993 resultados para university spin-offs
Resumo:
A vehicle may leave its travel lane for a number of reasons, such as driver error, poor surface conditions, or avoidance of a collision with another vehicle in the travel lane. When a vehicle leaves the travel lane, pavement edge drop-off poses a potential safety hazard because significant vertical differences between surfaces can affect vehicle stability and reduce a driver’s ability to handle the vehicle. Numerous controlled studies have tested driver response to encountering drop-offs under various conditions, including different speeds, vehicle types, drop-off height and shape, and tire scrubbing versus non-scrubbing conditions. The studies evaluated the drivers’ ability to return to and recover within their own travel lane after leaving the roadway and encountering a drop-off. Many of these studies, however, have used professional drivers as test subjects, so results may not always apply to the population of average drivers. Furthermore, test subjects are always briefed on what generally is to be expected and how to respond; thus, the sense of surprise that a truly naïve driver may experience upon realizing that one or two of his or her tires have just dropped off the edge of the pavement, is very likely diminished. Additionally, the studies were carried out under controlled conditions. The actual impact of pavement edge drop-off on drivers’ ability to recover safely once they leave the roadway, however, is not well understood under actual driving conditions. Additionally, little information is available that quantifies the number or severity of crashes that occur where pavement edge drop-off may have been a contributing factor. Without sufficient information about the frequency of edge drop-off-related crashes, agencies are not fully able to measure the economic benefits of investment decisions, evaluate the effectiveness of different treatments to mitigate edge drop-off, or focus maintenance resources. To address these issues, this report details research to quantify the contribution of pavement edge drop-off to crash frequency and severity. Additionally, the study evaluated federal and state guidance in sampling and addressing pavement edge drop-off and quantified the extent of pavement edge drop-off in two states. This study focused on rural two-lane paved roadways with unpaved shoulders, since they are often high speed facilities (55+ mph), have varying levels of maintenance, and are likely to be characterized by adverse roadway conditions such as narrow lanes or no shoulders.
Resumo:
Technology companies created from University research are known as "Academic Spin-Off" (ASO). These innovative companies play an important role for the technological, economical and social development of a country. This work discusses some aspects of ASO companies and their importance to Universities. It is also presented a fictitious history of Prof. João, a chemical researcher who will create an ASO company from his academic research work illustrating the basic steps involved in this process.
Resumo:
Life science-ala on rahoituksellisesti erittäin haastava, koska tuotekehitysputket ovat 10-15 vuoden pituisia ja voivat vaatia suuria etupainotteisia investointeja. Monet life science-alan yritykset ovat niin Suomessa kuin kansainvälisestikin syntyneet suoraan yliopistosta niin sanottuina spin-off-yrityksinä. Yrityksen perustaminen tutkimustiedon pohjalle on yksi akateemisen yrittäjyyden muodoista. Tässä tutkimuksessa tutkitaan akateemista yrittäjyyttä life science-alalla Suomessa. Suomessa life science-alan osaaminen on kansainvälistä huippua ja alalle on syntynyt useita spin-off-yrityksiä viime vuosina. Aiemmat tutkimukset ovat keskittyneet erityisesti agentti-päämiesongelmiin akateemisessa yrittäjyydessä ja life science alaa puolestaan on käsitelty usein pelkästään yhtenä alana. Tutkimuksessa pyritään analysoimaan life science-alan eri painopiste-alueita tarkemmin rahoitusstrategisesta näkökulmasta, koska ala ei ole homogeeninen. Akateemisen yrittäjyyden agenttiongelmaa pyritään tarkoittamaan Suomen yliopistomaailmassa life science-alalta käsin. Tutkimus toteutetaan kvalitatiivisena haastattelututkimuksena ja sitä tukevana tilinpäätöstietojen analysointina. Tutkimuksen tulokset vahvistavat agentti-päämiesongelmien olemassaolon suomalaisessa yliopistomaailmassa. Ongelmien osapuolina ovat niin akateemikot, yliopiston innovaatiopalvelut kuin TEKES:kin. Yrittäjät kaipaavat kokonaisvaltaisempaa apua, koska kokevat alalla liiketoimintaosaamisen puuttuvan monin paikoin. Alan vaatimien runsaiden tuotekehityspanostusten vuoksi alan yritykset ovat pitkään raskaasti tappiollisia. Yritysten valitsemat rahoitusratkaisut vaihtelevat suuresti. Kaikki tutkitut yritykset pyrkivät kasvamaan nykyisten ydintuotteidensa mukana ja ovat jo jossain määrin hankkineet rahoitusta kasvustrategiaansa varten. Alan pääomaintensiivisyydestä johtuen ovat monet yritykset kuitenkin suunnittelemassa tai jo päätyneet tekemään yhteistyötä integroituen alalla joko vertikaalisesti tai horisontaalisesti. Tutkimuksen tulokset vahvistavat aiemman käsityksen, jonka mukaan life science-alan yrityksiä on vaikea arvioida ulkopuolelta pelkästään tilinpäätöstietojen pohjalta, koska alkuvaiheessa rahoituskierrokset ja tappiolliset vuoden seuraavat toisiaan ja toisaalta yrityksen arvo sitoutuu pitkiin tuotekehitysputkiin, jotka eivät välttämättä näy tilinpäätöksessä. Tulokset tuovat esille merkittäviä yritysten kokemia ongelmia rahoituksen saannissa life science-alalla Suomessa sekä akateemisen yrittäjyyden epäkohtia yritystoiminnan näkökulmasta. Näiden tekijöiden huomioonottaminen ja laajempi kansainvälinen vertailu voivat auttaa suomalaisia yrityksiä tällä vahvalla osaamisalalla eteenpäin.
Resumo:
The superconducting transition temperature Tc of metallic glasses ZrxFelOO-x (x=80, 75), Zr75(NixFelOO-x)25 (x=75, 50, 25), and CU2SZr75 were measured under quasi-hydrostatic pressure up to 8 OPa (80kbar). The volume (pressure) dependence of the electron-phonon coupling parameters Aep for CU25Zr75 was calculated using the McMillan equatio11. Using this volume dependence of Aep and the modified McMillan equation which incorporates spin-fluctuations, the volume dependence of the spin fluctuation parameter, Asf, was determined in Zr75Ni25, ZrxFelOO-x , a11d Zr75(NixFelOO-x)25. It was found that with increasing pressure, spinfluctuations are suppressed at a faster rate in ZrxFe lOO-x and Zr75(NixFelOO-x)25, as Fe concentration is increased. The rate of suppression of spin-fluctuations with pressure was also found to be higher in Fe-Zr glasses than in Ni-Zr glasses of similar composition.
Resumo:
The frequency dependence of the electron-spin fluctuation spectrum, P(Q), is calculated in the finite bandwidth model. We find that for Pd, which has a nearly full d-band, the magnitude, the range, and the peak frequency of P(Q) are greatly reduced from those in the standard spin fluctuation theory. The electron self-energy due to spin fluctuations is calculated within the finite bandwidth model. Vertex corrections are examined, and we find that Migdal's theorem is valid for spin fluctuations in the nearly full band. The conductance of a normal metal-insulator-normal metal tunnel junction is examined when spin fluctuations are present in one electrode. We find that for the nearly full band, the momentum independent self-energy due to spin fluctuations enters the expression for the tunneling conductance with approximately the same weight as the self-energy due to phonons. The effect of spin fluctuations on the tunneling conductance is slight within the finite bandwidth model for Pd. The effect of spin fluctuations on the tunneling conductance of a metal with a less full d-band than Pd may be more pronounced. However, in this case the tunneling conductance is not simply proportional to the self-energy.
Resumo:
A ~si MAS NMR study of spin-lattice relaxation behaviour
in paramagnetic-doped crystalline silicates was undertaken,
using synthetic magnesium orthosilicate (forsterite) and
synthetic zinc orthosilicate (willemite) doped with 0.1% to
20% of Co(II), Ni(II), or CU(II), as experimental systems.
All of the samples studied exhibited a longitudinal
magnetization return to the Boltzmann distribution of nuclear
spin states which followed a stretched-exponential function of
time:
Y=exp [- (tjTn) n], O
Resumo:
The synthesis of 3-ethynylthienyl- (2.07), 3-ethynylterthienyl- (2.19) substituted qsal [qsalH = N-(8-quinolyl)salicylaldimine] and 3,3' -diethynyl-2,2' -bithienyl bridging bisqsal (5.06) ligands are described along with the preparation and characterization of eight cationic iron(III) complexes containing these ligands with a selection of counteranions [(2.07) with: SCN- (2.08), PF6- (2.09), and CI04- (2.10); (2.19) with PF6 - (2.20); (5.06) with: cr (5.07), SeN- (5.08), PF6- (5.09), and CI04- (5.10)]. Spin-crossover is observed in the solid state for (2.08) - (2.10) and (5.07) - (5.10), including a ve ry rare S = 5/2 to 3/2 spin-crossover in complex (2.09). The unusal reduction of complex (2.10) produces a high-spin iron(I1) complex (2.12). Six iron(II) complexes that are derived from thienyl analogues of bispicen [bispicen = bis(2-pyridylmethyl)-diamine] [2,5-thienyl substituents = H- (3.11), Phenyl- (3.12), 2- thienyl (3.13) or N-phenyl-2-pyridinalimine ligands [2,5-phenyl substituents = diphenyl (3.23), di(2-thienyl) (3.24), 4-phenyl substituent = 3-thienyl (3.25)] are reported Complexes (3.11), (3.23) and (3.25) display thermal spin-crossover in the solid state and (3.12) remains high-spin at all temperatures. Complex (3.13) rearranges to form an iron(II) complex (3.14) with temperature dependent magnetic properties be s t described as a one-dimensional ferromagnetic chain, with interchain antiferromagnetic interactions and/or ZFS dominant at low temperatures. Magnetic succeptibility and Mossbauer data for complex (3.24) display a temperature dependent mixture of spin isomers. The preparation and characterization of two cobalt(II) complexes containing 3- ethynylthienyl- (4.04) and 3-ethynylterhienyl- (4.06) substituted bipyridine ligands [(4.05): [Co(dbsqh(4.04)]; (4.07): [Co(dbsq)2(4.06)]] [dbsq = 3,5-dbsq=3,5-di-tert-butylI ,2-semiquinonate] are reported. Complexes (4.05) and (4.07) exhibit thermal valence tautomerism in the solid state and in solution. Self assembly of complex (2.10) into polymeric spheres (6.11) afforded the first spincrossover, polydisperse, micro- to nanoscale material of its kind. . Complexes (2.20), (3.24) and (4.07) also form polymers through electrochemical synthesis to produce hybrid metaUopolymer films (6.12), (6.15) and (6.16), respectively. The films have been characterized by EDX, FT-IR and UV-Vis spectroscopy. Variable-temperature magnetic susceptibility measurements demonstrate that spin lability is operative in the polymers and conductivity measurements confirm the electron transport properties. Polymer (6.15) has a persistent oxidized state that shows a significant decrease in electrical resistance.
Resumo:
Copper arsenite CuAs2O4 and Copper antimonite CuSb2O4 are S=1/2 (Cu2+ 3d9 electronic configuration) quasi-one-dimensional quantum spin-chain compounds. Both compounds crystallize with tetragonal structures containing edge sharing CuO6 octahedra chains which experience Jahn-Teller distortions. The basal planes of the octahedra link together to form CuO2 ribbon-chains which harbor Cu2+ spin-chains. These compounds are magnetically frustrated with competing nearest-neighbour and next-nearest-neighbour intrachain spin-exchange interactions. Despite the similarities between CuAs2O4 and CuSb2O4, they exhibit very different magnetic properties. In this thesis work, the physical properties of CuAs2O4 and CuSb2O4 are investigated using a variety of experimental techniques which include x-ray diffraction, magnetic susceptibility measurements, heat capacity measurements, Raman spectroscopy, electron paramagnetic resonance, neutron diffraction, and dielectric capacitance measurements. CuAs2O4 exhibits dominant ferromagnetic nearest-neighbour and weaker antiferromagnetic next-nearest-neighbour intrachain spin-exchange interactions. The ratio of the intrachain interactions amounts to Jnn/Jnnn = -4.1. CuAs2O4 was found to order with a ferromagnetic groundstate below TC = 7.4 K. An extensive physical characterization of the magnetic and structural properties of CuAs2O4 was carried out. Under the effect of hydrostatic pressure, CuAs2O4 was found to undergo a structural phase transition at 9 GPa to a new spin-chain structure. The structural phase transition is accompanied by a severe alteration of the magnetic properties. The high-pressure phase exhibits dominant ferromagnetic next-nearest-neighbour spin-exchange interactions and weaker ferromagnetic nearest-neighbour interactions. The ratio of the intrachain interactions in the high-pressure phase was found to be Jnn/Jnnn = 0.3. Structural and magnetic characterizations under hydrostatic pressure are reported and a relationship between the structural and magnetic properties was established. CuSb2O4 orders antiferromagnetically below TN = 1.8 K with an incommensurate helicoidal magnetic structure. CuSb2O4 is characterized by ferromagnetic nearest-neighbour and antiferromagnetic next-nearest-neighbour spin-exchange interactions with Jnn/Jnnn = -1.8. A (H, T) magnetic phase diagram was constructed using low-temperature magnetization and heat capacity measurements. The resulting phase diagram contains multiple phases as a consequence of the strong intrachain magnetic frustration. Indications of ferroelectricity were observed in the incommensurate antiferromagnetic phase.
Resumo:
The employment of the bridging/chelating Schiff bases, N-salicylidene-4-methyl-o-aminophenol (samphH2) and N-naphthalidene-2-amino-5-chlorobenzoic acid (nacbH2), in nickel cluster chemistry has afforded eight polynuclear Ni(II) complexes with new structural motifs, interesting magnetic and optical properties, and unexpected organic ligand transformations. In the present thesis, Chapter 1 deals with all the fundamental aspects of polynuclear metal complexes, molecular magnetism and optics, while research results are reported in Chapters 2 and 3. In the first project (Chapter 2), I investigated the coordination chemistry of the organic chelating/bridging ligand, N-salicylidene-4-methyl-o-aminophenol (samphH2). The general NiII/tBuCO2-/samphH2 reaction system afforded two new tetranuclear NiII clusters, namely [Ni4(samph)4(EtOH)4] (1) and [Ni4(samph)4(DMF)2] (2), with different structural motifs. Complex 1 possessed a cubane core while in complex 2 the four NiII ions were located at the four vertices of a defective dicubane. The nature of the organic solvent was found to be of pivotal importance, leading to compounds with the same nuclearity, but different structural topologies and magnetic properties. The second project, the results of which are summarized in Chapter 3, included the systematic study of a new optically-active Schiff base ligand, N-naphthalidene-2-amino-5-chlorobenzoic acid (nacbH2), in NiII cluster chemistry. Various reactions between NiX2 (X- = inorganic anions) and nacbH2 were performed under basic conditions to yield six new polynuclear NiII complexes, namely (NHEt3)[Ni12(nacb)12(H2O)4](ClO4) (3), (NHEt3)2[Ni5(nacb)4(L)(LH)2(MeOH)] (4), [Ni5(OH)2(nacb)4(DMF)4] (5), [Ni5(OMe)Cl(nacb)4(MeOH)3(MeCN)] (6), (NHEt3)2[Ni6(OH)2(nacb)6(H2O)4] (7), and [Ni6(nacb)6(H2O)3(MeOH)6] (8). The nature of the solvent, the inorganic anion, X-, and the organic base were all found to be of critical importance, leading to products with different structural topologies and nuclearities (i.e., {Ni5}, {Ni6} and {Ni12}). Magnetic studies on all synthesized complexes revealed an overall ferromagnetic behavior for complexes 4 and 8, with the remaining complexes being dominated by antiferromagnetic exchange interactions. In order to assess the optical efficiency of the organic ligand when bound to the metal centers, photoluminescence studies were performed on all synthesized compounds. Complexes 4 and 5 show strong emission in the visible region of the electromagnetic spectrum. Finally, the ligand nacbH2 allowed for some unexpected organic transformations to occur; for instance, the pentanuclear compound 5 comprises both nacb2- groups and a new organic chelate, namely the anion of 5-chloro-2-[(3-hydroxy-4-oxo-1,4-dihydronaphthalen-1-yl)amino]benzoic acid. In the last section of this thesis, an attempt to compare the NiII cluster chemistry of the N-naphthalidene-2-amino-5-chlorobenzoic acid ligand with that of the structurally similar but less bulky, N-salicylidene-2-amino-5-chlorobenzoic acid (sacbH2), was made.
Resumo:
The present thesis deals with the studies on certain aspects of pathological higher field theories .It brings to light some new abnormalities and new samples of abnormal theories and also puts forward a novel approach towards the construction of trouble free theories
Resumo:
The magnetic properties of Mn-doped ZnO (ZnO:Mn) nanorods grown by hydrothermal process at a temperature of 200 8C and a growth time of 3 h have been studied. The samples were characterized by using powder X-ray diffraction with Rietveld refinement, scanning electron microscopy, energy-dispersive X-ray analysis and SQUID magnetometry. Mn (3 wt%) and (5 wt%)-doped ZnO samples exhibit paramagnetic and ferromagnetic behavior, respectively, at room temperature. The spin-glass behavior is observed from the samples with respect to the decrease of temperature. At 10 K, both samples exhibit a hysteresis loop with relatively low coercivity. The room-temperature ferromagnetism in 5 wt% Mn-doped ZnO nanorods is attributed to the increase in the specific area of grain boundaries, interaction between dopant Mn2þ ions substituted at Zn2þ site and the interaction between Mn2þ ions and Zn2þ ions from the ZnO host lattice
Resumo:
To migrate successfully, birds need to store adequate fat reserves to fuel each leg of the journey. Migrants acquire their fuel reserves at stopover sites; this often entails exposure to predators. Therefore, the safety attributes of sites may be as important as the feeding opportunities. Furthermore, site choice might depend on fuel load, with lean birds more willing to accept danger to obtain good feeding. Here, we evaluate the factors underlying stopover-site usage by migrant Western Sandpipers (Calidris mauri) on a landscape scale. We measured the food and danger attributes of 17 potential stopover sites in the Strait of Georgia and Puget Sound region. We used logistic regression models to test whether food, safety, or both were best able to predict usage of these sites by Western Sandpipers. Eight of the 17 sites were used by sandpipers on migration. Generally, sites that were high in food and safety were used, whereas sites that were low in food and safety were not. However, dangerous sites were used if there was ample food abundance, and sites with low food abundance were used if they were safe. The model including both food and safety best-predicted site usage by sandpipers. Furthermore, lean sandpipers used the most dangerous sites, whereas heavier birds (which do not need to risk feeding in dangerous locations) used safer sites. This study demonstrates that both food and danger attributes are considered by migrant birds when selecting stopover sites, thus both these attributes should be considered to prioritize and manage stopover sites for conservation.
Resumo:
The NMR spin coupling parameters, (1)J(N,H) and (2)J(H,H), and the chemical shielding, sigma((15)N), of liquid ammonia are studied from a combined and sequential QM/MM methodology. Monte Carlo simulations are performed to generate statistically uncorrelated configurations that are submitted to density functional theory calculations. Two different Lennard-Jones potentials are used in the liquid simulations. Electronic polarization is included in these two potentials via an iterative procedure with and without geometry relaxation, and the influence on the calculated properties are analyzed. B3LYP/aug-cc-pVTZ-J calculations were used to compute the V(N,H) constants in the interval of -67.8 to -63.9 Hz, depending on the theoretical model used. These can be compared with the experimental results of -61.6 Hz. For the (2)J(H,H) coupling the theoretical results vary between -10.6 to -13.01 Hz. The indirect experimental result derived from partially deuterated liquid is -11.1 Hz. Inclusion of explicit hydrogen bonded molecules gives a small but important contribution. The vapor-to-liquid shifts are also considered. This shift is calculated to be negligible for (1)J(N,H) in agreement with experiment. This is rationalized as a cancellation of the geometry relaxation and pure solvent effects. For the chemical shielding, U(15 N) Calculations at the B3LYP/aug-pcS-3 show that the vapor-to-liquid chemical shift requires the explicit use of solvent molecules. Considering only one ammonia molecule in an electrostatic embedding gives a wrong sign for the chemical shift that is corrected only with the use of explicit additional molecules. The best result calculated for the vapor to liquid chemical shift Delta sigma((15)N) is -25.2 ppm, in good agreement with the experimental value of -22.6 ppm.