Evaluation of Tribological Properties of Transesterified Cottonseed Oil by Adding Silicon Dioxide (SiO2) as an Additive

The usage of vegetable oils has increased in many applications as they possess desirable lubrication properties. However, the use is limited due to poor tribological properties. Many researchers have attempted to explore the performance of various vegetable oils and the effect of adding anti-wear additives on tribological properties. In the present work, bio lubricant is obtained from pure cottonseed oil (CSO). Silicon Dioxide, a useful catalyst, is used as an anti-wear additive. Oleic Acid surface-modified Silicon Dioxide (OA-SiO2) is added at 0.25%, 0.5%, 0.75%, and 1% weight concentrations in transesterified cottonseed oil (TCSO). After the addition of OA-SiO2 nanoparticles, the improvement in the lubrication properties has been seen. A four-ball tester is used to measure the coefficient of friction (COF) and wear scar diameter (WSD) of CSO, TCSO, and additive-added TCSO as per ASTM standard D 4172. Friction and wear tests reveal that the TCSO with OA-SiO2 nanoparticles shows better tribological properties. It is observed that WSD and COF of TCSO are reduced by 11.85 % and 24.88 % respectively by adding 0.75 weight % of OA-SiO2 nanoparticles. Present work shows that TCSO, on adding OA-SiO2 additives, can be a strong alternative for mineral oil

Evaluation of Tribological Properties of Transesterified Cottonseed Oil by adding Silicon Dioxide (SiO2) as an additive

The usage of vegetable oils has increased in many applications as they possess desirable lubrication properties. However, the use is limited due to poor tribological properties. Many researchers have attempted to explore the performance of various vegetable oils and the effect of adding anti-wear additives on tribological properties. In the present work, bio lubricant is obtained from pure cottonseed oil (CSO). Silicon Dioxide, a useful catalyst, is used as an anti-wear additive. Oleic Acid surface-modified Silicon Dioxide (OA-SiO2) is added at 0.25%, 0.5%, 0.75%, and 1% weight concentrations in transesterified cottonseed oil (TCSO). After the addition of OA-SiO2 nanoparticles, the improvement in the lubrication properties has been seen. A four-ball tester is used to measure the coefficient of friction (COF) and wear scar diameter (WSD) of CSO, TCSO, and additive-added TCSO as per ASTM standard D 4172. Friction and wear tests reveal that the TCSO with OA-SiO2 nanoparticles shows better tribological properties. It is observed that WSD and COF of TCSO are reduced by 11.85 % and 24.88 % respectively by adding 0.75 weight % of OA-SiO2 nanoparticles. Present work shows that TCSO, on adding OA-SiO2 additives, can be a strong alternative for mineral oil

Cancer stem cells (CSCs) : metabolic strategies for their identification and eradication

Phenotypic and functional heterogeneity is one of the most relevant features of cancer cells within different tumor types and is responsible for treatment failure. Cancer stem cells (CSCs) are a population of cells with stem cell-like properties that are considered to be the root cause of tumor heterogeneity, because of their ability to generate the full rep- ertoire of cancer cell types. Moreover, CSCs have been invoked as the main drivers of metastatic dissemination and therapeutic resistance. As such, targeting CSCs may be a useful strategy to improve the effectiveness of classical anticancer therapies. Recently, metabolism has been considered as a relevant player in CSC biology, and indeed, onco- genic alterations trigger the metabolite-driven dissemination of CSCs. More interestingly, the action of metabolic pathways in CSC maintenance might not be merely a conse- quence of genomic alterations. Indeed, certain metabotypic phenotypes may play a causative role in maintaining the stem traits, acting as an orchestrator of stemness. Here, we review the current studies on the metabolic features of CSCs, focusing on the bio- chemical energy pathways involved in CSC maintenance and propagation. We provide a detailed overview of the plastic metabolic behavior of CSCs in response to microenvironment changes, genetic aberrations, and pharmacological stressors. In addition, we describe the potential of comprehensive metabolic approaches to identify and selectively eradicate CSCs, together with the possibility to ‘force’ CSCs within certain metabolic dependences, in order to effectively target such metabolic biochemical inflexibilities. Finally, we focus on targeting mitochondria to halt CSC dissemination and effectively eradicate cancer

Single-period ordering and pricing policies with markdown, multivariate demand and customer price sensitivity

This paper studies single-period ordering and markdown pricing policies for short lifecycle products (SLP) by considering differing customer price and time sensitivities. The SLP is assumed to have declining customer valuation (and price) over the selling season and multivariate demand, which is a function of the inventory level, price and time. Promotional markdown (in contrast to clearance markdown) becomes an indispensable part of a pricing policy in view of stock-dependent demand and isused as a mechanism for customer segmentation and price discrimination over time. To offer a realistic pricing, we consider the impact of highly price-sensitive customers who value the price of the product over its innovativeness and who act strategically by purchasing only during a'sale' at a markdown price. In this context, single-period inventory models are formulated to include markdown under two market scenarios, namely the homogenous market and thetwo-segment market a price insensitive (PI) segment; and a price sensitive (PS) segment. The assumption of non-overlapping segments is relaxed later, and PI customers are allowed to buy later on at a markdown price. The proposed profit-maximising models determine the optimal order size, initial price, markdown time, and price. The solution methods along with the optimality conditions are specified in detail. The results are discussed by using numerical examples, and model behavior with respect to parameters is presented along with the sensitivity analysis. The study reveals the benefits of market segmentation and markdown pricing which recognise high price-sensitive 'bargain hunter' customers and offers deeper discounts that yield greater profits. It also demonstrates the superiority of a markdown policy to a single pricing policy, and the benefits of considering the demand stimulating-effect of inventory

EXPERIMENTAL EVALUATION OF TEMPERATURE DISTRIBUTION IN JOURNAL BEARING OPERATING AT BOUNDARY/MIXED LUBRICATION REGIMES

The excessive rise of temperature in the journal bearing operating at boundary/mixed lubrication regimes. Journal bearing test set-up is used to measure the temperature along the circumference of the bearing specimen for different loading conditions. Here in this journal bearing of l/d ratio 1, diameter of journal is 60mm and the bearing length is 60mm, clearance is 0.06mm has been designed and tested to access the temperature rise of the bearing. The result shows that as the load on the bearing is increasing temperature also increasing. Temperature analysis of journal bearing is also done by the Ansys workbench software