201 |
Highly sensitive measurements of substrates and inhibitors on the basis of tyrosinase sensors and recycling systemsStreffer, Katrin January 2002 (has links)
Analytische Chemie heute meint nicht länger nur die große Messtechnik, die zeit- und kostenintensiv ist, die außerdem nur von qualifiziertem Personal zu bedienen ist und deren Resultate nur durch dieses Personal auswertbar sind. Meist erfordert diese sagen wir 'klassische analytische Messtechnik' auch noch spezielle Räumlichkeiten und oft eine relative große Menge an speziell vorbereiteten Proben. Neben dieser klassischen analytischen Messtechnik hat sich besonders in den letzten Jahren eine auf bestimmte Stoffgruppen und Anforderungen zugeschnittene Messtechnik durchgesetzt, die oft auch durch einen Laien bedient werden kann. Meist sind es sehr kleine Geräte. Auch die benötigten Probenvolumina sind klein und eine spezielle Probenvorbereitung ist nicht erforderlich. Ausserdem sind die Geräte einfach zu handhaben, billig sowohl in ihrer Herstellung als auch im Gebrauch und meist erlauben sie sogar eine kontinuierliche Messwerterfassung. <br />
<br />
Zahlreiche dieser in den letzten Jahren entwickelten Geräte greifen zurück auf 40 Jahre Forschung auf dem Gebiet der Biosensorik. Seit Clark und Lyons im Jahr 1962 in der Lage waren, mit einer einfachen Sauerstoffelektrode, ergänzt durch ein Enzym, Glucose zu messen, war die Entwicklung neuer Messtechnik nicht mehr aufzuhalten. Biosensoren, spezielle Messfühler, die aus einer Kombination aus biologischer Komponente (erlaubt eine spezifische Erkennung des Analyten auch ohne vorherige Reinigung der Probe) und einem physikalischen Messfühler (wandelt den primären physikochemischen Effekt in ein elektronisch messbares Signal um) bestehen, eroberten den Markt. <br />
<br />
Im Rahmen dieser Doktorarbeit wurden verschiedene Tyrosinasesensoren entwickelt, die je nach Herkunft und Eigenschaften der verwendeten Tyrosinase unterschiedliche Anforderungen erfüllen. Beispielsweise wurde einer dieser Tyrosinasesensoren für die Bestimmung phenolischer Verbindungen in Fluss- und Seewasserproben eingesetzt, und die mit diesem Sensor gemessenen Ergebnisse konnten sehr gut mit dem entsprechenden DIN-Test zur Bestimmung phenolischer Verbindungen korreliert werden. Ein anderer entwickelter Sensor zeigte eine sehr hohe Empfindlichkeit für Catecholamine, Substanzen die speziell in der medizinischen Diagnostik von Wichtigkeit sind. <br />
<br />
Ausserdem zeigten die ebenfalls im Rahmen dieser Doktorarbeit durchgeführten Untersuchungen zweier verschiedener Tyrosinasen, dass, will man in Zukunft noch empfindlichere Tyrosinasesensoren entwickeln, eine spezielle Tyrosinase (Tyrosinase aus Streptomyces antibioticus) die bessere Wahl sein wird, als die bisher im Bereich der Biosensorforschung verwendete Tyrosinase aus Agaricus bisporus. <br />
<br />
Desweiteren wurden erste Erfolge auf molekularbiologischem Gebiet erreicht, das heisst, dass Tyrosinasemutanten mit speziellen, vorher überlegten Eigenschaften, hergestellt werden sollen. Diese Erfolge können dazu genutzt werden, eine neue Generation an Tyrosinasesensoren zu entwickeln, Tyrosinasesensoren in denen Tyrosinase gerichtet gebunden werden kann, sowohl an den entsprechenden physikalischen Messfühler oder auch an ein anderes Enzym. Davon verspricht man sich deutlich minimierte Wege, die die zu bestimmende Substanz (oder deren Produkt) sonst zurücklegen müsste, was am Ende zu einer deutlich erhöhten Empfindlichkeit des resultierenden Biosensors führen sollte. / Today, analytical chemistry does not longer consist of only the big measuring devices and methods which are time consuming and expensive, which can furthermore only be handled by the qualified staff and in addition the results can also only be evaluated by this qualified staff. Usually, this technique, which shall be described in the following as 'classic analytic measuring technique', requires also rooms equipped especially and often a relative big quantity of the test compounds which should be prepared especially. Beside this classic analytic measuring technique, limited on definite substance groups and requests, a new measuring technique has gained acceptance particularly within the last years, which one can often be used by a layman, too. Often the new measuring technique has very little pieces of equipment. The needed sample volumes are also small and a special sample preparation isn't required. In addition, the new measuring instruments are simple to handle. They are cheap both in their production and in the use and they permit even a continuous measurement recording usually. <br />
<br />
Numerous of this new measuring instruments base on the research in the field of Biosensorik during the last 40 years. Since Clark and Lyon in the year 1962 were able to measure glucose with a simple oxygen electrode, completed by an enzyme the development of the new measuring technique did not have to be held back any longer. Biosensors, special pickups which consists of a combination from a biological component (permits a specific recognition of the analyte also without purification of the sample previously) and a physical pickup (convert the primary physicochemical effect into an electronically measurable signal), conquered the market. <br />
<br />
In the context of this thesis different tyrosinasesensors were developed which fulfilling the various requests, depending on origin and features of the used tyrosinase. One of the tyrosinasesensors for example was used for quantification of phenolic compounds in river and sea water and the results could correlated very well with the corresponding DIN-test for the determination of phenolic compounds. An other developed tyrosinasesensor showed a very high sensitiveness for catecholamines, substances which are of special importance in the medical diagnostics. <br />
<br />
In addition, the investigations of two different tyrosinases, which were carried out also in the context of this thesis, have shown, that a special tyrosinase (tyrosinase from Streptomyces antibioticus) will be the better choice as tyrosinase from Agaricus bisporus, which is used in the area of biosensor research till now, if one wants to develop in future even more sensitive tyrosinasesensors. <br />
<br />
Furthermore, first successes became reached on a molecular biological field, the production of tyrosinasemutants with special, before well-considered features. These successes can be used to develop a new generation of tyrosinasesensors, tyrosinasesensors in which tyrosinase can be bound directionally both to the corresponding physical pickup or also to another enzyme. From this one expects to achieve ways minimized which the substance to be determined (or whose product) otherwise must cover. Finally, this should result in an clearly visible increase of sensitivity of the Biosensor.
|
202 |
Waste management in BotswanaSuresh, Shashidhar, Vijayakumar, Vinodhkumar January 2012 (has links)
Waste is anything which is considered to be no longer useful to anyone. In reality, it actually possesses the ability to be the raw material for several other processes and applications. Improper handling of wastes could result in several environmental hazards such as air pollution, soil erosion, methane emissions, low birth rate and others. In developing countries, proper handling of wastes is one of the important topics to be focussed from an environmental perspective. This thesis aims to propose an improved waste collection system in Gaborone through investigating the current waste management practices in Gaborone from different perspectives. Several stakeholders were interviewed for gathering information related to the present waste legislations, waste collection, treatment, and disposal methods. A composition study was also conducted along with the other research teams in order to support the objective of this thesis. The results shows that the current waste management practices has certain flaws which the management has to overcome in order to avoid the environmental impacts caused by the waste generation in Gaborone. Basic Recycling and treatment facilities are absent in Gaborone. The local government do not have any updated plans for the proper handling of wastes. The obtained results are critically analysed to showcase the existing flaws in the waste management practices, and using the state of the art knowledge in waste management the research team suggests an improved waste collection system for Gaborone considering the economic and environmental conditions.
|
203 |
Syntheses and applications of soluble polyisobutylene (PIB)-supported transition metal catalystsTian, Jianhua 15 May 2009 (has links)
Soluble polymer supports facilitate the recovery and recycling of expensive
transition metal complexes. Recently, polyisobutylene (PIB) oligomers have been found
to be suitable polymer supports for the recovery of a variety of transition metal catalysts
using liquid/liquid biphasic separations after a homogeneous reaction. Our work has
shown that PIB-supported Ni(II) and Co(II) β-diketonates prepared from commercially
available vinyl terminated PIB oligomers possess catalytic activity like that of their low
molecular weight analogs in Mukaiyama epoxidation of olefins.
Carboxylic acid terminated PIB derivatives can act as carboxylate ligands for
Rh(II) cyclopropanation catalysts. An achiral PIB-supported Rh(II) carboxylate catalyst
showed good activity in cyclopropanation of styrene in hydrocarbon solvents, and could
be easily recycled nine times by a post reaction extraction. Further application of PIB
supports in asymmetric cyclopropanation reactions were investigated using PIBsupported
arenesulfonyl Rh(II) prolinates derived from L-proline as examples. The PIBsupported
chiral Rh carboxylates demonstrated moderate activity and were recovered and reused for four to five cycles. The prolinate catalyst prepared from PIB-anisole also
showed encouraging enantioselectivity and about 8% ee and 13% ee were observed on
trans- and cis-cyclopropanation product respectively.
Finally, PIB oligomers can be modified in a multi step sequence to prepare PIBsupported
chiral bisoxazolines that can in turn be used to prepare active, recyclable PIBsupported
Cu(I) bisoxazoline complexes for olefin cyclopropanation. These chiral
copper catalysts showed moderate catalytic activity and good stereoselectivity in
cyclopropanation of styrene. A chiral ligand prepared from D-phenylglycinol provided
the most effective stereo control and gave the trans- and cis-cyclopropanation product in
94% ee and 68% ee respectively. All three PIB-supported chiral bisoxazoline-Cu(I)
catalysts could be reused five to six times.
|
204 |
The Recycling Intentions of Sport Spectators: A Theory of Planned Behavior ApproachMcCullough, Brian Patrick 2011 May 1900 (has links)
Sport organizations have a negative impact on the environment but these
organizations have begun environmental initiatives to decrease their impact. Introducing
recycling programs not only offers visible environmental effort to decrease the
organization’s impact but such programs can provide financial savings for the
organization. Thus, my dissertation’s purpose is to understand the recycling intentions
of sport spectators by the means of three studies theoretically framed using the theory of
planned behavior.
Study 1 examined the recycling intentions of individuals after consuming plastic
water bottles within a campus environment. Participants were undergraduate students (N
= 144) enrolled in physical activity classes at a southwestern university in the United
States (males n=83, 57.6 percent, females n=60, 41.7 percent; mostly White n=96, 66.7 percent; age
M=19.6, SD=1.33). The results indicate that subjective norms (β = .29, p < .001) and
attitudes (β = .14, p < .05) towards recycling significantly predicted intentions to recycle
plastic bottles after consumption. Study 2 analyzed the recycling intentions within a sport context. Participants
(N=129) were adult spectators attending a weekend long youth baseball tournament in
the Southwest United States (women n=85, 65.9 percent, men n=40, 31.0 percent; predominately
White n=97, 75.2 percent; age M=44.47 years, SD=10.20). Similar to Study 1, subjective
norms (β = .27, p < .01) significantly predicted intentions to recycle. However, unlike
Study 1, perceived behavioral controls (β = .21, p < .05) were significant in predicting
intentions to recycle.
Lastly, Study 3 augmented my investigation to understand the unique context of
recycling intentions among sport spectators. I used qualitative research methods to
understand recycling intentions of spectators during a large scale-sporting event.
Participants (N=16) were adults that regularly attend college football games at a large
southwestern university (men n=10, women n=6; age M=37.44). The results indicate
that recycling within a sport context is unique considering the game day atmosphere.
Collectively, the findings from the three studies are discussed as to influence
decision-making policies within sport organizations to improve recycling programs and
to decrease the organization’s negative environmental impact. Finally, recommendations
are made for future research to understand recycling behaviors of sport spectators.
|
205 |
Cash Flow Analysis and Risk Evaluation Of Recycling Plants' Setting BOT into ActionWang, Jiunn-Liang 18 February 2002 (has links)
With the fast development in industry and commerce in Taiwan in recent years, a great deal of waste is called into being. Because the waste yards in every region reach saturation sequentially, it has become the domestic trend to build recycling plants in order to properly cope with the garbage problems. However, the conventional way the government puts up capital to build public works has to be confronted with adjustment owe of the governmental functions and the limits in finance. Therefore, privatizing the public works to introduce the non-governmental flexible operating methods and getting abundant capital to speed up the establishment of recycling plants and efficient operating goals have become the new critical points of public works in governmental environmental protection.
The establishment of recycling plants takes a large number of funds and long period, during which there are many variables and high risk, and the main consideration of BOT invested by private enterprises is the rate of return on investment, so private enterprises have to study and analyze very carefully and map out the investment policies about how to carry out an investment evaluation and how to minimize or circumvent all kinds of risks in the executive process.
Aimed at BOT¡¦s special properties of recycling plants, this research adopts the cash flow analysis and probes into the financial projects and risk control to provide the reference materials to factory owners who are interested in BOT and also the consideration of amending the BOT-related provisions to the relevant departments in government.
|
206 |
Recovery and evaluation of the solid products produced by thermocatalytic decomposition of tire rubber compoundsLiang, Lan 25 April 2007 (has links)
A thermal catalytic decomposition process has been developed to recycle used tire rubber. This process enables the recovery of useful products, such as hydrocarbons and carbon blacks. During the catalytic decomposition process, the tire rubber is decomposed into smaller hydrocarbons, which are collected in the process. The solid reaction residue, which normally consists of carbon black, catalysts, other inorganic rubber compound components, and organic carbonaceous deposits, was subjected to a series of treatments with the intention to recover the valuable carbon black and catalyst. The process economics depend strongly on the commercial value of the recovered carbon black and the ability to recover and recycle the catalysts used in the process. Some of the important properties of the recovered carbon black product have been characterized and compared with that of commercial-grade carbon blacks. The composition of the recovered carbon black was analyzed by TGA and EDX, the structure and morphology were studied through transmission electron microscopy (TEM), and the specific surface area was measured by BET nitrogen adsorption. The recovered products possess qualities at least comparable to (or even better than) that of the commercial-grade carbon black N660. Methods for increasing the market value of this recovered carbon black product are discussed. Anhydrous aluminum chloride (AlCl3) was used as the primary catalyst in the process. A catalyst recovery method based on the AlCl3 sublimation and recondensation was studied and found to be non-feasible. It is believed that the catalyst forms an organometallic complex with the decomposed hydrocarbons, such that it becomes chemically bonded to the residue material and hence not removable by evaporation. A scheme for the further study of the catalyst recovery is suggested.
|
207 |
noneLin, Wan-yin 17 July 2009 (has links)
For the purpose of creating a sustainable environment for the future generation, the government has recognized the importance of renewable resources, and actively takes on the strategies and measures by promoting the industries to recycling wastes in order to effectively improve the physical fitness of the industry. There are various ways to recycle waste materials, depends on the technology and the applications, one waste material can be classified into different ranks of recycled resource. Also, the market value of the recycled resource is judged by its ability to substitute the existing goods on the market.
Because of the high proportion of galvanized steel in the steel scrap, zinc would vaporize during the high temperature process; as a result, the electric arc furnace dust (EAF dust) would contain high proportion of zinc. According to the existing recycling technology, the proportion of zinc in EAF dust is around 20% to 30%, which is a valuable secondary resource for producing zinc. This research focuses on the recycling industry; the aim of this research is to find out its future trend and the bottlenecks to be overcome. Hopefully come up with constructive suggestions and specific strategies and measures.
The results suggest that the officials should set up standards for recycled products. What is also important is that the government should better plan the policies and regulations for recycling industry. Moreover, the results also show the users of the recycled materials care most about the quality of the product. Hence, the producers of crude zinc oxide should form strategic alliance in order to each the economic scales of production and develop recycling technology to elevate the quality of crude zinc oxide. Once the production meets the market demand, it will be able to expand the sales channels and establish a stable profit.
|
208 |
Producer responsibility for WEEE as a driver of ecodesign: Case studies of business responses to producer responsibility chargesGottberg, Annika 11 1900 (has links)
Due to potential environmental, resource and health problems associated with waste, waste
minimisation is a prioritised waste management strategy in many countries. Producer
responsibility policies promote waste minimisation by stipulating separate collection and
recycling of particular waste streams. In addition, a purpose of the policy is to encourage
product development that reduces waste generation and improves recyclability. It is
sometimes assumed that the financial responsibility assigned to producers for collection
and recycling of their end-of-life products will instigate waste minimising product
development in order to reduce costs. However, this view has also been contested.
Following the adoption of the WEEE Directive (2002/96/EC) all EU member states have to
implement producer responsibility for WEEE. Taking a qualitative multiple case study
approach, this study explores company responses to the costs of existing national producer
responsibility policies for WEEE in relation product development. The purpose is to inform
policy-making on the effectiveness of producer responsibility charges in achieving waste
minimising product development.
The study comprises both large companies and SMEs in the lighting equipments sector. It
also includes companies in EU member states without producer responsibility for WEEE in
order to see if there are any differences in waste-minimising product design among
countries and if national policies have an impact beyond national borders. Economic
principles and previous research findings on ecodesign make up the analytical framework
for the study.
Quantitative data on cost-benefits of ecodesign and waste minimisation achievements were
scarce. However, the company responses show that the costs imposed on the producers by
the WEEE policy have had little effect on product development so far. The costs can
generally be transferred to customers via product prices. The price increases were generally
small and without any negative effects on competitiveness. Other drivers such as bans on
certain substances, environmental industry product declarations, commercial advantages
including direct customer demands from for instance public procurers, are more effective.
|
209 |
Demontage komplexer Produkte in einer Kreislaufwirtschaft /Dinge, Achim. January 2000 (has links)
Thesis (doctoral)--Universität, Münster (Westfalen), 2000.
|
210 |
Über Untersuchungsmethoden als Beitrag zu einer verbesserten Abfallbewirtschaftung in lateinamerikanischen SchwellenländernRadon, Frank January 2009 (has links)
Zugl.: Dortmund, Techn. Univ., Diss., 2009
|
Page generated in 0.0724 seconds