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As lubricating oils are used, their performance deteriorates and they become contaminated. The purpose of this paper is to investigate the lubrication performance of reclaimed 5 W-30 a fully synthetic used engine oil (UEO) with wear tests after refining it from a solvent-based extraction method using solvent (1-PrOH) and adsorbent materials such as cement, celite and deep eutectic solvent (DES).

The treated oil mixtures were prepared by blending engine oils with various adsorbent materials at 5% (w/w) in organic 1-PrOH solvent at a UEO: solvent ratio of 1:2 (w/w). The measurement of kinematic viscosity, density, the total acid number (TAN) and elemental analysis of oil samples was done by the ASTM standards D445/D446, D4052, D974 and D6595, respectively. Adsorbents and treated oil samples characterized by SEM-EDX, FTIR and UV analysis, respectively. Meanwhile, lubricating performance in tribological applications was evaluated through the wear test device using a rotating steel alloy 1.2379 cylinder and a stationary 1.2738 pin under 20, 40 and 80 kg load conditions. Worn surface analysis was done with SEM and 2.5D images.

It was found that when using the combination of cement and celite as an adsorbent in the reclamation of used engine oil demonstrated better lubricant properties. The properties of used engine oil were improved in the manner of kinematic viscosity of 32.55 from 68.49 mm²/s, VI (Viscosity index) value of 154 from 130, TAN of 3.18 from 4.35 (mgKOH/g) and Fe content of 11 from 32 mg/L. The anti-wear properties of used engine oil improved by at least 32% when 5% cement and 5% celite adsorbent materials were used together.

The paper is based on findings from a fully synthetic 5 W-30 A5 multi-grade engine lubrication oil collected after driving approximately 12.000 km.

The results are significant, as they suggest practical regeneration of used engine oil is achievable. Additionally, blending fresh oil with reclaimed used engine oil in a 1:1 ratio reduced wear loss by over 10% compared to fresh oil.

Reusing used engine oils can reduce their environmental impact and bring economic benefits.

This study showed that the properties of UEO can be enhanced using the solvent extraction-adsorption method. Furthermore, the study provided valuable insights into the metal concentrations in engine oil samples and their impact on lubrication performance. The order of the number of the grooves quantity and the possibility of the observed scuffing region trend relative to the samples was UEO > 5W-30 fresh oil > Treated oil sample with the adsorbent cement and celite together.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0209/

The purpose of this paper is to examine the price level and volatility impacts of oil prices on energy mutual funds (EMFs). The authors also examine specific fund characteristics which might influence those interactions.

The authors test for volatility transmission between the oil prices and the funds in the sample. Later, the authors test to see which fund characteristics impact these volatility interactions.

The results show oil price movements lead majority of sample EMFs. The authors also find a volatility feedback relationship with most of the sample. Furthermore, the authors show the fund characteristics to be important indicators of these interactions. Morningstar rating, market capitalization and management tenure are found to be significant drivers of the relationships between EMFs and oil prices.

To the knowledge, there is not a study in literature which examines these relationships.

This paper aims to examine the interrelationships of monetary policy's structural shocks, the real exchange rate and stock prices.

According to quarterly data, variables such as gross domestic product, consumer price index, the real exchange rate, stock price and monetary policy indices in the structural vector autoregressions model are estimated. These variables' volatility is attributed to other variables’ structural shocks separately, and analysis of variance tables for all variables is presented.

The results show that structural shock on the exchange rate does not affect the stock price, but the monetary policy's structural shock positively impacts the real exchange rate. Moreover, the real exchange rate and monetary policy's structural shocks have a negative impact on the stock price index. However, no significant effect is found pertain to the real exchange rate structural shock, statistically.

To the best of the authors’ knowledge, the current study model is relatively novel in developing countries, and the study sought strength to develop knowledge on the subject of the study.

Along with accounting scandals in the past, academics, researchers, and legislators have focused on fraud. The purpose of this study is to examine postgraduate and doctoral studies, articles, and books about forensic accounting and fraud audit published between the years 2008 and 2018 in Turkey. For this purpose, a total of 96 studies have been examined and 35 of these are master’s theses, 10 of them are PhD theses, 45 of them are articles, and six of them are books. These studies were presented in tables as classified. The studies examined in our research are summarized as year they were published, the author, and the scope of the topic and in terms of results. The conclusions of this study can be summarized as follows: (a) the majority of thesis published about forensic accounting and fraud audit are in 2011 and following years. In addition, most of the theses are focused on forensic accounting review rather than fraud audit. (b) Results in the articles reviewed are in the same direction with theses. (c) There are very few books about fraud audit and forensic accounting. One of them is related to fraud audit, while the rest of them are related to forensic accounting and forensic accounting profession. We suggest extending the scope of the study and making to other countries.