Analysing the base of precast column in socket foundations with smooth interfaces

This paper analyzes the behavior of the base of a precast column in the socket foundation with smooth interfaces. This research is motivated by the lack of information and guidelines on the behavior of column bases in the embedded region. An experimental program with two full-scale specimens was carried-out. These two specimens had smooth interfaces at the internal faces of the socket, different embedded lengths and were subjected to loads with large eccentricities. The experimental results showed that the failure of the specimens occurred by the yielding of the longitudinal reinforcement out of the embedded region, while the transverse reinforcement was not very stressed. Some recommendations on the anchorage of the longitudinal reinforcement and a strut-and-tie model for the behavior of column bases in the embedded region are proposed.

Ultra-Fast Gradient LC Method for Omeprazole Analysis Using a Monolithic Column: Assay Development, Validation, and Application to the Quality Control of Omeprazole Enteric-Coated Pellets

A method was optimized for the analysis of omeprazole (OMZ) by ultra-high speed LC with diode array detection using a monolithic Chromolith Fast Gradient RP 18 endcapped column (50 x 2.0 mm id). The analyses were performed at 30 degrees C using a mobile phase consisting of 0.15% (v/v) trifluoroacetic acid (TFA) in water (solvent A) and 0.15% (v/v) TFA in acetonitrile (solvent B) under a linear gradient of 5 to 90% B in 1 min at a flow rate of 1.0 mL/min and detection at 220 nm. Under these conditions, OMZ retention time was approximately 0.74 min. Validation parameters, such as selectivity, linearity, precision, accuracy, and robustness, showed results within the acceptable criteria. The method developed was successfully applied to OMZ enteric-coated pellets, showing that this assay can be used in the pharmaceutical industry for routine QC analysis. Moreover, the analytical conditions established allow for the simultaneous analysis of OMZ metabolites, 5-hydroxyomeprazole and omeprazole sulfone, in the same run, showing that this method can be extended to other matrixes with adequate procedures for sample preparation.

On the construction of nearest neighbour balanced row-column designs

Nearest–neighbour balance is considered a desirable property for an experiment to possess in situations where experimental units are influenced by their neighbours. This paper introduces a measure of the degree of nearest–neighbour balance of a design. The measure is used in an algorithm which generates nearest–neighbour balanced designs and is readily modified to obtain designs with various types of nearest–neighbour balance. Nearest–neighbour balanced designs are produced for a wide class of parameter settings, and in particular for those settings for which such designs cannot be found by existing direct combinatorial methods. In addition, designs with unequal row and column sizes, and designs with border plots are constructed using the approach presented here.

Analysis of immunosuppressive proteins in serum of liver-transplanted rats by using an anti-LSF-1 affinity column

Liver suppressor factor one (LSF-1) is a 40-kDa immunosuppressive protein in the serum of rats 60 days after orthotopic liver transplantation (OLT) between the nonrejector combination of DA donors into PVG; recipients. In the present study, the purification of proteins from rat OLT serum taken 60 days after transplantation Mras performed by affinity chromatography using the anti-LSF-1 polyclonal antibody (pAb). The assessment of column eluates using anti-LSF-1 and OLT serum was studied using rat heart and liver transplantation models. Rejection was not suppressed by the administration of OLT serum in heart or liver allografts. However, heart allografts treated with peak eluates (450 mu g single shot im, dissolved in Intralipos) taken from the affinity OLT serum survived significantly longer than untreated rats (median = 36.5 days; n = 7 vs 6.5 days; n = 5, respectively, P = 0.011). The same treatment with anti-LSF-1 column eluates also prolonged liver allografts significantly (>200 days) than those in either the untreated group (median = 11 days; n = 7) or those which received only Intralipos (median = 10.5 days; n = 5, P = 0.019). Subsequent analysis of the N-terminal sequences of some of the proteins which were eluted from the affinity column revealed that the homology of a 30-kDa protein was identical to hemoglobin alpha-chain, a 59-kDa protein to granulocyte inhibitory factor, a 70-kDa and a 90-kDa to albumin and its precursor, respectively. Although the specific immunosuppressive component has not been isolated, our results suggested that the anti-LSF-1 column can extract immunosuppressive moiety of LSF-1 from OLT serum. (C) 1998 Academic Press.

Improved high-performance liquid chromatography determination of methotrexate and its major metabolite in plasma using a poly(styrene-divinylbenzene) column

A sensitive high-performance liquid chromatographic assay has been developed for measuring plasma concentrations of methotrexate and its major metabolite, 7-hydroxymethotrexate. Methotrexate and metabolite were extracted from plasma using solid-phase extraction. An internal standard, aminopterin was used. Chromatographic separation was achieved using a 15-cm poly(styrene-divinylbenzene) (PRP-1(R)) column. This column is more robust than a silica-based stationary phase. Post column, the eluent was irradiated with UV light, producing fluorescent photolytic degradation products of methotrexate and the metabolite. The excitation and emission wavelengths of fluorescence detection were at 350 and 435 nm, respectively. The mobile phase consisted of 0.1 M phosphate buffer (pH 6.5), with 6% N,N-dimethylformamide and 0.2% of 30% hydrogen peroxide. The absolute recoveries for methotrexate and 7-hydroxymethotrexate were greater than 86%. Precision, expressed as a coefficient of variation (n=6), was

On the effect of tracer density on axial dispersion in a batch oscillatory baffled column

In this paper, we report our modelling evaluation on the effect of tracer density on axial dispersion in a batch oscillatory baffled column (OBC). Tracer solution of potassium nitrite, its specific density ranged from 1.0 to 1.5, was used in the study, and was injected to the vertical column from either the top or bottom. Local concentration profiles are measured using conductivity probes at two locations along the height of the column. Using the experimental measured concentration profiles together with both 'Tank-in-Series' and 'Plug Flow with Axial Dispersion' models, axial dispersion coefficients were determined and used to describe the effect of specific tracer density on mixing in the OBC. The results showed that the axial dispersion coefficients evaluated by the two models are very similar in both magnitudes and trends, and the range of variations in such coefficients is generally larger for the bottom injection than for the top one. Empirical correlations linking the mechanical energy for mixing, the specific density of tracer and axial dispersion coefficient were established. Using these correlations, we identified the enhancements of up to 269% on axial dispersion for various specific tracer densities. (C) 2002 Elsevier Science B.V. All rights reserved.

Assessing the self-heating behaviour of Callide coal using a 2-metre column

A 2-m, adiabatic column has been successfully refurbished and recommissioned for coal self-heating research at The University of Queensland. Subbituminous coal from the Callide Coalfields reached thermal runaway in just under 19 days from a starting temperature of 20-22 degreesC. The coal was loaded as two layers, with an R-70 index of 2.73 degreesC h(-1) and 5.90 degreesC h(-1) for the upper layer and lower layer respectively. Initially, a hotspot developed in the upper layer between 120 and 140 cm from the air inlet due to moisture adsorption. After 7 days, self-heating in the lower half of the column began to take over, consistent with the higher R-70 index of this coal. The location of the final hotspot was approximately 60 cm from the air inlet. Further tests on Australian coals, with the column, will enable a better understanding of coal self-heating under conditions closely resembling mining, transport and storage of coal. The results from the column will also provide industry with the information needed to manage the coal self-heating hazard. (C) 2002 Elsevier Science Ltd. All rights reserved.

A strategy to extend reactive distillation column performance under catalyst deactivation

This work addresses the effects of catalyst deactivation and investigates methods to reduce their impact on the reactive distillation columns performance. The use of variable feed quality and reboil ratio are investigated using a rigorous dynamic model developed in gPROMS and applied to an illustrative example, i.e., the olefin metathesis system, wherein 2-pentene reacts to form 2-butene and 3-hexene. Three designs and different strategies on column energy supply to tackle catalyst deactivation are investigated and the results compared.

Basic dyestuffs removal from textile effluents using feathers: equilibrium, kinetic and column studies

This research work has been focused in the study of gallinaceous feathers, a waste that may be valorised as sorbent, to remove the Dark Blue Astrazon 2RN (DBA) from Dystar. This study was focused on the following aspects: optimization of experimental conditions through factorial design methodology, kinetic studies into a continuous stirred tank adsorber (at pH 7 and 20ºC), equilibrium isotherms (at pH 5, 7 and 9 at 20 and 45ºC) and column studies (at 20ºC, at pH 5, 7 and 9). In order to evaluate the influence of the presence of other components in the sorption of the dyestuff, all experiments were performed both for the dyestuff in aqueous solution and in real textile effluent. The pseudo-first and pseudo-second order kinetic models were fitted to the experimental data, being the latter the best fit for the aqueous solution of dyestuff. For the real effluent both models fit the experimental results and there is no statistical difference between them. The Central Composite Design (CCD) was used to evaluate the effects of temperature (15 - 45ºC) and pH (5 - 9) over the sorption in aqueous solution. The influence of pH was more significant than temperature. The optimal conditions selected were 45ºC and pH 9. Both Langmuir and Freundlich models could fit the equilibrium data. In the concentration range studied, the highest sorbent capacity was obtained for the optimal conditions in aqueous solution, which corresponds to a maximum capacity of 47± 4 mg g-1. The Yoon-Nelson, Thomas and Yan’s models fitted well the column experimental data. The highest breakthrough time for 50% removal, 170 min, was obtained at pH 9 in aqueous solution. The presence of the dyeing agents in the real wastewater decreased the sorption of the dyestuff mostly for pH 9, which is the optimal pH. The effect of pH is less pronounced in the real effluent than in aqueous solution. This work shows that feathers can be used as sorbent in the treatment of textile wastewaters containing DBA.

Copper, nickel and zinc removal by peanut hulls: batch and column studies in mono, tri-component systems and with real effluent

The main goal of this research study was the removal of Cu(II), Ni(II) and Zn(II) from aqueous solutions using peanut hulls. This work was mainly focused on the following aspects: chemical characterization of the biosorbent, kinetic studies, study of the pH influence in mono-component systems, equilibrium isotherms and column studies, both in mono and tri-component systems, and with a real industrial effluent from the electroplating industry. The chemical characterization of peanut hulls showed a high cellulose (44.8%) and lignin (36.1%) content, which favours biosorption of metal cations. The kinetic studies performed indicate that most of the sorption occurs in the first 30 min for all systems. In general, a pseudo-second order kinetics was followed, both in mono and tri-component systems. The equilibrium isotherms were better described by Freundlich model in all systems. Peanut hulls showed higher affinity for copper than for nickel and zinc when they are both present. The pH value between 5 and 6 was the most favourable for all systems. The sorbent capacity in column was 0.028 and 0.025 mmol g-1 for copper, respectively in mono and tri-component systems. A decrease of capacity for copper (50%) was observed when dealing with the real effluent. The Yoon-Nelson, Thomas and Yan’s models were fitted to the experimental data, being the latter the best fit.

Fractional order modelling of zero length column desorption response for adsorbents with variable particle sizes

This manuscript analyses the data generated by a Zero Length Column (ZLC) diffusion experimental set-up, for 1,3 Di-isopropyl benzene in a 100% alumina matrix with variable particle size. The time evolution of the phenomena resembles those of fractional order systems, namely those with a fast initial transient followed by long and slow tails. The experimental measurements are best fitted with the Harris model revealing a power law behavior.

Column-based databases: estudo exploratório no âmbito das bases de dados NoSQL

O aumento da quantidade de dados gerados que se tem verificado nos últimos anos e a que se tem vindo a dar o nome de Big Data levou a que a tecnologia relacional começasse a demonstrar algumas fragilidades no seu armazenamento e manuseamento o que levou ao aparecimento das bases de dados NoSQL. Estas estão divididas por quatro tipos distintos nomeadamente chave/valor, documentos, grafos e famílias de colunas. Este artigo é focado nas bases de dados do tipo column-based e nele serão analisados os dois sistemas deste tipo considerados mais relevantes: Cassandra e HBase.