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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

Kost, träning och återhämtning : En kvalitativ studie av idrottares uppfattningar / Nutrition, training and recovery : A qualitative study of athletes’ perceptions

Nilsson, Viktoria January 2016 (has links)
Background: Large components for athletes are nutrition, training and recovery. These components are subjects all by them selves in all kind of media. That woke my interest to find out more about the connections between nutrition, training and recovery and how much knowledge athletes have of them together. Objectives: The purpose of this study is to investigate how athletes feelings and experience of nutrition, training and recovery. Method: A qualitative approach was used to investigate athletes eye on nutrition, training and recovery. Ten interviews were done face to face and notes was taken since no recording were done. Results: The results of the study shows that athletes don’t have experience of nutrition, training and recovery together. Athletes have knowledge of nutrition, training and recovery one by one. The study showed the athletes the dependency of nutrition, training and recovery together. The athletes did all the components by themselves but had not the knowledge of how big the dependencies was between the components. The athletes wanted to learn more about the dependencies to take advantage of the components in their own training.
202

Ανάκτηση ανόργανων φωσφορικών από αστικά υδατικά λύματα

Ματσούκη, Νίκη 11 October 2013 (has links)
O φωσφόρος είναι ένα χημικό στοιχείο με πολλές λειτουργικότητες. Μία από τις βασικές χρήσεις του είναι ότι αποτελεί αναντικατάστατο λίπασμα ενώ επιπλέον είναι βασικό συστατικό του γενετικού υλικού, των κυτταρικών μεμβρανών, των οστών και των δοντιών, απαραίτητο στοιχείο της διατροφής ανθρώπων και ζώων κλπ. Η παρουσία υψηλών συγκεντρώσεων φωσφόρου στα υδάτινα οικοσυστήματα είναι ιδιαιτέρως βλαβερή καθώς αποτελεί την κύρια αιτία του ευτροφισμού. Αυξημένες ποσότητες φωσφόρου υπάρχουν στα αστικά υγρά απόβλητα, γεγονός που καθιστά αναγκαία την επεξεργασία τους για την απομάκρυνση του, πριν την τελική διάθεση τους στους υδάτινους αποδέκτες. Δεδομένου του ότι, ο φώσφορος προέρχεται από ορυκτά αποθέματα, τα οποία δεν είναι ανεξάντλητα, είναι επιβεβλημένη η ανάκτησή του, η οποία αποτελεί συμβολή στην αειφορία. Μία από τις μεθόδους ανάκτησης του φωσφόρου η οποία κερδίζει όλο και περισσότερο ερευνητικό ενδιαφέρον τα τελευταία χρόνια, είναι η καταβύθιση του με την μορφή στρουβίτη. Ο στρουβίτης, (MgΝΗ4PO4.6H2O) είναι ένα λευκό κρυσταλλικό στερεό το οποίο μπορεί να χρησιμοποιηθεί ως βραδέως αποδεσμευόμενο λίπασμα, εμπλουτίζοντας τις καλλιέργειες με τρία από πιο βασικά θρεπτικά συστατικά. Στην παρούσα εργασία μελετήθηκε η καταβύθιση στρουβίτη από υπέρκορα διαλύματα, η σύσταση των οποίων, προσομοιώνει την αντίστοιχη των αστικών υδατικών λυμάτων ως προς την περιεκτικότητα σε φωσφόρο και αμμωνία, σε αντιδραστήρα συνεχούς λειτουργίας του 1L. Η κινητική της καταβύθισης μελετήθηκε σε συνθήκες σταθερού υπερκορεσμού, pH 9.00 στους 25οC. Τα πειράματα πραγματοποιήθηκαν σε διαλύματα υπέρκορα ως προς στρουβίτη, στα οποία η στοιχειομετρική αναλογία των πλεγματικών ιόντων, ήταν 1:1:1 και 1:1:3 ως προς οποιοδήποτε από τα τρία ιόντα. Επίσης, μελετήθηκε καταβύθιση του στρουβίτη σε υπέρκορα διαλύματα παρουσία Na¬2SO4 και με διαβίβαση αέρα μέσω των διαλυμάτων. Τα αποτελέσματα των πειραμάτων έδειξαν, ότι ο ρυθμός καταβύθισης του στρουβίτη στα υπέρκορα διαλύματά του, εξαρτάται κυρίως από τον αντίστοιχο υπερκορεσμό, ο οποίος αποτελεί και την κινούσα δύναμη. Η ανάλυση των αποτελεσμάτων έγινε με την βοήθεια της κλασσικής θεωρίας πυρηνογένεσης. Η εξάρτηση του χρόνου επαγωγής, ο οποίος μεσολαβούσε μεταξύ της παρασκευής των υπέρκορων διαλυμάτων και της ανίχνευσης των πρώτων υπερκρίσιμων πυρήνων, από τον υπερκορεσμό, έδωσε τιμές για την επιφανειακή ενέργεια της σχηματιζόμενης φάσης ίσης με 15mJ/m2, ενώ ο αριθμός των δομικών μονάδων οι οποίες συγκροτούν τον κρίσιμο πυρήνα, βρέθηκε ίσος με 9. Επίσης, ο ρυθμός, φάνηκε να επηρεάζεται σε μικρό βαθμό από την σχετική αναλογία των πλεγματικών ιόντων. Συγκεκριμένα, όταν η αναλογία των ιόντων Mg :NH3 :P ήταν 3:1:1 ή 1:1:3, οι ρυθμοί οι οποίοι μετρήθηκαν ήταν μεγαλύτεροι σε σύγκριση με τους αντίστοιχους σε διαλύματα με αναλογία 1:1:1. Σε όλες τις περιπτώσεις, το βραδύ στάδιο στον μηχανισμό της καταβύθισης ήταν η επιφανειακή διάχυση των δομικών μονάδων στους υπερκρίσιμους πυρήνες. Το αποτέλεσμα αυτό είναι σε συμφωνία με τα αντίστοιχα σε διαφορετικές τιμές pH, και υποδηλώνει και στην περίπτωση αυτή, τον καθοριστικό ρόλο της επιφάνειας στην οποία λαμβάνει χώρα η πυρηνογένεση. Η παρουσία άλλων ουσιών στο διάλυμα, όπως το Na¬2SO4, είχε ως αποτέλεσμα την αύξηση του ρυθμού αυθόρμητης καταβύθισης του στρουβίτη στα υπέρκορα διαλύματά του. Η διαβίβαση αέρα μέσα από τα υπέρκορα διαλύματα, είχε ως αποτέλεσμα την επιτάχυνση του ρυθμού καταβύθισης σε βαθμό ανάλογο με τον αντίστοιχο παρουσία Na¬2SO4. / Phosphorus is a multifunctional chemical element. One of it’s significant uses is that it consists a non substituted fertilizer, moreover it is one of the basic components of DNA, of cell membranes, bones, teeth, an essential element in human and animal nutrition etc. Increased phosphorous concentration in water systems can be particularly damaging since it is the main cause of eutrophication. Increased amounts of phosphorous have been demonstrated in municipal wastewaters, so processing is required in order to remove phosphorous before final disposal to aquatic systems. Taking into consideration that phosphorus comes from mineral deposits that are not infinite, recovery is demanded, offering a contribution to sustainability. One of the recovery methods that is attracting more and more researcher’s interest over the past years is phosphorous precipitation as struvite. Struvite (MgΝΗ4PO4.6H2O) is a white mineral that can be used as a slow-release fertilizer, enriching agricultures with three of the basic nutrients. In the present study was investigated struvite precipitation in supersaturated solutions, with composition similar to that of municipal wastewaters in phosphorous and ammonia, in 1L continuously operated reactor. The kinetics of spontaneous precipitation was studied at constant solution supersaturation, pH 9.00 and 25οC. The experiments were carried out in supersaturated solutions with stoichiometric molar ratio of the ions 1:1:1 and 1:1:3 for any of the three ions. Struvite precipitation in supersaturated solutions was also studied in the presence of Na¬2SO4 and transmission of air in the solutions. The results showed that the rate of struvite precipitation in supersaturated solutions mainly depends on the supersaturation in respect to the precipitating solid, which is the driving force. Results analysis was performed in accordance to the classical nucleation theory. The dependence of the induction time, the period of time between the achievement of supersaturation and the formation of the first critical nucleus, from supersaturation, lead to surface energy for the newly formed phase 15mJ/m2, and the number of molecules in a critical nucleus was calculated p=9. The rate of struvite precipitation proved to have a minor dependence on the ratio of the ions. More specifically, when stoichiometric molar ratio of the ions Mg :NH3 :P was 3:1:1 or 1:1:3, the calculated rates were a bit higher compared to the ratios in supersaturated solutions with stoichiometric molar ratio 1:1:1. In all the cases the slow step in the mechanism of precipitation was surface diffusion of the solute molecules on the critical nuclei surface. The results are in accordance with those under different pH values and suggest the importance of the surface where nuclei formation takes place. The presence of other substances in the solution, such as Na¬2SO4, resulted in an increased rate of struvite spontaneous precipitation in supersaturated solutions. The transmission of air through the supersaturated solutions also increased the rate of precipitation in a way similar to that under the presence of Na2SO4.
203

Heat recovery in an air conditioning system

馬鏡澄, Ma, Kang-ching, Clement. January 1982 (has links)
published_or_final_version / Mechanical Engineering / Master / Master of Science in Engineering
204

A picosecond optoelectronic cross correlator using a gain modulated avalanche photodiode for measuring the impulse response of tissue

Kirkby, David Robert January 1999 (has links)
Human tissue is relatively transparent to light between 700 and 1000 nm in the near infrared (NIR). NIR spectroscopy is a technique that can measure non-invasively and safely, the optical properties of tissue. Several different types of spectroscopic instrumentation have currently been developed, ranging from simple continuous intensity systems, through to complex time and frequency resolved techniques. This thesis describes the development of a near infra-red time-resolved system, using an inexpensive avalanche photodiode (APD) detector and a microwave step recovery diode (SRD) in a novel way to implement a totally electronic crosscorrelator, with no moving parts. The aim of the work was to develop a simple instrument to monitor scattering changes in tissue during laser induced thermal therapy. The APD was gain-modulated by rapidly varying the bias voltage using electrical pulses generated by the SRD (120 ps full width half maximum (FWHM) and 8 V in amplitude). The resulting cross-correlator had a temporal resolution of 275 ps FWHM - significantly faster than the 750 ps FWHM of the APD when operating with a conventional fixed bias voltage. Spurious responses caused by the SRD were observed, which were removed by the addition of Schottky diodes on the SRD’s output, although this slightly degraded the system temporal resolution from 275 to 380 ps FWHM. The ability of the system to monitor scattering changes was tested using an IntralipidTM phantom containing infra-red absorbing dye. An 800 nm fibre coupled mode-locked (2 ps pulse width) laser source was used with the cross-correlator measuring the temporal point spread function (TPSF) at 5 to 30 mm away from the source fibre. Five different numerical algorithms to derive the scattering coefficient from the measured TPSF were compared. The optimum choice of algorithm was found to depend on whether absolute accuracy or minimum computation time is the most important consideration.
205

Forward in-situ combustion : Real-time mass and energy balances, reaction kinetics and control

Dudley, J. W. O. January 1988 (has links)
Enhanced oil recovery by dry forward in-situ combustion has been studied in a combustion tube. Twelve experiments are reported exploring the effects of three factors: oxygen flow, partial pressure and mole fraction, each factor at two levels. The pressures used went up to 790 kPa, and the oxygen mole fraction to 35%. It was discovered that the oxygen partial pressure had no statistically significant effect. The oil recovery was independent of the factors used. The combustion time was dominated by the oxygen flow, as were the reaction rates, while fuel and oxygen consumption depended mainly on the oxygen mole fraction. Increasing the oxygen mole fraction reduced the consumption figures. The reaction stoichiometry was substantially independent of the three factors. It was also found that the total pressure had no statistically significant effect on oil recovery, combustion time, reaction rates, fuel consumption or stoichiometry. The oil produced by the in-situ combustion process tended to be of lower viscosity and density than the original oil. Oil-water emulsions were produced which could not be broken. The experiments were controlled by a computer, and the PID control algorithms and associated equipment proved succesful. Linked in with the control routines was a model of the process to calculate fluid saturations and flows during the course of the experiment. Measured information was used directly in the mass and energy balances. The resultant fluid saturations supplied a reasonable match with experimental oil saturations from two experiments that were stopped early. The computed liquid production histories also matched up well with the experimental results. The oil saturations from the numerical model were used in developing a robust method for calculating reaction constants from the experimental data. A simplified surface-reaction scheme was used involv~ng low-temperature oxidation and fuel burnoff to explain the effects of flow, pressure and oxygen mole fraction on the process.
206

CHARACTERIZATION OF CARBON NANOTUBES BASED RESISTIVE AND CAPACITIVE GAS SENSORS

Ma, Ning 01 January 2007 (has links)
A preliminary gas detection study was conducted on as-grown multi-walled carbon nanotubes and anodized aluminum oxide (MWNTs/AAO) template. The material demonstrated room temperature gas sensitivity and p-type semiconductor characteristics. Plasma-etched MWNTs/AAO templates were employed to construct capacitive gas sensors. The capacitances of the sensors were sensitive to both reducing and oxidizing gases at room temperature. Single-walled carbon nanotubes (SWNTs) dispersed in binder andamp;aacute;-terpineol were applied on sensor platforms to form resistive gas sensors. The sensors demonstrated excellent sensitivity to low concentrations of reducing and oxidizing gases at room temperature, which suggests the p-type semiconducting behavior of SWNTs. The sensor recovery was found to be incomplete at room temperature in flow of nitrogen and air, thus possible solutions were investigated to enhance sensor performance. The sensor operating principles and suggestions for possible future work are discussed. The room temperature and air background functionality of the sensor suggest that SWNT is a promising gas sensing material for application in ambient conditions.
207

Texas disaster recovery capacity : the impacts of leadership structures on local resilience

Joslin, Nicole Marie 02 October 2014 (has links)
This report examines the leadership structures of four disaster recovery housing programs in two Texas communities in order to identify leadership models that contribute to future individual and community resilience. Disaster recovery is a physical and social process that requires both scientific knowledge of best practices and practical local knowledge of community context. The level of a community's physical, organizational, and social capacity relates directly to its ability to deliver needed disaster recovery services. The variation of capacity at all levels of governmental agencies and community organizations across Texas has become dramatically apparent over the last decade of disasters with clear consequences to the success of disaster recovery efforts. Information collected from those involved in the housing recovery efforts from two recent disasters in Texas, Hurricane Dolly in 2008 and the Bastrop Complex Wildfires in 2011, provide a window into the current governance models being employed. Communities in the Rio Grande Valley and Bastrop County are now administering multiple housing recovery efforts through assorted levels of government and community organization. By documenting and analyzing the structure of leadership in each program through quantitative and qualitative methods this report reconstructs the capacities of each leadership model that are relevant to articulated recovery goals. Findings from this analysis reveal opportunities for improvement in the design of future disaster recovery programs at the state and local level. / text
208

Development and study of dissolved gas flotation for biomass recovery after anaerobic treatment

Fisher, Michael Bryan January 1999 (has links)
No description available.
209

Erfarenhet, känsla och kommunikation på restaurang : En studie om personalen kan påverka gästens upplevelse med dessa förmågor när något oplanerat inträffar

Lundberg, Fanny, Karlsson, Sofia January 2015 (has links)
No description available.
210

Colloidal Silica as a Platform for Trace Protein Analysis and Recovery

Egas Proaño, David Alexis January 2011 (has links)
Early intervention in cancer and other illnesses is highly desired. The evolution of the proteomics field has benefited the possibility of getting to this goal by allowing researchers to look at different biomarkers. However, the high complexity of biological samples and the low levels at which biomarkers are found in these fluids make the analyses even more complicated.Protein microarrays have arisen as alternatives to traditional methods to look at multiple protein levels simultaneously with the benefit of high specificity, low limits of detection and the requirement of small samples. In this work, a significant improvement in net signals obtained with fluorescent detection (using three-dimensional scaffolds based on silica colloidal crystals -SCC-) is presented in contrast to commercially available flat substrates.A novel approach to extract trace proteins in solution and more complex matrices by using sub-micrometer silica particles as support for antibodies in affinity capture experiments is presented. Bovine Serum Albumin, Ephrin-receptor A2, Alpha-fetoprotein, and Prostate Specific Antigen have been used as model proteins. Recoveries of 90% or more are obtained with this method and reusability of the particles was achieved. MALDI-MS detection was successfully performed with the protein extracts which opens up the opportunity of further analysis such as determining post-translational modifications which is relevant when dealing with biomarker candidates.Last we present the use of our substrates as alternatives to conventional targets in mass spectrometry (MS). Traditional Matrix-assisted Laser Desorption Ionization MS (MALDI-MS) of proteins presents the problem of adduct formation with clusters from the matrix used in the process. Those adducts can affect the accurate determination of the molecular weight for a given protein and when could potentially mask slight differences in molecular weight of very similar proteins in mixtures. We present the alternative of using SCC on silicon wafers as a target for MALDI-MS samples. Our peak widths are extremely narrow and approach the one of the isotopic envelops. At the same time, porosity of our material seems to prevent the formation of adducts, which enables the differentiation of proteins with small molecular weight differences like mutants or same proteins from different sources.

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