Electro-thermal measurements and finite element method simulations of a spark plasma sintering device

Current, voltage and temperature measurements were performed at different points of the system to identify the controlling parameters of the spark plasma sintering (SPS) process. The very low inductance effects despite the high intensity current circulating through the SPS column justifies the use of Joule heating to characterize the phenomenon. The measurements also enabled the improvement and validation of an earlier electro-thermal numerical model developed using the finite element method (FEM). It has been shown that the electrical resistivity and the thermal conductivity of each of the elements are crucial parameters for the simulations. These parameters strongly modify the current modeled, thereby affecting the temperature distribution throughout the SPS column.     

Nonparametric modeling of carbon prices

This paper constitutes the first exercise of nonparametric modeling applied to carbon markets. The framework of analysis is carefully detailed, and the empirical application unfolds in the case of BlueNext spot and ECX futures prices. The data is gathered in daily frequency from April 2005 to April 2010. First, we document the presence of strong nonlinearities in the conditional mean functions. Second, the conditional volatility functions reveal an asymmetric and heteroskedastic behavior which is dramatically different between carbon spot and futures logreturns. The results for spot prices are also robust to subsamples' decomposition. Third, we show in an out-of-sample forecasting exercise that nonparametric modeling allows reducing the prediction error by almost 15% compared to linear AR models. This latter result is confirmed by the Diebold–Mariano pairwise test statistic.     

Rheology of fiber filled polymer melts: Role of fiber‐fiber interactions and polymer‐fiber coupling

An experimental study and a numerical modeling analysis are carried out to examine the effects of fiber‐fiber interactions and coupling between fiber orientation and polymer chains conformation on the rheological properties of fiber suspensions. The experimental study allowed examination of large fiber volume fractions up to 35% over a range of shear rates that spans eight decades. This study confirmed already known results and led to new ones. In particular, a peak in the steady shear viscosity at the low shear rate region is observed at large volume fractions. Furthermore, new results regarding the applicability of the Cox‐Merz rule, the behavior of the damping factor, and the end pressure drops are reported, and physical interpretations are proposed. The results of the numerical modeling showed that it is necessary to account for the polymer‐fiber coupling factor to obtain a good fit between the model predictions and the experimental measurements. Comparisons between the model predictions and the experimental measurements allowed study of the variation of the parameters that govern the fiber‐fiber interactions and the polymer‐fiber coupling with the properties of the suspension and the flow. POLYM. ENG. SCI., 45:385–399, 2005. © 2005 Society of Plastics Engineers     

Transition to adulthood as a parent-youth project: Governance transfer, career promotion, and relational processes.

This study determined how youth (ages 17-21) and their parents jointly constructed and acted on goals and strategies pertinent to the transition to adulthood. Twenty parent-youth dyads were followed over an 8-month period using the qualitative action-project method. Data included their joint conversations, video recall of internal processes, self-monitoring logs, and researcher telephone monitoring. Detailed and repeated analysis of elements, functional steps, and goals resulted in the identification of an explicit joint project for each dyad that the participants saw as pertinent to the transition to adulthood. These projects referred broadly to the youth development of identity and social inclusion in the adult world and included the specific projects of career promotion, governance transfer, and parent-youth relational processes. The findings illustrate the complexity of the transition-to-adulthood process as well as its joint construction by parent and youth. Implications for practice include identifying and following the joint parent-youth transition project. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In situ Li nuclear magnetic resonance observation of the electrochemical intercalation of lithium in graphite; 1st cycle

We show a continuous, in situ nuclear magnetic resonance (NMR) experiment on a lithium/graphite electrochemical cell. The objective is to study a commercial graphite currently used as negative electrodes in secondary lithium batteries. A plastic cell is made, with metallic lithium as the counter electrode and 1 mol dm⁻³ LiPF₆/ethylene carbonate (EC) + diethylcarbonate (DEC) electrolyte. The reversible capacity is 346 mAh/g and the irreversible capacity 55 mAh/g, measured in the galvanostatic mode, at a rate of C/20 (20 h for the theoretical capacity of LiC₆) for the first cycle. We show the first discharge and the first charge of the cell inside the magnet and record simultaneously and regularly (in real time) static ⁷Li NMR spectra. As expected, we observe the quadrupolar lines characteristic of the lithium graphite intercalation compounds (GICs). During the discharge, the two types of in-plane densities of Li are successively found that correspond to the dilute LiC₉, then to the dense LiC₆ configuration; during the charge, we observe the successive decrease of these states. The galvanostatic curve helps to identify the stages NMR signature and the stages coexistence.     

Greywater recycling in Vietnam — Application of the HUBER MBR process

Greywater is the part of domestic wastewater that is free of faeces. The volume and concentration of this separately collected wastewater flow depend on the consumer behaviour and vary according to its source. The average amount of greywater produced per day in a German household is 70 l per person, which is more than 50% of the total wastewater production [5]. This figure corresponds with the average figures provided for Chinese households (80 l per person/day, GB/T 50331-2002), but significantly exceeds the South African average of 20 l per person and day [1].Compared to domestic wastewater, greywater generally contains less organic pollutants, less nutrients but a high amount of tensides. The effluent from bath tubs, showers or wash hand basins contains for example a by approx. two decimal orders lower number of total and faecal coliform bacteria (Escherichiacoli) [2] and [6].Due to its relatively low content of pollutants, greywater is easy to treat with MBRs. The pollutants contained are decomposed by the bacteria of the activated sludge tank. The following membrane filtration unit separates the treated greywater from the activated sludge. The treated greywater is of high quality and hygienically safe so that it can be reused, alone or combined with rain water, for toilet flushing water, laundry washing or for irrigation purposes.Within the scope of the SANSED II research project HUBER has been successful in adapting the MBR system for greywater treatment to the specific conditions in Vietnam and testing the system in operation in a small city in the Mekong delta, South Vietnam. The wastewater from kitchen sinks and the bathrooms of a dormitory on the campus of Can Tho University was clarified in the HUBER GreyUse^® plant over a period of three months. The project aim was the production of high quality service water from greywater for safe reuse as toilet flush water.     

Carbon nanotubes for interconnects in future integrated circuits: The challenge of the density

A CVD process with a high density of CNTs has been developed on doped silicon material thanks to plasma pre-treatment of the catalyst. With this process small diameter double and triple wall CNTs with an average diameter of 3.8 nm have been grown. The density of the best materials on blanket substrate is larger than 10¹² cm^? 2. These materials have been successfully integrated in via holes with a diameter ranging between 1 µm and 0.3 µm with an equivalent density. In 140 nm hole diameter large 70 nm bundle formations have been observed. In these bundles a density of CNT walls close to 10¹³ cm^? 2 has been estimated.     

Improvement of measurement techniques for damping induced by micro-sliding

This paper deals with the damping caused by friction in joints. A new test bench is presented and justified by comparisons made with devices described in the literature. The purpose of this academic bench is to measure the damping induced by partial slip and friction in a planar joint. Moreover, allows uncoupling normal static and dynamic tangential forces. A new method for so-called stopped-sine excitation was developed. It allows more precise monitoring of the evolution of the vibration frequency and damping of non-linear modes. This method is associated with piezoelectric exciters for greater efficiency when stopping excitation. A large number of experimental results are presented and discussed. They are used to characterize the damping induced by micro-sliding in the bonds.     

Prolactin and growth hormone mRNA and protein characterization in SMtTW rat pituitary tumours

During human pregnancy, plasma corticotrophin-releasing hormone (CRH) levels rise from undetectable amounts prior to 20 weeks gestation to reach a peak near term, with an exponential rise during the final 5 weeks of gestation. Within hours of parturition plasma levels fall and rapidly return to undetectable baseline measurements. The appearance of CRH in maternal plasma has been attributed to the placental production and subsequent release into the maternal circulation of this hormone. Previous studies have shown that human placental extracts contain a CRH-like peptide and this has been reinforced by the observation of CRH mRNA in placental tissue. Initial attempts to identify the site of production using immunocytochemistry have led to conflicting results. This study attempts to clarify this situation by using a variety of highly specific anti-CRH antibodies to show the cellular expression of placental CRH. Intense CRH staining was observed in the syncytial trophoblast layer in first trimester and term chorionic villi, whilst the underlying cytotrophoblast appeared to be negative. The fetal membranes also contained CRH immunoreactivity with the cytotrophoblast cells in the chorionic membrane displaying the most intense staining. CRH immunoactivity was also observed in the amnion and in some cells in the decidua. As a model of cellular CRH expression, cytotrophoblast cells from term chorionic membrane were isolated and shown to be positive for CRH.