Columnar joints in the Patino Formation sandstones, Eastern Paraguay: a dynamic interaction between dyke intrusion, quartz dissolution and cooling-induced fractures

The Patino Formation sandstones, which crop out in Aregua neighborhood in Eastern Paraguay and show columnar joints near the contact zone with a nephelinite dyke, have as their main characteristics the high proportion of syntaxial quartz overgrowth and a porosity originated from different processes, initially by dissolution and later by partial filling and fracturing. Features like the presence of floating grains in the syntaxial cement, the transitional interpenetrative contact between the silica-rich cement and grains as well as the intense fracture porosity are strong indications that the cement has been formed by dissolution and reprecipitation of quartz from the framework under the effect of thermal expansion followed by rapid contraction. The increase of the silica-rich cement towards the dyke in association with the orthogonal disposition of the columns relative to dyke walls are indicative that the igneous body may represent the main heat source for the interstitial aqueous solutions previously existing in the sediments. At macroscopic scale, the increasing of internal tensions in the sandstones is responsible for the nucleation of polygons, leading to the individualization of prisms, which are interconnected by a system of joints, formed firstly on isotherm surfaces of low temperature and later on successive adjacent planes towards the dyke heat source.

A New Approach to the Prediction of Partition Coefficients in Water/Organic Interfaces

In the present work, a new approach for the determination of the partition coefficient in different interfaces based on the density function theory is proposed. Our results for log P(ow) considering a n-octanol/water interface for a large super cell for acetone -0.30 (-0.24) and methane 0.95 (0.78) are comparable with the experimental data given in parenthesis. We believe that these differences are mainly related to the absence of van der Walls interactions and the limited number of molecules considered in the super cell. The numerical deviations are smaller than that observed for interpolation based tools. As the proposed model is parameter free, it is not limited to the n-octanol/water interface.

Role of the triad N46, S106 and T107 and the surface charges in the determination of the acidic pH optimum of digestive lysozymes from Musca domestica

Structures of digestive lysozymes 1 and 2 from housefly (MdL1 and MdL2) show that S106-T107 delimit a polar pocket around E32 (catalytic acid/base) and N46 contributes to the positioning of 050 (catalytic nucleophile), whereas those residues are replaced by V109-A110 and D48 in the non-digestive lysozyme from hen egg-white (HEWL). Further analyses revealed that MdL1 and MdL2 surfaces are less positively charged than HEWL surface. To verify the relevance of these differences to the acidic pH optimum of digestive lysozymes it was determined that pKas of the catalytic residues of the triple mutant MdL2 (N46D-S106V-T107A) are similar to HEWL pKas and higher than those for MdL2. In agreement, triple mutant MdL2 and HEWL exhibits the same pH optimum upon methylumbelliferylchitotrioside. In addition to that, the introduction of six basic residues on MdL1 surface increased by 1 unit the pH optimum for the activity upon bacterial walls. Thus, the acidic pH optimum for MdL2 and MdL1 activities upon methylumbelliferylchitotrioside is determined by the presence of N46, S106 and T107 in the environment of their catalytic residues, which favors pKas reduction. Conversely, acidic pH optimum upon bacterial walls is determined by a low concentration of positive charges on the MdL2 and MdL1 surfaces. (C) 2010 Elsevier Inc. All rights reserved.

Purification, characterization and sequencing of the major beta-1,3-glucanase from the midgut of Tenebrio molitor larvae

The major beta-1,3-glucanase from Tenebrio molitor (TLam) was purified to homogeneity (yield, 6%; enrichment, 113 fold; specific activity, 4.4 U/mg). TLam has a molecular weight of 50 kDa and a pH optimum of 6. It is an encloglucanase that hydrolyzes beta-1,3-glucans as laminarin and yeast beta-1,3-1,6-glucan, but is inactive toward other polysaccharides (as unbranched beta-1,3-glucans or mixed beta-1,3-1,4-glucan from cereals) or disaccharides. The enzyme is not inhibited by high substrate concentrations and has low processivity (0.6). TLam has two ionizable groups involved in catalysis, and His, Tyr and Arg residues plus a divalent ion at the active site. A Cys residue important for TLam activity is exposed after laminarin binding. The cDNA coding for this enzyme was cloned and sequenced. It belongs to glycoside hydrolase family 16, and is related to other insect glucanases and glucan-binding proteins. Sequence analysis and homology modeling allowed the identification of some residues (E174, E179, H204, Y304, R127 and R181) at the active site of the enzyme, which may be important for TLam activity. TLam efficiently lyses fungal cells, suggesting a role in making available walls and cell contents to digestion and in protecting the midgut from pathogen infections. (C) 2009 Elsevier Ltd. All rights reserved.

Identification of lift-off mechanism failure for salt drill-in drilling fluid containing polymer filter cake through adsorption/desorption studies

Drilling fluid`s contact with the productive zone of horizontal or complex wells can reduce well productivity by fluid invasion in the borehole wall. Salted drilling drill-in fluid containing polymers has often been applied in horizontal or complex petroleum wells in the poorly consolidated sandstone reservoirs of the Campos basin, Rio de Janeiro, Brazil. This fluid usually consists of natural polymers such as starch and xanthan gum, which are deposited as a filter cake on the wellbore wall during the drilling. Therefore, the identification of a lift-off mechanism failure, which can be detachment or blistering and pinholing, will enable formulation improvements. increasing the chances of success during filter cake removal in open hole operations. Likewise, knowledge of drill-in drilling fluid adsorption/desorption onto sand can help understand the filter cake-rock adhesion mechanism and consequently filter cake lift-off mechanism failures. The present study aimed to identify the lift-off failure mechanism for this type of fluid filter cake studying adsorption/desorption onto SiO(2) using solutions of natural polymers, lubricants, besides the fluid itself. Ellipsometry was employed to measure this process. The adsorption/desorption studies showed that the adsorbed layer of drilling fluid onto the walls of the rock pores is made up of clusters of polymers, linked by hydrogen bonds, which results in a force of lower cohesion compared to the electrostatic interaction between silica and polymers. Consequently, it was found that the most probable filter cake failure mechanism is rupture (blistering and pinholing), which results in the formation of ducts within the filter cake. (C) 2009 Elsevier B.V. All rights reserved.

Thin films of xyloglucans for BSA adsorption

In this work. XG extracted from Tamarindus indica (XGT) and Copaifera langsdorffii (XGC) seeds were deposited onto Si wafers as thin films. The characteristics of XGT and XGC adsorbed layers were compared with a commercial XG sample (TKP, Tamarind kernel powder) by ellipsometry, and atomic force microscopy (AFM). Moreover, the adsorption of oxidized derivative of XGT (To60) onto amino-terminated Si wafers and the immobilization of bovine serum albumin (BSA) onto polysaccharides covered wafers, as a function of pH, were also investigated. The XG samples presented molar ratios Glc:Xyl:Gal of 2.4:2.1:1 (XGC) 2.8: 23: 1 (XGT) and 1.91.91 (TKP). The structure of XGT and XGC was determined by O-methy alditol acetate derivatization and showed similar features, but XGC confirmed the presence of more alpha-D-Xyl branches due to more beta-D-Gal ends. XGT deposited onto Si adsorbed as fibers and small entities uniformly distributed, as evidenced by AFM, while TPK and XGC formed larger aggregates. The thickness of To60 onto amino-terminated surface was similar to that determined for XGT onto Si wafers. A maximum in the adsorbed amount of BSA occurred close to its isoelectric point (5.5). These findings indicate that XGT and To60 are potential materials for the development of biomaterials and biotechnological devices. (C) 2008 Elsevier B.V. All rights reserved.

Iron oxide nanoparticles and VO(x)/Hexadecylamine nanotubes composite

In this work, we present the synthesis and characterization of a hybrid nanocomposite constituted by iron oxide nanoparticles and vanadium oxide/Hexadecylamine (VO(x)/Hexa) nanotubes. Transmission Electron Microscopy (TEM) images show small particles (around 20 nm) in contact with the external wall of the multiwall tubes, which consist of alternate layers of VO(x) and Hexa. By Energy Dispersive Spectroscopy (EDS), we detected iron ions within the tube walls and we have also established that the nanoparticles are composed of segregated iron oxide. The samples were studied by Electron Paramagnetic Resonances (EPR) and dc-magnetization as a function of the magnetic field. The analysis of the magnetization and EPR data confirms that a fraction of the V atoms are in the V(4+) electronic state and that the nanoparticles exhibit a superparamagnetic behavior. The percentage of V and Fe present in the nanocomposite was determined using Instrumental Neutron Activation Analysis (INAA). (C) 2008 Elsevier B.V. All rights reserved.

Synthesis of L1(0) Fe-Pd films by electrodeposition and thermal annealing

Fe-Pd alloy films have been prepared by electrochemical deposition from an alkaline electrolyte containing Fe sulfate, Pd chloride and 5-sulfosalicylic acid onto polycrystalline titanium substrates. The as-deposited films were nanocrystalline and magnetically soft (coercivity similar to 25 Oe). L1(0) Fe-Pd films with a (111) preferred orientation were obtained by post-deposition thermal annealing of films with composition about 37 at% Fe in an (Ar + 5% H-2) gas flow at 500 degrees C. Such films exhibit hard magnetic properties, with a coercivity up to 1880 Oe, and a slightly anisotropic magnetic response, with a larger in-plane remanence. Preliminary magnetic investigations support magnetization switching through pinning of domain walls. (c) 2008 Elsevier B.V. All rights reserved.

Sign Painting Department

In this section of the Sign Painting Department several students are shown working on projects. Decorating the walls are numerous signs, likely painted by students in the department. Black and white photograph.

Informationssäkerhet inom grafiska företag

The study shows the current need for security solutions concerning work with information in different areas.Investigations will show important solutions for printers’ needs to meet the increasingly harder demands forfast and safe digital communications. Important factors to be analyzed in the investigations are: access todifferent types of information, workers authority of information, access to the data base register internallyand externally, production solutions for an effective fault detection and data base solutions fororders and distribution.Planned and unplanned stops result in a standard of value in interruptions. Internal data bases areprotected by so-called “Fire Walls���, “Watch Dogs” and Virtual Private Networks. Offset plates are locked infor a definitive range of time. Subsequent destruction and remaining sheets are shredded and recycled. Alldocumentation is digital, in business control systems, which guarantees that no important documents arelying around in working places. Fault detection work is facilitated by the ability to fully track the order numberson incoming orders.

Solar energy studies and extramural learning

Extramural learning refers to the educational process that takes place outside the walls of the school (or the university). Extramural learning that takes place in a science center is characterized by hands-on and interactivity. Interactive solar energy exhibits are particularly well suited for out-door science centers. The paper presents some solar energy hands-on exhibits and extramural activities that the author has initiated and participated in.

Simulation of Photovoltaic Panel Production as Complement to Ground Source Heat Pump System

This master thesis presents a new technological combination of two environmentally friendly sources of energy in order to provide DHW, and space heating. Solar energy is used for space heating, and DHW production using PV modules which supply direct current directly to electrical heating elements inside a water storage tank. On the other hand a GSHP system as another source of renewable energy provides heat in the water storage tank of the system in order to provide DHW and space heating. These two sources of renewable energy have been combined in this case-study in order to obtain a more efficient system, which will reduce the amount of electricity consumed by the GSHP system.The key aim of this study is to make simulations, and calculations of the amount ofelectrical energy that can be expected to be produced by a certain amount of PV modules that are already assembled on a house in Vantaa, southern Finland. This energy is then intended to be used as a complement to produce hot water in the heating system of the house beside the original GSHP system. Thus the amount of electrical energy purchased from the grid should be reduced and the compressor in the GSHP would need fewer starts which would reduce the heating cost of the GSHP system for space heating and providing hot water.The produced energy by the PV arrays in three different circuits will be charged directly to three electrical heating elements in the water storage tank of the existing system to satisfy the demand of the heating elements. The excess energy can be used to heat the water in the water storage tank to some extent which leads to a reduction of electricity consumption by the different components of the GSHP system.To increase the efficiency of the existing hybrid system, optimization of different PV configurations have been accomplished, and the results are compared. Optimization of the arrays in southern and western walls shows a DC power increase of 298 kWh/year compared with the existing PV configurations. Comparing the results from the optimization of the arrays on the western roof if the intention is to feed AC power to the components of the GSHP system shows a yearly AC power production of 1,646 kWh.This is with the consideration of no overproduction by the PV modules during the summer months. This means the optimized PV systems will be able to cover a larger part of summer demand compared with the existing system.

Passive crosslaminated timber buildings : Final report Cerbof-project no. 76

In this project, Stora Enso’s newly developed building system has been further developed to allow building to the Swedish passive house standard for the Swedish climate. The building system is based on a building framework of CLT (Cross laminated timber) boards. The concept has been tested on a small test building. The experience gained from this test building has also been used for planning a larger building (two storeys with the option of a third storey) with passive house standard with this building system. The main conclusions from the project are:  It is possible to build airtight buildings with this technique without using traditional vapour barriers. Initial measurements show that this can be done without reaching critical humidity levels in the walls and roof, at least where wood fibre insulation is used, as this has a greater capacity for storing and evening out the moisture than mineral wool. However, the test building has so far not been exposed to internal generation of moisture (added moisture from showers, food preparation etc.). This needs to be investigated and this will be done during the winter 2013-14.  A new fixing method for doors and windows has been tested without traditional fibre filling between them and the CLT panel. The door or window is pressed directly on to the CLT panel instead, with an expandable sealing strip between them. This has been proved to be successful.  The air tightness between the CLT panels is achieved with expandable sealing strips between the panels. The position of the sealing strips is important, both for the air tightness itself and to allow rational assembly.  Recurrent air tightness measurements show that the air tightness decreased somewhat during the first six months, but not to such an extent that the passive house criteria were not fulfilled. The reason for the decreased air tightness is not clear, but can be due to small movements in the CLT construction and also to the sealing strips being affected by changing outdoor temperatures.  Long term measurements (at least two years) have to be carried out before more reliable conclusions can be drawn regarding the long term effect of the construction on air tightness and humidity in the walls.  An economic analysis comparing using a concrete frame or the studied CLT frame for a three storey building shows that it is probably more expensive to build with CLT. For buildings higher than three floors, the CLT frame has economic advantages, mainly because of the shorter building time compared to using concrete for the frame. In this analysis, no considerations have been taken to differences in the influence on the environment or the global climate between the two construction methods.

Minimization of stock weight during close-die forging of a spindle

In this paper, Finite Element method and full-scale experiments have been used to study a hot forging method for fabri-cation of a spindle using reduced initial stock size. The forging sequence is carried out in two stages. In the first stage, the hot rolled cylindrical billet is pre-formed and pierced in a closed die using a spherical nosed punch to within 20 mm of its base. This process of piercing or impact extrusion leads to high strains within the work piece but requires high press loads. In the second stage, the resulting cylinder is placed in a die with a flange chamber and upset forged to form a flange. The stock mass is optimized for complete die filling. Process parameters such as effective strain distribution, material flow and forging load in different stages of the process are analyzed. It is concluded from the simulations that minor modifications of piercing punch geometry to reduce contact between the punch and emerging vertical walls of the cylinder appreciably reduces the piercing load. In the flange chamber, a die surfaces angle of 52° instead of 45° is pro-posed to ensure effective material flow and exert sufficient tool pressure to achieve complete cavity filling. In order to achieve better compression, it is also proposed to shorten both the length of the inserted punch and the die “tongues” by a few mm.

Energieffektivisering av klimatskal med hänsyn till kulturhistorisk värdering : Fallstudier av tre befintliga småhus från 1900-talet ur bevarandesynpunkt

Allt hårdare lagkrav gör att det är svårt att energieffektivisera befintliga byggnader utan att förändra deras utseende. Syftet med examensarbetet är att utreda hur stor energieffektivisering, för tre befintliga småhus uppförda under 1900-talet, som är möjlig att uppnå genom förbättring av byggnadernas klimatskal, det vill säga tak, väggar, golv, fönster och dörrar, utan att förvanska byggnadernas utseende och samtidigt bevara deras kulturhistoriska värden. Arbetet bestod av en förstudie där tre byggnader identifierades, ett undersökningsskede där information om byggnaderna togs fram och ett slutsatsskede där energibesparande åtgärdsförslag togs fram och utvärderades. Byggnader som var goda representanter för sin tid och stil söktes. Byggnader från 1910-talet, 1930-talet och 1970-talet, lokaliserades. Sedan gjordes det fallstudier med intervjuer och inventeringar. För att utreda byggnadens klimatskal utfördes u-värdesberäkningar och energiberäkningar av befintliga byggander och byggnader baserade på föreslagna åtgärdsförslag. Ingen av byggnaderna nådde efter föreslagna åtgärder ner till passivhuskravet 59 kWh/år/m2 Atemp eller BBR-kravet 110 kWh/år/m2 Atemp för en byggnads specifika energianvändning. Den största möjliga energieffektivisering för de tre byggnaderna uppförda under 1900-talet, som är möjlig att uppnå utan att förvanska byggnadernas utseende och samtidigt bevara deras kulturhistoriska värden är 13,0 kWh/år/m2 Atemp, 49,7 kWh/år/m2 Atemp respektive 64,8 kWh/år/m2 Atemp. Slutsatser från arbetet är att byggnader från 1910-tal kan åtgärdas genom att isolera fönstren, sätta dit en extra dörr på insidan av ytterdörren samt tilläggsisolera snedtaket. Byggnader från 1930-tal kan åtgärdas genom att isolera fönstren med en isolerruta på insidan av fönstret och dörrarna med en extra dörr på insidan av ytterdörren. Byggnader från 1970-tal kan åtgärda fönstren genom att byta ut dem till energifönster, ingen åtgärd för golvet men fasaden isoleras utvändigt med vakuumisolering. Byggnaden från 1970-talet klarade sig bäst i jämförelsen eftersom den var i autentiskt skick från början vilket gjorde att förbättringen blev större än för till exempel byggnaden från 1910-talet som redan var ombyggd innan åtgärder föreslogs.