Bioremediation of diesel oil contaminated soil and water

Diesel spills contaminate aquatic and terrestrial environments. To prevent the environmental and health risks, the remediation needs to be advanced. Bioremediation, i.e., degradation by microbes, is one of the suitable methods for cleaning diesel contamination. In monitored natural attenuation technique are natural processes in situ combined, including bioremediation, volatilization, sorption, dilution and dispersion. Soil bacteria are capable of adapting to degrade environmental pollutants, but in addition, some soil types may have indigenous bacteria that are naturally suitable for degradation. The objectives for this work were (1) to find a feasible and economical technique to remediate oil spilled into Baltic Sea water and (2) to bioremediate soil contaminated by diesel oil. Moreover, the aim was (3) to study the potential for natural attenuation and the indigenous bacteria in soil, and possible adaptation to degrade diesel hydrocarbons. In the aquatic environment, the study concentrated on diesel oil sorption to cotton grass fiber, a natural by-product of peat harvesting. The impact of diesel pollution was followed in bacteria, phytoplankton and mussels. In a terrestrial environment, the focus was to compare the methods of enhanced biodegradation (biostimulation and bioaugmentation), and to study natural attenuation of oil hydrocarbons in different soil types and the effect that a history of previous contamination may have on the bioremediation potential. (1) In the aquatic environment, rapid removal of diesel oil was significant for survival of tested species and thereby diversity maintained. Cotton grass not only absorbed the diesel but also benefited the bacterial growth by providing a large colonizable surface area and hence oil-microbe contact area. Therefore use of this method would enhance bioremediation of diesel spills. (2) Biostimulation enhances bioremediation, and (3) indigenous diesel-degrading bacteria are present in boreal environments, so microbial inocula are not always needed. In the terrestrial environment experiments, the combination of aeration and addition of slowly released nitrogen advanced the oil hydrocarbon degradation. Previous contamination of soil gives the bacterial community the potential for rapid adaptation and efficient degradation of the same type of contaminant. When the freshly contaminated site needs addition of diesel degraders, previously contaminated and remediated soil could be used as a bacterial inoculum. Another choice of inoculum could be conifer forest soil, which provides a plentiful population of degraders, and based on the present results, could be considered as a safe non-polluted inoculum. According to the findings in this thesis, bioremediation (microbial degradation) and monitored natural attenuation (microbial, physical and chemical degradation) are both suitable techniques for remediation of diesel-contaminated sites in Finland.

Technique for Using Fine-Grained Soil in Reinforced Earth

The performance of reinforced earth structures depends on the mobilization of interfacial shearing resistance between soil and reinforcement. This criterion typically eliminates the use of fine-grained soil as a backfill material in reinforced earth structures. Considering the distribution of induced interfacial shear stress in soil around the surface of the reinforcement, it has been shown that only a thin zone of frictional material around the reinforcement is required to mobilize almost full interfacial shearing resistance of sand. Six series of pullout tests have been conducted, with different types of reinforcement, to study the effect of thickness of sand (frictional material) around the reinforcement on the pullout resistance. Sawdust and kaolin clay have been used as bulk backfill material, providing the soil with negligible friction. With low-friction-strength soil as bulk material, a 15-mm thickness of sand around the reinforcement is required to increase the interfacial shearing resistance to that with sand as the bulk material. With this new technique, low-frictional fine-grained soils can be used as bulk backfill material in reinforced earth constructions.

A measurement technique for low frequencies

A technique for the measurement of frequency within a cycle of a periodic input is described. This can be useful for quicker measurement of low frequencies.

Energy efficient asymmetric binary search switching technique for SAR ADC

An asymmetric binary search switching technique for a successive approximation register (SAR) ADC is presented, and trade-off between switching energy and conversion cycles is discussed. Without using any additional switches, the proposed technique consumes 46% less switching energy, for a small input swing (0.5 V-ref (P-P)), as compared to the last reported efficient switching technique in literature for an 8-bit SAR ADC. For a full input swing (2 V-ref (P-P)), the proposed technique consumes 16.5% less switching energy.

Amplitude Frequency Response Measurement: A Simple Technique

A simple method is described to combine a modern function generator and a digital oscilloscope to configure a setup that can directly measure the amplitude frequency response of a system. This is achieved by synchronously triggering both instruments, with the function generator operated in the ``Linear-Sweep'' frequency mode, while the oscilloscope is operated in the ``Envelope'' acquisition mode. Under these conditions, the acquired envelopes directly correspond to the (input and output signal) spectra, whose ratio yields the amplitude frequency response. The method is easy to configure, automatic, time-efficient, and does not require any external control or interface or programming. This method is ideally suited to impart hands-on experience in sweep frequency response measurements, demonstrate resonance phenomenon in transformer windings, explain the working principle of an impedance analyzer, practically exhibit properties of network functions, and so on. The proposed method is an inexpensive alternative to existing commercial equipment meant for this job and is also an effective teaching aid. Details of its implementation, along with some practical measurements on an actual transformer, are presented.

A geodesic-based triangulation technique for damage location in metallic and composite plates

Lamb-wave-based damage detection methods using the triangulation technique are not suitable for handling structures with complex shapes and discontinuities as the parametric/analytical representation of these structures is very difficult. The geodesic concept is used along with the triangulation technique to overcome the above problem. The present work is based on the fundamental fact that a wave takes the minimum energy path to travel between two points on any multiply connected surface and this reduces to the shortest distance path or geodesic. The geodesics are computed on the meshed surface of the structure using the fast marching method. The wave response matrix of the given sensor configuration for the healthy and the damaged structure is obtained experimentally. The healthy and damage response matrices are compared and their difference gives the time information about the reflection of waves from the damage. A wavelet transform is used to extract the arrival time information of the wave scattered by the damage from the acquired Lamb wave signals. The computed geodesics and time information are used in the ellipse algorithm of triangulation formulation to locate the loci of possible damage location points for each actuator-sensor pair. The results obtained for all actuator-sensor pairs are combined and the intersection of multiple loci gives the damage location result. Experiments were conducted in aluminum and composite plate specimens to validate this method.

Precursor Dependent Microstructure Evolution and Nonstoichiometry in Nanostructured Cerium Oxide Coatings Using the Solution Precursor Plasma Spray Technique

A solution precursor plasma spray (SPPS) technique has been used for direct deposition of cerium oxide nanoparticles (CNPs) from various cerium salt solutions as precursors. Solution precursors were injected into the hot zone of a plasma plume to deposit CNP coatings. A numerical study of the droplet injection model has been employed for microstructure development during SPPS. The decomposition of each precursor to cerium oxide was analyzed by thermogravimetric-differential thermal analysis and validated by thermodynamic calculations. The presence of the cerium oxide phase in the coatings was confirmed by X-ray diffraction studies. Transmission electron microscopy studies confirmed nanocrystalline (grain size <14 nm) characteristic of the coatings. X-ray photoelectron spectroscopy studies indicated the presence of a high concentration of Ce3+ (up to 0.32) in the coating prepared by SPPS. The processing and microstructure evolution of cerium oxide coatings with high nonstoichiometry are reported.

Single‐gate deep level transient spectroscopy technique

A new deep level transient spectroscopy technique is suggested which allows the deep level parameters to be obtained from a single temperature scan. Using large ratio t2/t1 of the measurement gate positions t1 and t2 and analyzing the steep high‐temperature side of the peak, it is demonstrated that the deep level activation energy can be determined with high accuracy.

Carotid Surgery : A posse ad esse non valet consequentia

According to a large body of evidence, carotid endarterectomy (CEA) can prevent strokes, provided that appropriate inclusion criteria and high-quality perioperative treatment methods are utilised with low complication rates. From the patient s perspective, it is of paramount importance that the operation is as safe and effective as possible. From the community s point of view, it is important that CEA provision prevents as many strokes as possible. In order to define the stroke preventing potential of CEA in different communities, a comparison between eight European countries and Australia was performed including 53 077 carotid interventions. A more detailed evaluation was performed in Finland, the United Kingdom and Egypt. It could be estimated that many potentially preventable strokes occur due to insufficient diagnostics and CEA provision. The number of CEAs should be at least doubled in the Helsinki region. The theoretical power of CEA provision in stroke prevention varied significantly between the countries. Delay from symptom to surgery has been identified as one of the most important factors influencing the effectiveness of CEA. In 2008 only 11% of CEAs in Helsinki university central hospital (HUCH) were performed within the recommended14 days. Registered data of 673 CEAs in HUCH during 2000-2005 was analyzed. There was no systematic error that would have changed the outcome analysis. However it is important that registers are audited regularly and cross matching of different registries is possible. A previously unpublished method of combining medial mandibulotomy, neck incision and carotid artery interposition was carried out as a collaboration of maxillofacial, ear, nose and throat and vascular surgeons. Five patients were operated on with a technique that was feasible and possible to perform with little morbidity, but due to the significant risks involved, this technique should be reserved for carefully selected cases. In stroke prevention, organisational decisions seem far more important than details in interventional procedures when CEA is performed with low complication rates, as was the case in the present study. A TIA clinic approach with close co-operation between the on-call vascular surgeons, neurologists and radiologists should be available at all centres treating these patients. Patients should have a direct and fast admission to the hospital performing CEA.

A mimetic-based frequency domain technique for automatic generation of EEG reports

This paper describes a novel mimetic technique of using frequency domain approach and digital filters for automatic generation of EEG reports. Digitized EEG data files, transported on a cartridge, have been used for the analysis. The signals are filtered for alpha, beta, theta and delta bands with digital bandpass filters of fourth-order, cascaded, Butterworth, infinite impulse response (IIR) type. The maximum amplitude, mean frequency, continuity index and degree of asymmetry have been computed for a given EEG frequency band. Finally, searches for the presence of artifacts (eye movement or muscle artifacts) in the EEG records have been made.

A novel laser direct write technique for fabrication of thin film MICs

A technique for fabrication of thin-film circuits for microwave integrated circuit (MIC) application is presented. This low-cost fabrication technique utilizes laser direct write of copper patterns on alumina substrates. The method obviates the need for photomasks and photolithography. The film deposition mechanism, deposit film analysis, and MIC fabrication sequence are presented. Performance evaluation of MICs fabricated using this technique is also included

Desorptio/fotoionisaatio ilmanpaineessa takavarikoitujen huumausaineiden, steroidien ja räjähdysaineiden tutkimuksessa

Tutkimuksen tarkoituksena oli selvittää desorptio/fotoionisaatio ilmanpaineessa tekniikan (engl. desorption atmospheric pressure photoionization, DAPPI) soveltuvuutta rikosteknisen laboratorion näytteiden analysointiin. DAPPI on nopea massaspektrometrinen ionisaatiotekniikka, jolla voidaan tutkia yhdisteitä suoraan erilaisilta pinnoilta. DAPPI:ssa käytetään lämmitettyä mikrosirua, joka suihkuttaa höyrystynyttä liuotin- ja kaasuvirtausta kohti näytettä. Näytteen pinnan komponentit desorboituvat lämmön vaikutuksesta, jonka jälkeen ionisoituminen tapahtuu VUV-lampun emittoimien fotonien avulla.DAPPI:lla tutkittiin takavarikoituja huumausaineita, anabolisia steroideja ja räjähdysaineita sekä niiden jäämiä erilaisilta pinnoilta. Lisäksi kartoitettiin DAPPI:n mahdollisuuksia ja rajoituksia erilaisille näytematriiseille ilman näytteiden esikäsittelyä. Takavarikoitujen huumausaineiden tutkimuksessa analysoitiin erilaisia tabletteja, jauheita, kasvirouheita, huumekasveja (khat, oopium, kannabis) ja sieniä. Anabolisia steroideja tunnistettiin tableteista sekä ampulleista, jotka sisälsivät öljymäistä nestettä. Jauheet ripoteltiin kaksipuoliselle teipille ja analysoitiin siltä. Muut näytteet analysoitiin sellaisenaan ilman minkäänlaista esikäsittelyä, paitsi nestemäisten näytteiden kohdalla näyte pipetoitiin talouspaperille, joka analysoitiin DAPPI:lla. DAPPI osoittautui nopeaksi ja yksinkertaiseksi menetelmäksi takavarikoitujen huumausaineiden ja steroidien analysoimisessa. Se soveltui hyvin rikoslaboratorion erityyppisten näytteiden rutiiniseulontaan ja helpotti erityisesti huumekasvien ja öljymäisten steroidiliuosten tutkimusta. Massaspektrometrin likaantuminen pystyttiin ehkäisemään säätämällä näytteen etäisyyttä sen suuaukosta. Likaantumista ei havaittu huolimatta näytteiden korkeista konsentraatioista ja useita kuukausia jatkuneista mittauksista. Räjähdysaineiden tutkimuksessa keskityttiin seitsemän eri räjähdysaineen DAPPI-MS-menetelmän kehitykseen; trinitrotolueeni (TNT), nitroglykoli (NK), nitroglyseriini (NG), pentriitti (PETN), heksogeeni (RDX), oktogeeni (HMX) ja pikriinihappoä Nämä orgaaniset räjähteet ovat nitraattiyhdisteitä, jotka voidaan jakaa rakenteen puolesta nitroamiineihin (RDX ja HMX), nitroaromaatteihin (TNT ja pikriinihappo) sekä nitraattiestereihin (PETN, NG ja NK). Menetelmäkehityksessä räjähdysainelaimennokset pipetoitiin polymetyylimetakrylaatin (PMMA) päälle ja analysoitiin siitä. DAPPI:lla tutkittiin myäs autenttisia räjähdysainejäämiä erilaisista matriiseista. DAPPI:lla optimoitiin jokaiselle räjähdysaineelle sopiva menetelmä ja yhdisteet saatiin näkymään puhdasaineina. Räjähdysainejäämien analysoiminen erilaisista rikospaikkamateriaaleista osoittautui haastavammaksi tehtäväksi, koska matriisit aiheuttivat itsessään korkean taustan spektriin, josta räjähdysaineiden piikit eivät useimmiten erottuneet tarpeeksi. Muut desorptioionisaatiotekniikat saattavat soveltua paremmin haastavien räjähdysainejäämien havaitsemiseksi.