Given the lack of economic sensitivity to supply-side oil shocks and the strong response to shifts in oil demands, greater pressure on the domestic economy is likely when Vietnam increases its dependence on oil imports.

Article
Publication date: 20 January 2023

Ujjawal Sawarn and Pradyumna Dash

This study aims to examine the uncertainty spillover among eight important asset classes (cryptocurrencies, US stocks, US bonds, US dollar, agriculture, metal, oil and…

Abstract

Purpose

This study aims to examine the uncertainty spillover among eight important asset classes (cryptocurrencies, US stocks, US bonds, US dollar, agriculture, metal, oil and gold) using weekly data from 2014 to 2020. This study also examines the US macro uncertainty and US financial stress spillover on these assets.

Design/methodology/approach

The authors use time–frequency connectedness method to study the uncertainty spillover among the asset classes.

Findings

This study’s findings revealed that the uncertainty spillover is time-varying and peaked during the 2016 oil supply glut and COVID-19 pandemic. US stocks are the highest transmitter of uncertainty to all other assets, followed by the US dollar and oil. US stocks (US dollar and oil) transmit uncertainty in long (short) term. Furthermore, US macro uncertainty is the net transmitter of uncertainty to the US stocks, industrial metals and oil markets. In contrast, US financial stress is the net transmitter of uncertainty to the US bonds, cryptocurrencies, the US dollar and gold markets. US financial stress (US macro uncertainty) has long (short)-term effects on asset price volatility.

Originality/value

This study complements the studies on volatility spillover among the important asset classes. This study also includes recently financialized asset classes such as cryptocurrencies, agricultural and industrial commodities. This study examines the macro uncertainty and financial stress spillover on these assets.

Details

Studies in Economics and Finance, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1086-7376

Keywords

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