39 research outputs found
Effect of chemical composition on hot cracking susceptibility (HCS) using various hot cracking criteria
No full textThe paper aims to evaluate the effect of chemical composition on the Hot Cracking Susceptibility (HCS) using mechanical and non-mechanical hot cracking criteria during solidification. The criteria were SKK as a mechanical criterion. Feurer, Clyne Davis, and Katgerman as non-mechanical criteria. The criteria were implemented at various parameters to evaluate their abilities in the hot cracking susceptibility (HCS) prediction at varied chemical composition. In this study, The Mg content was varied in Al9Zn (1, 1.5, 2, 2.5 %wt.) Mg2Cu alloys and Cu content in Al9Zn2Mg (1, 1.5, 2, 2.5 %wt.) Cu alloys. The validation of the result is also conducted by comparing with the experimental data. Based on Feurer criterion, The hot cracking initiates at lower temperature and at higher critical rate of feeding and shrinkage with Cu content, and the hot cracking initiates at higher temperature with Mg content, and it initiates at higher critical rate of feeding and shrinkage from 1 up to 1.5 of Mg, and the critical rate of feeding and shrinkage remains constant from 1.5 up to 2.5 of Mg. Based on Clyne & Davies, the HCS decreases with Cu content from 1 up to 2 of Cu, and it increases from 2 up to 2.5 of Cu. The HCS decreases with Mg content from 1 up to 2 of Mg, and it remains constant from 2 up to 2.5 of Mg. Based on Katgerman criterion, the HCS decreases with Cu content from 1 up to 1.5 of Cu, it increases from 1.5 up to 2 of Cu, and it decreases from 2 up to 2.5 of Cu. The HCS decreases sequentially with Mg content. Based on SKK criterion, the HCS curves shift to the right with Cu content which means that the hot cracking initiates at lower temperature, and the HCS curves shift to the left with Mg content which means that the hot cracking initiates at higher temperature with Mg content. The Feurer, Clyne & Davies, and some specific range for SKK criteria are in agreement for the effect of Cu content on HCS of alloys, and Katgerman and some specific range for Clyne&Davies criteria are in agreement for the effect of Mg content on HCS of alloys.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Joris Di
CUTTING AND PASTING OF MORSE FUNCTIONS (Research on topology and differential geometry using singularity theory of differentiable maps)
Full text linkCobordism groups of various types of Morse functions have been studied separately by several authors including Ikegami, Kalmar, Saeki, Yamamoto, and the author. In this article, we propose a conceptually new approach for studying cobordism groups of several types of Morse functions within a single unifying framework. Our method is crucially based on certain cutting and pasting relations for manifolds that have been used before to define SKK-groups of manifolds. We provide an explicit isomorphism between the cobordism group of Morse functions and SKK-groups. Moreover, we sketch an application of our framework to cobordism theory for Morse functions with boundary, and raise some problems for future study concerning Morse functions with index constraints and circle-valued Morse functions
On the Effectiveness of Central Bank Intervention in the Foreign Exchange Market: The Case of Slovakia 1999-2007
No full textThis paper investigates the effect of the National Bank of Slovakia's (NBS) intervention in the SKK/EUR foreign exchange market from 1999 through 2007 (the time period covering Slovakia's preparation for EU accession and euro adoption) on the level of the SKK/EUR exchange rate. The study asks 2 questions. Did the National Bank of Slovakia's sterilized interventions in the market for the koruna and the euro from 1999-2007 have an effect on the level of the koruna's exchange rate with the euro? If so, for how long did this effect last? High-frequency, intraday data on both foreign exchange rates and sterilized NBS interventions in the market for the koruna and the euro is analyzed using OLS to this end. The frequency of this data allows the author to counteract the perennial endogeneity problem of studies on central bank intervention. 3 conclusions are offered. First, NBS intervention from 1999-2007 had a statistically significant impact on the level of the SKK/EUR exchange rate in the short-term. Second, this short-term effect was statistically insignificant after 2 hours and 40 minutes had passed following each NBS intervention trade, implying the effect of intervention dissipates over-time. Third, given the short-term impact of NBS intervention, this tactic could be considered an expensive policy tool for influencing the level of a country's exchange rate, as intervention can require a central bank to draw down substantially on its foreign exchange reserves
USER RATIONALITAT, NORMEN UND INSTITUTIONEN: DIE EVOLUTION SOZIOKULTURELLEN KAPITALS ALS MODELL FUR INSTITUTIONELLE VERANDERUNGEN
Full text linkRad upućuje na plodnost kombiniranja sociologijskog i ekonomijskog
pristupa analizi institucionalne dinamike, jednog od središnjih
fenomena unutar korpusa obiju disciplina. Razlikovanjem neformalnih
i formalnih institucija te naglašavanjem uloge tzv. sociokulturnog
kapitala (SKK) kao mosta između njih, autor izvodi makrostrukturu
institucionalne dinamike. Razmatranje nekoliko empirijskih primjera
čvrsto povezuje institucionalnu dinamiku - i njezino inverzno lice,
perzistenciju - s konfiguracijom SKK-a. U završnome dijelu autor izlaže
skicu evolucijskog modela institucionalne promjene, koji uključuje
ograničenu-i-"ukorijenjenu" racionalnost, mehanizam konformističke
imitacije i povijesno konfigurirani SKK.The paper suggests that a joint sociological and economic approach
to institutional dynamics, one of the core phenomena in both
disciplines, yields important results. In the first part the author delineates
informal and formal institutions and then concentrates on the
bridging role of socio-cultural capital (SCC). In the second part of
the paper several hypotheses are proposed linking the structure of
SCC - especially the scope of cooperation and the verticali horizontal
organization as its basic dimensions - with the institutional dynamics
and persistence. The analysis of the macro structure of institutional
dynamics points out thatthe institutional path- dependency
should be interpreted in terms of the differentiai socio-cultural configuration.
Discussing the cases of Suq (bazaar), Mafia, and medieval
guilds, the author offers a simple evolutionary model of institutional
change.Vorliegende Arbeit verweist auf die vorteilhafte Koppelung des soziologischen
und des 6konomischen Zugangs bei der Analyse institutioneller
Dynamik, eines der Hauptphanornene im Korpus sowohl
der Soziologie als auch der Okonomie. Der Verfasser unterscheidet
zwischen unformalen und formalen Institutionen und betont
die Rolle des sog. soziokulturellen Kapitals (SKK) als eines Verbindungsglieds
zwischen ihnen; auf diese Weise ermittelt er die Makrostruktur
institutioneller Dynamik. Durch eine Untersuchung verschiedener
empirischer Beispiele wird institutionelle Dynamik - sowie
deren inversive Seite, die Persistenz - mit der Konfiguration soziokulturellen
Kapitals in enge Verbindung gebracht. Der Verfasser
skizziert abschlieBend ein Evolutionsmodell institutioneller Veranderungen,
das eine besehrankte und "verwurzelte" Hanonalitšt, ferner
den Mechanismus konformistischer Imitation sowie geschichtlich
konfiguriertes soziokulturelles Kapital umfaBt
Health-Care Providers' Preparedness for H1N1/09 Influenza Prevention and Treatment in Dar es Salaam, Tanzania.
Full text link\ud
In Tanzania, the first case of H1N1/09 influenza was reported in September 2009. By March 2010, the reported number of cases was 770 with one death. Due to shortage of qualified human resources, essential medicines and laboratory supplies in health facilities, it was not known how well health-care providers in the country were prepared to deal with the pandemic. The study was conducted from December 2009 to May 2010 in public hospitals and private community pharmacies in Dar es Salaam, Tanzania. Fifty-three prescribers and 200 dispensers were interviewed to assess their knowledge on the prevention and treatment of H1N1/09 influenza, and dissemination of correct information to the public regarding the pandemic. Most participants had inadequate knowledge on the transmission, prevention and management of H1N1/09 influenza. The majority of prescribers knew neither the antiviral drugs recommended for the treatment of H1N1 influenza (64%) nor their adverse effects (92.5%). The drug dispensers' knowledge was also inadequate regarding the transmission, prevention and treatment of H1N1/09 influenza. Forty-one (20.5%) salespersons without formal training in pharmaceutical or medical sciences were found dispensing and supervising the pharmacies. Most participants had misconceptions on how H1N1/09 virus was transmitted. The results of the study revealed gaps in the knowledge of the health-care providers on the prevention and treatment of H1N1/09 influenza infection. This indicates the need for strengthening of health-care systems and provision of continuing education and professional development for health-care providers on new and re-emerging diseases in the community.\u
Creatio ex nihilo jako problem kosmologiczny i egzegetyczny?
Full text linkThe doctrine creatio ex nihilo is today a fundamental belief in Catholic theology of creation. It is sometimes questioned based on the “current” state of knowledge provided by modern physical cosmology. On the other hand, theology itself points to its support in texts such as Prov 8,22–29; 2 Mcc 7,28; Sap 11,17; Rom 4,17; Hbr 11,3. In the following article the author points out, on the one hand, the lack of contradiction between contemporary cosmological knowledge and the doctrine creatio ex nihilo, and on the other hand, the fact that the biblical texts themselves cited in its support do not directly express such a belief about the beginnings of the universe. This is due to the context of these statements and the attachment to the traditional way of thinking about the beginning of everything (Gen 1,1–2: primordial chaos)
Uncertainty and the value of cash holdings
No full textWe find that a firm facing higher uncertainty has a higher value of cash. This effect is attributed to the increased value of the option to wait and see as well as the aggravated financial constraints and mitigated agency conflicts. (C) 2017 Elsevier B.V. All rights reserved.SSCIARTICLE43-4815
Tajemnica wcielenia i odkupienia Chrystusa w mistycznym doświadczeniu św. Faustyny Kowalskiej
Full text linkThe author of the article examines the mystery of the Incarnation and Redemption of Christ in light of the message of Scripture and the mystical experiences of St. Faustina Kowalska. Divine Mercy, as the foundation of faith, is fully revealed through the life, death, and resurrection of Christ. In the Bible, these events are portrayed as the fulfillment of God’s eternal plan of salvation, aimed at restoring humanity to communion with the Father. The mystical experiences of St. Faustina, recorded in her Diary, deepen the understanding of the biblical message of Mercy. A comparison of these two sources reveals their complete coherence, particularly regarding God’s love for sinners and the significance of Christ’s sacrificial death on the cross. The study suggests that St. Faustina’s visions may serve as a unique commentary on Scripture, helping contemporary believers to more profoundly discover God’s merciful love
Effect of Main Elements (Zn, Mg, and Cu) on Hot Tearing Susceptibility During Direct-Chill Casting of 7xxx Aluminum Alloys
No full textNew 7xxx aluminum alloys with high alloying contents are being designed, which could induce serious hot tearing defects during direct-chill (DC) casting. Among all factors affecting hot tearing of 7xxx alloys, undoubtedly alloying elements play a significant role. In this study, the effect of main alloying elements (Zn, Mg, and Cu) on hot tearing of grain-refined Al-xZn-yMg-zCu alloys was investigated by a dedicated hot tearing rating apparatus simulating the DC-casting process. It was found that the minimum and maximum hot tearing susceptibilities occur for 4 to 6 and 9 wt pct Zn, respectively, indicating the complicated effect of Zn content. The hot tearing resistance of grain-refined Al-9Zn-yMg-zCu alloys is enhanced with increasing Mg content but is deteriorated with increasing Cu content. This can be attributed to the interaction of the thermal stresses, melt feeding, and final eutectics. The observed tendencies of the main alloying elements on hot tearing were also confirmed for four commercial 7xxx alloys. In addition, both the load value at non-equilibrium solidus and the SKK criterion proposed by Suyitno et al. using measured load developments were found to be good indicators in predicting hot tearing susceptibility. This study can provide a beneficial guide in designing 7xxx alloys considering the potential occurrence of hot cracks beforehand.</p
Supervision Mining System : Reconstruction of Supervision of Socially Equitable Upstream Oil and Gas Sector in Indonesia
No full textThe principle of people's welfare is implied in the fifth precept of Pancasila which reads "social justice for all Indonesian people". Pancasila is the philosophy of the state (Philosofische Gronslag) and a state policy that contains fundamental values that are the basis for the achievement of the Indonesian state. The state ideal contained in the preamble of the 1945 NRI Constitution shows the characteristics of the welfare state (Welfare State) that mandates the State to be responsible for the welfare of the people. This is confirmed in Article 33 of the 1945 NRI Constitution that the earth's water and natural wealth in it are controlled by the State and used as much as possible for the welfare of the people. The article then becomes a constitutional foundation as well as the direction of arrangements in the management of natural resources based on social justice to provide real added value to the national economy. As well as Oil and Gas (Migas) is a strategic natural resource as well as a vital commodity that controls the lives of many people and has an important role in the national economy so that its managers must provide prosperity and welfare of the people. One of the upstream oil and gas business activities that have an important role as a driver of the national economy is the upstream oil and gas sector. The upstream oil and gas sector will provide significant benefits if managed and supervised properly. In order to carry out these supervisions, the government established the Oil and Gas Implementing Agency (BP Migas) as the power holder of the upstream oil and gas sector. But after the issuance of the Constitutional Court decision No. 36 / PUU-X / 2012, BP Migas was dissolved because it was considered unconstitutional. As a result of the law in 2013, the Government established SKK Migas to carry out upstream management of Oil and Gas. But the existence of SKK Migas in practice does not guarantee the creation of more effective upstream oil and gas supervision. The disproportionate soaring cost recovery shows the weakness of SKK Migas in conducting supervision and control of the upstream oil and gas sector. Therefore, an effective supervision system is needed to increase the productivity of the upstream oil and gas sector and national welfare. Based on these problems, the author initiated a supervision mining system which is a new model of supervision that is ideal to accommodate the implementation of upstream oil and gas business activities based on the value of social justice
