Biolubricants: Raw materials,chemical modifications and environmental benefits

The depletion of the world's crude oil reserve, increasing crude oil prices, and issues related to conservation have brought about renewed interest in the use of bio‐based materials. Emphasis on the development of renewable, biodegradable, and environmentally friendly industrial fluids, such as lubricants, has resulted in the widespread use of natural oils and fats for non‐edible purposes. In this study, we have reviewed the available literature and recently published data related to bio‐based raw materials and the chemical modifications of raw materials. Additionally, we have analyzed the impacts and benefits of the use of bio‐based raw materials as functional fluids or biolubricants. The term biolubricants applies to all lubricants, which are both rapidly biodegradable and non‐toxic to humans and other living organisms, especially in aquatic environments. Biodegradability provides an indication of the persistence of the substance in the environment and is the yardstick for assessing the eco‐friendliness of substances. Scientists are discovering economical and safe ways to improve the properties of biolubricants, such as increasing their poor oxidative stability and decreasing high pour points. “Green” biolubricants must be used for all applications where there is an environmental risk.     

Rheological properties of model dairy emulsions as affected by high pressure homogenization

The aim of this work was to evaluate the effect of different homogenization pressures on the rheological properties of model dairy emulsions. Solutions of sodium caseinate and whey protein concentrate at 2% + 1% and 2% + 2% (w/v) were emulsified with milk fat at the final contents of 5%, 8% and 15% (w/v). Raw and pasteurized emulsions were subjected to conventional (15/3 MPa) and high pressure (97/3 MPa and 147/3 MPa) homogenization. Differences in viscosity were observed according to fat content, protein ratio, heat treatment and pressure homogenization conditions. Gel networks formed in 8% and 15% fat content emulsions after pasteurization and high pressure homogenization. Gel strength was mostly affected by protein and fat contents.Dynamic high pressure may be used to produce emulsion gels with modulated structures which could be exploited low fat formulations.Industrial relevanceTexture influences people's acceptance of food and may be more important than the flavor in some products. Gelation of emulsions was observed after pasteurization and high pressure homogenization treatments, depending on fat and protein contents. Dynamic high pressure may be an alternative tool to improve viscoelastic properties and mouth feel of emulsions by providing a weak gel structure in the system. These characteristics can be exploited for low fat and low additive formulations.     

Synthesis of poly(vinyl alcohol)‐graft‐poly(ε‐caprolactone) and poly(vinyl alcohol)‐graft‐poly(lactide) in melt with magnesium hydride as catalyst

Grafting of poly(ε‐caprolactone) (PCL) and poly(lactide) (PLA) chains on poly(vinyl alcohol) backbone (PVA degree of hydrolysis 99%) was investigated using MgH₂ environmental catalyst and melt‐grown ring‐opening polymerization (ROP) of ε‐caprolactone (CL) and L ‐lactide (LA), that avoiding undesirable toxic catalyst and solvent. The ability of MgH₂ as catalyst as well as yield of reaction were discussed according to various PVA/CL/MgH₂ and PVA/LA/MgH₂ ratio. PVA‐g‐PCL and PVA‐g‐PLA were characterized by ¹H‐ and ¹³C‐NMR, DSC, SEC, IR. For graft copolymers easily soluble in tetrahydrofuran (THF) or chloroform, wettability and surface energy of cast film varied in relation with the length and number of hydrophobic chains. Aqueous solution of micelle‐like particles was realized by dissolution in THF then addition of water. Critical micelle concentration (CMC) decreased with hydrophobic chains. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A survey of mobile and wireless technologies for augmented reality systems

Recent advances in hardware and software for mobile computing have enabled a new breed of mobile augmented reality (AR) systems and applications. A new breed of computing called ‘augmented ubiquitous computing’ has resulted from the convergence of wearable computing, wireless networking, and mobile AR interfaces. In this paper, we provide a survey of different mobile and wireless technologies and how they have impact AR. Our goal is to place them into different categories so that it becomes easier to understand the state of art and to help identify new directions of research. Copyright © 2008 John Wiley & Sons, Ltd.     

New antistatic charge and electromagnetic shielding effectiveness from conductive epoxy resin/plasticized carbon black composites

Recently, there is an increasing interest in electromagnetic interference shielding due to the rapid increase in electromagnetic pollution and the wide use of commercial and military products. Conducting polymer composites were prepared in the presence of epoxy resin and plasticized carbon black (CB). The structural characteristics of the composites were examined by means of scanning electron microscopy, cross linking density, and interparticle distance among conductive particles. The mechanical properties such as Young's modulus, elongation at break, and hardness of the composites were investigated as a function of CB content. The results indicated that CB could improve the composite microstructure. The higher mechanical behavior than green epoxy can be attributed to the interaction between CB particles and epoxy resin. The conductivity, mobility carriers, and number of charges of the composites at room temperature were found to be dependent on CB content. The applicability of the composites to antistatic charge dissipation was examined. Dependence of the microwave properties of the epoxy/CB composites on the volume fraction of CB particles and frequency were studied. Moreover the permittivity as a function of frequency of the composites was studied. The electromagnetic wave shielding of epoxy/CB composites is dominant by both reflection and absorption. Composites can find applications in antistatic charge dissipation and in suppression of electromagnetic interference and stealth technology. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers