Autoclaved desulfurization slag bricks:an opportunity for carbon capture

Abstract. The goal for this thesis was to study the effects of carbon mineralization to the desulfurization slag based mortar and paste samples using autoclave carbonation procedure. During the study, the effects of different carbonation conditions to the compressive strength and crystal structure of a slag brick were tested. Additionally, a number of different mixtures of sand, slag and water were tested to find the most durable and workable composition. In the first phase of the study, bricks made with different ratios of sand and slag were tested for their compressive strength, in order to find the most durable composition. The results of this phase were used to find the optimal mixture and process conditions to produce as durable bricks as possible with mild reaction conditions and short carbonation time. In the second phase, the most durable mixture was carbonated for varying time periods to test the effect of the reaction time to the durability of the brick. The effect of the carbonation in general was also tested, by doing control batches of the identical mixtures with nitrogen pressurizing. Another test parameter was the slag type used, for which basic oxygen furnace slag was tested as a substitute for desulfurization slag. After these optimization tests were done, three different mixtures were analyzed using TGA, XRD and SEM imaging for phase composition analysis. As a result of this study, bricks with compressive strength of over 20 MPa were produced. Samples without carbon dioxide had almost ten times lower compressive strength in otherwise identical conditions. This master’s thesis was part of the FLOW-project. In this project, the fibre and particle engineering research unit of the University of Oulu studies utilization of the by-products of the steel industry.Tiivistelmä. Tämän diplomityön tavoitteena oli tutkia hiilidioksidin sitouttamista rikinpoistokuonaan ja näin syntyneen materiaalin toimivuutta betonin korvaamisessa rakennusaineena. Työn aikana selvitettiin erilaisten autoklaavi-karbonointiolosuhteiden vaikutusta materiaalin kestävyyteen ja mikrorakenteeseen, sekä haettiin optimaalista hiekan, kuonan ja veden suhdetta mahdollisimman kestävän kuonapohjaisen materiaalin valmistamiseksi. Työn ensimmäisessä vaiheessa tutkittiin eri hiekan ja kuonan suhteilla valmistettujen näytteiden puristuskestävyyttä lujimman seoksen löytämiseksi. Tulosten perusteella valittiin jatkotutkimuksiin lupaavimmat näytteet, tavoitteena saada mahdollisimman kestävä lopputulos mahdollisimman lyhytkestoisella karbonointireaktiolla ja suurella kuonaosuudella. Työn toisessa vaiheessa kestävintä seostyyppiä karbonoitiin eri aikamääriä, tarkoituksena testata reaktioajan vaikutusta lopputuotteen kestävyyteen. Karbonoinnin vaikutusta ylipäätään lopputuotteeseen tutkittiin tekemällä kontrollinäytteitä typpipaineistetussa reaktorissa. Myös vaihtoehtoista kuonatyyppiä kokeiltiin raaka-aineena rikinpoistokuonan tilalla. Lopuksi kolmen eri seoksen näytteitä tutkittiin lujuuden lisäksi lämpöstabiiliuden osalta TGA-analyysillä ja kiderakenteen osalta XRD-analyysillä ja elektronimikroskoopilla. Suoritetun tutkimuksen perusteella saatiin tuotettua näytepaloja, joiden puristuslujuus oli 20 MPa. Puristuslujuus oli noin kymmenen kertaa lujempi, kuin vastaavalla näytteellä ilman hiilidioksidia. Diplomityö oli osa FLOW-projektia, jossa Oulun yliopiston kuitu- ja partikkelitekniikan tutkimusyksikkö tutkii kiertotalouden ratkaisuja teräksenvalmistuksen sivuvirtojen jatkokäyttöön

Fabrication and Comprehensive Modeling of Ion-Exchanged Bragg Opitcal Add-Drop Multiplexers

Optical add–drop multiplexers (OADMs) based on asymmetric Y branches and tilted gratings offer excellent-performance in wavelength-division multiplexed systems. To simplify waveguide fabrication, ion-exchange techniques appear to be an important option in photosensitive glasses. Optimum OADM performance depends on how accurately the waveguide fabrication process and tilted Bragg grating operation are understood and modeled. Results from fabrication and comprehensive modeling are compared for ion-exchange processes that use different angles of the tilted grating. The transmission and reflection spectra for the fabricated and simulated OADMs show excellent agreement. The OADM’s performance is evaluated in terms of the measured characteristics of the Y branches and tilted gratings

Ion-exchanged waveguide add/drop filter

An add/drop filter is fabricated using ion-exchanged waveguides and photowritten Bragg gratings. The device exhibits 20 dB extinction ratios and 3 dB bandwidths of 0.4 nm (100 GHz)

Generalized Parton Distributions from Hadronic Observables: Zero Skewness

We propose a physically motivated parametrization for the unpolarized generalized parton distributions. At zero value of the skewness variable, $\zeta$, the parametrization is constrained by simultaneously fitting the experimental data on both the nucleon elastic form factors and the deep inelastic structure functions. A rich phenomenology can be addressed based on this parametrization. In particular, we track the behavior of the average: {\it i)} interparton distances as a function of the momentum fraction, $X$, {\it ii)} $X$ as a function of the four-momentum transfer, $t$; and {\it iii)} the intrinsic transverse momentum $k_\perp$ as a function of $X$. We discuss the extension of our parametrization to $\zeta \neq 0$ where additional constraints are provided by higher moments of the generalized parton distributions obtained from {\it ab initio} lattice QCD calculations.Comment: 42 pages, 21 figure

Long term life dissatisfaction and subsequent major depressive disorder and poor mental health

<p>Abstract</p> <p>Background</p> <p>Poor mental health, especially due to depression, is one of the main public health problems. Early indicators of poor mental health in general population are needed. This study examined the relationship between long-term life dissatisfaction and subsequent mental health, including major depressive disorder.</p> <p>Method</p> <p>Health questionnaires were sent to a randomly selected population-based sample in 1998 and repeated in 1999 and 2001. In 2005, a clinically studied sub-sample (n = 330) was composed of subjects with (n = 161) or without (n = 169) repeatedly reported adverse mental symptoms at all three previous data collection times. Clinical symptom assessments were performed with several psychometric scales: life satisfaction (<b>LS</b>), depression (<b>HDRS, BDI</b>), hopelessness (<b>HS</b>), mental distress (<b>GHQ</b>), dissociative experiences (<b>DES</b>), and alexithymia (<b>TAS</b>). The long-term life dissatisfaction burden was calculated by summing these life satisfaction scores in 1998, 1999, 2001 and dividing the sum into tertiles. Psychiatric diagnoses were confirmed by SCID-I for DSM-IV in 2005. Logistic regression analyses were performed to assess the studied relationship.</p> <p>Results</p> <p>The previous life dissatisfaction burden associated with adverse socio-demographic, life style and clinical factors. In adjusted logistic regression analyses, it was independently and strongly associated with subsequent major depressive disorder in 2005, even when the concurrent LS score in 2005 was included in the model. Excluding those with reported major depressive disorder in 1999 did not alter this finding.</p> <p>Limitations</p> <p>MDD in 1999 was based on self-reports and not on structured interview and LS data in 2001-2005 was not available.</p> <p>Conclusions</p> <p>The life satisfaction burden is significantly related to major depressive disorder and poor mental health, both in cross-sectional and longitudinal settings.</p

Buried Ion-Exchanged Glass Wavelengths: Burial-Depth Dependence on Waveguide Width

A detailed theoretical and experimental study of the depth dependence of buried ion-exchanged waveguides on waveguide width is reported. Modeling, which includes the effect of nonhomogeneous time-dependent electric field distribution, agrees well with our experiments showing that burial depth increases linearly with waveguide width. These results may be used in the proper design of integrated optical circuits that need waveguides of different widths at different sections, such as arrayed waveguide gratings

Polarisation-independent Bragg gratings in ion-exchanged glass channel waveguides

The polarisation dependence of Bragg gratings photowritten in ion-exchanged glass waveguides is characterised for waveguides with different mask-opening widths and burial depths. It is found that polarisation-independent gratings can be written in waveguides with a wide variation in fabrication parameters

The association between major depressive disorder, use of antidepressants and bone mineral density (BMD) in men.

OBJECTIVE: Both depression and use of antidepressants have been negatively associated with bone mineral density (BMD) but mainly in studies among postmenopausal women. Therefore, the aim of this study was to investigate these relationships in men. METHODS: Between 2006 and 2011, 928 men (aged 24-98 years) from the Geelong Osteoporosis Study completed a comprehensive questionnaire, clinical measurements and had BMD assessments at the forearm, spine, total hip and total body. Major depressive disorder (MDD) was identified using a structured clinical interview (SCID-I/NP). The cross-sectional associations between BMD and both MDD and antidepressant use were analyzed using multivariable linear regression. RESULTS: Of the study population, 84 (9.1%) men had a single MDD episode, 50 (5.4%) had recurrent episodes and 65 (7.0%) were using antidepressants at the time of assessment. Following adjustments, recurrent MDD was associated with lower BMD at the forearm and total body (-6.5%, P=0.033 and -2.5%, P=0.033, respectively compared to men with no history of MDD), while single MDD episodes were associated with higher BMD at the total hip (+3.4%, P=0.030). Antidepressant use was associated with lower BMD only in lower-weight men (&lt;75-110 kg depending on bone site). CONCLUSIONS: Both depression and use of antidepressants should be taken into account as possible risk factors for osteoporosis in men