Press Dewatering of Sludge with Applications of an Electric Field

In the paper industry today, there is a rising concern over the question of what to do with the paper mill sludge. Although in the past most of the sludge was sent to a landfill, this disposal method is becoming less and less acceptable due to increasing environmental concerns, decreasing landfill space and increasing costs. Since sludge contains a large fraction of water, one of the alternatives is to increase the dewaterability of the sludge through the use of electrokinetic forces. Increased dewatering of the sludge would allow for more economical alternatives to sludge disposal, such as incineration, as well as decrease the sludge handling, transportation, and disposal costs by reducing both volume and weight. The main objective of this thesis was to determine if the application of an electric current through a sludge press would increase the amount of dewatering in the sludge. A simulated press that allowed for the sludge to be pressed in-between two charged screens and water to be collected from both the top and bottom of the press was designed and constructed. During experimentation, drainage amounts and final sludge consistency was collected under varying voltage applications and compared to a control run with no voltage. From the results, it could be concluded that the application of an electric field did indeed help increase the dewaterability of the sludge. The results also show that ion migration does take place in the sludge with positively charged particles carrying water molecules towards the negatively charged screen. Further studies in applying this concept at higher pressing consistencies as well as other applications is recommended

A merger in the dusty, z=7.5z=7.5 galaxy A1689-zD1?

The gravitationally-lensed galaxy A1689-zD1 is one of the most distant spectroscopically confirmed sources ($z=7.5$). It is the earliest known galaxy where the interstellar medium (ISM) has been detected; dust emission was detected with the Atacama Large Millimetre Array (ALMA). A1689-zD1 is also unusual among high-redshift dust emitters as it is a sub-L* galaxy and is therefore a good prospect for the detection of gaseous ISM in a more typical galaxy at this redshift. We observed A1689-zD1 with ALMA in bands 6 and 7 and with the Green Bank Telescope (GBT) in band $Q$. To study the structure of A1689-zD1, we map the mm thermal dust emission and find two spatial components with sizes about $0.4-1.7$\,kpc (lensing-corrected). The rough spatial morphology is similar to what is observed in the near-infrared with {\it HST} and points to a perturbed dynamical state, perhaps indicative of a major merger or a disc in early formation. The ALMA photometry is used to constrain the far-infrared spectral energy distribution, yielding a dust temperature ($T_{\rm dust} \sim 35$--$45$\,K for $\beta = 1.5-2$). We do not detect the CO(3-2) line in the GBT data with a 95\% upper limit of 0.3\,mJy observed. We find a slight excess emission in ALMA band~6 at 220.9\,GHz. If this excess is real, it is likely due to emission from the [CII] 158.8\,$\mu$m line at $z_{\rm [CII]} = 7.603$. The stringent upper limits on the [CII]/$L_{\rm FIR}$ luminosity ratio suggest a [CII] deficit similar to several bright quasars and massive starbursts.Comment: 9 pages, accepted to MNRAS, in pres

Detection of CO from SMM J16359+6612, The Multiply Imaged Submillimeter Galaxy Behind A2218

We report the detection of CO ($J$=3$\to$2) line emission from all three multiple images (A,B and C) of the intrinsically faint ($\simeq$ 0.8 mJy) submillimeter-selected galaxy SMM J16359+6612. The brightest source of the submm continuum emission (B) also corresponds to the brightest CO emission, which is centered at $z$=2.5168, consistent with the pre-existing redshift derived from \Ha. The observed CO flux in the A, B and C images is 1.2, 3.5 and 1.6 Jy \kms respectively, with a linewidth of $500\pm 100$ \kms. After correcting for the lensing amplification, the CO flux corresponds to a molecular gas mass of $\sim 2\times 10 ^{10} h_{71}^{-2}$ \Msun, while the extent of the CO emission indicates that the dynamical mass of the system $\sim9\times10^{10}$ \Msun. Two velocity components are seen in the CO spectra; these could arise from either a rotating compact ring or disk of gas, or merging substructure. The star formation rate in this galaxy was previously derived to be $\sim$100--500 \Msun \yr. If all the CO emission arises from the inner few kpc of the galaxy and the galactic CO-to-H$_2$ conversion factor holds, then the gas consumption timescale is a relatively short 40 Myr, and so the submm emission from SMM J16359+6612 may be produced by a powerful, but short-lived circumnuclear starburst event in an otherwise normal and representative high-redshift galaxy.Comment: Appearing in the 2004 October 10 issue of the Astrophysical Journal Letters, Volume 614, L5-L

Origin and significance of 'dispersed facies' basal ice: Svínafellsjökull, Iceland

Dispersed facies basal ice - massive (i.e. structureless) ice with dispersed debris aggregates - is present at the margins of many glaciers and, as a product of internal glacial processes, has the potential to provide important information about the mechanisms of glacier flow and the nature of the subglacial environment. The origin of dispersed facies is poorly understood, with several hypotheses having been advanced for its formation, and there is disagreement as to whether it is largely a sedimentary or a tectonic feature. We test these established hypotheses at the temperate glacier Svfnafellsjokull, Iceland, and find that none fully account for dispersed facies characteristics at this location. Instead, dispersed facies physical, sedimentological and stable-isotope (5180, 8D) characteristics favour a predominantly tectonic origin that we suggest comprises the regelation and straininduced metamorphism of debris-rich basal ice that has been entrained into an englacial position by tectonic processes operating at the base of an icefall. Further thickening of the resultant dispersed facies may also occur tectonically as a result of ice flow against the reverse bed slope of a terminal overdeepening. Lack of efficient subglacial drainage in the region of the overdeepening may limit basal melting and thus favour basal ice preservation, including the preservation of dispersed facies. Despite the relatively low sediment content of dispersed facies (~1.6% by volume), its thickness (up to 25 m) and ubiquity at Svfnafellsjokull results in a significant contribution to annual sediment discharge (1635-3270 m3 a"1) that is ~6.5 times that contributed by debris-rich stratified facies basal ice

Seasonal changes in brain serotonin transporter binding in short 5-HTTLPR-allele carriers but not in long-allele homozygotes

Several findings suggest seasonal variations in the serotonin (5-HT) system. We sought evidence for seasonal variation in the serotonin transporter (5-HTT). We found that length of daylight time in minutes correlates negatively with 5-HTT binding in the putamen and the caudate, with a similar tendency in the thalamus, but no such association in the midbrain. In the putamen, an anatomical region with a dense serotonin innervation that is implicated in processing of aversive stimuli, we found a significant gene*daylight effect with a negative correlation between the 5-HTT binding and daylight time in carriers of the short 5-HTTLPR allele, but not in carriers of the long allele. The neurobiological endophenotype identified here directly links activation studies, showing responses on the neural circuit level, with dynamic changes in transporter expression measured in vivo

Dynamic targeting of the replication machinery to sites of DNA damage

Components of the DNA replication machinery localize into discrete subnuclear foci after DNA damage, where they play requisite functions in repair processes. Here, we find that the replication factors proliferating cell nuclear antigen (PCNA) and RPAp34 dynamically exchange at these repair foci with discrete kinetics, and this behavior is distinct from kinetics during DNA replication. Posttranslational modification is hypothesized to target specific proteins for repair, and we find that accumulation and stability of PCNA at sites of damage requires monoubiquitination. Contrary to the popular notion that phosphorylation on the NH2 terminus of RPAp34 directs the protein for repair, we demonstrate that phosphorylation by DNA-dependent protein kinase enhances RPAp34 turnover at repair foci. Together, these findings support a dynamic exchange model in which multiple repair factors regulated by specific modifications have access to and rapidly turn over at sites of DNA damage

Project evaluation in animal research – Possibilities for Harmonization in Nordic Countries

This paper is a report of discussion between responsible persons throughout the Nordic region on the activities, issues and problems encountered with evaluating project applications for experimental work involving the use of animals. Harmonization of the actions of responsible authorities in the evaluation of animal experimental projects is encouraged by policy makers at the European level, and the possibilities to encourage this are discussed. While the process of evaluation and the composition of the committees are broadly similar across the region there are differences. Applications are often made with insufficient attention, better guidance and simplification may improve this. Training was identified as a common problem, and training sources are available which could be used. The inclusion of persons with experimental design and statistical expertise is recommended.   It is concluded that it would be to the benefit of each committee if there were communication between the committees in the Nordic states, to share best practice and flag common errors and problems

Nonperturbative 2D Gravity, Punctured Spheres and Θ\Theta-Vacua in String Theories

We consider a model of 2D gravity with the coefficient of the Einstein-Hilbert action having an imaginary part $\pi/2$. This is equivalent to introduce a $\Theta$-vacuum structure in the genus expansion whose effect is to convert the expansion into a series of alternating signs, presumably Borel summable. We show that the specific heat of the model has a physical behaviour. It can be represented nonperturbatively as a series in terms of integrals over moduli spaces of punctured spheres and the sum of the series can be rewritten as a unique integral over a suitable moduli space of infinitely punctured spheres. This is an explicit realization \`a la Friedan-Shenker of 2D quantum gravity. We conjecture that the expansion in terms of punctures and the genus expansion can be derived using the Duistermaat-Heckman theorem. We briefly analyze expansions in terms of punctured spheres also for multicritical models.Comment: 12 pages + 2 figures available upon request. LaTeX Fil