Modeling of fermentative hydrogen production from sweet sorghum extract based on modified ADM1

The Anaerobic digestion model 1 (ADM1) framework can be used to predict fermentative hydrogen production, since the latter is directly related to the acidogenic stage of the anaerobic digestion process. In this study, the ADM1 model framework was used to simulate and predict the process of fermentative hydrogen production from the extractable sugars of sweet sorghum biomass. Kinetic parameters for sugars’ consumption and yield coefficients of acetic, propionic and butyric acid production were estimated using the experimental data obtained from the steady states of a CSTR. Batch experiments were used for kinetic parameter validation. Since the ADM1 does not account for metabolic products such as lactic acid and ethanol that are crucial during the fermentative hydrogen production process, the structure of the model was modified to include lactate and ethanol among the metabolites and to improve the predictions. The modified ADM1 simulated satisfactorily batch experiments although further modifications could be made in order to further improve the predictions for the hydrogenogenic process.     

Classical and alternative fuel mix optimization in cement production using mathematical programming

In this paper a systematic methodology is presented for the simultaneous optimal selection of raw materials, fossil fuels and alternative fuels in cement production. The aim is to offer a generic mathematical formulation that can be used as the basis for developing case specific mathematical formulations that can assist the strategic decision-making process. The mathematical model presented takes into consideration the essential elements of a cement plant operation. The final formulation is a mixed integer linear programming problem that aims at minimizing the overall operating cost. A realistic case study is presented which demonstrates the usefulness of the proposed mathematical programming methodology.     

Information and competitive equilibria in the housing market

This paper derives necessary and sufficient conditions for the existence and occurrence likelihood of competitive equilibria in urban land and housing markets: (i) when there is imperfect information causing costly search trips and (ii) when land and housing are differentiated according to between‐zone and within‐zone heterogeneity. Such competitive equilibria are contingent on the possibility that consumers spill over into the markets of less preferred zones. The main conclusions are that markets tend to be partitioned into homogeneous sub‐groups and when they do not, heterogeneity may hamper the effectiveness of search and hence work against the existence of competitive equilibria.     

Development and evaluation of alternative processes for sterilization and deodorization of cork barks and natural cork stoppers

Cork taint, one of the most known off-flavours in wine, is usually attributed to the presence of the aromatic compound 2,4,6-trichloroanisole (2,4,6-TCA) in cork stoppers made from the bark of the cork oak, Quercus suber. There are many major chemical/biochemical pathways through which 2,4,6-TCA can be formed during cork production. The estimated incidence of cork-tainted wine bottles ranges from 2–to 7%, costing global wine industry approximately US$ 10 billion annually. During this study, a laboratory-scale system was designed and constructed, to efficiently treat cork bark and stopper samples using ozone and/or other sterilizing gases, such as steam, via sequential application of pulsed vacuum–pressure cycles. The developed physicochemical processes were studied and evaluated in order to achieve both sterilization conditions and 2,4,6-TCA removal without affecting the mechanical and bottling properties of cork. According to the results, the application of ozone alone seems to be a promising treatment method for cork barks. However, the pulsed treatment ensures both sufficient removal (99%) of both bacteria and moulds from cork stoppers when combined with ozone or steam and satisfactory deodorization of cork stoppers achieving high percentages (90%) of 2,4,6-TCA removal when combined with steam. The operating cost of each alternative process (plain or pulsed, with or without ozone and/or steam) was estimated and compared, in laboratory scale, for the selection of the most efficient process, taking into account technicoeconomical aspects.     

Rapid prototyping for orthopaedic surgery

During pregnancy, mouse uterine epithelial cells produce and secrete a large amount of macrophage colony-stimulating factor (M-CSF/CSF-1). Macrophages accumulate and proliferate in the undecidualized endometrium of the pregnant uterus. Observations showed that macrophages expressed scavenger receptor class A (type I and type II) and class C (macrosialin). Scavenger receptors appeared to be involved in the removal of apoptotic cells in the degenerated decidual tissue. The expression of class A and class C scavenger receptor mRNAs in the uterus of pregnant mice was elevated but the expression of class B scavenger receptor (CD36) mRNA was similar to that of non-pregnant mice. The expression of various cytokines and chemokines, including M-CSF, monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein 1-alpha (MIP1-alpha), was enhanced in the uterus of pregnant mice, suggesting that these molecules regulate macrophage chemotaxis and immunological function in the uterus. These findings imply that the pregnant uterus provides a microenvironment for the recruitment, differentiation, and proliferation of macrophages and the regulation of scavenger receptor and cytokine expression for a successful pregnancy.