Classical and Cosserat plasticity and viscoplasticity models for slow granular flow

We consider models for the rheology of dense, slowly deforming granular materials based of classical and Cosserat plasticity, and their viscoplastic extensions that account for small but finite particle inertia. We determine the scale for the viscosity by expanding the stress in a dimensionless parameter that is a measure of the particle inertia. We write the constitutive relations for classical and Cosserat plasticity in stress-explicit form. The viscoplastic extensions are made by adding a rate-dependent viscous stress to the plasticity stress. We apply the models to plane Couette flow, and show that the classical plasticity and viscoplasticity models have features that depart from experimental observations; the prediction of the Cosserat viscoplasticity model is qualitatively similar to that of Cosserat plasticity, but the viscosities modulate the thickness of the shear layer.

Evidence of episodic brittle faulting in the cratonic part of the Peninsular India and its implications for seismic hazard in slow deforming regions

The region around Waclakkancheri, in the province of Kerala, India, which lies in the vicinity of Palghat-Cauvery ;hear zone (within the Precambrian crystalline terrain), has been a site of microseismic activity since 1989. Earlier studies had identified a prominent WNW-ESE structure overprinting on the E-W trending lineaments associated with Palghat-Cauvery shear zone. We have mapped this structure, located in a chamockite quarry near Desamangalam, Waclakkancheri, which we identify as a ca. 30 km-long south dipping reverse fault. This article presents the characteristics of this fault zone exposed on the exhumed crystalline basement and discusses its significance in understanding the earthquake potential of the region. This brittle deformation zone consists of fracture sets with small-scale displacement and slip planes with embedded fault gouges. The macroscopic as well as the microscopic studies of this fault zone indicate that it evolved through different episodes of faulting in the presence of fluids. The distinct zones within consolidated gouge and the cross cutting relationship of fractures indicate episodic fault activity. At least four faulting episodes can be recognized based on the sequential development of different structural elements in the fault rocks. The repeated ruptures are evident along this shear zone and the cyclic behavior of this fault consists of co-seismic ruptures alternating with inter-seismic periods, which is characterized by the sealed fractures and consolidated gouge. The fault zone shows a minimum accumulated dip/oblique slip of 2.1 m in the reverse direction with a possible characteristic slip of 52 cm (for each event). The ESR dating of fault gouge indicates that the deformation zone records a major event in the Middle Quaternary. The empirical relationships between fault length and slip show that this fault may generate events M >= 6. The above factors suggest that this fault may be characterized as potentially active. Our study offers some new pointers that can be used in other slow deforming cratonic hinterlands in exploring the discrete active faults.

Look-alike, sound-alike medication errors: A novel case concerning a Slow-Na, Slow-K prescribing error

A 59-year-old man was mistakenly prescribed Slow-Na instead of Slow-K due to incorrect selection from a drop-down list in the prescribing software. This error was identified by a pharmacist during a home medicine review (HMR) before the patient began taking the supplement. The reported error emphasizes the need for vigilance due to the emergence of novel look-alike, sound-alike (LASA) drug pairings. This case highlights the important role of pharmacists in medication safety.

Quasi-2D XY Magnetic Properties and Slow Relaxation in a Body Centered Metal Organic Network of [Co-4] Clusters

Octahedral Co2+ centers have been connected by mu(3)-OH and mu(2)-OH2 units forming [Co-4] clusters which are linked by pyrazine forming a two-dimensional network. The two-dimensional layers are bridged by oxybisbenzoate (OBA) ligands giving rise to a three-dimensional structure. The [Co-4] clusters bond with the pyrazine and the OBA results in a body-centered arrangement of the clusters, which has been observed for the first time. Magnetic studies reveal a noncollinear frustrated spin structure of the bitriangular cluster, resulting in a net magnetic moment of 1.4 mu B per cluster. For T > 32 K, the correlation length of the cluster moments shows a stretched-exponential temperature dependence typical of a Berezinskii-Kosterlitz-Thouless model, which points to a quasi-2D XY behavior. At lower temperature and down to 14 K, the compound behaves as a soft ferromagnet and a slow relaxation is observed, with an energy barrier of ca. 500 K. Then, on further cooling, a hysteretic behavior takes place with a coercive field that reaches 5 Tat 4 K. The slow relaxation is assigned to the creation/annihilation of vortex-antivortex pairs, which are the elementary excitations of a 2D XY spin system.

1-D hydrogen-bonded organization of hexanuclear {3d-4f-5d} complexes: evidence for slow relaxation of the magnetization for [{LMe2Ni(H2O)Ln(H2O)4.5}2{W(CN)8}2] with Ln = Tb and Dy

Heterometallic {3d-4f-5d} aggregates with formula [{LMe2Ni(H2O)Ln(H2O)4.5}2{W(CN)8}2]·15H2O, (LMe2 stands for N,N-2,2-dimethylpropylenedi(3-methoxysalicylideneiminato) Schiff-base ligand) with Ln = Gd, Tb, Dy, have been obtained by reacting bimetallic [LMe2Ni(H2O)2Ln(NO3)3] and Cs3{W(CN)8} in H2O. The hexanuclear complexes are organized in 1-D arrays by means of hydrogen bonds established between the solvent molecules coordinated to Ln and the CN ligands of an octacyanometallate moiety. The X-ray structure was solved for the Tb derivative. Magnetic behavior indicates ferromagnetic {W–Ni} and {Ni–Ln} interactions (JNiW = 18.5 cm-1, JNiGd = 1.85 cm-1) as well as ferromagnetic intermolecular interactions mediated by the H-bonds. Dynamic magnetic susceptibility studies reveal slow magnetic relaxation processes for the Tb and Dy derivatives, suggesting SMM type behavior for these compounds.

Slow pressure modes in thin accretion discs

Thin accretion discs around massive compact objects can support slow pressure modes of oscillations in the linear regime that have azimuthal wavenumber m = 1. We consider finite, flat discs composed of barotropic fluid for various surface density profiles and demonstrate through WKB analysis and numerical solution of the eigenvalue problem - that these modes are stable and have spatial scales comparable to the size of the disc. We show that the eigenvalue equation can be mapped to a Schrodinger like equation. The analysis of this equation shows that all eigenmodes have discrete spectra. We find that all the models we have considered support negative frequency eigenmodes; however, the positive eigenfrequency modes are only present in power-law discs, albeit for physically uninteresting values of the power-law index beta and barotropic index gamma.

Inverted slot-mode slow-wave structures for traveling-wave tubes

The dispersion and impedance characteristics of an inverted slot-mode (ISM) slow-wave structure computed by three different techniques, i.e., an analytical model based on a periodic quasi-TEM approach, an equivalent-circuit model, and 3-D electromagnetic simulation are obtained and compared. The comparison was carried out for three different slot-mode structures at S-, C-, and X-bands. The approach was also validated with experimental measurements on a practical X-band ISM traveling-wave tube. The design of ferruleless ISM slow-wave structures, both in circular and rectangular formats, has also been proposed and the predicted dispersion characteristics for these two geometries are compared with 3-D simulation and cold-test measurements. The impedance characteristics for all three designs are also compared.

Epigallocatechin gallate is a slow-tight binding inhibitor of enoyl-ACP reductase from Plasmodium falciparum

Epigallocatechin gallate (EGCG) is known to have numerous pharmacological properties. In the present study, we have shown that EGCG inhibits enoyl–acyl carrier protein reductase of Plasmodium falciparum (PfENR) by following a two-step, slow, tight-binding inhibition mechanism. The association/isomerization rate constant (k5) of the reversible and loose PfENR–EGCG binary complex to a tight [PfENR–EGCG]* or EI* complex was calculated to be 4.0 × 10−2 s−1. The low dissociation rate constant (k6) of the [PfENR–EGCG]* complex confirms the tight-binding nature of EGCG. EGCG inhibited PfENR with the overall inhibition constant (Ki*) of 7.0 ± 0.8 nM. Further, we also studied the effect of triclosan on the inhibitory activity of EGCG. Triclosan lowered the k6 of the EI* complex by 100 times, lowering the overall Ki* of EGCG to 97.5 ± 12.5 pM. The results support EGCG as a promising candidate for the development of tea catechin based antimalarial drugs.

Slow m=1 instabilities of softened gravity Keplerian discs

We present the simplest model that permits a largely analytical exploration of the m =1 counter-rotating instability in a `hot' nearly Keplerian disc of collisionless self-gravitating matter. The model consists of a two-component softened gravity disc, whose linear modes are analysed using the Wentzel-Kramers-Brillouin approximation. The modes are slow in the sense that their (complex) frequency is smaller than the Keplerian orbital frequency by a factor which is of order the ratio of the disc mass to the mass of the central object. Very simple analytical expressions are derived for the precession frequencies and growth rates of local modes; it is shown that a nearly Keplerian discm must be unrealistically hot to avoid an overstability. Global modes are constructed for the case of zero net rotation.

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.

Analysis of Ridge-Loaded Folded-Waveguide Slow-Wave Structures for Broadband Traveling-Wave Tubes

An E-plane serpentine folded-waveguide slow-wave structure with ridge loading on one of its broad walls is proposed for broadband traveling-wave tubes (TWTs) and studied using a simple quasi-transverse-electromagnetic analysis for the dispersion and interaction impedance characteristics, including the effects of the beam-hole discontinuity. The results are validated against cold test measurements, an approximate transmission-line parametric analysis, an equivalent circuit analysis, and 3-D electromagnetic modeling using CST Microwave Studio. The effect of the structure parameters on widening the bandwidth of a TWT is also studied.

The ratio of diffusion coefficient to mobility for slow electrons in dry air

Using Huxley's solution of the diffusion equation for electron-attaching gases, the ratio of diffusion coefficient D to mobility μ for electrons in dry air was measured over the range 3·06 × 10-17

Voittoa tavoittelemattoman organisaation brandin rakentaminen. Case Slow Food

Tämän pro gradu-tutkielman tavoitteena oli kartoittaa voittoa tavoittelemattoman Slow Food-organisaation brandiin liitettyjä mielikuvia ja niitä tekijöitä, joilla brandin tavoitekuvaa tulisi jatkossa rakentaa. Koska nykyisin brandi ei ole enää pelkkien liikeyritysten yksityisomaisuutta, tutkimuksen teoreettinen asemointi perustui yhtäältä organisaation tunnettuuden kasvattamiseen brandin rakentamisen avulla ja toisaalta voittoa tavoittelemattoman toimintaympäristön erityispiirteiden näkökulmaan. Case-osion avulla haluttiin tarkastella globalisaation ja elintarviketalouden keskittymiselle vaihtoehtoisen, paikallisuuteen perustuvan ruokajärjestelmän vaikutuksia, mahdollisuuksia ja haasteita. Tutkimuksen empiirinen osuus muodostui laadullisesta tapaustutkimuksesta, jonka kohteena oli Slow Food-organisaatio. Tutkimus suoritettiin haastattelemalla kahtatoista Slow Food-organisaation sidosryhmien edustajaa Italian Piemontessa henkilökohtaisin haastatteluin, joiden pohjana oli brandi identiteetin elementeistä luodut kaksi teemaa: mielleyhtymiin ja arvoväittämään liittyvät tekijät. Aineiston analysoinnissa käytettiin teemoittelua ja sisällönanalyysia. Tutkimuksen lähestymistapa oli abduktiivinen. Tulosten mukaan Slow Food-brandi identifioituu sidosryhmilleen ensisijaisesti luotettavan ruoan kautta, johon katsottiin kuuluvan aidot, puhtaat raaka-aineet ja paikallisesti tuotetun ja jalostamattoman ruoan hyvä jäljitettävyys. Myös tiettyyn paikkaan ja arvoihin sidottujen kokemusten ja odostusten täyttymisen kautta saatu sosiaalinen ja kulttuurinen jatkuvuus nimettiin brandin vahvuudeksi. Lisäksi vastuullisen tuottamisen ja kuluttamisen sekä aitojen makujen ja laadukkaan ruokavalion edistäminen korostuivat jonkin verran vastauksissa. Näillä perusvahvuuksilla toivottiin brandin identiteettiä rakennettavan myös tulevaisuudessa. Haastateltavien mielestä Slow Food-organisaatio erilaistaa itsensä muista ensisijaisesti lupaamalla yksilölle korkealuokkaisia, aitoja tuotteita ja palveluja, joilla on henkilökohtaisten hyötyjen lisäksi positiivisia seuraamuksia myös oman alueen työllisyyden ja talouden kehitykseen. Organisaation tulisi myös jatkossa luoda uskottavuutta toimintaansa eritoten sen kautta, että brandi lunastaa lupauksensa laadusta ja aitoudesta. Toisaalta erottautuakseen muista lähi- ja luomuruokabrandeista Slow Food-brandin arvoväittämässä tulisi tulevaisuudessa selkeämmin korostua myös toiminnan voittoa tavoittelemattomuus ja brandiin liittyvä elämyksellisyys. Sidosryhmien kiinnostusta ja brandin lupauksen tehoa alentaviksi tekijöiksi nimettiin yleinen ruoan arvostuksen väheneminen sekä Slow Food-tuotteiden ja -palvelujen korkea hinta, huono saatavuus ja näkyvyys. Keskeisimpinä ratkaisuina pidettiin kuluttajien informatiivisen tiedon lisäämisen ohella pientuottajien verkostoitumista ja uusia yhteistyön muotoja kuten tuottajien yhteisiä jakeluketjuja ja paikallismyymälöitä. Näiden lisäksi brandin tunnistettavuuden parantaminen ja aktiivisempi tarjonta kyltityksin, tuotteiden pysyvän läsnäolon ja vähittäiskaupan mukaantulon kautta sekä eräät muut markkinoinnin osa-alueet kuten sosiaalinen media, Internet ja kansainväliset ruoka-alan tapahtumat nimettiin brandin lupausta kirkastaviksi elementeiksi. Pientuotannon lisääminen verotuksen kohdentumisen muutoksilla nähtiin keinoksi pudottaa paikallisen ruoan hintaa.Toisaalta korkeaa hintaa perusteltiin laadukkaaseen imagoon liittyvien argumenttien lisäksi luonnollisen kysynnän kasvulla, jota arveltiin saatavan tulevaisuudessa suurista ikäluokista, yhä kasvavasta koulutus- ja tulotasosta sekä valveutuneemmista kuluttajista.