Basic Column Research Articles

Recycling basic columns of the splitting preconditioner in interior point methods

Recycling basic columns of the splitting preconditioner in interior point methods

Design of Optimized RP-HPLC Method for Quantitative Analysis of Bisoprolol Fumarate in Bulk and Pharmaceutical Dosage Form

In this study an effective method was developed to assay Bisoprolol fumarate in tablets dosage form. The chromatographic separation was achieved on Reprosil pure basic C18 analytical column. A mixture of acetonitrile + Potassium dihydrogen phosphate buffer (0.050 mol L-1) (30:70 V/V), pH 3.5 was used as the mobile phase, effluent flow rate monitored at 1.0 mL/min, and UV detection at 233 nm. In forced degradation studies, the effects of acid, base, oxidation, UV light and temperature which were investigated showed no interference in the peak of drug. The proposed method was validated in terms of specificity, linearity, robustness, precision and accuracy. The method was linear at concentrations ranging from 5µg/mL to 17.5µmg/mL, precise (intra- and inter-day relative standard deviations R.S.D. < 2 %), (r2 = 0.9995).

A branch-and-price-and-cut algorithm for operating room scheduling under human resource constraints

In this paper, we address an integrated operating room planning and scheduling problem that includes, with fine detail, constraints commonly encountered in practice (i.e., sequence, capacity and due date constraints) and for human resources other than surgeons, i.e., nurses. A new model of the sequence-dependent operating room cleaning times that arise because of surgeries with different infection levels is considered. To solve this difficult integrated planning and scheduling problem, we devise a branch-and-price-and-cut algorithm based on the time-indexed formulation of the problem. The basic column generation scheme relies on a label-correcting algorithm that we purposely developed for solving the pricing problems that are modeled as single operating room scheduling problems with time-dependent costs and sequence-dependent cleaning times. The pricing problems are strongly NP-Hard. The efficiency of the label-correcting algorithm is ensured by dominance rules among labels and by two algorithms for computing the upper and lower bound of labels. An effective cutting procedure, inspired by Benders’ decomposition and based on duality theory for linear programming, is developed for tightening the linear relaxation of the problem. With instances from the literature and that we generated, we conduct a numerical study to demonstrate the computational effectiveness of the solution method.

Structural isomers of di-p-benzidithiaoctaphyrins.

The cis and trans structural isomers of di-p-benzidithiaoctaphyrins were synthesized by adopting two different synthetic routes using readily available precursors under acid-catalyzed conditions, and the isomers were separated using basic alumina column chromatography. 1D and 2D NMR spectroscopy were used to deduce the molecular structures of the macrocycles, which also helps to differentiate the cis isomer from the trans isomer. DFT studies revealed that both the cis and trans isomers adopt figure of eight conformations but exhibit clear differences in their structural features, and the trans isomer is more distorted than the cis isomer. Experimental and theoretical studies revealed that both the cis and trans isomers are nonaromatic stable macrocycles and show subtle differences in their structure, spectral and redox properties. The cis and trans isomers of di-p-benzidithiaoctaphyrin exhibit nonaromatic absorption features in the visible-NIR region, and electrochemical studies revealed their electron-rich nature. TD-DFT studies are in agreement with the experimental observations.

Bilinearization-reduction approach to integrable systems

The paper is a review of the bilinearization-reduction method which provides an approach to obtain solutions to integrable systems. Many integrable coupled systems can be bilinearized and their solutions are presented in terms of double Wronskians (or double Casoratians in discrete case). The bilinearization-reduction method is based on bilinear equations and solutions in double Wronskian/Casoratian form. For those integrable equations that are reduced from coupled systems, one can first solve the unreduced coupled system, obtaining their solutions in double Wronskian/Casoratian form, then, implement suitable reduction techniques, so that solutions of the reduced equation can be obtained as reductions of those of the unreduced coupled system. The method proves effective in solving not only classical integrable equations but also the nonlocal ones. The so-called nonlocal integrable equations were introduced by Ablowitz and Musslimani via reductions with reverse-space (or reverse-time, or reverse-space-time). Note that this method particularly provides a convenient bilinear approach to solve nonlocal integrable systems. In this review, the nonlinear Schrödinger hierarchy and the differential-difference nonlinear Schrödinger equation are employed as demonstrative examples to elaborate this method. These two examples will be pedagogically helpful in understanding the reduction technique. The reduction is implemented by imposing suitable constraints on the basic column vectors of the double Wronskian/Casoratian. Realizations of the constraints are converted to solve a set of matrix equations which varies with the constraints. Special solutions of the matrix equations are provided, which are also helpful in understanding the eigenvalue structure of the involved spectral problems corresponding to the considered equations. Other examples include the Fokas-Lenells equation and the nonlinear Schrödinger equation with nontrivial background. Since many nonlinear equations with physical significance are integrable as reductions of integrable coupled systems, the paper provides a review as well as an introduction about the bilinearization-reduction method that can be used to solve these nonlinear integrable models.

Synthesis and Studies of Fused Benzo-Benzisapphyrins.

A series of rare examples of fused benzo-benzisapphyrins were synthesized readily by (3 + 2) condensation of benzodipyrrole-derived diol and para-benzitripyrrane in the presence of 0.5 equiv of TFA in CH2Cl2 under inert atmosphere conditions accompanied by DDQ oxidation in open air. The crude compounds were separated by basic alumina column chromatography and afforded pure fused benzo-benzisapphyrins in 20-22% yields. The fused sapphyrins were characterized in detail by high-resolution mass spectrometry (HRMS) and one-dimensional (1D) and two-dimensional (2D) NMR spectroscopy. The 1H NMR spectra recorded at both 298 and at 233 K clearly exhibited the presence of a strong diatropic ring current in benzo-benzisapphyrins, and the macrocycles are of aromatic nature. The DFT-optimized structure of benzo-benzisapphyrin revealed that the macrocycle was planar to a great extent due to the rigid structure of the dibenzopyrrole moiety, and the NICS(0) value of -11.2 ppm supports the aromatic nature of macrocycles. The absorption spectra of benzo-benzisapphyrins showed three weak Q bands approximately in the region of 650-900 nm and a strong Soret band at 480 nm, along with a shoulder band at ∼510 nm. The diprotonated derivative generated by the addition of excess TFA to the benzo-benzisapphyrin macrocycle exhibited bathochromically shifted absorption bands compared to the free base macrocycle.

The major problems between main contractors and subcontractors in construction projects in Egypt

Projects usually need continuous coordination among the participants in terms of scope of work, quickness, and timing during the execution phase to be completed without delay. Sub-contracting is a common practice in civil engineering projects. Subcontractors carry out a large part of the work done in construction projects. Thus, selecting the right subcontractor basically contributes to the project’s success. In this study, it was targeted to explore the causes of the mainconflicts between the contractor and subcontractors and the responsibility distribution of these causes. The basic columns of any project are main contractor and subcontractor, so the relationship between them must be good and effective in achieving the project's goals on time. A questionnaire was surveyed among the projects' parties (including the owner, the main contractor, the sub-contractor, and the consultant). The survey covered how to determine the party responsible for factors leading to dispute, and factors contributing to effective interface between main contractors and sub-contractors. Statistical analysis was carried out on the observations of the respondents of the survey using SPSS software. The mean score of each factor, degree of importance, and ranking was determined and the p-value was deduced using the Kruskal-wallis test to compare between the projects' parties. Also, the significance of each factor used in the questionnaire was determined. The conclusions of the study revealed factors that enhance the relationships, such as contract progress payment done on time, the problems related to the main contractor such as delay in contract progress payment, the problems related to subcontractor such as work delay and the problems related to other sources such as price escalation of material and labor. The results showed good acceptable limits of homogeneity and reliability including communications, financial, workper formance, contract, and other sources. The study recommended a framework that can be implemented to improve such relationships such as compliance with the terms of the contract and choosing contractors specialized in the required works. The main contribution of the study is improving the relationship between main contractor and sub contractor, state the problems facing the relationship to set the methods that can be used to processed with and that helps to success in the projects and development the construction sector in Egypt. This study opens the way for continued development of model parameters that will aid in effectively treating this subject area.

Strategizing practical implementation of additional condenser-reboilers (CR) to reduce power consumption of a dual purity cryogenic single column gaseous oxygen plant

A basic single column cryogenic air separation plant refluxed by nitrogen has a single condenser-reboiler (CR) that produces gaseous oxygen simultaneously at dual purities of 90% and 99.5% at 10 bar and 40 bar, respectively. This basic plant consumes about 42,000 kW in an integrated steel plant of 5 million tons per year. Saving power even by a small percentage holds a great promise to reduce the production cost of steel. In place of pressurizing the entire recycled nitrogen flow to 5.1 bar that feeds the condenser-reboiler of the basic plant, some portions of nitrogen in the modified plant is required at 4.3 bar and 2.8 bar to feed the additional condenser-reboilers. Nitrogen compressor accounts for 20–25% of the net power consumption and putting additional condenser-reboilers reduces it by 15–23% that leads to an overall reduction of the power of 5.4%. As a single column plant can produce pure and impure oxygen simultaneously at different proportions, this paper determines the additional number of reboilers to be installed, their locations in the column and other plant parameters keeping oxygen recovery intact above 99%. The analysis evolves the strategy of operating recycled nitrogen compressors at multiple pressures in modified plant having three condenser-reboilers.

Generalized Assignment for Multi-Robot Systems via Distributed Branch-And-Price

In this article, we consider a network of agents that has to self-assign a set of tasks while respecting resource constraints. One possible formulation is the generalized assignment problem, where the goal is to find a maximum payoff while satisfying capability constraints. We propose a purely distributed branch-and-price algorithm to solve this problem in a cooperative fashion. Inspired by classical (centralized) branch-and-price schemes, in the proposed algorithm, each agent locally solves small linear programs, generates columns by solving simple knapsack problems, and communicates to its neighbors a fixed number of basic columns. We prove finite-time convergence of the algorithm to an optimal solution of the problem. Then, we apply the proposed scheme to a generalized assignment scenario, in which a team of robots has to serve a set of tasks. We implement the proposed algorithm in a Robot Operating System testbed and provide experiments for a team of heterogeneous robots solving the assignment problem.

Diterpenoid alkaloids from roots of Aconitum kongboense

The chemical constituents from the roots of Aconitum kongboense were studied. Twenty-five diterpenoid alkaloids were isolated from the 95% methanol extract of the roots of A. kongboense by silica gel, reverse-phase silica gel and basic alumina column chromatography. They included a new aconitine-type diterpenoid alkaloid, named as kongboensenine(1), and twenty-four known ones(2-25), i.e., acotarine F(2), acotarine G(3), 14-acetyltalatisamine(4), talatisamine(5), indaconitine(6), yunaconitine(7), chasmanine(8), 6-epi-foresticine(9), homochasmanine(10), 8-deacetyl-yunaconitine(11), chasmaconitine(12), ajaconine(13), franchetine(14), ezochasmanine(15), crassicautine(16), 14-O-deacylcrassicausine(17), genicunine A(18), falconeridine(19), sachaconitine(20), liljestrandisine(21), 8-methyl-14-acetyltalatisamine(22), kongboendine(23), 14-benzoylchasmanine(24) and pseudaconine(25). Their structures were elucidated by common spectroscopic methods including high-resolution electrospray ionization mass spectrometry(HR-ESI-MS) and nuclear magnetic resonance(NMR) techniques. Compounds 2-4, 10, 13, 15-19 and 21-22 were isolated from this plant for the first time. Experimental results showed that all compounds did not have a significant inhibitory activity against acetylcholinesterase(AChE).

Structural considerations in zeotropic distillation sequences with multiple feeds

The separation of multiple feed streams with some common components using sequences of distillation columns produces a rich space of alternatives that must be considered. In this work, we present the main structural characteristics of sequences generated when we want to take advantage of the synergies of common components in multiple feed streams to reduce both, energy consumption and the total number of distillation columns. In general, the sequence of separation tasks of the whole system can be obtained from the sequences of separation tasks of each one of the feeds. However, the integration in actual columns is not so straightforward and we must consider aspects like the optimal location of feeds in multiple-feed columns; and the alternatives of integration of common sub-mixtures (when possible) in actual columns. Besides, the optimal sequence of separation tasks for each feed is not necessarily the same when all of them are considered simultaneously. We show that the minimum number of actual columns, without considering further intensification, depends on the number of components in each feed and on the possibilities of integration of common sub-mixtures, so we extend the concepts of regular and basic column sequences to deal with these new situations. The examples show the potential savings in energy and number of columns compared to maintain isolated each feed; mixing the feed streams or an incorrect integration.

Experimental Research on Reinforced Concrete Columns Strengthened with Steel Jacket and Concrete Infill

Experimental research on axially compressed columns made from reinforced concrete (RC) and RC columns strengthened with a steel jacket and additional fill concrete is presented in this paper. A premade squared cross-section RC column was placed inside a steel tube, and then the space between the column and the tube was filled with additional concrete. A total of fourteen stub axially compressed columns, including nine strengthened specimens and five plain reinforced concrete specimens, were experimentally tested. The main parameter that was varied in the experiment was the compressive strength of the filler concrete. Three different concrete compression strength classes were used. Test results showed that all three cross-section parts (the core column, the fill, and the steel jacket) worked together in the force-carrying process through all load levels, even if only the basic RC column was loaded. The strengthened columns exhibited pronounced ductile behavior compared to the plain RC columns. The influence of the test parameters on the axial compressive strength was investigated. In addition, the specimen failure modes, strain development, and load vs. deformation relations were registered. The applicability of three different design codes to predict the axial bearing capacity of the strengthened columns was also investigated.

Assessment of adolescent idiopathic scoliosis from body scanner image by finite element simulations.

Adolescent idiopathic scoliosis, is a three-dimensional spinal deformity characterized by lateral curvature and axial rotation around the vertical body axis of the spine, the cause of which is yet unknown. The fast progression entails regular clinical monitoring, including X-rays. Here we present an approach to evaluate scoliosis from the three-dimensional image of a patient’s torso, captured by an ionizing radiation free body scanner, in combination with a model of the ribcage and spine. A skeletal structure of the ribcage and vertebral column was modelled with computer aided designed software and was used as an initial structure for macroscopic finite element method simulations. The basic vertebral column model was created for an adult female in an upright position. The model was then used to simulate the patient specific scoliotic spine configurations. The simulations showed that a lateral translation of a vertebral body results in an effective axial rotation and could reproduce the spinal curvatures. The combined method of three-dimensional body scan and finite element model simulations thus provide quantitative anatomical information about the position, rotation and inclination of the thoracic and lumbar vertebrae within a three-dimensional torso. Furthermore, the simulations showed unequal distributions of stress and strain profiles across the intervertebral discs, due to their distortions, which might help to further understand the pathogenesis of scoliosis.

Universal gold nanoparticle modified hybrid monolithic substrate developed for facile in-column post-functionalization

Organic-inorganic hybrid monolithic columns, due to the comprehensive advantages, have been applied as promising solid-phase separation matrices for pretreatment of complex samples in biomedical and environmental analyses, however, a tremendous time and efforts are cost to optimize the preparation methods of hybrid monolithic columns with different functional groups for various target analytes. Herein, we proposed a strategy to develop basic hybrid monolithic column materials for flexible and facile post-functionalization. Three kinds of single-functionalized (amine, thiol, and carboxyl) and two kinds of bi-functionalized (amine and thiol, and amine and carboxyl) hybrid monolithic columns were immobilized with gold nanoparticles (GNPs) as intermediary bridge to construct the universal substrates. The GNPs adsorption capacities of the five hybrid monoliths were compared through qualitative characterization and quantitative analysis. Thioglycolic acid (TGA) and an aptamer against human α-thrombin were respectively used for further functionalizing the substrates to select the most suitable hybrid monolith for optional post-functionalization. It was reported for the first time that the coverage density of TGA on functionalized monolithic column modified by GNPs was 168.41 nmol μL−1. Notably, the coverage density (2205.8 pmol μL−1) of the aptamer decorated on the hybrid monolithic column was significantly higher than most other similar materials in published works. After that, the aptamer functionalized hybrid monolithic column screened out was applied for the solid-phase microextraction of thrombin, which possessed excellent adsorption selectivity in interference experiment. Consequently, the developed GNPs modified amine- and thiol-bi-functionalized hybrid monolithic column is an attractive universal substrate to realize easy and efficient post-modification of separation materials for other target analytes in complex samples avoiding a lot of time and labor consumption in the optimization of process preparation.

Effect of piperine and its analogs on pharmacokinetic properties of sorafenib tosylate: Bioanalytical method development and validation

Sorafenib tosylate (ST) is a drug of choice for the treatment of advanced hepatocellular carcinoma. The bioavailability of ST varies from 29% to 38% due to the presence of food, medication, and other factors. Moreover, the dose of ST (400 mg twice a day) is also higher due to its poor bioavailability. Piperine is known as a natural bioenhancer, and the use of a bioenhancer ultimately leads to a synergistic effect. In this study, the development and validation of a precise, accurate, and reproducible bioanalytical method was carried out using reversed-phase high-performance liquid chromatography (RP-HPLC). The objective of the study is to determine the effect of piperine and its analogs on the pharmacokinetics of ST using rats. The dose of ST alone and in combination with piperine and its analogs, given orally to male Wistar rats in suspension form, and the drug plasma concentration was examined using a validated RP-HPLC bioanalytical method. The separation of piperine and ST was achieved on the Chromatopak basic C18 HPLC column with the dimension of 250 mm × 4.6 mm × 5 μm, guarded along with the phenomenex guard column using ACN:Water:Formic Acid (70:29.5:0.5 v/v) as the mobile phase at 280 nm (isosbestic point of piperine and ST). The pharmacokinetic data of ST, along with piperine, exhibit a significant increase in area under the curve (AUC) of ST (1.66-fold), while the two derivatives of piperine (5a and 5d) exhibited almost double the increase in AUC compared to piperine (2.58 and 2.42-fold, respectively).

Forecasting the construction cost by using unit based estimation model

Generally, the construction projects will take a long duration to complete. In this context predicting price escalation and estimating construction costs are major steps for project estimators, contractors and owners. The pricing process is a challenging job due to fluctuations in construction elements and that trend increasing over the long term. Many forecasting techniques like Earned Value Management (EVM) have been developed in recent years to handle the complexity of prediction problems whereas the present work explain an approach to forecasting the total cost of construction project, based on the information available from a basic project cost system, i.e., to-date cost. These data are collected and calculated on a daily or weekly basis for each account and then added for the total project. In the case study project (Hostel Building with G + 14) the basic construction elements like column, beams and slab are considered as products and find the unit production cost based on the Estimated at Completion (EAC) data and then used to forecast to Estimate to Complete (ETC).

A Mixed Circular/Linear Dual-Polarized Phased Array Concept for Automotive Radar—Planar Antenna Designs and System Evaluation at 78 GHz

A planar antenna array front end for automotive applications in the 78 GHz band is discussed and evaluated. Separate antenna arrays for transmit and receive are realized on RF substrate with the objective to provide a very cost-effective and compact design. The basic array column consists of 10 dual-polarized square patch elements and launches a fan beam that illuminates a wide sector in azimuth but a narrow sector in elevation. The orthogonal linear polarizations are combined via a microstrip quadrature power splitting network in order to excite a single circularly polarized wave on transmit. On receive, the array column is arranged multiple times next to each other to allow for digital beamforming in azimuthal direction. A prototype consisting of three receiving columns has been fabricated and measured. Grating lobes are reduced to an overall sidelobe level of less than −10 dB by a time-division multiplex scheme that switches through several transmit arrays in different locations. Radar system simulations based on the measured antenna patterns demonstrate a very good discrimination of elementary polarimetric scattering objects.

A Heterogeneous Parallel LU Factorization Algorithm Based on a Basic Column Block Uniform Allocation Strategy

Most supercomputers are shipped with both a CPU and a GPU. With the powerful parallel computing capability of GPUs, heterogeneous computing architecture produces new challenges for system software development and application design. Because of the significantly different architectures and programming models of CPUs and GPUs, conventional optimization techniques for CPUs may not work well in a heterogeneous multi-CPU and multi-GPU system. We present a heterogeneous parallel LU factorization algorithm for heterogeneous architectures. According to the different performances of the processors in the system, any given matrix is partitioned into different sizes of basic column blocks. Then, a static task allocation strategy is used to distribute the basic column blocks to corresponding processors uniformly. The idle time is minimized by optimized sizes and the number of basic column blocks. Right-looking ahead technology is also used in systems configured with one CPU core to one GPU to decrease the wait time. Experiments are conducted to test the performance of synchronization and load balancing, communication cost, and scalability of the heterogeneous parallel LU factorization in different systems and compare it with the related matrix algebra algorithm on a heterogeneous system configured with multiple GPUs and CPUs.

DIGITAL SURVEY AND ALGORITHMIC MODELING IN HBIM. TOWARDS A LIBRARY OF COMPLEX CONSTRUCTION ELEMENTS

Abstract. In the study of built heritage, the introduction of BIM models provides the advantage of a set of data that can be shared between different platforms. Despite the continuous progress in research, the modeling processes of complex construction elements, typical of historical architectures, always require a certain attention and care that involve considerable investments in terms of both resources and time. In this paper we present the first results of an ongoing research aimed at considering possible methods that can allow a simplification of the modeling processes of elements of historical architectures in the BIM environment. In particular, the research aims to explore the possibilities offered by the algorithmic modeling of complex construction elements. In the study of historical architecture, an enough recurring theme concerns those elements that can be traced back to the principles of architectural orders. In the survey of historical architecture, a quite recurring case study concerns those elements or parts of building ruled by the principles of architectural orders. One of the first elements taken into consideration was that of the column that, in its articulation in base, shaft and capital, offers three different levels of complexity of the modeling process very suitable for the research path. Starting with a collection of data acquired from digital photogrammetric modeling, we considered a initial set of different case studies that allowed us to conduct a first working hypothesis by embracing a quite wide range of possible variations starting from a basic column.

A clean-up method for determination of multi-classes of persistent organic pollutants in sediment and biota samples with an aliquot sample

In the present study, we developed a novel method to simultaneously detect eight classes of persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), polychlorinated naphthalenes (PCNs), organochlorine pesticides (OCPs), short-chain chlorinated paraffins (SCCPs) and Dechlorane Plus (DP), in sediment and fish tissue samples. The samples were extracted by accelerated solvent extraction (ASE) system, and the extracts were purified and fractionated into fraction1 and fraction2 with multi-layer silica gel column, followed by further fractionation using a basic alumina column (fraction1) and a Florisil column (fraction2), respectively. Finally, fractions were analyzed with different chromatographic columns and different detectors according to the properties of a chemical compound. The limit of detection for eight classes of POPs ranged from 1 to 30 pg/gdw in fish tissue samples, and from 1 to 33 pg/gdw in sediment samples, except for SCCPs (from 5.6 to 7.6 ng/g in fish tissue samples, and from 1.2 to 8.3 ng/gdw in sediment samples). The recoveries of eight classes of POPs spiked in fish tissue and sediment samples ranged from 43% to 120%, and from 45% to 115%, respectively. The relative standard deviation (RSD) was less than 25%. The accuracy of method was satisfactorily demonstrated by analysis of standard reference materials NIST SRM 1649b and WMF-01. In addition, the newly developed method was successfully applied for analysis of sediment and fish samples collected from the Baiyangdian Lake.