In Geräten und Anlagen des Stromnetzes werden Steckverbinder mit hoher Stromtragfähigkeit eingesetzt, wenn bewegliche Teile kontaktiert werden oder Betriebsmittel mit geringem Aufwand montier- und demontierbar sein müssen. Die elektrische Verbindung der Leiter wird dabei oft mit federnden Kontaktelementen realisiert. Die Kontaktelemente müssen als Teil der Strombahn während der Lebensdauer des Geräts den Betriebsstrom im Kiloampere-Bereich und im Fehlerfall bis zu einige Sekunden lang den eine Größenordnung höheren Kurzschlussstrom tragen. In der vorliegenden Arbeit wurden Rechenmodelle für die innere Erwärmung von Hochstrom-Kontaktsystemen im stationären Dauerbetrieb und im transienten Kurzschlussfall entwickelt. Das elektrische und mechanische Langzeitverhalten im Temperaturbereich (105…180) °C wurde experimentell mit stromdurchflossenen, fettgeschmierten Modellsteckverbindern, die regelmäßig getrennt und neu gesteckt wurden, untersucht. Modellerstellung, Rechnungen und Versuche wurden beispielhaft mit Kontaktelementen vom Typ Multilam durchgeführt. Kontaktelemente und Leiter bestanden aus versilbertem Kupfer. Für das stationäre Betriebsverhalten wurden die mit der analytischen Spannungs-Temperatur-Beziehung nach Kohlrausch berechneten Ergebnisse mit einem Erwärmungsversuch verifiziert. Die Temperaturdifferenz zwischen Kontaktelement und Leiter ist bei Standardanwendungen, wie in Schaltanlagen, mit ≤ 3 K sehr klein. Deshalb ist die Leitertemperatur als Zielgröße beim Dimensionieren der Dauerstrombelastbarkeit ausreichend. Bei Kurzschlussstrombelastung wurde im Kontaktsystem eine schnelle, räumlich unterschiedlich ausgeprägte Erwärmung numerisch berechnet. Leiter und Kontaktelement erwärmen sich kontinuierlich, wobei die mittlere Endübertemperatur im Kontaktelement aufgrund des kleineren stromtragenden Querschnitts eine Größenordnung höher ist. Die Kontakte führen bei 50 Hz-Wechselstrom aufgrund ihrer vernachlässigbaren Wärmekapazität 100 Hz-Temperaturzyklen aus. Dabei können die Maximaltemperaturen noch deutlich größer als die mittlere Temperatur der Kontaktelemente sein. Im Langzeitversuch waren nach 16 000 h Betriebszeit bei 180 °C und regelmäßigen simulierten Steckvorgängen die Verbindungskräfte noch genügend groß, um die elektrischen Anforderungen eines neuen Kontaktsystems zu erfüllen. Allerdings führte bei einer Betriebstemperatur von 105 °C ein thermisch instabiles Schmierfett zum vorzeitigen elektrischen Ausfall eines Teils der Steckverbinder. / Switchgear and devices for the power grid use high-power connectors if moving parts have to be contacted or equipment shall be easily mountable and dismountable. The electrical connection of the conductors is often realized by spring-loaded contact elements. As part of the main circuit, contact elements must carry the full operating current in the kiloampere-range for the entire service life of the device. In case of a fault, the short-circuit current, which is one order of magnitude larger, has to be carried for up to several seconds. In this thesis, calculation models for the inner temperature rise of high-power contact systems in steady-state continuous operation, as well as for the transient short-circuit load case were developed. Electrical and mechanical long-term performance in the temperature range from 105 to 180 °C was experimentally investigated with current carrying, grease-lubricated model connectors which were regularly unplugged and replugged. Modelling, calculations and experiments were exemplarily carried out with Multilam contact elements. Conductors and contact element consisted of silver-plated copper. The analytical voltage-temperature relation was used to calculate the steady-state performance; calculations were verified with a temperature-rise test. The temperature difference from contact element to conductors is very small (≤ 3 K) for standard applications like switchgear. Thus, it is sufficient to use the conductor temperature as a criterion for the design of the continuous ampacity of high-power contact systems. At short-time load, a fast spatially inhomogeneous temperature rise was numerically calculated. Conductor and contact element continuously heat up; due to the smaller current carrying cross section, median final temperature rise in the contact element is one order of magnitude larger than in the conductors. Because of their negligible thermal capacity, contacts perform 100 Hz temperature cycles at 50 Hz AC load; the maximum contact temperatures may be significantly higher than the median temperature of the contact elements. In the long-term test, after 16 000 h operating time at 180 °C and regular plugging operations, contact elements maintained enough joint force to meet the requirements of a new contact system. At 105 °C however, a thermally instable grease led to electrical failure of part of the connectors.

Cette thèse s’interesse à l’étude des effets des sociétés de Capital-Investissement (SCI) sur la performance des introductions en bourse. La démarche suivie pour argumenter cette thèse nous a conduits, dans une première partie, à justifier notre positionnement théorique et à définir nos hypothèses de recherche. Cette étape nous a orientée vers l’analyse des caractéristiques des introductions en bourse et l’analyse du rôle des SCI notamment sur le marché des introductions en bourse. Nous avons construit une argumentation autour du rôle des SCI en matière de résolution des asyémtries informationnelles caractérisant les sociétés introduites en bourse. Les SCI, étant dotées d’une capacité à concevoir des contrats, d’un réseau de connaissance et d’une expertise, pourraient atténuer les conflits d’agence et émettre un signal positif sur le marché d’IPOs. En revanche, ces sociétés pourraient se retrouver face au problème de sélection adverse au moment de la décision d’investissement et/ou adopter un comportement opportuniste pour servir leurs intérêts. La vérification empirique de cette problèmatique est développée dans la deuxième partie de notre thèse. Elle consiste à comparer la performance à court et à long terme des sociétés financées de celles non financées par CI, ensuite analyser cette performance en foction de l’affiliation institutionnelle des SCI et enfin, expliquer cette performance en fonction de la réputation des SCI et des stratégies d’intermédiation de celles-ci, notamment la syndication, le financement séquentiel et la distribution des droits aux cash-flows et au contrôle / In this dissertation, it is tried to understand the effects of Venture Capital Firms (VCF) on the performance of VC-backed listed companies in France. To do this research, we try to develop, in the first part, theoretical framework and define research hypothesis. This part leads us to examine characteristics of initial public offerings (IPOs) and the role of venture capitalists particularly in conducting an IPO. We develop the argument around the role of VCF in resolving informational problems, characteristics of IPO’s market. A VCF, being specialists to draw up contract with entrepreneurs and possessing expertise and knowledge network, could diminish conflicts of interests and certify IPOs. However, these firms could run a problem of adverse selection and/or adopt opportunistic behaviour to serve their own interests. The empirical validation of this problem is dealt with in second part of this dissertation. It consists, in first place, to compare performance of VC backing IPOs to Non-VC backing IPOs. In second place, we determine the relation between the performance of VC backing IPOs and the institutional affiliation of VCF. In last part, we test explanatory power of reputation of VCF and their mechanisms of intermediation, particularly, syndication, staged financing and distribution of cash-flows and control rights

本研究主要探討生技產業公開說明書之風險因子揭露對首次公開發行公司5年內的獲利能力做研究，想得知風險因子的揭露是否會影響公司獲利時間的長短。本研究以美國生技產業首次公開發行公司為研究對象，樣本期間為1997年至2012年。 許多文獻指出越來越多公司在尚未獲利前即先行上市，但公司未來的前景及獲利能力卻充滿高度的不確定性，而透過資訊的揭露可使該不確定性下降，因透過揭露，投資者可以了解公司營運狀況及表現，對公司價值能做較正確之判斷， 此時願意提供資金給公司營運，充足的資金使公司未來獲利機會上升。 本研究參考過去文獻，建立資訊揭露的四級指標加上風險因子所揭露的項目多寡，系統性地衡量生技公司公開說明書之風險因子，並以存活分析檢測假說。實證結果顯示：風險因子的內容描述越著重在某些特定資訊，例如：顧客資訊、重要員工資訊、量化資訊的表達、公司未來不確定性、財務需求時，公司未來獲利能力機會大增，而當更進一步的探究時，又發現對顧客資訊和量化資訊的表達越具體，越詳細時，也會使公司未來獲利機會上升。 / This study investigates whether disclosure of risk factors in the prospectus will influence the probability of the biotech firms to attain profitability. Data is collected for biotech companies of U.S IPOs issued from1997 to2012 as the research sample. Many extant empirical evidences indicate that the proportion of firms going public prior to achieving profitability has been increasing over time. There is considerable uncertainty regarding the long-term economic viability of these firms at the time of going public. Disclosures in the prospector may mitigate the effects of ex-ante uncertainty about firm’s value, and disclosures are potentially important means for management to communicate firm performance and governance to outside investors. Therefore, firms can raise more money by disclosing more information in IPO prospectors, because more information reperesent lower uncertainty between investors and firms.This study uses risk factors in the prospectus as concern issue and expects that the quantity of risk factors and the content or description of risk factors will influence the uncertainty and would mitigate investors’ concern. Referring to past literature, this study builds four-class index for disclosure score and uses two classifications of risk factors to systematically measure risk factors in the prospectus. The empirical results show that a biotech IPO with more information or some specific information of risk factors, like disclosures of main customers and key employees, will experience good performance after IPO. In addition, more detail descriptions in quantitative risk factors and customers’ information contributed to better performance in the future. In conclusion, disclosure of risk factors in the prospectus are related to firms’ probability of profitability after IPO as expected.

Inledning: Historiskt sett har IPO:er ofta varit underprissatta vilket har resulterat i att de i genomsnitt haft en hög initial avkastning, det vill säga, hög avkastning den första handelsdagen. Detta har skapat en uppfattning om att nyintroduktioner är ett bra investeringsalternativ för de som vill ha en avkastning utöver det normala. Syfte: Syftet med uppsatsen är att studera huruvida aktiers utveckling på kort och lång sikt påverkas av variabler som bolagets storlek, ålder, branschtillhörighet, noteringsperiod och könsfördelning i styrelsen. Syftet är också att undersöka huruvida IPO:er är underprissatta och om de underpresterar på lång sikt. För att studera detta har aktier noterade på Stockholmsbörsen, Aktietorget och First North mellan år 2013 och 2014 analyserats. Metod: För att kunna genomföra denna studie har ett kvantitativt tillvägagångssätt tillämpats. Vidare har en deduktiv ansats använts då avsikten var att analysera det insamlade materialet utifrån tidigare forskning. Urvalet består av 56 bolag där sekundärdata inhämtats via Nasdaq OMX, Nordnets- och Avanzas webbsida samt Skatteverket. Teori: Den teoretiska referensramen som studien baseras på består av teorier som har skapats kring hur IPO:er presterar på kort och lång sikt och varför de presterar som de gör. Vidare presenteras tidigare forskning kring hur könsfördelning i bolagsstyrelser kan påverka bolagens utveckling. Resultat och slutats: Resultatet visade att IPO:er på kort sikt blir överprissatta då de haft en negativ initial utveckling. Resultatet visade vidare att IPO:er överpresterar på lång sikt samt att de mest underprissatta IPO:erna presterar bäst. För de oberoende variablerna storlek, ålder, branschtillhörighet, noteringsperiod och könsfördelning i styrelsen kunde inga signifikanta samband återfinnas. / Introduction: Historically, IPO’s have often been underpriced, which has resulted in a high initial return on average, i.e. high return on the first trading day. This has created the perception that new introduction is a good investment option for those who want an abnormal return. Purpose: The purpose of this study is to examine whether the short- and long-term performance of IPO’s are affected by variables as firm size, firm age, industry affiliation, issue period and gender diversity on board of directors. The purpose is also to determine whether IPO’s are underpriced and if they underperform in the long run. To study this, Initial Public Offerings on First North, Aktietorget and Stockholmsbörsen during the period of 2013 to 2014 have been analyzed. Methodology: To implement this study, a quantitative approach has been applied. Furthermore, a deductive approach was used since the purpose was to analyze the collected material based on previous research. The data selection consists of 56 firms were the secondary data has been obtained from Nasdaq OMX, Nordnet website, Avanza website and The Swedish Tax Agency. Theory: The theoretical frame that the study is based on consists of theories that were created regarding how IPO’s perform in short- and long-term and why they perform as they do. Furthermore, earlier research is presented which examine how gender diversity in board of directors affect corporate performance. Result and conclusions: The result in this study shows that in the short run, IPO's are overpriced due to a negative initial return. Further, the result show that IPO's outperform other companies, and the most underpriced shares perform better in the long run. For the dependent variables size, age, industry affiliation, listing period and gender diversity, no relationship of statistical significance could be found.

In Geräten und Anlagen des Stromnetzes werden Steckverbinder mit hoher Stromtragfähigkeit eingesetzt, wenn bewegliche Teile kontaktiert werden oder Betriebsmittel mit geringem Aufwand montier- und demontierbar sein müssen. Die elektrische Verbindung der Leiter wird dabei oft mit federnden Kontaktelementen realisiert. Die Kontaktelemente müssen als Teil der Strombahn während der Lebensdauer des Geräts den Betriebsstrom im Kiloampere-Bereich und im Fehlerfall bis zu einige Sekunden lang den eine Größenordnung höheren Kurzschlussstrom tragen. In der vorliegenden Arbeit wurden Rechenmodelle für die innere Erwärmung von Hochstrom-Kontaktsystemen im stationären Dauerbetrieb und im transienten Kurzschlussfall entwickelt. Das elektrische und mechanische Langzeitverhalten im Temperaturbereich (105…180) °C wurde experimentell mit stromdurchflossenen, fettgeschmierten Modellsteckverbindern, die regelmäßig getrennt und neu gesteckt wurden, untersucht. Modellerstellung, Rechnungen und Versuche wurden beispielhaft mit Kontaktelementen vom Typ Multilam durchgeführt. Kontaktelemente und Leiter bestanden aus versilbertem Kupfer. Für das stationäre Betriebsverhalten wurden die mit der analytischen Spannungs-Temperatur-Beziehung nach Kohlrausch berechneten Ergebnisse mit einem Erwärmungsversuch verifiziert. Die Temperaturdifferenz zwischen Kontaktelement und Leiter ist bei Standardanwendungen, wie in Schaltanlagen, mit ≤ 3 K sehr klein. Deshalb ist die Leitertemperatur als Zielgröße beim Dimensionieren der Dauerstrombelastbarkeit ausreichend. Bei Kurzschlussstrombelastung wurde im Kontaktsystem eine schnelle, räumlich unterschiedlich ausgeprägte Erwärmung numerisch berechnet. Leiter und Kontaktelement erwärmen sich kontinuierlich, wobei die mittlere Endübertemperatur im Kontaktelement aufgrund des kleineren stromtragenden Querschnitts eine Größenordnung höher ist. Die Kontakte führen bei 50 Hz-Wechselstrom aufgrund ihrer vernachlässigbaren Wärmekapazität 100 Hz-Temperaturzyklen aus. Dabei können die Maximaltemperaturen noch deutlich größer als die mittlere Temperatur der Kontaktelemente sein. Im Langzeitversuch waren nach 16 000 h Betriebszeit bei 180 °C und regelmäßigen simulierten Steckvorgängen die Verbindungskräfte noch genügend groß, um die elektrischen Anforderungen eines neuen Kontaktsystems zu erfüllen. Allerdings führte bei einer Betriebstemperatur von 105 °C ein thermisch instabiles Schmierfett zum vorzeitigen elektrischen Ausfall eines Teils der Steckverbinder.:Einleitung Hochstrom-Kontaktsysteme – Stand der Technik Theorie der Kontakte bei hoher Strombelastung Stationäres elektrisch-thermisches Betriebsverhalten Transientes elektrisch-thermisches Betriebsverhalten Langzeitverhalten Zusammenfassung Ausblick / Switchgear and devices for the power grid use high-power connectors if moving parts have to be contacted or equipment shall be easily mountable and dismountable. The electrical connection of the conductors is often realized by spring-loaded contact elements. As part of the main circuit, contact elements must carry the full operating current in the kiloampere-range for the entire service life of the device. In case of a fault, the short-circuit current, which is one order of magnitude larger, has to be carried for up to several seconds. In this thesis, calculation models for the inner temperature rise of high-power contact systems in steady-state continuous operation, as well as for the transient short-circuit load case were developed. Electrical and mechanical long-term performance in the temperature range from 105 to 180 °C was experimentally investigated with current carrying, grease-lubricated model connectors which were regularly unplugged and replugged. Modelling, calculations and experiments were exemplarily carried out with Multilam contact elements. Conductors and contact element consisted of silver-plated copper. The analytical voltage-temperature relation was used to calculate the steady-state performance; calculations were verified with a temperature-rise test. The temperature difference from contact element to conductors is very small (≤ 3 K) for standard applications like switchgear. Thus, it is sufficient to use the conductor temperature as a criterion for the design of the continuous ampacity of high-power contact systems. At short-time load, a fast spatially inhomogeneous temperature rise was numerically calculated. Conductor and contact element continuously heat up; due to the smaller current carrying cross section, median final temperature rise in the contact element is one order of magnitude larger than in the conductors. Because of their negligible thermal capacity, contacts perform 100 Hz temperature cycles at 50 Hz AC load; the maximum contact temperatures may be significantly higher than the median temperature of the contact elements. In the long-term test, after 16 000 h operating time at 180 °C and regular plugging operations, contact elements maintained enough joint force to meet the requirements of a new contact system. At 105 °C however, a thermally instable grease led to electrical failure of part of the connectors.:Einleitung Hochstrom-Kontaktsysteme – Stand der Technik Theorie der Kontakte bei hoher Strombelastung Stationäres elektrisch-thermisches Betriebsverhalten Transientes elektrisch-thermisches Betriebsverhalten Langzeitverhalten Zusammenfassung Ausblick

In recent years, deep geothermal energy has been widely exploited through closed-loop borehole heat exchanger system for building heating. In order to precisely evaluate the sustainable heat extraction capacity and the impact of different designs and operating parameters, two heat transfer models are implemented in the open-source scientific software OpenGeoSys (OGS), with respect to the Deep Borehole Heat Exchanger (DBHE) and Enhanced U-tube Borehole Heat Exchanger (EUBHE) system. Besides, three types of boundary conditions are implemented, including the constant inflow temperature, the constant heat extraction rate, and constant building thermal power that integrates the ground source heat pump (GSHP) module. By applying the two BHE models, the influence of different designs and operating parameters on the GSHP system is evaluated. The sustainable heat extraction capacity and efficiency of a deep EUBHE system are predicted. Moreover, its performance and efficiency are further compared against the 2-DBHE array system that has the same total borehole length. It is found that the soil thermal conductivity is the most important parameter in the design of DBHE and EUBHE systems. The sustainable specific heat extraction rate of the EUBHE system is 86.5 W/m higher than an array with 2 DBHEs. Under the building thermal load of 1.225 MW, the total electricity consumed by the EUBHE system is approximately 27 % less than the 2-DBHE array over 10 years. The average Coefficient of System Performance (CSP) value of the EUBHE system is 1.66 higher over 10 heating seasons. The two numerical models implemented in the OpenGeoSys software can be used to predict and optimize the thermal characteristics of the closed-loop DBHE and EUBHE systems in real projects.

No description available.

Concrete is the most widely used construction material worldwide, yet, it presents major sustainability drawbacks due to the CO2 released during the manufacturing of its main constituent, cement. Several approaches are used to improve concrete’s eco-efficiency and reduce the binder intensity index, a metric used to measure the eco-efficiency of concrete, to a value below that of conventional concrete mixtures (i.e., 10 kg/m3.MPa-1 for 25-40 MPa mixtures). Particle Packing Models (PPM) is consequently an approach that can be used to enhance system packing density, reducing cement content while increasing hardened state properties and durability (i.e., reducing porosity). However, packed mixtures normally present issues in the fresh state while their hardened state performance is not fully comprehended. Therefore, this Ph.D. project proposes a new mix-design method called PPM-MP approach to develop eco-efficient mixtures. First, a detailed laboratory investigation was conducted on mixtures developed using the proposed approach in order to understand their fresh and hardened state performance. Concrete samples containing distinct ranges of cement content (320, 250, 200, 150 kg/m3) and slump (180, 90, and 20 +/- 20 mm) were fabricated and a wide range of fresh state tests (pH, temperature, fresh density, air content, slump and rheology over time) and hardened state tests (apparent porosity, surface electrical resistivity, compressive strength, and modulus of elasticity) were performed over time. Then, its performance against the alkali-silica reaction (ASR) induced expansion and deterioration, which is one of the leading and most damaging distress mechanisms issues in durability, was evaluated. In this section of the project, four sustainable concrete mixtures developed with varying cement content (e.g., 325, 250, 200, and 150 kg/m3) were developed and compared to a control mixture containing 420 kg/m3 of cement content. The mixtures were tested over a year under Concrete prism test (CPT) setup, which is the current method used to evaluate concrete ASR and using three different non-boosted test setups (i.e., Wrapped - W, Soaked - S, and Encapsulated - E). Moreover, two distinct types of highly reactive aggregates (e.g., Springhill Greywacke coarse aggregate and Texas Polymictic sand) were selected. Microscopic analysis was used to better understand the impact of ASR on sustainable mixtures, as well as the differences in ASR-damage and crack propagation under different test protocols. The results show the feasibility of producing an eco-efficient mixture in a more efficient manner which may contribute to the Net Zero Concrete targets. The proposed PPM-MP approach improves the sustainability of concrete mixtures and can be used for specific projects requiring 28-day compressive strength ranging from 18 to 45 MPa and slumps (180, 90, and 20 +/- 20 mm).

No description available.

本研究透過台灣創投基金的聲譽、國際化和政治連結等信號(Signal)，探討創投基金對於新創公司初次公開發行後的長期表現的影響。本研究之實證結果發現，創投基金的聲譽越高以及國際化程度越高，對於新創公司的長期表現有正向影響，但是創投基金與國發基金的政治連結卻產生非單一面向的結果，政治連結僅對於新創公司的長期研發投入具有正面顯著影響。政治連結會帶來負向的效果可能由於國發基金所推行的政策影響，或者是其中具有裙帶資本主義的干擾，導致受到國發基金所投資的創投基金對於新創公司的長期表現帶來負面影響。由本研究的結果我們可知若新創公司得到具有高聲譽或國際化的創投投資是對於其未來發展是有所幫助，所以新創公司在尋找創投基金合作時，可以以此作為考量的標準。 / In this research, venture capital reputation, degrees of internationalization, and the political links formed by venture capitals and Taiwanese National Development Fund are hypothesized to influence the long-run performance of start-ups. By utilizing a unique dataset of venture capital investment, we could investigate the sources of higher long-run performance of venture capital teams. Besides, we also inquire the impact of internationalization and political links of venture capitals on the performance of stat-up business. The results show that venture capitals with higher reputation or degrees of internalization impacts positively on long-term performance of start-ups. However, the political links formed between venture capitals and Taiwanese National Development Fund only affects business innovation measures positively. The policy focused or the crony capitalism long existing between Taiwanese National Development Fund and venture capitals can both be the major reasons to trigger the mixed investment influence. Thus, this research can shed some light on the intrinsic factors driving positive investment results other than the venture capital reputations.