Field Reduction Electrodes for the Possible Improvement in the Pollution Flashover Performance of Porcelain Insulators

In this paper an attempt is made to study accurately, the field distribution for various types of porcelain/ceramic insulators used forhigh voltage transmission. The surface charge Simulation method is employed for the field computation. Novel field reduction electrodes are developed to reduce the maximum field around the pin region. In order to experimentally scrutinize the performance of discs with field reduction electrodes, special artificial pollution test facility was built and utilized. The experimental results show better improvement in the pollution flashover performance of string insulators.

Optimization of friction stir welding parameters for dissimilar aluminum alloys

Assembly consisting of cast and wrought aluminum alloys has wide spread application in defense and aero space industries. For the efficacious use of the transition joints, the weld should have adequate strength and formability. In the present investigation, A356 and 6061 aluminum alloys were friction stir welded under tool rotational speed of 1000-1400 rpm and traversing speed of 80-240 mm/min, keeping other parameters same. The variable process window is responsible for the change in total heat input and cooling rate during welding. Structural characterization of the bonded assemblies exhibits recovery-recrystallization in the stirring zone and breaking of coarse eutectic network of Al-Si. Dispersion of fine Si rich particles, refinement of 6061 grain size, low residual stress level and high defect density within weld nugget contribute towards the improvement in bond strength. Lower will be the tool rotational and traversing speed, more dominant will be the above phenomena. Therefore, the joint fabricated using lowest tool traversing and rotational speed, exhibits substantial improvement in bond strength (similar to 98% of that of 6061 alloy), which is also maximum with respect to others. (C) 2010 Elsevier Ltd. All rights reserved.

Stadilaispojat, rikokset ja lastensuojelu : Viisi tapaustutkimusta kuudelta vuosikymmeneltä

Societal reactions to norm breaking behavior of children reveal, how we understand childhood, the relations between generations and communitie's ratio of tolerance. In Finland the children that repeatedly commit crimes receive social service measures that are based on Child Welfare Act. In the city of Helsinki (Stadi in the slang of Helsinki) existed an agency specifically established for ill-behaving children until the 1980's, agter which an unified agency for the maltreated and maladjusted children was founded. Through five boys' welfare cases, this research aims at defining what kind of positions, social relations and structures are constructed in the social dynamics of these children's everyday lives. The cases cover different decades from the 1940s to the present. At the same time the cases reflect the child welfare and societal practices, and reveal how the communities have participated in constructing deviance in different eras. The research is meta-theoretically based on critical realism and specifically on Roy Bhaskar's transformative model of social activity. The cases are analyzed in the framework of Edwin M. Lemert's societal reaction theory. Thus the focus of the study is on the wide structural context of the institutional and societal definitions of deviance. The research is methodologically based on a qualitative multiple case study research. The primary data consist of classified child welfare case files collected from the archives of the city of Helsinki. The data of the institutional level consist of the annual reports from 1943 to 2004 and the ordinances from 1907 onwards, and of various committee documents produced in the law-making process of child welfare, youth and criminal legislation of the 20th century. Empirical finding are interpreted in a dialogue with previous historical and child welfare research, contemporary literature and studies on the urban development. The analysis is based on Derek Layder's model of adaptive theory. The research forms a viewpoint to the historical study of child welfare, in which the historical era, its agents and the dynamics of their mutual relations are studied through an individual level reconstruction based on the societal reaction theory. The case analyses reveal how the positions of the children form differently in the different eras of child welfare practices. In the 1940s the child is positioned as a psychopath and a criminal type. The measures are aimed at protecting the community from the disturbed child, and at adjusting the individual by isolation. From 1960s to 1980s the child is positioned as a child in need of help and support. The child becomes a victim, a subject that occupies rights, and a target of protection. In the turn of the millennium a norm breaking child is positioned as a dangerous individual that, in the name of the community safety, has to be confined. The case analyses also reveal the prevailing academic and practical paradigms of the time. Keywords: childhood, youth, child protection, child welfare, delinquency, crime, deviance, history, critical realism, case study research

Sampled longest common prefix array

When augmented with the longest common prefix (LCP) array and some other structures, the suffix array can solve many string processing problems in optimal time and space. A compressed representation of the LCP array is also one of the main building blocks in many compressed suffix tree proposals. In this paper, we describe a new compressed LCP representation: the sampled LCP array. We show that when used with a compressed suffix array (CSA), the sampled LCP array often offers better time/space trade-offs than the existing alternatives. We also show how to construct the compressed representations of the LCP array directly from a CSA

Formation of an oxo-radical of peroxovanadate during reduction of diperoxovanadate with vanadyl sulfate or ferrous sulfate

Formation of oxygen radicals during reduction of H2O2 or diperoxovanadate with vanadyl sulfate or ferrous sulfate was indicated by the 1:2:2:1 electron spin resonance (ESR) signals of the DMPO adduct typical of standard radical dotOH radical. Signals derived from diperoxovanadate remained unchanged in the presence of ethanol in contrast to those from H2O2. This gave the clue that they represent a different radical, possibly radical dotOV(O2)2+, formed on breaking a peroxo-bridge of diperoxovanadate complex. The above reaction mixtures evolved dioxygen or, when NADH was present, oxidized it rapidly which was accompanied by consumption of dioxygen. Operation of a cycle of peroxovanadates including this new radical is suggested to explain these redox activities both with vanadyl and ferrous sulfates. It can be triggered by ferrous ions released from cellular stores in the presence of catalytic amounts of peroxovanadates.

Slow rotation of a sphere in a non-Newtonian fluid with or without suction or injection

The flow generated by the rotation of a sphere in an infinitely extending fluid has recently been studied by Goldshtik. The corresponding problem for non-Newtonian Reiner-Rivlin fluids has been studied by Datta. Bhatnagar and Rajeswari have studied the secondary flow between two concentric spheres rotating about an axis in the non-Newtonian fluids. This last investigation was further generalised by Rajeswari to include the effects of small radial suction or injection. In Part A of the present investigation, we have studied the secondary flow generated by the slow rotation of a single sphere in non-Newtonian fluid obeying the Rivlin-Ericksen constitutive equation. In Part B, the effects of small suction or injection have been studied which is applied in an arbitrary direction at the surface of the sphere. In the absence of suction or injection, the secondary flow for small values of the visco-elastic parameter is similar to that of Newtonian fluids with inclusion of inertia terms in the Oseen approximation. If this parameter exceeds Kc = 18R/219, whereR is the Reynolds number, the breaking of the flow field takes place into two domains, in one of which the stream lines form closed loops. For still higher values of this parameter, the complete reversal of the sense of the flow takes place. When suction or injection is included, the breaking of the flow persists under certain condition investigated in this paper. When this condition is broken, the breaking of the flow is obliterated.

Flow of an electrically conducting non-newtonian fluid between two rotating coaxial cones in the presence of external magnetic field due to an axial current

Bhatnagar and Rathna (Quar. Journ. Mech. Appl. Maths., 1963,16, 329) investigated the flows of Newtonian, Reiner-Rivlin and Rivlin-Ericksen fluids between two rotating coaxial cones. In case of the last two types of fluids, they predicted the breaking of secondary flow field in any meridian plane. We find that such breaking is avoided by the application of a sufficiently strong azimuthal magnetic field arising from a line current along the axis of the cones.

Effective models of two-flavor QCD: finite $\mu$ and $m_q$-dependence

We study effective models of chiral fields and Polyakov loop expected to describe the dynamics responsible for the phase structure of two-flavor QCD at finite temperature and density. We consider chiral sector described either using linear sigma model or Nambu-Jona-Lasinio model and study the phase diagram and determine the location of the critical point as a function of the explicit chiral symmetry breaking (i.e. the bare quark mass $m_q$). We also discuss the possible emergence of the quarkyonic phase in this model.

Loading of itraconazole into porous silica and silicon microparticles: characterization and dissolution tests

Most new drug molecules discovered today suffer from poor bioavailability. Poor oral bioavailability results mainly from poor dissolution properties of hydrophobic drug molecules, because the drug dissolution is often the rate-limiting event of the drug’s absorption through the intestinal wall into the systemic circulation. During the last few years, the use of mesoporous silica and silicon particles as oral drug delivery vehicles has been widely studied, and there have been promising results of their suitability to enhance the physicochemical properties of poorly soluble drug molecules. Mesoporous silica and silicon particles can be used to enhance the solubility and dissolution rate of a drug by incorporating the drug inside the pores, which are only a few times larger than the drug molecules, and thus, breaking the crystalline structure into a disordered, amorphous form with better dissolution properties. Also, the high surface area of the mesoporous particles improves the dissolution rate of the incorporated drug. In addition, the mesoporous materials can also enhance the permeability of large, hydrophilic drug substances across biological barriers. T he loading process of drugs into silica and silicon mesopores is mainly based on the adsorption of drug molecules from a loading solution into the silica or silicon pore walls. There are several factors that affect the loading process: the surface area, the pore size, the total pore volume, the pore geometry and surface chemistry of the mesoporous material, as well as the chemical nature of the drugs and the solvents. Furthermore, both the pore and the surface structure of the particles also affect the drug release kinetics. In this study, the loading of itraconazole into mesoporous silica (Syloid AL-1 and Syloid 244) and silicon (TOPSi and TCPSi) microparticles was studied, as well as the release of itraconazole from the microparticles and its stability after loading. Itraconazole was selected for this study because of its highly hydrophobic and poorly soluble nature. Different mesoporous materials with different surface structures, pore volumes and surface areas were selected in order to evaluate the structural effect of the particles on the loading degree and dissolution behaviour of the drug using different loading parameters. The loaded particles were characterized with various analytical methods, and the drug release from the particles was assessed by in vitro dissolution tests. The results showed that the loaded drug was apparently in amorphous form after loading, and that the loading process did not alter the chemical structure of the silica or silicon surface. Both the mesoporous silica and silicon microparticles enhanced the solubility and dissolution rate of itraconazole. Moreover, the physicochemical properties of the particles and the loading procedure were shown to have an effect on the drug loading efficiency and drug release kinetics. Finally, the mesoporous silicon particles loaded with itraconazole were found to be unstable under stressed conditions (at 38 qC and 70 % relative humidity).

Symmetry and shape issues in nanostructure growth

Symmetry plays a key role in dictating the equilibrium morphology of crystals. However, several growth morphologies that deviate from the point group symmetry are routinely observed under several different growth conditions. In this article, we present a summary of symmetry-breaking mechanisms that are operative for crystals grown from the vapour phase as well as those formed as a result of wet chemical synthesis. This understanding is crucial for rationalizing the variety of morphologies observed during nanocrystal synthesis and also providesa rational framework for the synthesis of anisotropic nanostructures.

Modern Societal Impulses and their Nordic Manifestations : On Emancipation and Constraint in Societal Development

The 1980s and the early 1990s have proved to be an important turning point in the history of the Nordic welfare states. After this breaking point, the Nordic social order has been built upon a new foundation. This study shows that the new order is mainly built upon new hierarchies and control mechanisms that have been developed consistently through economic and labour market policy measures. During the post-war period Nordic welfare states to an increasing extent created equality of opportunity and scope for agency among people. Public social services were available for all and the tax-benefit system maintained a level income distribution. During this golden era of Nordic welfare state, the scope for agency was, however, limited by social structures. Public institutions and law tended to categorize people according to their life circumstances ascribing them a predefined role. In the 1980s and 1990s this collectivist social order began to mature and it became subject to political renegotiation. Signs of a new social order in the Nordic countries have included the liberation of the financial markets, the privatizing of public functions and redefining the role of the public sector. It is now possible to reassess the ideological foundations of this new order. As a contrast to widely used political rhetoric, the foundation of the new order has not been the ideas of individual freedom or choice. Instead, the most important aim appears to have been to control and direct people to act in accordance with the rules of the market. The various levels of government and the social security system have been redirected to serve this goal. Instead of being a mechanism for redistributing income, the Nordic social security system has been geared towards creating new hierarchies on the Nordic labour markets. During the past decades, conditions for receiving income support and unemployment benefit have been tightened in all Nordic countries. As a consequence, people have been forced to accept deteriorating terms and conditions on the labour market. Country-specific variations exist, however: in sum Sweden has been most conservative, Denmark most innovative and Finland most radical in reforming labour market policy. The new hierarchies on the labour market have co-incided with slow or non-existent growth of real wages and with a strong growth of the share of capital income. Slow growth of real wages has kept inflation low and thus secured the value of capital. Societal development has thus progressed from equality of opportunity during the age of the welfare states towards a hierarchical social order where the majority of people face increasing constraints and where a fortunate minority enjoys prosperity and security.

Tablettien soveltuvuus annosjakeluun

Koneellinen annosjakelu on kasvava lääkehuollon osa-alue, jossa lääkkeet pakataan koneellisesti pieniin annoskertakohtaisiin pusseihin kahden viikon erissä. Aikaisemmin lääkevalmisteiden soveltuvuutta koneelliseen annosjakeluun ei ole systemaattisesti tutkittu. Tutkimus tehtiin yhteistyössä Espoonlahden apteekin annosjakeluyksikön kanssa ja sen tavoitteena oli määrittää annosjakeluprosessin kannalta optimaaliset ominaisuudet annosjaeltavalle tabletille rikkoutumisten ja siirtymien vähentämiseksi. Rikkoutuminen on lääkevalmisteen murentumista, puolittumista tai muuta rikkoutumista annosjakelun aikana. Siirtymä on lääkevalmisteen jakelu väärään annospussiin. Prosentuaalisesti rikkoutumisia ja siirtymiä on jakelumäärästä hyvin vähän, mutta määrällisesti paljon ja koko ajan enemmän koneellisen annosjakelun yleistyessä. Rikkoutumiset ja siirtymät aiheuttavat paljon lisätyötä pussien korjaamisen takia, joten niiden määrää on pyrittävä vähentämään. Lisäksi tavoitteena oli selvittää lääkkeiden valmistajilta kysyttävissä olevat asiat lääkevalmisteiden ominaisuuksista ja säilyvyydestä, jotta voitaisiin päätellä valmisteen soveltuvuus koneelliseen annosjakeluun kirjallisen tiedon perusteella. Tutkimuksen tulosten perusteella rikkoutumisten ja siirtymien vähentämiseksi optimaalinen tablettivalmiste annosjakeluun on pienehkö tai keskisuuri, päällystetty, luja ja jakouurteeton ja optimaalinen ilman suhteellinen kosteustaso annosjakeluyksikön tuotantotiloissa olisi noin 30 – 40 %. Lääkkeiden valmistajilta kysyttäviä seikkoja ovat koon, päällysteen, murtolujuuden ja jakouurteen lisäksi valmisteen säilyvyys alkuperäispakkauksen ulkopuolella sekä valmisteen valo-, lämpö- ja kosteusherkkyys. Rikkoutumisten ja siirtymien lisäksi tutkittiin myös kosteusherkän asetyylisalisyylihappovalmisteen (Disperin 100 mg) säilyvyyttä 25 °C ja 60 % RH olosuhteissa, koska tuotantotilojen ilman kosteustasoa ei ole säädelty. Säilyvyystutkimuksen kesto oli neljä viikkoa. Se on riittävä, koska se on enimmäisaika, jonka tabletit ovat annosjakeluprosessin yhteydessä pois alkuperäispakkauksestaan ennen käyttöä. Tabletteja säilytettiin avoimessa alkuperäispakkauksessa (purkki), suljetussa alkuperäispakkauksessa, annosjakelukoneen kasetissa ja kahdessa erilaisessa annospussissa (uusi ja käytössä oleva materiaali). Tulosten mukaan annosjakelukoneen kasetti suojaa kosteudelta yhtä huonosti kuin avoin purkki. Uusi pussimateriaali sen sijaan suojaa kosteudelta paremmin kuin tällä hetkellä käytössä oleva materiaali. Raman -spektroskopiamittausten perusteella asetyylisalisyylihappotableteissa ei ehdi neljän viikon seurannan aikana tapahtua asetyylisalisyylihapon hajoamista salisyylihapoksi. Kosteus heikentää tablettien murtolujuutta, mikä saattaa aiheuttaa enemmän rikkoutumisia. Kosteustaso olisi hyvä olla säädettävissä vakioksi tuotantotiloissa tai purkaa tabletit kasetteihin mahdollisimman lähellä jakelua rikkoutumisten ehkäisemiseksi, etenkin ilman kosteustason ollessa korkea. Lisäksi tutkittiin lääkevalmisteen lämpöherkkyyttä koska annosjakelukoneen saumauslaite altistaa annospussit noin 75 °C lämmölle, jos annosjakelukone pysäytetään kesken työn. Tutkimus tehtiin XRPD:llä, jolla voidaan säätää näytteen lämpötilaa. Lämpöherkkyystutkimusten perusteella 75 °C lämpö ei ehdi tunnin aikana aiheuttaa muutoksia karbamatsepiinitabletissa (Neurotol 200 mg). Tuloksista selvisi, että tutkitun valmisteen sisältämä karbamatsepiini ei kuitenkaan ole lämpöherkin muoto, joten muita lämpöherkkiä lääkevalmisteita tulisi tutkia lisätiedon saamiseksi lämmön vaikutuksista.

Developing Peer-To-Peer Web Applications

As the virtual world grows more complex, finding a standard way for storing data becomes increasingly important. Ideally, each data item would be brought into the computer system only once. References for data items need to be cryptographically verifiable, so the data can maintain its identity while being passed around. This way there will be only one copy of the users family photo album, while the user can use multiple tools to show or manipulate the album. Copies of users data could be stored on some of his family members computer, some of his computers, but also at some online services which he uses. When all actors operate over one replicated copy of the data, the system automatically avoids a single point of failure. Thus the data will not disappear with one computer breaking, or one service provider going out of business. One shared copy also makes it possible to delete a piece of data from all systems at once, on users request. In our research we tried to find a model that would make data manageable to users, and make it possible to have the same data stored at various locations. We studied three systems, Persona, Freenet, and GNUnet, that suggest different models for protecting user data. The main application areas of the systems studied include securing online social networks, providing anonymous web, and preventing censorship in file-sharing. Each of the systems studied store user data on machines belonging to third parties. The systems differ in measures they take to protect their users from data loss, forged information, censorship, and being monitored. All of the systems use cryptography to secure names used for the content, and to protect the data from outsiders. Based on the gained knowledge, we built a prototype platform called Peerscape, which stores user data in a synchronized, protected database. Data items themselves are protected with cryptography against forgery, but not encrypted as the focus has been disseminating the data directly among family and friends instead of letting third parties store the information. We turned the synchronizing database into peer-to-peer web by revealing its contents through an integrated http server. The REST-like http API supports development of applications in javascript. To evaluate the platform’s suitability for application development we wrote some simple applications, including a public chat room, bittorrent site, and a flower growing game. During our early tests we came to the conclusion that using the platform for simple applications works well. As web standards develop further, writing applications for the platform should become easier. Any system this complex will have its problems, and we are not expecting our platform to replace the existing web, but are fairly impressed with the results and consider our work important from the perspective of managing user data.

Developing Peer-To-Peer Web Applications

As the virtual world grows more complex, finding a standard way for storing data becomes increasingly important. Ideally, each data item would be brought into the computer system only once. References for data items need to be cryptographically verifiable, so the data can maintain its identity while being passed around. This way there will be only one copy of the users family photo album, while the user can use multiple tools to show or manipulate the album. Copies of users data could be stored on some of his family members computer, some of his computers, but also at some online services which he uses. When all actors operate over one replicated copy of the data, the system automatically avoids a single point of failure. Thus the data will not disappear with one computer breaking, or one service provider going out of business. One shared copy also makes it possible to delete a piece of data from all systems at once, on users request. In our research we tried to find a model that would make data manageable to users, and make it possible to have the same data stored at various locations. We studied three systems, Persona, Freenet, and GNUnet, that suggest different models for protecting user data. The main application areas of the systems studied include securing online social networks, providing anonymous web, and preventing censorship in file-sharing. Each of the systems studied store user data on machines belonging to third parties. The systems differ in measures they take to protect their users from data loss, forged information, censorship, and being monitored. All of the systems use cryptography to secure names used for the content, and to protect the data from outsiders. Based on the gained knowledge, we built a prototype platform called Peerscape, which stores user data in a synchronized, protected database. Data items themselves are protected with cryptography against forgery, but not encrypted as the focus has been disseminating the data directly among family and friends instead of letting third parties store the information. We turned the synchronizing database into peer-to-peer web by revealing its contents through an integrated http server. The REST-like http API supports development of applications in javascript. To evaluate the platform s suitability for application development we wrote some simple applications, including a public chat room, bittorrent site, and a flower growing game. During our early tests we came to the conclusion that using the platform for simple applications works well. As web standards develop further, writing applications for the platform should become easier. Any system this complex will have its problems, and we are not expecting our platform to replace the existing web, but are fairly impressed with the results and consider our work important from the perspective of managing user data.

Dynamics of capacitively coupled double quantum dots

We consider a double dot system of equivalent, capacitively coupled semiconducting quantum dots, each coupled to its own lead, in a regime where there are two electrons on the double dot. Employing the numerical renormalization group, we focus here on single-particle dynamics and the zero-bias conductance, considering in particular the rich range of behaviour arising as the interdot coupling is progressively increased through the strong-coupling (SC) phase, from the spin-Kondo regime, across the SU(4) point to the charge-Kondo regime, and then towards and through the quantum phase transition to a charge-ordered ( CO) phase. We first consider the two-self-energy description required to describe the broken symmetry CO phase, and implications thereof for the non-Fermi liquid nature of this phase. Numerical results for single-particle dynamics on all frequency scales are then considered, with particular emphasis on universality and scaling of low-energy dynamics throughout the SC phase. The role of symmetry breaking perturbations is also briefly discussed.