Cooling of a composite slab

A mixed boundary value problem associated with the diffusion equation, that involves the physical problem of cooling of an infinite parallel-sided composite slab, is solved completely by using the Wiener-Hopf technique. An analytical expression is derived for the sputtering temperature at the quench front being created by a cold fluid moving on the upper surface of the slab at a constant speed v. The dependence of the various configurational parameters of the problem under consideration, on the sputtering temperature, is rather complicated and representative tables of numerical values of this important physical quantity are prepared for certain typical values of these parameters. Asymptotic results in their most simplified forms are also obtained when (i) the ratio of the thicknesses of the two materials comprising the slab is very much smaller than unity, and (ii) the quench-front speed v is very large, keeping the other parameters fixed, in both the cases.

Power Minimization for CDMA under Colored Noise

Rate-constrained power minimization (PMIN) over a code division multiple-access (CDMA) channel with correlated noise is studied. PMIN is. shown to be an instance of a separable convex optimization problem subject to linear ascending constraints. PMIN is further reduced to a dual problem of sum-rate maximization (RMAX). The results highlight the underlying unity between PMIN, RMAX, and a problem closely related to PMIN but with linear receiver constraints. Subsequently, conceptually simple sequence design algorithms are proposed to explicitly identify an assignment of sequences and powers that solve PMIN. The algorithms yield an upper bound of 2N - 1 on the number of distinct sequences where N is the processing gain. The sequences generated using the proposed algorithms are in general real-valued. If a rate-splitting and multi-dimensional CDMA approach is allowed, the upper bound reduces to N distinct sequences, in which case the sequences can form an orthogonal set and be binary +/- 1-valued.

CAE-based prediction of projectile residual velocity for impact on single and multi-layered metallic armour plates

The present, paper deals with the CAE-based study Of impact of jacketed projectiles on single- and multi-layered metal armour plates using LS-DYNA. The validation of finite element modelling procedure is mainly based on the mesh convergence study using both shell and solid elements for representing single-layered mild steel target plates. It, is shown that the proper choice of mesh density and the strain rate-dependent material properties are essential for all accurate prediction of projectile residual velocity. The modelling requirements are initially arrived at by correlating against test residual velocities for single-layered mild steel plates of different depths at impact velocities in the ran.-c of approximately 800-870 m/s. The efficacy of correlation is adjudged, in terms of a 'correlation index', defined in the paper: for which values close to unity are desirable. The experience gained for single-layered plates is next; used in simulating projectile impacts on multi-layered mild steel target plates and once again a high degree of correlation with experimental residual velocities is observed. The study is repeated for single- and multi-layered aluminium target plates with a similar level of success in test residual velocity prediction. TO the authors' best knowledge, the present comprehensive study shows in particular for the first time that, with a. proper modelling approach, LS-DYNA can be used with a great degree of confidence in designing perforation-resistant single and multi-layered metallic armour plates.

Evaluation of Vestibular Function with Visual Feedback Posturography and Motorized Head Impulse Test.

Objectives: To evaluate the applicability of visual feedback posturography (VFP) for quantification of postural control, and to characterize the horizontal angular vestibulo-ocular reflex (AVOR) by use of a novel motorized head impulse test (MHIT). Methods: In VFP, subjects standing on a platform were instructed to move their center of gravity to symmetrically placed peripheral targets as fast and accurately as possible. The active postural control movements were measured in healthy subjects (n = 23), and in patients with vestibular schwannoma (VS) before surgery (n = 49), one month (n = 17), and three months (n = 36) after surgery. In MHIT we recorded head and eye position during motorized head impulses (mean velocity of 170º/s and acceleration of 1 550º/s²) in healthy subjects (n = 22), in patients with VS before surgery (n = 38) and about four months afterwards (n = 27). The gain, asymmetry and latency in MHIT were calculated. Results: The intraclass correlation coefficient for VFP parameters during repeated tests was significant (r = 0.78-0.96; p < 0.01), although two of four VFP parameters improved slightly during five test sessions in controls. At least one VFP parameter was abnormal pre- and postoperatively in almost half the patients, and these abnormal preoperative VFP results correlated significantly with abnormal postoperative results. The mean accuracy in postural control in patients was reduced pre- and postoperatively. A significant side difference with VFP was evident in 10% of patients. In the MHIT, the normal gain was close to unity, the asymmetry in gain was within 10%, and the latency was a mean ± standard deviation 3.4 ± 6.3 milliseconds. Ipsilateral gain or asymmetry in gain was preoperatively abnormal in 71% of patients, whereas it was abnormal in every patient after surgery. Preoperative gain (mean ± 95% confidence interval) was significantly lowered to 0.83 ± 0.08 on the ipsilateral side compared to 0.98 ± 0.06 on the contralateral side. The ipsilateral postoperative mean gain of 0.53 ± 0.05 was significantly different from preoperative gain. Conclusion: The VFP is a repeatable, quantitative method to assess active postural control within individual subjects. The mean postural control in patients with VS was disturbed before and after surgery, although not severely. Side difference in postural control in the VFP was rare. The horizontal AVOR results in healthy subjects and in patients with VS, measured with MHIT, were in agreement with published data achieved using other techniques with head impulse stimuli. The MHIT is a non-invasive method which allows reliable clinical assessment of the horizontal AVOR.

A simple analog controller for single-phase half-bridge rectifier and its application to transformerless UPS

A simple, low-cost, constant frequency, analog controller is proposed for the front-end half-bridge rectifier of a single-phase transformerless UPS system to maintain near unity power factor at the input and zero dc-offset voltage at the output. The controller generates the required gating pulses by comparing the input current with a periodic, bipolar, linear carrier without sensing the input voltage. Two voltage controllers and a single integrator with reset are used to generate the required carrier. All the necessary control operations can be performed without using any PLL, multiplier and/or divider. The controller can be fabricated as a single integrated circuit. The control concept is validated through simulation and also experimentally on an 800W half-bridge rectifier. Experimental results are presented for ac-dc application, and also for ac-dc-ac UPS application with both sinusoidal and nonlinear loads. The simulation and experimental results agree well.

Kansallisen konsensuskulttuurin jäljillä : Globalisaatioajan Suomi Helsingin Sanomissa

The dissertation analyzes Finnish consensual culture in public discussion and journalism in Helsingin Sanomat (HS). The consensual Finnish political culture has evolved and persisted over a long period of time and it has been affected by historical circumstances as well as the dynamics of political and journalistic structures and actors. A historical chronology is drawn in the study regarding the nature and development of consensus culture in 20th century Finland. This political culture is traced by looking at public discussion on globalization at the turn of the millennium. Globalization as a concept has been contested and various societal actors have given different meanings to it. This research looks at how the globalization discussion in HS during the years 1992-2004 constructs consensus. Helsingin Sanomat (and its predecessor Päivälehti) has been an important actor in Finnish journalism and the public sphere almost since its founding 120 years ago. The history of the paper is tightly connected to Finland s general political history and history of the public sphere. Moreover, the paper s connections to the societal elite have always been close. The central question in this research was to see how the globalization discussion in HS evolved in relation to consensus as well as legitimate controversies. As a result it is stated that the globalization question has clearly divided the Finnish societal actors. The most powerful societal elites (government, most civil servants, corporate sector) had a profile of being pro globalization. They communicated their globalization strategy as a national, unified way of thinking. Other elites which have been losing their influence (the president, labor union, part of members of parliament), as well as civil society actors tried to bring forward conflicting views in relation to globalization. The paper did give some room to these elements, but on the other hand it also tried to keep up the consensual discussion culture especially in the editorial section. In line with its traditions Helsingin Sanomat strived to create national unity. At the same time it did not give adequate attention to the changes brought about by globalization to the positions and roles of various elites and civil society actors. In this discussion HS seemed more like a medium of the state than as a critical and independent actor. Journalism has an important role in upholding and also reviving the Finnish political culture and public discussion. From this point of view it is problematic if the area of so called legitimate controversy in broad societal questions like globalization becomes very limited. As the Finnish elites are small and there is no considerable competition between them, journalism should actively bring up controversial issues. This task becomes complicated, however, if the elite circles are closed up and no initiatives come from their ranks. Political decision making as well as democracy can suffer, if issues are not brought to the public agenda.

BER-optimized linear parallel interference cancellers for multicarrier DS-CDMA systems

In this paper, we consider the design and bit-error performance analysis of linear parallel interference cancellers (LPIC) for multicarrier (MC) direct-sequence code division multiple access (DS-CDMA) systems. We propose an LPIC scheme where we estimate and cancel the multiple access interference (MAT) based on the soft decision outputs on individual subcarriers, and the interference cancelled outputs on different subcarriers are combined to form the final decision statistic. We scale the MAI estimate on individual subcarriers by a weight before cancellation. In order to choose these weights optimally, we derive exact closed-form expressions for the bit-error rate (BER) at the output of different stages of the LPIC, which we minimize to obtain the optimum weights for the different stages. In addition, using an alternate approach involving the characteristic function of the decision variable, we derive BER expressions for the weighted LPIC scheme, matched filter (MF) detector, decorrelating detector, and minimum mean square error (MMSE) detector for the considered multicarrier DS-CDMA system. We show that the proposed BER-optimized weighted LPIC scheme performs better than the MF detector and the conventional LPIC scheme (where the weights are taken to be unity), and close to the decorrelating and MMSE detectors.

Simulation of wavelength/time multiple-pulses-per-row fiber-optic CDMA network

Passive wavelength/time fiber-optic code division multiple access (WIT FO-CDMA) network is a viable option for highspeed access networks. Constructions of 2-D codes, suitable for incoherent WIT FO-CDMA, have been proposed to reduce the time spread of the 1-D sequences. The 2-D constructions can be broadly classified as 1) hybrid codes and 2) matrix codes. In our earlier work [141, we had proposed a new family of wavelength/time multiple-pulses-per-row (W/T MPR) matrix codes which have good cardinality, spectral efficiency and at the same time have the lowest off-peak autocorrelation and cross-correlation values equal to unity. In this paper we propose an architecture for a WIT MPR FO-CDAM network designed using the presently available devices and technology. A complete FO-CDMA network of ten users is simulated, for various number of simultaneous users and shown that 0 --> 1 errors can occur only when the number of interfering users is at least equal to the threshold value.

Theory of laminar flame propagation with non-normal diffusion.

A study has been made of the problem of steady, one-dimensional, laminar flame propagation in premixed gases, with the Lewis number differing from (and equal to) unity. Analytical solutions, using the method of matched asymptotic expansions, have been obtained for large activation energies. Numerical solutions have been obtained for a wide range of the reduced activation temperature parameter (n {geometrically equal to} E/RTb), and the Lewis number δ. The studies reveal that the flame speed eigenvalue is linear in Lewis number for first order and quadratic in Lewis number for second order reactions. For a quick determination of flame speeds, with reasonable accuracy, a simple rule, expressing the flame speed eigenvalue as a function of the Lewis number and the centroid of the reaction rate function, is proposed. Comparisons have been made with some of the earlier works, for both first and second order reactions.

Towards a United States of Africa? Combining Zambian and AU level debate.

Globalisaatio on luonut uuden maailmanjärjestelmän jonka myötä yksittäisten valtioiden vaikutusvalta on vähentynyt entisestään. Tämä pitää paikkansa erityisesti kehittyvien maiden kohdalla, esimerkiksi Afrikassa. Afrikka on pyrkinyt taistelemaan globalisaation tuomia negatiivisia vaikutuksia vastaan alueellistumisen ja maanosan yhtenäisyyttä ajavien hankkeiden kautta jo vuosikymmenien ajan, mutta toistaiseksi tulokset eivät ole olleet vakuttavia. Tällä hetkellä Afrikan Unionissa keskustellaan hankkeesta muodostaa Afrikan Yhdysvallat. Aiemmista hankkeista poiketen tämän uuden aloitteen ajatus perustuu ylikansallisuudelle, jossa yksittäiset valtiot luovuttavat valtaansa ylikansallisille elimille, kuten Afrikan Unionin hallitukselle. Näin ollen on tärkeää tarkastella aloitetta Afrikan Yhdysvaltojen perustamiseksi ja arvioida, voisiko tällainen ylikansallinen organisaatio auttaa Afrikkaa kääntämään globalisaation haittavaikutukset myönteisiksi. Tämä Pro Gradu-tutkielma väittää sen olevan mahdollista, mutta vain siinä tapauksessa että Afrikka on valmis hyväksymään yhtenäisyyden rajoitukset. Aiemman tutkimuksen vähyyden vuoksi on myös tarpeen tutkia Afrikan Yhdysvalloista kansallisilla tasoilla käytävää keskustelua. Tämän vuoksi tässä tutkielmassa painotetaan esimerkkimaa Sambian kautta yhden Afrikan Unionin jäsenmaan keskinäistä keskustelua aiheesta ja verrataan sitä Afrikan Unionin tason keskusteluun. Tutkielma sisältää kirjallisuuskatsauksen sekä tapaustutkimuksen. Tutkimusaineisto koostuu sambialaisista sanomalehtiotteista sekä Sambian valtion ja Afrikan Unionin virallisista asiakirjoista. Pääasiallisena tutkimusmenetelmänä on laadullinen sisällönanalyysi. Teoreettinen viitekehys perustuu afrikkalaisen valtion ja kansalaisyhteiskunnan, alueellistumisen, globalisaation hallinnan, pan-afrikkalaisuuden ja poliittisen integraation teorioihin sekä historialliseen katsaukseen Afrikan yhtenäisyydestä. Perimmäisenä tarkoituksena on lisätä ymmärrystä afrikkalaisesta valtiosta ja politiikasta. Tutkimuksen tulosten mukaan on havaittavissa aukko valtioiden virallisten toimijoiden näkemysten ja kansalaisyhteiskunnan huolenaiheiden välillä. Viralliset toimijat näyttävät olevan kansalaisyhteiskuntaa vahvemmin Afrikan Yhdysvaltojen kannalla. Virallisten toimijoiden korostaessa Afrikan aatteellista yhtenäisyyttä kansalaisyhteiskunta on huolissaan sen toteutumisesta käytännössä. Esiin nousee myös kysymys 'afrikkalaisesta' identiteetistä ja kansalaisuudesta sekä kommunikaatiosta valtion ja kansalaisten välillä.

Implications of Bohmian quantum ontology for psychopathology

This article discusses the prospects of quantum psychiatry from a Bohmian point of view, which provides an ontological interpretation of quantum theory, and extends such ontology to include mind. At first, we discuss the more general relevance of quantum theory to psychopathology. The basic idea is that because quantum theory emphasizes the role of wholeness, it might be relevant to psychopathology, where breakdown of unity in the mental domain is a key feature. We then discuss the role of information in psychopathology, and consider the connections with quantum theory in this area. In particular, we discuss David Bohm’s notion of active information, which arises in the ontological interpretation of quantum theory, and is suggested to play a fundamental role as the bridge between mind and matter. Some such bridge is needed if we are to understand how subtle mental properties are able to influence more manifest physical properties in the brain (all the way to the molecular and possibly microtubular level), and how changes in those possibly quantum‐level physical processes are able to influence higher cognitive functions. We also consider the implications of the notion of active information for psychopathology. The prospects of implementing the Bohmian scheme in neuroquantal terms are then briefly considered. Finally, we discuss some possible therapeutic implications of Bohm’s approach to information and the relation of mind and matter.

Implications of Bohmian quantum ontology for psychopathology

This article discusses the prospects of quantum psychiatry from a Bohmian point of view, which provides an ontological interpretation of quantum theory, and extends such ontology to include mind. At first, we discuss the more general relevance of quantum theory to psychopathology. The basic idea is that because quantum theory emphasizes the role of wholeness, it might be relevant to psychopathology, where breakdown of unity in the mental domain is a key feature. We then discuss the role of information in psychopathology, and consider the connections with quantum theory in this area. In particular, we discuss David Bohm’s notion of active information, which arises in the ontological interpretation of quantum theory, and is suggested to play a fundamental role as the bridge between mind and matter. Some such bridge is needed if we are to understand how subtle mental properties are able to influence more manifest physical properties in the brain (all the way to the molecular and possibly microtubular level), and how changes in those possibly quantum‐level physical processes are able to influence higher cognitive functions. We also consider the implications of the notion of active information for psychopathology. The prospects of implementing the Bohmian scheme in neuroquantal terms are then briefly considered. Finally, we discuss some possible therapeutic implications of Bohm’s approach to information and the relation of mind and matter.

On the ignition and extinction problems in forced convection systems

In this paper the problem of ignition and extinction has been formulated for the flow of a compressible fluid with Prandtl and Schmidt numbers taken as unity. In particular, the problems of (i) a jet impinging on a wall of combustible material and (ii) the opposed jet diffusion flame have been studied. In the wall jet case, three approximations in the momentum equation namely, (i) potential flow, (ii) viscous flow, (ii) viscous incompressible with k = 1 and (iii) Lees' approximation (taking pressure gradient terms zero) are studied. It is shown that the predictions of the mass flow rates at extinction are not very sensitive to the approximations made in the momentum equation. The effects of varying the wall temperature in the case (i) and the jet temperature in the case (ii) on the extinction speeds have been studied. The effects of varying the activation energy and the free stream oxidant concentration in case (ii), have also been investigated.

Kiista, eheys, unohdus : Vapaussodan muistaminen suojeluskunnan ja veteraaniliikkeen toiminnassa 1918-1944

Conflict, Unity, Oblivion: Commemoration of the Liberation War by the Civic Guard and the Veterans´ Union in 1918-1944 The Finnish Civil War ended in May 1918 as a victory for the white side. The war was named by the winners as the Liberation War and its legacy became a central theme for public commemorations during the interwar period. At the same time the experiences of the defeated were hindered from becoming a part of the official history of Finland. The commemoration of the war was related not only to the war experience but also to a national mission, which was seen fulfilled with the independence of Finland. Although the idea of the commemoration was to form a unifying non-political scene for the nation, the remembrance of the Liberation War rather continued than sought to reconcile to the conflict of 1918. The outbreak of the war between the Soviet Union and Finland in 1939 immediately affected the memory culture. The new myth of the Miracle of the Winter War, which referred to the unity shown by the people, required a marginalization of controversial memory of the Liberation War. This study examines from the concepts of public memory and narrative templates how the problematic experience of a civil war developed to a popular public commemoration. Instead of dealing with the manipulative and elite-centered grandiose commemoration projects, the study focuses on the more modest local level and emphasizes the significance of local memory agents and narrative templates of collective memory. The main subjects in the study are the Civil Guard and the Veterans´ Union. Essential for the widespread movement was the development of the Civic Guard from a wartime organization to a peacetime popular movement. The guards, who identified themselves trough the memories and the threats of civil war, formed a huge network of memory agents in every corner of the country. They effectively linked both local memory with official memory and the civic society with the state level. Only with the emergence of the right wing veteran movement in the 30ies did the tensions grow between the two levels of public memory. The study shows the diversity of the commemoration movement of the Liberation War. It was not only a result of a nation-state project and political propaganda, but also a way for local communities to identify and strengthen themselves in a time of political upheaval and uncertainty.

Effect of impulsive change of wall velocity and wall temperature in viscous heat-conducting gas

A study of compression waves produced in a viscous heat-conducting gas by the impulsive start of a one-dimensional piston and by the inpulsive change of piston wall temperature is made using Laplace Transform Technique for Prandt1 number unity. Expressions for velocity, temperature and density have also been obtained using small-time expansion procedure in this case. For arbitrary Prandt1 number solutions have been developed using large-time expansion procedure. A number of graphs exhibiting the distribution of the fluid velocity, temperature and density have been drawn.