Explosion characteristics of synthesised biogas at various temperatures

Biogas is considered as a valuable source of renewable energy. Indeed, it can be turned into useful energy (heat, electricity, fuel) and can contribute to reduce greenhouse gas emissions. Knowledge of its safety characteristics is a very important practical issue. Experimental investigation of synthesised biogas explosion characteristics was conducted in a 20-L sphere at various temperatures (30-70 degrees C) and at atmospheric pressure. The studied biogas was made of 50% methane (CH(4)) and 50% carbon dioxide (CO(2)). It was also saturated with humidity: this composition is frequently met in digesters during waste methanisation. There are two inert gases in biogas: water vapour and carbon dioxide. Its vapour water content rises along with temperature. The presence of these inert gases modifies considerably biogas characteristics compared to the ones of pure methane: explosion limits are lowered and beyond 70 degrees C, water vapour content is sufficient to inert the mixture. Furthermore, explosion violence (estimated with the maximum rate of pressure rise values, (dp/dt)(max)) is three times lower for biogas than for pure methane at ambient temperature.     

Determination of charge density and adsorption behaviour of DMAEA-Q-based cationic polymers by fluorimetric analysis

In wastewater and sludge treatment, cationic polymers are applied at large scale. A correct determination of the charge density and adsorption efficiency is of high importance for an economic and ecologically sound operation. Although several analytical techniques exist for charge density and polymer concentration determination, they often suffer from laborious sample pretreatment, complex instrumentation or interference from background components present in sludge. In this work, an alternative method has been studied to determine the charge density of an important series of cationic polymers used in water and sludge treatment, viz. copolymers containing quaternised dimethylaminoethylacrylate (DMAEA-Q). The method is based on the basic hydrolysis of the cationic moiety, resulting in choline chloride, which is measured by a fluorimetric technique based on the enzymatic conversion of choline. It was demonstrated that the new technique ensures a highly reliable determination of the charge density of these polymers, based on a comparison with the traditional charge titration technique and the data supplied by the manufacturer. Moreover, the specificity of the enzymatic conversion method also allows the determination of non-adsorbed polymer in conditioned sludge samples, without interference from other components. As a consequence, it enables the determination of the optimal polymer dose in practical conditioning and dewatering operations.     

Methodologie d'etude d'approvisionnement en granulats d'un grand centre urbain: Paris

The reduction of reserves in alluvial materials as well as the restricted extractions on alluvial sites and the sterilization of many deposits (industrial and urban constructions, environmental problems, ...), acutely rises the problem of the supply of aggregates for some large consumer centers, such as the Paris area. In order to insure the continuity of this supply, it is, henceforth, urgent to search for substitution materials and to focus on methods that will allow the promotion of their use in construction and facilitate their practicability. In this perspective, it is necessary to carry out studies that would aim at proposing solutions of possible substitutes to the concerned parties: quarry managers, transporters, contractors and local representatives. The present contribution specifizes the contents of multidisciplinary studies that are to be carried out and the technical proceedings to realize them.     

An aggregation procedure for the deterministic job-shop problem

A new approach is proposed in this paper to solve the job-shop scheduling problem. Instead of considering operations or machines, the construction of partial schedules by dealing with jobs, one after the other, is suggested. A partial schedule for given jobs is characterized by the sequence of their operations on each machine. The principle of the algorithm is to aggregate a new job on the current schedule, i.e. to insert its operations without altering the previous order. Two main theoretical results are presented: firstly, the selection procedure for jobs and secondly, the aggregation algorithm. Next the method is explained using a simple example. Finally, the authors present and comment on computational results for an implementation of the algorithm, for some well-known job-shop problems.     

Local treatment of breast carcinoma: when is breast-saving therapy not indicated?

Conservative treatment of breast cancer is now an accepted oncological procedure. It further allows a good functional and cosmetic result. This treatment needs more skills and time than mastectomy, as it does not only include a surgical excision but also a postoperative local radiotherapy and a sometimes difficult follow-up during many years. The contraindications for conservative breast cancer therapy are numerous and depend on factors as tumor, patient and radiotherapy. As more than 1100 patients have been treated since 1977 in our area at a single radiooncological center by a breast conserving procedure. We have confirmed or defined criteria which lead to a good local tumor control as well as to good functional and cosmetic results.     

Interleukin 12 unmasks HLA class I differences during mixed lymphocyte reaction induced interferon gamma production

We investigated the genetic control of IFN-gamma release during MLR and its relationship with TNF-alpha and IL-12. Blocking experiments demonstrated the IFN-gamma dependence of TNF-alpha production and the significant contribution of IL-12 to IFN-gamma secretion. We studied informative pairs allowing the evaluation of the relative importance of HLA class I and class II antigens. Maximal IFN-gamma secretion allowing discrimination between fully HLA different and identical subjects required 5 days. In class I different but DRB1 identical pairs, a moderate but discriminant IFN-gamma release was found. Exogenous IL-12 addition after 24 hours of preactivation by MLR resulted in a marked enhancement of IFN-gamma production at day 2. In pairs differing only by class I antigens, the discriminating capacity was significantly increased as compared to values obtained in absence of IL-12 at day 2 (p < 0.004) and at day 5 (p < 0.004). The crucial role of class I antigens on IFN-gamma release was further substantiated by the blocking action of the W6/32 mAb directed against a monomorphic epitope common to all HLA-A, -B, and -C antigens. We conclude that IFN-gamma production during MLR is under the control of class I antigens. Furthermore, exogenous IL-12 strongly amplifies their influence.     

Science behind total androgen blockade: from gene to combination therapy

Probably the most important finding in the endocrine therapy of prostate cancer is that the testicles and adrenals contribute approximately equal amounts of dihydrotestosterone (DHT), the active androgen that stimulates normal and cancerous prostatic cell growth and function. Structure of the cDNAs and genes encoding most of the enzymes responsible for the transformation of the adrenal precursor dehydroepiandrosterone (DHEA) into DHT have recently been elucidated, namely 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase, 17 beta-hydroxysteroid dehydrogenase, and 5 alpha-reductase. With the action of these enzymes, DHT is then made locally in the prostate from circulating DHEA of adrenal origin. Given such an important role of the adrenals, it is essential to use a pure antiandrogen for maximal blockade of the interaction of DHT with the androgen receptor while the testicles are blocked by orchiectomy or treatment with a luteinizing hormone-releasing hormone (LHRH) super-agonist. This combination therapy was first developed to treat advanced prostate cancer. The multicenter clinical data recently obtained confirm our original data and demonstrate the major importance of the intracrine or in situ formation of androgens in the human prostate from the inactive adrenal steroid precursors. Combination therapy thus permits, for the first time, to prolong life in advanced prostate cancer and, most importantly, offers the possibility of a major improvement in the efficacy of a curative therapy, namely, radical prostatectomy in early stage disease.     

Infection due to Klebsiella rhinoscleromatis in two patients infected with human immunodeficiency virus

Two cases of rhinoscleroma in patients infected with the human immunodeficiency virus (HIV) who had stayed in an area of endemic Klebsiella rhinoscleromatis are reported. One of the patients presented with oropharyngeal lesions, an unusual clinical picture. Both patients suffered from a major cellular immune deficiency. The importance of Klebsiella rhinoscleromatis infection in AIDS-related oropharyngeal pathology and the possible treatment of such infection in HIV-positive patients are not yet clearly established.     

Microsegregation and solidification cracking of an HR-160 weld overlay

The solidification behaviour (microsegregation, secondary phase formation, solidification temperature range) of a Haynes HR-160 weld overlay deposited on 2.25 Cr-IMo steel by gas metal arc welding has been examined. Results of differential thermal analysis and various microscopy techniques conducted on an all-weld-metal sample indicate the overlay terminates solidification at ≈1290°C by the formation of a (Ti-S)-rich second phase distributed semi-continuously along grain boundaries. The semi-continuous morphology of the second phase, combined with an increase in the solidification temperature range induced by the second phase, promoted solidification cracking in the overlay deposit. Electron probe microanalysis (EPMA) was used to reveal patterns of elemental segregation within the weld overlay. The EPMA data was used with basic solidification theory to estimate values for equilibrium distribution coefficients of major alloying elements and the values are found to be similar to results previously reported for Incoloy 909. This revised version was published online in November 2006 with corrections to the Cover Date.