I takt med medielandskapets föraändring så utvecklas möjligheterna för medier att positionera sig digitalt alltmer. Denna kandidatuppsats har som syfte att undersöka hur denna förändring påverkar de svenska dagstidningarna när det kommer till Apples iPad. Vår frågeställning är således; hur tar svenska dagstidningar sig an iPad som en ny medieplattform?Vi har valt att använda oss utav kvalitativa intervjuer med de ledande aktörerna på den svenska dagstidningsmarknaden. Eftersom det här är ett så pass nytt och outforskat område finns det begränsat med relevant teori att tillgå. Vi har som hjälp använt oss av teorier om nya medier och digitalisering där vi bland annat har tittat på Internets framväxt. Det vi har kommit fram till i vår kandidatuppsats är att det är en ny marknad fylld av experiment och tester för att utveckla den perfekta modellen över hur man som dagstidning ska positionera sig på iPad. De resultat vi har kommit fram till idag komer med största sannolikhet att ändras inom ett par år. Både för att tekniken förbättras och skapar fler möjligheter, samt att konkurrenter ändrar förhållandena på marknaden.

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This study generated two cyanide dihydratase (CynD) mutants of Bacillus pumilus C1 with improved activity at higher pH by random mutagenesis. The purpose of this study was to create enzyme variants better suited to degrade cyanide under the harsh conditions of industrial applications. We employed error-prone PCR to construct a library of CynD mutants. A high throughput screening system was developed to screen the library for improved activity. Two mutants were identified that could degrade cyanide at pH10 whereas the wild-type enzyme was inactive at pH9 or higher. The mutants each had three amino acid substitutions compared to the wild-type enzyme. The mutants were also more stable than the wild-type enzyme at 42oC. E327G was identified as one of the key amino acids that are responsible for the improved activity. The goal of the second project was to convert substrate specificity of the Bacillus sp. OxB-1 nitrilase to that of a cyanidase by mutagenesis or construction of hybrid genes. The OxB-1 nitrilase of Bacillus sp. shows a high level of identity with the cyanide dihydratases from B. pumilus C1 and P. stutzeri AK61 but utilizes different substrate. This provides a valuable resource to study the substrate specificity determinants of cyanide degrading enzymes. One deletion mutant and four hybrid proteins were constructed based on the alignment information. The constructed proteins were all unable to degrade cyanide.

Iron oxide-bearing minerals have long been recognized as an effective reactive media for arsenic-contaminated groundwater remediation. This research aimed to develop a technique that could facilitate in situ oxidative precipitation of Fe3+ in a soil (sand) media for generating a subsurface iron oxide-based reactive barrier that could immobilize arsenic (As) and other dissolved metals in groundwater. A simple in situ arsenic treatment process was successfully developed for treating contaminated rural groundwater using iron oxide-coated sand (IOCS). Using imbibition flow, the system facilitated the dispersive transport of ferrous iron (Fe2+) and oxidant solutions in porous sand to generate an overlaying blanket where the Fe2+ was oxidized and precipitated onto the surface as ferric oxide. The iron oxide (FeOx) emplacement process was significantly affected by (1) the initial surface area and surface-bound iron content of the sand, (2) the pH and solubility of the coating reagents, (3) the stability of the oxidant solution, and (4) the chemical injection schedule. In contrast to conventional excavate-and-fill treatment technologies, this technique could be used to in situ replace a fresh iron oxide blanket on the sand and rejuvenate its treatment capacity for additional arsenic removal. Several bench-scale experiments revealed that the resultant IOCS could treat arsenic-laden groundwater for extended periods of time before approaching its effective life cycle. The adsorption capacity for As(III) and As(V) was influenced by (1) the amount of iron oxide accumulated on the sand surface, (2) the system pH, and (3) competition for adsorption sites from other groundwater constituents such as silicon (Si) and total dissolved solids (TDS). Although the IOCS could be replenished several times before exhaustion, the life cycle of the FeOx reactive barrier may be limited by the gradual loss of hydraulic conductivity induced by the imminent reduction of pore space over time.

This study presents detailed procedures for site assessment, remedial system design, and optimization of the remedial action operation (RAO) for the petroleum-hydrocarbons contaminated sites. In this work, a petroleum-hydrocarbons contaminated site located in southern Taiwan was selected. Contaminants of concerns (CoCs) from leaking underground storage tanks (USTs) and associated piping included mono-aromatics (e.g., benzene, toluene, ethyl-benzene, xylenes), naphthalene, and aliphatic hydrocarbons. The direct push (DP) technology was adopted for soil gas and soil samples collection. CoCs in the affected subsurface soils and the aquifers were determined by solid-phase micro-extraction/gas chromatography/mass spectrometry and several other analytic instruments. Site investigation via various tests was conducted to evaluate the geology, hydrogeology, bioactivity and free product availability. Based on results of specific site characterization, successful hydraulic containment and substantial recovery of observed free-phase petroleum product were achieved. During the process of field-scale remediation, a test cell which was equipped with a subset of monitoring points and numerous different function active wells (injection well, extraction well, monitoring well, soil gas monitoring probe, reference well and recovery well) was used for remedial system evaluation. A treatment train consisting of the source control treatment and in situ groundwater treatment technology was employed in this study. The former included a vertical containment barrier (i.e., slurry wall) and three pumping wells, whereas the latter included some passive remedial activities. Approximately 87% to 95% decline of the CoCs concentration was observed in those monitor wells after 135 days of operation. Results show that the spilled light non-aqueous phase liquids (LNAPLs) could be efficiently contained and removed using the treatment train system. The treatment train application could be successfully used to reduce the concentrations of CoCs in groundwater to satisfactory levels. Benzene was found to be the only compound in groundwater violating the groundwater pollution control standard. The risk assessment process including hazard identification and exposure assessment was conducted to assess the risk impact of benzene on the human health. Using the methodology approved by ASTM and American Petroleum Institute (API), the baseline carcinogenic risk (9.0E-07) and risk-based groundwater screening level for benzene (0.660 mg/L) were determined. The BIOPLUME III model was also applied to simulate the transport and fate of benzene in site groundwater. Results from this study indicate that site assessment coupled with the treatment train could be used to reduce the concentrations of CoCs in groundwater and soil to satisfactory levels efficiently and effectively.

This research was aimed to investigate the enhancement of electrokinetic (EK) remediation arsenate-contaminated soil by permeable reaction barrier (PRB). All experiments, which experimental parameters included the position, materials, and quantity of PRB, processing fluid types, potential gradients, and treatment time, were conducted in two types of EK systems. One was Pyrex glass cylindrical cells with dimension of 4.2 cm (£r) ¡Ñ 12 cm (L) and the other was a small pilot-scale modulus with dimension of 36cm (L) ¡Ñ18cm (W) ¡Ñ18cm cm (H). The PRBs were composed of four kinds of reaction materials, which included commercial zero valent iron (Fe(0)C), manufactured zero valent iron (Fe(0)M), commercial hydrous ferric oxide (FeOOHC), and manufactured hydrous ferric oxide (FeOOHM), mixed with ottawa sand in a ratio of 1:2,respectively, and installed in the anode, middle, and cathode side of the EK systems. For 5-day EK cylindrical cell tests, the results showed that the PRB installation would result in a lower electroosmosis permeability (Ke) and a higher removal efficiency of arsenate. The arsenate removal efficiency of EK system with PRB was in the range of 43.89-70.25%, which was 1.5~2.6 times greater than that without PRB, and the value of Ke was in the range of 4.30-12.61¡Ñ10-6 cm2/V-s. The soil pH after EK/PRB treatment was much closer to natural and more arsenate was collected in the anode reservoir. Moreover, the remediation performance of FeOOHC as PRB materials was much better than other materials. For EK pilot-scale modulus tests, it was shown that the removal efficiency of arsenate was effectively enhanced as improved experimental parameters and, however, led to increase the treatment cost. In EK modulus without PRB, the removal efficiency of arsenate, elctroosmosis permeability, and energy consumption were 27.76%, 3.30-5.39¡Ñ10-6 cm2/V-s, and 1724.81 kWh/m3, respectively. Furthermore, the treatment cost was NT 9583/m3. As increasing treatment time, graphite electrode, potential gradient, and quantity of PRB materials, the removal efficiency of arsenate increased to as high as 45.11-71.22% and the treatment cost also increased up to NT 24,800-57,730/m3. As investigated the binding form of arsenate with soil after EK/PRB treatment, it was found that the arsenate ¡Vsoil binding forms of Fe-Mn oxide bound, organically bound, and residual in the soil section behind the PRB were much easier transformed to the forms of exchangeable and carbonate bound. The transformation rate reached as high as 72.5% and it increased with treatment time. However, the Fe-Mn oxide bound was still the main binding form, 61.6-81.6%, in the soil section prior to the PRB. The removal mechanism of arsenate contaminated soil remediation was dominated by electromigration, electrolysis, and electroosmosis in EK system without PRB. And, in EK/PRB system, the removal of arsenate from soil was mainly resulted from adsorption rather than redox reaction by PRB. To sum up, the PRB can effectively enhance the electrokinetic remediation of arsenate contaminated soil by choosing the right PRB materials and operation parameters.

The effect of heterogeneity correlation scale (&amp / #61548 / ) of hydraulic conductivity (K), equilibrium distribution coefficient (Kd) and mass transfer rate (&amp / #61537 / ) on the design and cost of the P&amp / T remediation system for different heterogeneity levels (defined by the variance (&amp / #963 / 2lnK)) and parameter distributions under the rate-limited sorption conditions was evaluated in this study. In addition, the impacts of initial amount of contaminant mass and plume configuration on the remediation design and cost were explored. The effects of different K heterogeneity and remediation design conditions on the length of remediation period, the influence of &amp / #61548 / anisotropy of K, correlation between K and Kd, and Kd and &amp / #61537 / , and the fraction of equilibrium sorption sites (f) on the pump-and-treat (P&amp / T) design and cost were the other studied subjects. In this study, simulation-optimization approach, in which a groundwater flow and contaminant transport simulation model was linked with a genetic algorithm (GA) library, was used. Results showed that not only the amount of PCE mass initially present in the aquifer was important in terms of P&amp / T design, cost and remediation time, but also the location and size of the high and low K regions defined by &amp / #955 / lnK as well as the magnitudes of K represented by geometric mean and &amp / #963 / 2lnK were influential. It was also found that P&amp / T designs utilizing higher numbers of wells with lower pumping rates may be more robust predicting the time-to-compliance compared to a single well with higher pumping rate for aquifers heterogeneous in K. Homogenous Kd assumption might cause serious error in both the design and the cost of remediation. The magnitude of this error may change depending on the spatial distribution of K and Kd, &amp / #955 / lnKd, &amp / #963 / 2lnKd and &amp / #963 / 2lnK. The effect of heterogeneity in &amp / #61537 / on the design and cost of remediation may or may not be significant depending on K, Kd and &amp / #61537 / distributions, &amp / #61548 / ln&amp / #61537 / and &amp / #963 / 2ln&amp / #61537 / . Increased amount of kinetically sorbed mass defined by decreased f value resulted in more costly remediation.

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The purpose of this study was to evaluate the treatment efficiency of phenol contaminated soils by electrokinetic (EK) process conducted in sand boxes (60 cm¡Ñ30 cm¡Ñ30 cm; L¡ÑW¡ÑH). The electric field strength, electrode polarity reverse, and Fenton reagent were employed as the experimental factors in this study to assess the variations of soil characteristics, potential difference, and residual phenol concentration distribution during a treatment period of 20 days and after the treatment. It was found that the anode reservoir pH decreased to around 2 and the cathode reservoir pH increased to approximately 12 after 2~3 days of treatment in the no electrode polarity reverse system. However, the variation of pH in the anode and cathode reservoirs was less obvious in the case with electrode polarity reverse. No matter a constant potential system or a constant current system was employed, a general trend of a lower pH at the anode reservoir and a higher pH at the cathode reservoir would be found. The acid front generated at the anode reservoir flushed across the soil specimen toward the cathode and the base front advanced toward the anode. However, in the central region of sand box, unsaturated and saturated soil specimen maintain neutral. For EK or EK-Fenton experiments, under the constant potential conditions, the potential difference relative to the cathode versus the distance from anode was found to have a linear relationship at the beginning of the electrical potential application. As the treatment time elapsed, the potential gradient became non-linear. Nevertheless, there was no remarked potential gradient change in the case with electrode polarity reverse. Although capillarity has resulted in an increase of the moisture content of unsaturated soil (from 25.34% to 30% after 20 days), electroosmotic (EO) flow was not obvious in the unsaturated zone. For the experiments with electrode polarity reverse, they had a much greater EO flow quantity, the electroosmotic permeability coefficients for constant potential and constant current systems were 6.42¡Ñ10-6 cm2/V¡Es and 9.47¡Ñ10-6 cm2/V¡Es, respectively. It was also found that the existence of contaminants did reduce the EO flow quantity. Regardless of the employment of a constant potential or constant current system, the maximum destruction and removal efficiency (DRE) of phenol was obtained for EK-Fenton process. The maximum DRE values of phenol for both constant potential and constant current systems were found to be 78.06% and 80.11%, respectively. However, the DRE of phenol was found to be much lower for the system with electrode polarity reverse. It was postulated that the destruction efficiency of phenol was less obvious than the removal efficiency in the electrode polarity reverse system. In addition, a frequent reverse of electrode polarity also resulted in a frequent change of EO flow direction. Thus, a flow hysteresis of phenol in the soil compartment was found.

Nitroglycerin (NG) is a toxic explosive commonly found in soil and contaminated groundwater at old manufacturing plants and military ranges. When NG enters an aquifer, it behaves as a dense non-aqueous phase liquid (DNAPL). Nitroglycerin is an impact sensitive explosive and therefore excavating the area to remove or treat the contaminant can be dangerous. In situ bioremediation and natural attenuation of NG have been proposed as remediation alternatives and it is therefore necessary to understand the degradation mechanisms of NG in contaminated soil and groundwater and investigate the potential for using bioremediation at contaminated sites. Many bacteria have been isolated for the ability to transform NG as a source of nitrogen, but no isolates have used NG as a sole source of carbon, nitrogen, and energy. We isolated Arthrobacter JBH1 from NG contaminated soil by selective enrichment with NG as the sole growth substrate. The degradation pathway involves a sequential denitration to 1,2-dinitroglycerin (DNG) and 1-mononitroglycerin (MNG) with simultaneous release of nitrite. Flavoproteins of the Old Yellow Enzyme (OYE) family capable of removing the first and second nitro groups from NG have been studied in the past and we identified an OYE homolog in JBH1 capable of selectively producing the 1 MNG intermediate. To our knowledge, there is no previous report on enzymes capable transforming MNG. Here we show evidence that a glycerol kinase homolog in JBH1 is capable of transforming 1 MNG into 1-nitro-3-phosphoglycerol, which could be later introduced into a widespread pathway, where the last nitro group is removed. Overall, NG is converted to CO2 and biomass and some of the nitrite released during denitration is incorporated into biomass as well. As a result, NG can be now considered a growth substrate, which changes the potential to bioremediate NG contaminated sites. The magnitude of the effect of biodegradation processes in the fate of NG in porous systems was unknown, and we have been able to quantify these effects, determine degradation rates, and have evidence that bioaugmentation with Arthrobacter sp. strain JBH1 could result in complete mineralization in contaminated soil and sediments contaminated with NG, without the addition of other carbon sources. Site specific conditions have the potential to affect NG degradation rates in situ. Experiments were conducted to investigate NG degradation at various pH values and NG concentrations, and the effects of common co-contaminants on NG degradation rates. Arthrobacter JBH1 was capable of growing on NG at pH values as low as 5.1 and NG concentrations as high as 1.2 mM. The presence of explosive co-contaminants at the site such as trinitrotoluene and 2,4-dinitrotoluene lowered NG degradation rates, and could potentially result in NG recalcitrance. Collectively, these results provide the basis for NG bioremediation and natural attenuation at sites contaminated with NG without the addition of other sources of carbon. Nonetheless, careful attention should be paid to site-specific conditions that can affect degradation rates.