Performance and reliability of advanced High-K/Metal gate stacks (Invited Paper)

This paper provides a systematic study of mobility performance and Bias Temperature Instabilities (BTI) reliability in advanced dielectrics stacks. By studying a large variety of dielectric stacks we clearly demonstrate that mobility performance, interface defects Nit and Negative BTI reliability are strongly correlated. All are affected by nitrogen species N which is clearly identified as the main mobility killer when it reaches unintentionally the Si interface during the deposition of nitrided gates or the nitridation steps.     

Modelling solar effects on the heat and mass transfer in a street canyon, a simplified approach

In urban areas, the climatic loads on buildings in summer conditions are largely affected by solar radiation. In this paper a modified simplified method for radiant interchange determination is used in a solar energy study. The good agreement with the radiosity method allows one to use this simplified method in the street canyon case. In a building pilot study, parametric analysis and building thermal behaviour can be assessed by simplified models which are useful for long-period simulation. Then this radiant interchange model is introduced in a zonal model of a canyon street and performed with a variable climatic conditions show case. The solar radiation is the only driving force in the street air movement. The interest of such approach for complex coupled phenomena studies is highlighted by obtained results and the assessment of variable climatic loads for different building zones can be considered with the model detailed herein. Future developments are planned in order to improve simulation accuracy by the addition of other local phenomena.     

Assessment of temperature gradient effects on moisture transfer through thermogradient coefficient

The objective of this paper is to describe moisture transfer through porous material due to temperature gradient. For that purpose, an experimental device was set up to assess moisture flux under isothermal and non-isothermal conditions. This involves placing samples between two compartments with controlled air conditions and monitoring relative humidity and temperature profiles inside the samples over the time. To interpret these results, we proposed to express the mass flux in terms of two driving potentials: water vapor content gradient and temperature gradient. Accordingly, thermogradient coefficient was calculated and discussed. It represents the difference between the moisture fluxes under isothermal and non-isothermal conditions. The impact of temperature gradient on the moisture buffer value (MBV) was also considered through a numerical experiment taking into account thermogradient coefficient. Results show that temperature gradient implies a relative variation of the MBV for about 14%. Thus, it would be better to consider non-isothermal conditions for its assessment.     

Engineering the Surface Chemistry and Morphology of Polymeric Carbon Nitrides Towards Greener Heterogeneous Catalysts for Biodiesel Synthesis

Biodiesel remains one of the most promising alternatives to replace fossil fuel-derived petrodiesel. Nonetheless, conventional biodiesel synthesis relies on homogeneous alkali-based catalysts that involve long and tedious purification steps , increasing biodiesel production costs. Heterogeneous catalysts have emerged as promising alternatives to circumvent these drawbacks, as they can easily be recovered and reused. Herein, polymeric carbon nitride dots and nanosheets are synthesized through a solid-phase reaction between urea and sodium citrate. Their morphology and surface chemistry are tuned by varying the precursor's ratio, and the materials are investigated as catalysts in the transesterification reaction of canola oil to biodiesel. A conversion of > 98% is achieved using a 5 wt% catalyst loading, oil to methanol ratio of 1:36 at 90 °C for 4 h, with the performance maintained over at least five reuse cycles. In addition, the effect of the transesterification reaction parameters on the reaction kinetics is evaluated, which follows a pseudo-first-order (PFO) regime. Combined with a deep understanding of the catalyst's surface, these results have allowed us to propose a reaction mechanism similar to the one observed for homogenous alkali catalysts. These carbon nitride-based nanoparticles offer a metal-free and cost-effective alternative to conventional homogeneous and metal-based heterogeneous catalysts.     

Multi‐agent distributed intelligent system based on fuzzy decision making

Generally decision making for solving ill‐structured problems in DSS takes place in uncertain situations. The main drawbacks of existing traditional DSS are inefficiencies associated with dealing with complex models and large databases. Usually a fuzzy DSS has many input variables and, hence, its knowledge base, containing the totality of fuzzy rules, is very large. Large rule base leads to disadvantages in speed, reliability, and complexity of DSS. This paper introduces an alternative concept for designing fuzzy DSS based on multi‐agent distributed artificial intelligent technology and fuzzy decision making. The main idea of the proposed DSS is based on granulation of the overall system intelligence between cooperative autonomous intelligent agents capable of competing and cooperating with each other in order to propose a total solution to the problem and organization (combining individual solutions) of the proposed solution into the final solution. It is supposed that every agent in DSS is characterized by a set of fuzzy criteria of unequal importance and definition of a “winner” agent is based on multi‐criteria fuzzy decision making involving unequal objectives. © 2000 John Wiley & Sons, Inc.     

Plasma‐modified poly(vinyl alcohol) membranes for the dehydrationof ethanol

Non‐porous poly(vinyl alcohol) (PVA) membranes prepared by a cast‐evaporating technique were covered with an allyl alcohol or acrylic acid plasma‐polymerized layer. The wettability and the surface energy, as well as the chemical nature of the deposit, were assigned by X‐ray photoelectron spectroscopy (XPS) and Fourier‐transform infrared spectroscopy (FTIR). The ability of the modified membranes for dehydrating the water/ethanol azeotropic mixture by pervaporation was studied at 25, 40 and 60 °C. The best selectivity (α = 250 at 25 °C) was obtained in the case of the allyl alcohol plasma treatment. The results obtained are discussed on the basis of the hydrophilicity as well as in terms of the weakly crosslinked superficial layer that favoured the membrane swelling. Copyright © 2003 Society of Chemical Industry     

Extraction and functional properties of gelatin from the skin of cuttlefish (Sepia officinalis) using smooth hound crude acid protease-aided process

The characteristics and functional properties of gelatin from skin cuttlefish (Sepia officinalis) were investigated and compared to those of halal bovine gelatin (HBG). The gelatin extraction efficiency was improved by an acid-swelling process in the presence of smooth hound crude acid protease extract (SHCAP). The yields of gelatins from cuttlefish skin after 48 h with acid and with crude acid protease (15 units/g alkaline-treated skin) were 2.21% and 7.84%, respectively. The gelatin from skin cuttlefish had high protein (91.35%) but low fat (0.28%) contents. Compared to HBG, the cuttlefish-skin gelatin (CSG) has different amino acids composition than halal bovine gelatin. CSG contained slightly low hydroxyproline and proline (180‰) than HBG (219‰), whereas the content of serine was higher (49‰ versus 29‰). The gel strength of the gelatin gel from CSG (181 g) was lower than that of HBG (259 g) (p < 0.05) possibly due to lower hydroxyproline content. Cuttlefish-skin gelatin exhibited a similar emulsifying activity but greater emulsifying and foam stability than the halal bovine gelatin (p < 0.05). Foam formation ability, foam stability and water-holding capacity of CSG were slightly lower than those of the HBG, but fat-binding capacity was higher in the cuttlefish gelatin.     

Changes in phytate and minerals during germination and cooking of fenugreek seeds

The effects of germination, cooking and roasting on the phytic acid content, total phosphorus, water soluble inorganic phosphorus and mineral content of fenugreek seeds have been estimated. After 96 h germination, the dry weight of fenugreek seeds decreased while total ash content increased. Phytase and phosphatase activity of the ungerminated and germinated seeds have been assayed. It is observed that during germination the phytic acid values diminish and the water soluble inorganic phosphorus values increase. Phytase activity which is absent in the ungerminated seeds originates after germination and the phosphatase activity is increased in the germinated seeds. Heat treatment practised in cooking and roasting fenugreek seeds has less effect on phytate elimination than does germination. Changes in calcium, magnesium, iron, manganese, copper and zinc are found to be dependent on the loss of dry weight which occurs during processing of fenugreek seeds.