Continuous beer production methods: A review of chances and risks

Beer brewing is one of the oldest biotechnological processes applied by humans. The production methods are comparatively complex and time consuming, which is the reason why inventors and scientists have steadily attempted to improve its manufacturing. During the industrial revolution more and more processes where done continuously in order to increase production efficiency. Breweries where trying to modify the classical batch modes into a continuous production process but were unsuccessful. Nearly all approaches failed due to changes of the beer quality. The presentation shall give a brief overview of different continuous production concepts tested in the past 150 years. Furthermore risks and chances of this technology will be critically discussed. Also a simple, alternative concept for continuous main beer fermentation will be presented with which a high quality product could be produced continuously

Càlcul del corrent crític en materials superconductors

L’objectiu d’aquest treball és resoldre una problemàtica a l’hora de solucionar computacionalment sistemes d’equacions tan grans (Matrius de fins a 64Gb d’espai en el disc) que no caben a la memòria RAM del ordinador. El codi creat té com a finalitat evitar errors del tipus “out of memory”-que l’ordinador no pot manipular una matriu tan gran perquè no hi cap a la memòria que té disponible, o errors del tipus “maximum size allowed exeded”-limitacions en el disseny del programa que manipula les matrius-. Per dur a terme un projecte d’aquestes característiques s’ha de recórrer a l’ utilització d’algoritmes anomenats out-of-core. Aquesta tècnica permet fer operacions a matrius sense tenir-les carregades en memòria. Per exemple, intentar fer la descomposició qr() amb Matlab per una matriu de 4Gb dóna l’error de manca de memòria per crear-la, ja que no hi cap a la memòria RAM de l’ordinador en qüestió. En canvi, amb el nostre programa, es pot franquejar aquesta limitació. L’abast d’aquest treball és principalment crear una rutina out-of-core que s’aplica al terme A i B del sistema d’equacions següent per simplificar significativament l’aïllament outof-core posterior de la solució X. [ � ] [ � ] = [ � ] A matriu coneguda m·n B vector conegut m X vector incògnita n. La rutina prèvia al càlcul de la solució que s’ha adaptat per que sigui out-of-core és la descomposició QR per reflexió d’hiperplans de Householder. D’altre banda, també s’ha adaptat l’operació d’aïllament de la solució per funcionar out-of-core. S’ha programat en llenguatge MATLAB ja que és un llenguatge molt enfocat en la optimització de càlculs matricials, el que ens permetrà fer uns tipus de càlculs que trigarien un temps molt més significatiu si fos programat en un altre llenguatge. Tot el codi desenvolupat en aquest projecte es pot utilitzar també en Octave. Parlant en termes corrents, la tàctica out-of-core és utilitzar el disc dur per substituir la memòria RAM. Això permet que un ordinador normal pugui fer una tasca molt demandant en recursos, altrament reservada a sistemes d’ordinadors, o a parts de superordinadors. L’únic contrapunt és que, per se, aquest mètode triga un temps significati

Two-channel Kondo physics due to As vacancies in the layered compound ZrAs1.58Se0.39

We address the origin of the magnetic-field independent -|A| T^{1/2} term observed in the low-temperature resistivity of several As-based metallic systems of the PbFCl structure type. For the layered compound ZrAs_{1.58}Se_{0.39}, we show that vacancies in the square nets of As give rise to the low-temperature transport anomaly over a wide temperature regime of almost two decades in temperature. This low-temperature behavior is in line with the non-magnetic version of the two-channel Kondo effect, whose origin we ascribe to a dynamic Jahn-Teller effect operating at the vacancy-carrying As layer with a C_4 symmetry. The pair-breaking nature of the dynamical defects in the square nets of As explains the low superconducting transition temperature T_{\rm{c}}\approx 0.14 K of ZrAs_{1.58}Se_{0.39}, as compared to the free-of-vacancies homologue ZrP_{1.54}S_{0.46} (T_{\rm{c}}\approx 3.7 K). Our findings should be relevant to a wide class of metals with disordered pnictogen layers.Comment: 17 pages, 8 figures; submitte

Synthesis of Alkaline Earth Diazenides MAEN2 (MAE = Ca, Sr, Ba) by Controlled Thermal Decomposition of Azides under High Pressure

The alkaline earth diazenides MAEN2 with MAE = Ca, Sr and Ba were synthesized by a novel synthetic approach, namely, a controlled decomposition of the corresponding azides in a multianvil press at highpressure/ high-temperature conditions. The crystal structure of hitherto unknown calcium diazenide (space group I4/mmm (no. 139), a = 3.5747(6) Å, c = 5.9844(9) Å, Z = 2, wRp = 0.078) was solved and refined on the basis of powder X-ray diffraction data as well as that of SrN2 and BaN2. Accordingly, CaN2 is isotypic with SrN2 (space group I4/mmm (no. 139), a = 3.8054(2) Å, c = 6.8961(4) Å, Z = 2, wRp = 0.057) and the corresponding alkaline earth acetylenides (MAEC2) crystallizing in a tetragonally distorted NaCl structure type. In accordance with literature data, BaN2 adopts a more distorted structure in space group C2/c (no. 15) with a = 7.1608(4) Å, b = 4.3776(3) Å, c = 7.2188(4) Å, β = 104.9679(33)°, Z = 4 and wRp = 0.049). The N−N bond lengths of 1.202(4) Å in CaN2 (SrN2 1.239(4) Å, BaN2 1.23(2) Å) correspond well with a double-bonded dinitrogen unit confirming a diazenide ion [N2]2−. Temperature-dependent in situ powder X-ray diffractometry of the three alkaline earth diazenides resulted in formation of the corresponding subnitrides MAE2N (MAE = Ca, Sr, Ba) at higher temperatures. FTIR spectroscopy revealed a band at about 1380 cm−1 assigned to the N−N stretching vibration of the diazenide unit. Electronic structure calculations support the metallic character of alkaline earth diazenides

Structure and electronic properties of new model dinitride systems: A density-functional study of CN2, SiN2, and GeN2

The dinitrides CN2, SiN2, and GeN2 in assumed pyrite-type structures are studied by means of density functional theory using both ultrasoft pseudopotentials and the augmented spherical wave (ASW) method. The former two materials constitute the large-x limit of the broader class of CNx and SiNx compounds, which are well known for their interesting mechanical and electronic properties. For CN2 a large bulk modulus B_0 of 405 GPa was determined . While SiN2 is found to be a wide band gap compound, the calculated gaps of CN2 and GeN2 are considerably smaller. The trends in structural and electronic properties as e.g. bond lengths, band gaps and covalency are well understood in terms of the interplay of different types of bonding.Comment: 9 pages, 5 figure

Framing the future of privacy: citizens’ metaphors for privacy in the coming digital society

Privacy is one of the pressing issues of the digital age. New technologies and surveillance practices continuously present new privacy threats. This paper reports an exploratory qualitative study on non-experts’ metaphors for privacy in future society using focus group material from three countries: Finland, Germany and Israel. Using thematic analysis, four metaphorical frames for privacy are constructed: ‘dodo’, ‘hemline’, ‘savings’ and ‘foundations of our home’. The frames are analysed using the causal layered analysis method to uncover their systemic and worldview components. Taken together, the metaphorical frames highlight two key concerns of individuals: their struggle for control over a dominating future, on the one hand, and the problem of trust in collective means of privacy protection, on the other hand. The article concludes that the views of non-experts need to be included in broad societal discussion about a desirable future society and the role of privacy in that society. This discussion needs to seriously consider systemic interconnections that challenge privacy as well as the whole ecosystem of metaphorical frames for privacy.</p

Improving thermoelectric performance of TiNiSn by mixing MnNiSb in the half-Heusler structure

The thermoelectric properties of n type semiconductor, TiNiSn is optimized by partial substitution with metallic, MnNiSb in the half Heusler structure. Herein, we study the transport properties and intrinsic phase separation in the system. The Ti1-xMnxNiSn1-xSbx alloys were prepared by arc-melting and were annealed at temperatures obtained from differential thermal analysis and differential scanning calorimetry results. The phases were characterized using powder X-ray diffraction patterns, energy dispersive X-ray spectroscopy, and differential scanning calorimetry. After annealing the majority phase was TiNiSn with some Ni rich sites and the minority phases was majorly Ti6Sn5, Sn, and MnSn2. Ni rich sites were caused by Frenkel defects, this led to a metal-like behavior of the semiconducting specimens at low temperature. For x up to 0.05 the samples showed an activated conduction, whereas for x>0.05 they showed metallic character. The figure of merit for x=0.05 was increased by 61% (ZT=0.45) in comparison to the pure TiNiSn.Comment: 7 pages and 5 figures. Submitted to Physical Chemistry Chemical Physics - RSC Publishing on 6th of October, 201