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Strukturiranje sol-gel funkcionaliziranih celuloznih hibridnih materialov in njihova karakterizacija
Get PDFThe goal of this thesis is the structuring of cellulose nanocrystals using different organofunctional silane compounds and different cationic species to prepare highly functional materials with tailored properties. In addition different new aspects and approaches for the structural characterization of functionalised cellulose nanocrystals (CNC) functionalised with different organofunctionalalkoxysilanes as well as cationic species have been introduced.
Cellulose nanocrystals (CNC) are prepared using three different acidic conditions to hydrolyse microcrystalline cellulose (MCC). The sulphuric acid hydrolysis introduces highly negative charged sulphate groups on the CNC. The aqueous nanocrystalline cellulose suspensions (aNCS) are analysed in terms of ζ-potential related to the pH and concentration to investigate the stability while dynamic light scattering (DLS) is used to investigate the size distribution. The hydrochloric acid hydrolysis in contrast only removes the amorphous regions but the so obtained CNC are less stabilized (decreased ζ-potential) and tend to agglomerate very fast. The use of the mixture of both acids (HCl and H2SO4) during the hydrolysis of MCC introduces less sulphate groups compared with the sulphuric acid hydrolysis. AFM investigations show that the shapes of the CNC are highly influenced by the hydrolysis conditions. While the shape of the H2SO4 hydrolysed CNC is rod like, while the shape of the other two CNC samples is more spherical in nature. One of the major topic in this work is the analysis of aNCS in aqueous solutions by small angle x-ray scattering (SAXS). The use of the generalized indirect Fourier transformation (GIFT) method allows the analysis of these systems and structural properties such as shape, size and surface charge of aNCS can be assessed. Using this kind of characterisation it can be seen that the shape of the H2SO4 hydrolysed CNC is definitely rod like while the other CNC sample can be described with spheres. In addition to the aNCS characterisation different substrates (Si-wafer, glass slides, polystyrene, etc.) are equipped with aNCS using a variety of different deposition methods (e.g. spin coating, solution casting, dip coating). The resulting films are studied in terms of morphology AFM, SARFUS and SEM. Sophisticated scattering techniques are employed for surface structural characterisation as grazing incidence small angel x-ray scattering. The determination of surface free energies allows conclusions about the hydrophilicity and hydrophobicity as well as the interaction capacity with different liquids. It can be seen that besides the hydrophilic nature of the CNC also hydrophobic interactions are present. The highly negative charged CNC sample which was prepared using sulphuric acid hydrolysis is found to be best suitable for the further hybridization with different organofunctional silanes and for the layer by layer approach (LBL) with different cationic species.
The organofunctionalalkoxysilanes which were used in this study can be divided into three groups (e.g filler, surface functionalisation silanes, cross linking silanes). Depending on the nature of the organic residue the silanes are capable to introduce functionalities with enhanced hydrophobic and olephobic properties. The surface energies are investigated using contact angle method, while the surface energies are calculated using three different model approaches (OWRK, Wu, Acid-Base). The most increased hydrophobic and oleophobic properties were measured for trimethylfluorophenylsilantriol (PFTEOS). The morphology of the coated silanes is investigated using SAFRUS technique. It can be seen that nearly all silanes can be coated as homogeneous films onto different substrates (Si-wafer, SURFs, glass slides) with different methods (spin coating, solution casting). The macroscopic appearance of solution casted silanes is investigated using optical microscopy. The differences of the structural nature of the so obtained coatings and detaching films were investigated...Namen doktorske naloge je strukturiranje celuloznih nano-kristalov z uporabo različnih organsko-funkcionalnih silanov in različnih kationskih sredstev za pripravo funkcionalnih materialov s kontroliranimi lastnostmi.Disertacija je razdeljena v štiri dele.
V prvem delu smo se osredotočili predvsem na pripravo in karakterizacijo celuloznih nano-kristalov (CNC), ki smo jih sintetizirali pri različnih hidroliznih pogojih. Kot vir celuloze je bila uporabljena mikrokristalina celuloza (MCC), pridobljena iz bombaža, za hidrolizo pa smo uporabili žveplovo in klorovo kislino, ter mešanico obeh. Glavni namen tega dela raziskave je stabilizacija celuloznih nano-kristalov v različnih topilih, kar smo dosegli z uvedbo sulfatnih estrov na površino delcev, ki zagotavljajo elektrostatični odboj. Te skupine izkazujejo negativni naboj v celotnem pH območju in tako učinkovito stabilizirajo CNC delce. Celuloznim nano-kristalom smo določili ζ-potencial v odvisnosti od pH vrednosti disperzije ter koncentracije delcev, z dinamičnim sipanjem svetlobe (DLS) pa smo določili njihov raztros velikosti. Eden najpomembnejših dosežkov predstavljene raziskave je analiza koncentriranih vodnih disperzij celuloznih nano-kristalov z ozkokotnim rentgenskim sipanjem (SAXS).Uporaba posplošene indirektne Fourierjeve transformacije (generalized indirect Fourier transformationGIFT) omogoča določitev strukturnih lastnosti CNC delcev, kot so oblika, velikost ter površinski naboj. Celulozne nano-kristale smo nanesli na različne substrate (silicijeve ploščice, objektna stekla, polistirenske ploščice) z različnimi načini nanašanja. Morfologijo nastalih filmov smo analizirali z uporabo mikroskopije na atomsko silo (AFM), Sarfus tehniko ter vrstično elektronsko mikroskopijo. Za karakterizacijo površin smo prav tako uporabili sofisticirano sipalno metodo, kar predstavlja drugi pomemben dosežek predstavljenega doktorskega dela.Z določanjem proste površinske energije smo raziskali hidrofilno – hidrofoben značaj pripravljenih plasti ter njihovo interakcijsko sposobnost z različnimi tekočinami.Filme, ki smo jih formirali v vodi in etanolu smo analizirali z ozkokotnim in širokokotnim rentgenskim sipanjem, ter tako določili nanometrske lastnosti CNC delcev.Zelo nabiti CNC delci, pripravljeni s hidrolizo z žveplovo kislino, so se izkazali za najprimernejše za nadaljnjo funkcionalizacijo z različnimi organsko-funkcionalnimi silani ter za plastenje z različnimi kationskimi sredstvi.
Drugi del disertacije se osredotoča na karakterizacijo različnih organsko-funkcionalnih silanov. Uporabljene silane lahko razdelimo v tri skupineprvo skupino predstavljajo silani, ki ne hidrolizirajo in se uporabljajo kot polnilci. V drugi skupini se nahajajo silani za funkcionalizacijo površinti imajo tri organske skupine vezane na silicijev atom in le eno skupino, ki hidrolizira. Tretjo skupino pa predstavljajo zamreževalni silani z le eno organsko skupino in tremi skupinami, ki hidrolizirajo in omogočajo zamreženje.Vse alkoksisilane smo hidrolizirali v kislem etanolu ter raziskali njihovo uporabnost. Z merjenjem površinske napetosti smo ugotavljali tendenco akumuliranja silanov na tekoče-plinski fazni meji. Predhodno hidrolizirane raztopine silanov smo nanesli na različne substrate ( silicijeve ploščice, objektna stekla, polistirenske ploščice). Makroskopsko morfologijo teh plasti smo raziskali z optično mikroskopijo in Sarfus tehniko, z določanjem stičnih kotov pa smo okarakterizirali površinsko energijo nastalih filmov.
V tretjem delu disertacije je opisana priprava in karakterizacija hibridnih materialov
Directional location of buried objects using three-component magnetic borehole data demonstrated for the case of a drill string
No full textOne of the main applications of magnetic field measurements in boreholes is the detection of unexploded ordnance or buried utility structures like pipes or tiebacks. Even though the advantage of fully oriented magnetic vector measurements have long been recognized and could significantly reduce costs and risks, the tools used for those purposes typically measure only the total magnetic field, the vertical and horizontal components or gradients thereof. The Gottingen Bohrloch Magnetometer uses three fibre optic gyros to record its orientation and thus enables us to compute high-quality three-component magnetic vector data regardless of borehole orientation. The measurements described in this paper were run in the scientific borehole Cuxhaven Ludingworth 1/1A, which was drilled as a part of the 'Coastal Aquifer Test field' project to study the dynamics of the saltwater/freshwater interface. As the drill string got stuck during drilling of the first borehole, a second hole was drilled in the immediate vicinity. The drill string lies at a depth between 80 and 114 m at a distance of only 2.5 m southeast of the borehole used for the measurements, making it an ideal target to demonstrate the benefits of vector magnetic surveys. Although the theories to calculate magnetic fields of objects with different shapes is well established and do not need to be tested, they almost exclusively include approximations of the geometry. It is not obvious whether these approximations are suited to describe real data, or whether additional effects or refinements have to be considered. We use both a simplified monopole model and a cylinder model to fit the data and are able to determine the position of the drill string within a statistical error of approximately 10 cm. Additionally, we show that the location of the drill string could not have been determined by measurements of the total field or its horizontal and vertical component alone and that those methods would require the drilling of additional boreholes to obtain an unambiguous result.Empting Kran- und Handelsgesellschaf
Accelerating total body irradiation with large field modulated arc therapy in standard treatment rooms without additional equipment
No full textPurpose The aim of this study was to develop a generic and ultra-efficient modulated arc technique for treatment with total body irradiation (TBI) without additional equipment in standard treatment rooms. Methods A continuous gantry arc between 300 degrees and 70 degrees composed of 26 subarcs (5 degrees per subarc) using a field size of 40 x 40 cm(2) was used to perform the initial beam data measurements. The profile was measured parallel to the direction of gantry rotation at a constant depth of 9 cm (phantom thickness 18 cm). Beam data were measured for single 5 degrees subarcs, dissecting the individual contribution of each subarc to a certain measurement point. The phantom was moved to 20 measurement positions along the profile. Then profile optimization was performed manually by varying the weighting factors of all segments until calculated doses at all points were within +/- 1 %. Finally, the dose distribution of the modulated arc was verified in phantom thicknesses of 18 and 28 cm. Results The measured profile showed a relative mean dose of 99.7 % [standard deviation (SD) 0.7 %)] over the length of 200 cm at a depth of 9 cm. The measured mean effective surface dose (at a depth of 2 cm) was 102.7 % (SD 2.1 %). The measurements in the 28 cm slab phantom revealed a mean dose of 95.9 % (SD 2.9 %) at a depth of 14 cm. The mean dose at a depth of 2 cm was 111.9 % (SD 4.1 %). Net beam-on-time for a 2 Gy fraction is approximately 8 min. Conclusion This highly efficient modulated arc technique for TBI can replace conventional treatment techniques, providing a homogeneous dose distribution, dosimetric robustness, extremely fast delivery, and applicability in small treatment rooms, with no need for additional equipment
Paleomagnetic inclination and declination from three‐component borehole magnetometer data—New insights from logging in the Louisville seamounts
No full textWe carried out measurements of the magnetic field vector at two sites during Integrated Ocean Drilling Program (IODP) Expedition 330 to the Louisville Seamount Chain. The aim was to impose constraints on the magnetization direction and to contribute to the reconstruction of possible hot spot motion. The measurements were conducted using the Gottingen Borehole Magnetometer (GBM). It comprises three fiber optic gyros (FOG) that can be used to reorient the magnetic field data. To improve accuracy, we are using a new algorithm that combines FOG data and data of two inclinometers. As can be evaluated by comparing downlog and uplog of the measurements, the three-dimensional magnetic field data obtained is of good quality. An interpretation of the magnetic field data using a state of the art method based on horizontal layers yields results inconsistent with measurements of the natural remanent magnetization (NRM) of drill core samples. In the following, we define the magnetization from the horizontal layer as apparent magnetization and develop a new interpretation method based on dipping layers. Our method includes a new approximate forward modeling algorithm and considerably improves the consistency of the borehole measurements and the NRM data. We show that a priori information about the geometry of a layer is required to constrain the inclination and declination of magnetization. Especially the azimuth of a layer and the declination of magnetization cannot be determined separately. Using azimuth and layer dip information from borehole images, we obtain constraints on inclination and declination for one particular layer.DFG [Ho1506/21-1, Le1293/2-1
Convective characteristics of Fe
Get PDFContext. Solar convection is visible as a net blueshift of absorption lines, which becomes apparent when observing quiet Sun granulation. This blueshift exhibits variations from the disc centre to the solar limb due to differing projection angles onto the solar atmosphere.
Aims. Our goal is to investigate convective Doppler velocities based on observations from the disc centre to the solar limb. Consequently, we aim to improve our understanding of atmospheric hydrodynamics and contribute to the improvement of solar and stellar atmospheric models.
Methods. We used resolved quiet-Sun spectra to investigate the convective velocity shifts of more than 1000 Fe
Are There Options to Prevent Early Occurring Deaths in Acute Myocardial Infarction: Prospective Evaluation of All < 24 h In-Hospital Deaths, 2004-2006-The MONICA/KORA Augsburg Infarction Registry
Get PDFObjectives: To provide valid clinical data of early in-hospital deaths with presumed acute myocardial infarction (AMI) who are often not included in clinical trials or registries. Methods: From August 2004 to August 2006 all patients (age 25-84 years) dying within 24 h after hospitalization in a large tertiary care academic teaching hospital were screened regarding an underlying cardiovascular cause of death. Results: After validation, 79 out of 1,352 patients remained with a final diagnosis of AMI. Sixty-six percent of these experienced prehospital cardiac arrest or shock. In 37% no resuscitation attempts were performed in-hospital, the most common reason being multimorbidity. Only 23% could be transferred to coronary angiography for revascularisation attempts. An independent panel of clinicians judged that only in one patient would another management strategy have been promising. Of interest, 33% of the deceased patients had typical or atypical chest pain the days before the lethal event. Conclusion: A large percentage of AMI patients who died soon after hospitalization were in critical circulatory state directly before hospitalization. In 37%, in-hospital resuscitation attempts were omitted for understandable reasons. Options for improvement in acute care in the investigated setting were not found. However, in one third of the cases earlier preventive measures might have been reasonable. Copyright (C) 2010 S. Karger AG, Base
Analysis of the Importance of SMART Therapy in the German Asthma Network
No full textHinze C, Ehmann R, Jandl M, et al. Analyse des Stellenwertes der SMART Therapie im German Asthma Network. Pneumologie . 2024;78(Suppl. 1):S5
Reorientation of three‐component borehole magnetic data
No full textThree-component borehole magnetics provide important additional information compared to total field or horizontal and vertical measurements. These data can be used for several tasks such as the localization of ferromagnetic objects, the determination of apparent polar wander curves and the computation of the magnetization of rock units. However, the crucial point in three-component borehole magnetics is the reorientation of the measured data from the tool's frame to the geographic reference frame North, East and Downwards. For this purpose, our tool, the Gottinger Borehole Magnetometer, comprises three orthogonally aligned fibre optic gyros along with three fluxgate sensors. With these sensors, the vector of the magnetic field along with the tool rotation can be recorded continuously during the measurement. Using the high-precision gyro data, we can compute the vector of the magnetic anomaly with respect to the Earth's reference frame. Based on the comparison of several logs measured in the Outokumpu Deep Drill Hole (OKU R2500, Finland), the repeatability of the magnetic field vector is 0.8 degrees in azimuthal direction, 0.08 degrees in inclination and 71 nT in magnitude.DFG [HO 1506/16 1, LE 1293/1 1
Narrative Language as an Expression of Individual and Group Identity
No full textScientific Narrative Psychology integrates quantitative methodologies into the study of identity. Its methodology, Narrative Categorical Analysis, and its toolkit, NarrCat, were both originally developed by the Hungarian Narrative Psychology Group. NarrCat is for machine-made transformation of sentences in self-narratives into psychologically relevant, statistically processable narrative categories. The main body of this flexible and comprehensive system is formed by Psycho-Thematic modules, such as Agency, Evaluation, Emotion, Cognition, Spatiality, and Temporality. The Relational Modules include Social References, Semantic Role Labeling (SRL), and Negation. Certain elements can be combined into Hypermodules, such as Psychological Perspective and Spatio-Temporal Perspective, which allow for even more complex, higher level exploration of composite psychological processes. Using up-to-date developments of corpus linguistics and Natural Language Processing (NLP), a unique feature of NarrCat is its capacity of SRL. The structure of NarrCat, as well as the empirical results in group identity research, is discussed
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
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