The development of a wax layer on the interior wall of a circular pipe transporting heated oil: the effects of temperature-dependent wax conductivity

In this paper, we develop and significantly extend the thermal phase change model, introduced in Needham et al. (QJMAM 67:93–125, 2014), describing the process of paraffinic wax layer formation on the interior wall of a circular pipe transporting heated oil, when subject to external cooling. In particular, we allow for the natural dependence of the solidifying paraffinic wax conductivity on local temperature. We are able to develop a complete theory, and provide efficient numerical computations, for this extended model. Comparison with recent experimental observations is made, and this, together with recent reviews of the physical mechanisms associated with wax layer formation provide significant support for the thermal model considered here.

Heated Corn Oil and 2,4-Decadienal Suppress Gastric Emptying and Energy Intake in Humans

Consumption of 2,4-decadienal (2,4-DD) delays gastric emptying (GE) rate in animals. Oil heating produces 2,4-DD and other aldehydes. Here we examined whether heated oil affects GE rate and food intake in humans, and whether it is mediated by 2,4-DD. In the first experiment, 10 healthy volunteers consumed 240-g pumpkin soup with 9.2 g of heated (HO) or non-heated corn oil (CO). Subsequently, 17 participants consumed pumpkin soup containing 3.1 g of either heated corn oil (HO), 1 mg 2,4-DD + non-heated corn oil (2,4-DD), or non-heated corn oil (CO). Sixty minutes following pumpkin soup, cod roe spaghetti was provided, and then energy intake was determined. To evaluate GE rate, 13C breath test (Experiment 1) and ultrasonography (Experiments 1 and 2) were used. The results from the Experiment 1 confirmed that consumption of heated corn oil reduced GE rate. Experiment 2 showed a delayed GE rate in HO and 2,4-DD trials compared with CO trial (p < 0.05). Energy intake was approximately 600–650 kJ lower in HO and 2,4-DD trials compared with CO trial (p < 0.05). These findings suggest that 2,4-DD, either formed by oil heating or added to food, contributes to suppressing GE rate and energy intake.

METHODS OF TRANSPORTATION AND NON-ISOTHERMAL MOVEMENT OF RHEOLOGICAL COMPLEX OILS

The article examines the non-isothermal effect of rheological compound oil and clarifies some methods of transportation of complex rheological characteristic oil and the effect of viscous liquids in pipes. The article presents several ways to improve oil transportation. These methods include the transportation of complex rheological oil with gas-saturated, thermally prepared, heated water. The most common method is to transport oil by heating with complex rheological properties. The pipeline through which heated oil is transported is called the hot pipeline. The article clarifies the movement of viscous liquids in pipes. Keywords: rheological oils, complex rheological properties, gas-saturated, thermally prepared, graphoanalysis, Gas-saturated transportation

The investigation of effects of environmental conditions on fatigue strength and spring stiffness of rubber materials

Rubber materials are widely used in many applications. The most important applications of rubber materials are seals, tires, gaskets, hoses, hydraulic-pneumatic systems and vibration absorbers. Today, the working environment of rubbers varies. It has become important to see the responses of developed rubber materials to these challenging working conditions. Most rubber parts are subjected to fluctuating loads that can cause fatigue damage in their work environments. In this study, fatigue strength and spring stiffness of rubber materials under different environmental conditions is investigated. Three general factors that affect fatigue strength of rubber materials are the effects of mechanical loading, environmental effects and the effects of rubber formulation. In this study these factors are examined. For this purpose, fatigue strength and spring stiffness of natural rubber (NR), specially developed natural rubber (S-NR) and ethylene propylene diene monomer (EPDM) rubber were examined. The fatigue tests of rubber samples were performed before and after aging processes. During the study, the static and dynamic stiffness values of the rubber materials were examined before and after aging processes. As a result of experimental study, it was found that fatigue life decreases as a result of accelerated aging and annealing in heated oil processes for NR, EPDM and S-NR samples. Annealing in heated oil process is more effective in reducing fatigue life of rubber samples compared to accelerated aging. In this study, it is seen that S-NR rubber has the highest fatigue strength among rubber materials tested. It has been determined that production of samples with the semi-active vulcanization system is the most important parameter in increasing fatigue strength. In S-NR samples produced with the semi-active vulcanization system, the loss in spring stiffness occurring under different aging conditions is less compared to the loss in spring stiffness in conventional vulcanization system produced NR and EPDM samples.

Ginger and turmeric lipid-solubles attenuate heated oil-induced cardio-hepatic oxidative stress via the up-regulation of nuclear factor erythroid 2-related factor 2 and decrease blood pressure in rats

Deep-fried vegetable oils are reused multiple times to save costs, and their chronic consumption may cause organ dysfunction. In this study, we assessed the modulatory effects of lipid-solubles from ginger and turmeric that may migrate to oils during heating, on the cardio-hepatic antioxidant defence response and blood pressure in rats. Male Wistar rats were fed with: (1) control (native rapeseed (N-CNO) or native sunflower (N-SFO)) oil, (2) heated (heated rapeseed (H-CNO) or heated sunflower (H-SFO)) oil and (3) heated oil with ginger or turmeric (heated rapeseed oil with ginger (H-CNO + GI) or heated rapeseed oil with turmeric (H-CNO + TU), heated sunflower oil with ginger (H-SFO + GI) or heated sunflower oil with turmeric (H-SFO + TU)) for 120 d. Oxidative stress (OS) markers, antioxidant enzymes, nitric oxide synthase-2 (NOS-2), intercellular adhesion molecule-1 (ICAM-1), nuclear factor erythroid 2-related factor 2 (NRF-2), markers of hepatic and cardiac function and blood pressure were assessed. Feeding heated oils (H-CNO or H-SFO) (1) increased OS markers, NOS-2 and ICAM-1 expression; (2) decreased antioxidant enzyme activity and NRF-2 level; (3) increased marker enzymes of hepatic and cardiac function and (4) increased systolic and diastolic blood pressure significantly (P < 0·05), when compared with respective native oils (N-CNO or N-SFO). However, feeding oils heated with ginger or turmeric positively countered the changes induced by heated oils. Consumption of repeatedly heated oil causes cardio-hepatic dysfunction by inducing OS through NRF-2 down-regulation. Lipid-solubles from ginger and turmeric that may migrate to oil during heating prevent the oxidative stress and blood pressure triggered by heated oils in rats.