Slurry Hydroconversion of Solid Kraft Lignin to Liquid Products Using Molybdenum- and Iron-Based Catalysts

Kraft lignin is an abundantly available and largely underutilized renewable material with potential for production of biobased fuels and chemicals. This study reports the results of a series of slurry hydroprocessing experiments with the aim of converting solid Kraft lignin to liquid products suitable for downstream refining in more conventional reactors. Experiments reported in this study were conducted by feeding a lignin slurry to an already hot, liquid-filled reactor to provide momentaneous heating of the lignin to the reaction temperature. This modified batch procedure provided superior results compared to the regular batch experiments, likely since unwanted repolymerization and condensation reactions of the lignin during the heating phase was avoided, and was therefore used for most of the experiments reported. Experiments were performed using both an unsupported Mo-sulfide catalyst and Fe-based catalysts (bauxite and hematite) at varied reaction temperatures, pressures, and catalyst loadings. The use of Mo-sulfide (0.1% Mo of the entire feed mass) at 425 \ub0C and 50 bar resulted in complete conversion of the Kraft lignin to nonsolid products. Very high conversions (>95%) could also be achieved with both sulfided bauxite or hematite at the same temperature and pressure, but this required much higher catalyst loadings (6.25% bauxite or 4.3% hematite of the total feed mass), and around 99% conversion could be achieved at higher temperatures but at the expense of much higher gas yields. Although requiring much higher loadings, the results in this study suggest that comparatively nonexpensive Fe-based catalysts may be an attractive alternative for a slurry-based process aimed at the hydroconversion of solid lignin to liquid products. Possible implementation strategies for a slurry-based hydroconversion process are proposed and discussed

Cheminformatics-aided pharmacovigilance: application to Stevens-Johnson Syndrome

Objective Quantitative Structure-Activity Relationship (QSAR) models can predict adverse drug reactions (ADRs), and thus provide early warnings of potential hazards. Timely identification of potential safety concerns could protect patients and aid early diagnosis of ADRs among the exposed. Our objective was to determine whether global spontaneous reporting patterns might allow chemical substructures associated with Stevens-Johnson Syndrome (SJS) to be identified and utilized for ADR prediction by QSAR models

Massive star formation in Wolf-Rayet galaxies. V: Star formation rates, masses and the importance of galaxy interactions

(Abridged) We have performed a comprehensive analysis of a sample of 20 starburst galaxies, most of them classified as Wolf-Rayet galaxies. In this paper, the last of the series, we analyze the global properties of our galaxy sample using multiwavelength data (X-ray, FUV, optical, NIR, FIR, and radio). The agreement between our Ha-based SFR and those provided by indicators at other wavelengths is remarkable, but we consider that the new Ha-based calibration provided by Calzetti et al. (2007) should be preferred over older calibrations. The FUV-based SFR provides a powerful tool to analyze the star-formation activity in both global and local scales independently to the Ha emission. We provide empirical relationships between the ionized gas mass, neutral gas mass, dust mass, stellar mass, and dynamical mass with the B-luminosity. Although all mass estimations increase with increasing luminosity, we find important deviations to the general trend in some objects, that seem to be consequence of their particular evolutionary histories. We investigate the mass-metallicity relations and conclude that both the nature and the star-formation history are needed to understand the relationships between both properties. The majority of the galaxies follow a Schmidt-Kennicutt scaling law of star-formation that agrees with that reported in individual star-forming regions within M~51 but not with that found in normal spiral galaxies. We found a relation between the reddening coefficient and the warm dust mass indicating that the extinction is mainly internal to the galaxies. Considering all data, we found that 17 up to 20 galaxies are clearly interacting or merging with low-luminosity dwarf objects or HI clouds. We conclude that interactions do play a fundamental role in the triggering mechanism of the strong star-formation activity observed in dwarf starburst galaxies.Comment: 33 pages, 21 figures, accepted for publication by A&

Fetal programming and subsequent risks in adulthood : Are the associations confounded by genetic and/or environmental factors?

The fetal origins hypothesis proposes that fetal growth is inversely associated with subsequent adult disease risk. The objective of this thesis was to investigate whether familial (shared environmental and genetic) factors confound the association between birth weight and risks of hypertension, low intellectual performance, and type-2 diabetes. We performed three large population-based studies of singleton born boys conscripted for military service (Papers I-III) to investigate the association between birth characteristics and risk of high systolic blood pressure and low intellectual performance in early adulthood. We found that males born light for gestational age (<-2 standard deviation scores [SDs]) were at a 14 % increased risk of high systolic blood pressure and 22 % increased risk of low intellectual performance, after adjusting for social and maternal factors (Papers I and II). In sibling analyses we found that the association between birth weight for gestational age and risk of high systolic blood pressure was similar within and between full siblings. In contrast, the associations between birth weight, birth length, and head circumference and risks of low intellectual performance were weaker within siblings, compared with between siblings. Thus, whereas the association between birth weight for gestational age and risk of high systolic blood pressure is independent of familial factors, the associations between measurements of fetal growth and risk of low intellectual performance are at least partly confounded by familial factors. Furthermore, it appears that during early stages of gestation, birth length and head circumference is of greater concern for intellectual development than birth weight, whose importance may increase with gestation (Paper III). To investigate if the association between birth weight and risk of hypertension in adulthood is confounded by shared environmental or genetic factors, we performed a study on the association in a sample of middle aged and elderly Swedish like-sexed twins. We found that a 500-g decrease in birth weight was associated with a 42 % increased risk of hypertension in the whole cohort of twins. Co-twin control analyses showed that corresponding risks within dizygotic and monozygotic twin pairs were 34 % and 74 %, respectively. The results suggest that the inverse association between birth weight and hypertension is independent of shared familial environment and genetic factors. To assess whether there is a familial link between birth weight and type-2 diabetes, we studied the association between offspring birth weight for gestational age and parental risk of type-2 diabetes in the twin sample used in Paper IV. Decreasing offspring birth weight for gestational age (with 1 SDs) was associated with a 72 % increased risk of type-2 diabetes among fathers, and 57 % decreased risk among mothers, independent of measured social factors. Furthermore, we found that both the mother s and father s risk of type-2 diabetes associated with decreasing offspring birth weight was similar within and between twin pairs, although slightly smaller within pairs effects were found among fathers. Thus, the well established association between paternal type-2 diabetes and offspring birth weight seems to primarily be due to unique environmental factors experienced by each twin and its offspring

Dimensioning of inventory levels in a VMI relationship at Atlas Copco Tools AB

VMI (Vendor managed inventory) is a relationship between vendor and customer where the vendor manage the customer’s inventory. After the first VMI rollout in February 2006, Atlas Copco identified problems with the definition of the max – and min inventory levels. The purpose of the thesis is to redefine the max – and min levels and identify the important variables in inventory dimensioning. Atlas Copco Tools VMI relation with the vendor Enics has been studied. Two general types of VMI relationships have been detected from the empirical study. The consignment inventory has been identified to be a self regulated system. In the case where the customer owns their own inventory there is a larger incentive for the customer to control the inventory level with a max level. The results are divided into two sections: Inventory cut up and inventory variables. The max – and min system should be redefined as a max – safety level system. The reason is that the safety level is defined to cover variations in demand and therefore should the vendor not be judged on basis on the ability to keep the inventory level above the safety level. The target level will work as a cycle stock and vary directly with lot size. To optimize the target level the lot size must be optimized. The authors recommend that lot size is determined by an adjustment of the EOQ (Economic Order Quanity) model. This results in an inventory level that shares logistics costs between the participants in the VMI relationship. The adjustment will be based on the delivery batch sizes to help optimize transportation planning and warehouse handling of full pallet at the distribution warehouse. The trade off between the deviation from the EOQ and the gain from the above mentioned factors were considered to be positive.Validerat; 20101217 (root