The mechanism of inclusion removal from liquid steel by gas bubbling and bubble attachment in the tundish is complex due to the great number of variables involved, and it is even more difficult to ...study because of the turbulent flow conditions. The main objective of this work is to analyze and improve the understanding of the alumina inclusion removal rate by bubble attachment and by gas bubbling fluid dynamics effects. The results show that the inclusion collection probability mainly depends on the attachment mechanism by collision. This parameter was determined by calculating the induction time, which is shorter when the rupture time and the formation time of a stable three phases contact (particle/liquid/gas) are ignored than when it is fully considered, affecting the attachment probability. In addition, to achieve acceptable inclusion removal, a smaller bubble diameter is required, such as 1 mm. This consideration is almost impossible to achieve during tundish operation; a more realistic bubble diameter around 10 mm is employed, resulting in a very inefficient inclusion removal process by bubble attachment. Nevertheless, in a real casting tundish the inclusion removal rate employing argon bubbling is efficient; is mainly due to the fluid flow pattern changes rather than bubble attachment. Consequently, it is imperative to consider the summation of both removal mechanisms to compute a better approximation of this important operation.
In this first paper, we combine a structural analysis of the near-IR surface brightness profiles and NII rotation curves for the galaxies in the pair NGC 5953/5954 to model the mass distribution in ...each member by using two independent axisymmetric analytical mass models: (1) a standard model given by the sum of a spherical bulge with the Sersic law, a stellar exponential disk, and a cold dark matter halo represented by the improved fitting formula of Navarro et al.; and (2) a simple model given by the sum of a spherical bulge, a finite oblate spheroid representing the disk, and a spherical dark halo, all three mass components with simple density laws. In our surface brightness fits, a central luminous source is considered in both galaxies. We obtained K-band M/L ratios, Y sub(D), Y sub(B), for the disks and bulges, and total masses for each mass component in both galaxies. With the standard model we find in NGC 5953, (Y sub(D),Y sub(B)) = (0.29 super(+1) sub(-0.29), 0.37 + or - 0.03) M sub(middot in circle)/L sub(middot in circle), and in NGC 5954, (Y sub(D), Y sub(B)) = (0.88 + or - 0.18, 0.21 + or - 0.09) M sub(middot in circle)/L sub(middot in circle). Corresponding values found with the simple model are (Y sub(D), Y sub(B)) = (1.41 + or - 0.15, 0.29 + or - 0.04) M sub(middot in circle)/L sub(middot in circle) and (Y sub(D), Y sub(B)) = (0.51 + or - 0.05, 0.52 super(+0.23) sub(-0.12)) M sub(middot in circle)/L sub(middot in circle). Our M/L estimates are compared with predictions from other methods in the literature, finding reasonable agreement. The dark halos estimated using the simple model have a small mass, of the order of 10 super(7) M sub(middot in circle), within the maximum distance in the rotation velocity data.
In order to optimize steel flow and maximize the contact time of the inclusions with the slag layer inside the tundish, a proper flow-control arrangement must be designed, considering the shape, the ...dimensions of the prototype, and the plant operating conditions of the tundish. Physical and mathematical modeling has been used in this study, in a complementary fashion, to evaluate the influence of turbulence-inhibiting devices on the velocity fields, tracer dispersion, small- and large-particle trajectories, flow-pattern characteristics, and grade changes in a large-volume tundish. From the water model and mathematical simulation results, a flow-control system with the best performance was identified; this system must contribute to improving the productivity and cleanliness of the continuous-cast steel.
ABSTRACT This study characterized the clinical, radiological, ultrasound, and necroscopic findings of a case of Arnold-Chiari type II malformation in a Gir breed calf from Brazil. The animal was ...hospitalized at sixty days of age, in permanent sternal recumbency, cutaneous appendix at the 4th lumbar vertebra and kyphoscoliosis of the caudal and lumbosacral thoracic spine. Radiographic examination of the spine and skull revealed spina bifida and suspected occipital hypoplasia. Upon examination of myelography with an injection of lumbar and atlantooccipital contrast, it was possible to visualize the meningocele at the 4th lumbar vertebra region and findings at the rhombencephalon level of increased regional pressure with failure to fill the contrast in the posterior fossa, in the presence of clear demarcation of the circumvolutions of the cerebral cortex and the subarachnoid space of the cervical spinal cord. Ultrasonographic examination of the cerebellum showed an insinuation of the cerebellar worm through the foramen magnum. The animal did not show changes in complete blood count, biochemical series, and cerebrospinal fluid and was negative for Pestivirus. There was a worsening of the clinical conditions and the animal died. This malformation of unknown etiology must be studied as a differential diagnosis of the nervous system disorders.
RESUMO Este estudo caracterizou os achados clínicos, radiológicos, ultrassonográficos e necroscópicos de um caso de malformação de Arnold-Chiari tipo II em uma bezerra Gir no Brasil. O animal foi hospilatizado aos 60 dias de idade, apresentando decúbito esternal permanente, apêndice cutâneo na altura da quarta vértebra lombar e cifoescoliose da coluna vertebral torácica caudal e lombossacra. Ao exame radiográfico da coluna e do crânio, foram observadas espinha bífida e suspeita de hipoplasia occipital. Ao exame de mielografia com injeção de contraste lombar e atlanto-occipital, foi possivel visualizar a meningocele na altura da quarta vértebra lombar e achados em nível rombencefálico de aumento da pressão regional com falha de preenchimento do contraste na fossa posterior, na presença de nítida demarcação das circunvoluções do córtex cerebral e do espaço subaracnoide da medula espinhal cervical. Ao exame ultrassonográfico do cerebelo, foi observada insinuação do verme cerebelar através do forame magno. O animal não apresentou alterações em hemograma completo, série bioquímica e fluido cérebro-espinhal e foi negativo para Pestivirus. Houve uma piora do quadro clínico e o animal morreu. Essa malformação de etiologia desconhecida deve ser estudada como um diagnóstico diferencial.
The anionic complexes Cu(L
1−)
3
1−, L
−
=
dopasemiquinone or L-dopasemiquinone, were prepared and characterized. The complexes are stable in aqueous solution showing intense absorption bands at ca. ...605
nm for Cu(II)-L-dopasemiquinone and at ca. 595
nm for Cu(II)-dopasemiquinone in the UV–vis spectra, that can be assigned to intraligand transitions. Noradrenaline and adrenaline, under the same reaction conditions, did not yield Cu-complexes, despite the bands in the UV region showing that noradrenaline and adrenaline were oxidized during the process. The complexes display a resonance Raman effect, and the most enhanced bands involve ring modes and particularly the νCC
+
νCO stretching mode at ca. 1384
cm
−1. The free radical nature of the ligands and the oxidation state of the Cu(II) were confirmed by the EPR spectra that display absorptions assigned to organic radicals with
g
=
2.0005 and
g
=
2.0923, and for Cu(II) with
g
=
2.008 and
g
=
2.0897 for L-dopasemiquinone and dopasemiquinone, respectively. The possibility that dopamine and L-dopa can form stable and aqueous-soluble copper complexes at neutral pH, whereas noradrenaline and adrenaline cannot, may be important in understanding how Cu(II)-dopamine crosses the cellular membrane as proposed in the literature to explain the role of copper in Wilson disease.
This study aimed to verify the correlation between murine measurements and retroperitoneal adipose tissue in rats exposed to the high-fat diet. Material and methods: Wistar male adult rats, ...descendants of mothers who consumed a high-fat diet during pregnancy and lactation and fed the same diet after weaning were used. At 60 days of life, body weight, longitudinal axis and waist circumference (WC) were measured. The Body Mass Index (BMI) and the Lee Index were calculated for a posterior analysis of the correlation with the amount of retroperitoneal adipose tissue dissected on the same day. For analysis of the data, the Pearson correlation test was used, considering statistical significance for p <0.05. Results: Body weight had a weak correlation (r= 0.31; p= 0.38) with retroperitoneal adipose tissue. While the longitudinal correlated moderately and negative (r= -0.40; p= 0.25). Abdominal circumference (r= 0.62; p= 0.05), body mass index (r= 0.61; p= 0.03) and Lee (r= 0.69; p= 0.03) correlated moderately and positively with adipose tissue. Conclusion: Among the measured murine measurements, weight and longitudinal axis were not good indicators to represent accumulation of retroperitoneal adipose tissue in rats. However, Lee's index seems to be the best murine marker to diagnose the accumulation of retroperitoneal fat. BMI, CA and Lee index were murine parameters with higher correlation.
Hazard Analysis and Risk Assessment (HARA)in the automotive industry, is a structured process described in the ISO 26262 standard in force for the development of safety-related systems comprised of ...electrical, electronic and software components. Risks that are identified for malfunctioning behaviour of an item should be classified in terms ofAutomotive Safety Integrity Level (ASIL)in function of discrete qualifications ofControllability (C), Severity (S)andExposure (E). Even though the standard gives definitions and examples on how to select the correct qualification, in practice, this exercise strongly depends on expert judgement, and therefore is (i) time-consuming and (ii) a qualification may differ for the same risk if it is analysed by different teams. This paper shows how simulations can be used to reduce the dependence on expert judgement and can automate part of the HARA process in order to assess a large number of scenarios, making the process less error prone and reducing the required design time. The paper describes theSimulation Aided Hazard Analysis and Risk Assessment (SAHARA)method that models hazardous situations from textual descriptions, integrates an item model into a vehicle model, simulates its behaviour and interaction with the environment and evaluates the generated traces through contract-based analysis to estimate C, S, E and ASIL.
Biopolymers such as carboxymethyl cellulose and hyaluronic acid are alternative substrates for conformable organic light-emitting diodes (OLEDs). However, drawbacks such as mechanical stress ...susceptibility can hinder the device’s performance under stretched conditions. To overcome these limitations, herein, we developed a nanocomposite based on CMC/HA (carboxymethyl cellulose/hyaluronic acid) and synthetic Laponite, intending to improve the mechanical strength without compromising the film flexibility and transparency (transmittance >80%; 380–700 nm) as substrates for conformable OLEDs. From XRD, FTIR, CP-MAS NMR, and TGA/DTG characterization techniques, it was possible to conclude the presence of Laponite randomly dispersed between the polymer chains. CMC/HA with 5% (w/w) Laponite, CMC/HA 5, presented a higher tensile strength (370.6 MPa) and comparable Young’s modulus (51.0 ± 1.2 MPa) in comparison to the nanocomposites and pristine films, indicating a better candidate for the device’s substrates. To produce the OLED, the multilayer structure ITO/MoO3/NPB/TCTA:Ir(ppy)3/TPBi:Ir(ppy)3/BPhen/LiF was deposited onto the CMC/HA 5 substrate. The OLEDs fabricated using CMC/HA 5 substrates showed higher luminance (12 kcd/m2) and irradiance (0.9 mW/cm2) values when compared with those based on commercial bacterial cellulose. However, the same device presented a lower efficiency (3.2 cd/A) due to a higher current density. Moreover, the OLED fabricated onto the Laponite-modified biopolymer presented reproducible behavior when submitted to continuous bending stress. Thus, CMC/HA 5 demonstrates potential as a transparent conductor substrate for biopolymer-based OLEDs with comparable performance to commercial bacterial cellulose features.
Pain-related catastrophising is a maladaptive coping strategy known to have a strong influence on clinical pain outcomes and treatment efficacy. Notwithstanding, little is known about its ...neurophysiological correlates. There is evidence to suggest catastrophising is associated with resting-state EEG frontal alpha asymmetry (FAA) patterns reflective of greater relative right frontal activity, which is known to be linked to withdrawal motivation and avoidance of aversive stimuli. The present study aims to investigate whether such a relationship occurs in the situational context of experimental pain. A placebo intervention was also included to evaluate effects of a potential pain-relieving intervention on FAA. 35 participants, including both chronic pain patients and healthy subjects, completed the Pain Catastrophising Scale (PCS) questionnaire followed by EEG recordings during cold pressor test (CPT)-induced tonic pain with or without prior application of placebo cream. There was a negative correlation between FAA and PCS-subscale helplessness scores, but not rumination or magnification, during the pre-placebo CPT condition. Moreover, FAA scores were shown to increase significantly in response to pain, indicative of greater relative left frontal activity that relates to approach-oriented behaviours. Placebo treatment elicited a decrease in FAA in low helplessness scorers, but no significant effects in individuals scoring above the mean on PCS-helplessness. These findings suggest that, during painful events, FAA may reflect the motivational drive to obtain reward of pain relief, which may be diminished in individuals who are prone to feel helpless about their pain. This study provides valuable insights into biomarkers of pain-related catastrophising and prospects of identifying promising targets of brain-based therapies for chronic pain management.
PDF
