King Saud University

About: King Saud University is a education organization based out in Riyadh, Saudi Arabia. It is known for research contribution in the topics: Population & Adsorption. The organization has 22106 authors who have published 57908 publications receiving 1042234 citations. The organization is also known as: Riyadh University.

Recent development on surface texturing in enhancing tribological performance of bearing sliders

Abstract: Surface texturing is a surface modification approach, resulting in an improvement in tribological performance such as friction and wear resistance. Surface texturing can be performed either as a protruded or recessed asperity, with the latter being more popular due to advantages in terms of micro-lubrication and ease of manufacturing. There are a number of ways of material preparation for surface texturing, with the laser surface texturing being the most popular because of its flexibility and high accuracy. The performance of textured surface depends on the geometrical characteristics of the surface texture and the operating condition of the bearing components. In hydrodynamic and mixed lubrication, microcavity in negative surface texture acts as a reservoir for fluid lubricant, while in boundary lubrication, it traps wear particles to reduce further abrasion. In the past, tremendous amount of research effort has been put into the study of surface texturing, with an aim to investigate the underlying effect of surface texturing on tribological performance. This paper presents a critical review of research and development on surface texturing over the past decades, highlighting design, optimization and fabrication of surface texture, and their effects on tribological performance in terms of friction and load bearing capacity under different lubrication regimes. Numerical modelling approaches involving Reynolds and Navier–Stokes equations employed to understand and determine the tribological behaviour are discussed and compared with respect to experimental investigations. Thin film coatings on textured surface have been found to be a promising means to further reduce friction and increase wear life.

Depth of invasion, tumor budding, and worst pattern of invasion: Prognostic indicators in early-stage oral tongue cancer

Abstract: Background Oral (mobile) tongue squamous cell carcinoma (SCC) is characterized by a highly variable prognosis in early-stage disease (T1/T2 N0M0). The ability to classify early oral tongue SCCs into low-risk and high-risk categories would represent a major advancement in their management. Methods Depth of invasion, tumor budding, histologic risk-assessment score (HRS), and cancer-associated fibroblast (CAF) density were studied in 233 cases of T1/T2 N0M0 oral tongue SCC managed in 5 university hospitals in Finland. Results Tumor budding (≥5 clusters at the invasive front of the tumor) and depth of invasion (≥4 mm) were associated with poor prognosis in patients with early oral tongue SCC (hazard ratio [HR], 2.04; 95% confidence interval [CI], 1.17–3.55; HR, 2.55; 95% CI, 1.25–5.20, respectively) after multivariate analysis. The HRS and CAF density did not predict survival. However, high-risk worst pattern of invasion (WPOI), a component of HRS, was also an independent prognostic factor (HR, 4.47; 95% CI, 1.59–12.51). Conclusion Analyzing the depth of invasion, tumor budding, and/or WPOI in prognostication and treatment planning of T1/T2 N0M0 oral tongue SCC is recommended. © 2013 The Authors. Head Neck 36: 811–818, 2014

Uniform Ordered Two-Dimensional Mesoporous TiO2 Nanosheets from Hydrothermal-Induced Solvent-Confined Monomicelle Assembly

Abstract: Two-dimensional (2D) nanomaterials have been the focus of substantial research interest recently owing to their fascinating and excellent properties. However, 2D porous materials have remained quite rare due to the difficulty of creating pores in 2D nanostructures. Here, we have synthesized a novel type of single-layered 2D mesoporous TiO2 nanosheets with very uniform size and thickness as well as ordered mesostructure from an unprecedented hydrothermal-induced solvent-confined assembly approach. The F127/TiO2 spherical monomicelles are first formed and redispersed in ethanol and glycerol, followed by a hydrothermal treatment to assemble these subunits into single-layered 2D mesostructure owing to the confinement effect of highly adhered glycerol solvent. The obtained 2D mesoporous TiO2 nanosheets have a relative mean size at around 500 × 500 nm and can be randomly stacked into a bulk. The TiO2 nanosheets possess only one layer of ordered mesopores with a pore size of 4.0 nm, a very high surface area of 2...

Blockchain-Based Agri-Food Supply Chain: A Complete Solution

Abstract: Supply chains are evolving into automated and highly complex networks and are becoming an important source of potential benefits in the modern world. At the same time, consumers are now more interested in food product quality. However, it is challenging to track the provenance of data and maintain its traceability throughout the supply chain network. The traditional supply chains are centralized and they depend on a third party for trading. These centralized systems lack transparency, accountability and auditability. In our proposed solution, we have presented a complete solution for blockchain-based Agriculture and Food (Agri-Food) supply chain. It leverages the key features of blockchain and smart contracts, deployed over ethereum blockchain network. Although blockchain provides immutability of data and records in the network, it still fails to solve some major problems in supply chain management like credibility of the involved entities, accountability of the trading process and traceability of the products. Therefore, there is a need of a reliable system that ensures traceability, trust and delivery mechanism in Agri-Food supply chain. In the proposed system, all transactions are written to blockchain which ultimately uploads the data to Interplanetary File Storage System (IPFS). The storage system returns a hash of the data which is stored on blockchain and ensures efficient, secure and reliable solution. Our system provides smart contracts along with their algorithms to show interaction of entities in the system. Furthermore, simulations and evaluation of smart contracts along with the security and vulnerability analyses are also presented in this work.