Static Times Research Articles

Granulation behaviour of increasingly hydrophobic mixtures

Abstract Wet granulation is the formation of powder particle assemblies bound by a liquid binder. Granules are produced in order to prevent mixture segregation, improve flow characteristics and ease of powder handling. The liquid binder droplets penetrate into, and bind together, powder particles being agitated in a mixer. Real granulation formulations are complex and challenging. The difficulty of achieving controlled water based wet granulation of a formulation containing a hydrophobic component is one such challenge that is receiving increasing attention in academic and industrial research. The present work has focussed on the granulation of multicomponent batches, specifically mixtures of hydrophilic Granulac230 (lactose) and hydrophobic limestone, using different spray droplet sizes and impeller speeds. The granulation behaviour of the batches is assessed in terms of granule size and compositional distributions on increasing the hydrophobic content of the batch. Transitions in granulation behaviour are reported as the hydrophobic content of the batch is increased. The granulation behaviour is linked to static powder bed penetration times by assigning ‘compositional zones’, which could be used as a predictive tool in formulation and process development In addition, a new preferential nucleation and layering mechanism is proposed to describe the experimental data and better understand how the ‘compositional zones’ of granulation behaviour have arisen.

Supercritical fluid extraction of free amino acids from broccoli leaves

The extraction of free amino acids (AAs) from broccoli leaves using supercritical fluid extraction (SFE) with CO2 modified with methanol, is presented in this work. The effect of the different variables was studied, showing the percentage of methanol a strong influence on the extraction. The best results in terms of extraction yield were obtained at 250bar, 70°C, 35% methanol as organic modifier, a flow rate of 2mL/min, and 5min and 30min as static and dynamic extraction times, respectively. The extraction yield obtained with the SFE method was comparable to that obtained employing conventional solvent extraction with methanol–water (70:30) and minor than using water, but the relative proportion of the AAs in the extracts was very different. For example, the use of SFE allowed the enrichment in proline and glutamine of the extracts. The selected conditions were applied to obtain SFE extracts of broccoli leaves from different varieties (Naxos, Nubia, Marathon, Parthenon and Viola). The highest levels of AAs were found in the SFE extracts from the Nubia variety.

The Tölz Temporal Topography Study: Mapping the visual field across the life span. Part II: Cognitive factors shaping visual field maps

Part I described the topography of visual performance over the life span. Performance decline was explained only partly by deterioration of the optical apparatus. Part II therefore examines the influence of higher visual and cognitive functions. Visual field maps for 95 healthy observers of static perimetry, double-pulse resolution (DPR), reaction times, and contrast thresholds, were correlated with measures of visual attention (alertness, divided attention, spatial cueing), visual search, and the size of the attention focus. Correlations with the attentional variables were substantial, particularly for variables of temporal processing. DPR thresholds depended on the size of the attention focus. The extraction of cognitive variables from the correlations between topographical variables and participant age substantially reduced those correlations. There is a systematic top-down influence on the aging of visual functions, particularly of temporal variables, that largely explains performance decline and the change of the topography over the life span.

A Rapid and Effective Method for Simultaneous Determination of Residual Sulfonamides and Sarafloxacin in Pork and Chicken Muscle by High Performance Liquid Chromatography with Accelerated Solvent Extraction–Solid Phase Extraction Cleanup

A rapid and effective high performance liquid chromatographic (HPLC) method with accelerated solvent extraction (ASE)-solid phase extraction cleanup was developed for the determination of sulfonamide and sarafloxacin residues in pork and chicken muscle. Four residues were extracted with acetic acid-acetonitrile at 70°C under 10.3 MPa pressure and 5 min static times with 2 static cycles. The standard curves for the determination of four residues have good linearity (r>0.999). The method limits of quantification (LOQs) were 4-12 μg.kg-1. Intra- and inter-day precisions (RSDs) were 0.3-1.5% and 0.7-1.8%, respectively. Their average recoveries with four spiked levels ranged from 83% to 108% with the RSD of 0.3-1.5%. This method provides an effective extraction procedure and high sensitivity, and can be applied for the determination of 4 residual drugs in pork and chicken muscle at lower than their MRL levels.

Optimisation of supercritical fluid extraction of essential oil components of Diplotaenia cachrydifolia: Box–Behnken design

Essential oil of Diplotaenia cachrydifolia cultivated in Iran was obtained by supercritical fluid extraction (SFE) method. The oils were analysed by capillary gas chromatography using flame ionisation and mass spectrometric detections. The compounds were identified according to their retention indices and mass spectra (EI, 70 eV). The effects of different parameters, such as pressure, temperature, modifier volume and extraction times (dynamic and static), on the SFE were inspected by a fractional factorial design (25−2) to identify the significant parameters and their interaction. It showed that static and dynamic times had no effect on the extraction. Finally, a Box–Behnken design was applied to obtain the optimum condition of the significant parameters. The optimal condition was obtained as 30.2 MPa for pressure, 65.6°C for temperature and 258.4 µL for modifier volume. The main components that were extracted with SFE were dillapiole (35.1%), limonene (33.5%) and α-calacorene (25.5%).

Transpositionen ins Glück? Jáchym Topols Kurzroman „Anděl“

Abstract The novel “Anděl / Angel Station” delivers an another example of the unusual writing style of the Czech author Jáchym Topol after “Sestra / City Sister Silver”. In his early narratives the author deals with the harrowing times after 1991 not only thematically, but also on a structural and linguistic level. This troubling thriller, driven by the search for happiness in threatening static times, unfolds into an allegory – and proclaims a story of salvation both psychedelic and from an “unreliable” perspective. The paper shows how this allegory is produced through a specific poetic of transpositions, by examples of displacement figures on the spatio-temporal level, on the level of motifs and the specific development of the story. In doing so, a glance is cast on the changes that are made through translation (drawing on the example of the German translation) and by transferring the novel to other media (here, above all, the resulting film).

Recent Salmon Declines: A Result of Lost Feeding Opportunities Due to Bad Timing?

As the timing of spring productivity blooms in near-shore areas advances due to warming trends in global climate, the selection pressures on out-migrating salmon smolts are shifting. Species and stocks that leave natal streams earlier may be favoured over later-migrating fish. The low post-release survival of hatchery fish during recent years may be in part due to static release times that do not take the timing of plankton blooms into account. This study examined the effects of release time on the migratory behaviour and survival of wild and hatchery-reared coho salmon (Oncorhynchus kisutch) using acoustic and coded-wire telemetry. Plankton monitoring and near-shore seining were also conducted to determine which habitat and food sources were favoured. Acoustic tags (n = 140) and coded-wire tags (n = 266,692) were implanted into coho salmon smolts at the Seymour and Quinsam Rivers, in British Columbia, Canada. Differences between wild and hatchery fish, and early and late releases were examined during the entire lifecycle. Physiological sampling was also carried out on 30 fish from each release group. The smolt-to-adult survival of coho salmon released during periods of high marine productivity was 1.5- to 3-fold greater than those released both before and after, and the fish's degree of smoltification affected their downstream migration time and duration of stay in the estuary. Therefore, hatchery managers should consider having smolts fully developed and ready for release during the peak of the near-shore plankton blooms. Monitoring chlorophyll a levels and water temperature early in the spring could provide a forecast of the timing of these blooms, giving hatcheries time to adjust their release schedule.

Analysis of essential oil of Zhumeria majdae extracted by SFE

Traditional methods for isolating essential oils from plant materials, such as steam distillation and solvent extraction have some draw backs due to the heat instability of essential oil and the presence of residual organic solvent in the extract. Thus, the use of super critical fluid extractions (SFE) for extraction of essential oils has received increasing attention to this traditional techniques [1, 2]. An experimental flow-type apparatus has been designed for the extraction of the essential oil from Zhumeria majdae (Lamiaceae) with super critical carbon dioxide. In the present study, the operating conditions for extraction were conducted at the pressure of 200bar, the temperature of 37°C, the carbon dioxide rate of 0.3 liter per min, the dynamic extraction time of 20min with different static times of 30, 45 and 60min. Main compounds were found to be linalool (73.8, 72.5, 41.5%, respectively) after analysis by GC/MS with a HP5-MS column. In comparison with other samples obtained by hydro distillation, SFE oil (static times of 30, 45min) contains higher amount of linalool.

Supercritical fluid extraction combined with dispersive liquid–liquid microextraction as a sensitive and efficient sample preparation method for determination of organic compounds in solid samples

The supercritical fluid extraction (SFE) followed by the dispersive liquid–liquid microextraction (DLLME) has been developed for extraction and determination of polycyclic aromatic hydrocarbons (PAHs) in marine sediments. PAHs were employed as model compounds to assess the extraction procedure and were determined by gas chromatography–flame ionization detection (GC–FID). SFE of PAHs was performed at 313 K and 253.2 bar, at static and dynamic times 10 and 30 min, respectively. The extracted PAHs were collected in 1 mL of acetonitrile. Subsequently, 16 μL of chlorobenzene (as extraction solvent) was added to collecting solvent (1.0 mL of acetonitrile). Then, the resulted mixture was injected into 5.0 mL of aqueous solution, rapidly. After centrifugation, the PAHs in the sedimented phase were analyzed by GC–FID. Effects of significant parameters on the extraction in SFE and DLLME methods were investigated. Under the optimum conditions, the calibration plots were linear in the range of 0.4–41.6 mg kg −1 and the limits of detection (LODs) were 0.2 mg kg −1 for all of the analytes. Analysis of PAHs in different solid samples showed that the improved technique has great potential for PAHs analysis in marine sediments. SFE–DLLME leads to high preconcentration factor, easy use of DLLME in solid samples and solving the main problem of SFE that is the extra step (vaporization of large volume of toxic organic solvent) after extraction needed prior to final analysis.

Development of an Automated Processing Method to Detect Coronary Motion for Coronary Magnetic Resonance Angiography

On coronary MR angiography (CMRA), cardiac motions worsen the image quality. To improve the image quality, detection of cardiac especially for individual coronary motion is very important. Usually, scan delay and duration were determined manually by the operator. We developed a new evaluation method to calculate static time of individual coronary artery. At first, coronary cine MRI was taken at the level of about 3 cm below the aortic valve (80 images/R-R). Chronological change of the signals were evaluated with Fourier transformation of each pixel of the images were done. Noise reduction with subtraction process and extraction process were done. To extract higher motion such as coronary arteries, morphological filter process and labeling process were added. Using these imaging processes, individual coronary motion was extracted and individual coronary static time was calculated automatically. We compared the images with ordinary manual method and new automated method in 10 healthy volunteers. Coronary static times were calculated with our method. Calculated coronary static time was shorter than that of ordinary manual method. And scan time became about 10% longer than that of ordinary method. Image qualities were improved in our method. Our automated detection method for coronary static time with chronological Fourier transformation has a potential to improve the image quality of CMRA and easy processing.

The Effectiveness of an Unstable Sandal on Low Back Pain and Golf Performance

The objectives of this study were to assess the effect of unstable sandals on (1) low back pain (LBP) in golfers with undiagnosed moderate LBP, (2) static and dynamic balance, and (3) golf performance. This was a 6-week prospective study where subjects were randomized to a control group and an intervention group. Baseline measurements were recorded in the Human Performance Laboratory. Forty male golfers with nonspecific moderate LBP. The intervention group wore unstable shoes for 6 weeks, and the control group wore their regular golf shoes. Low back pain, timed balance, and golf performance were assessed at baseline and at 6 weeks. Changes were compared through independent samples t tests. (1) There was a significant difference between groups in the change of perceived LBP scores in the laboratory (test group: -17.5/100 mm, control: -3.6/100 mm) and in the comparison of the first week entries to the last week entries recorded in logbooks (test group: -10.7/100 mm, control group: +2.6/100 mm). (2) There was no significant change in the static or dynamic balance times. (3) There was no significant change in golf performance between the intervention and control groups. The results indicate that unstable sandals can be used to reduce moderate lower back pain in this population of golfers without negatively affecting performance.

Skill Acquisition While Operating In-Vehicle Information Systems: Interface Design Determines the Level of Safety-Relevant Distractions

This study tested whether the ease of learning to use human-machine interfaces of in-vehicle information systems (IVIS) can be assessed at standstill. Assessing the attentional demand of IVIS should include an evaluation of ease of learning, because the use of IVIS at low skill levels may create safety-relevant distractions. Skill acquisition in operating IVIS was quantified by fitting the power law of practice to training data sets collected in a driving study and at standstill. Participants practiced manual destination entry with two route guidance systems differing in cognitive demand. In Experiment 1, a sample of middle-aged participants was trained while steering routes of varying driving demands. In Experiment 2, another sample of middle-aged participants was trained at standstill. In Experiment 1, display glance times were less affected by driving demands than by total task times and decreased at slightly higher speed-up rates (0.02 higher on average) than task times collected at standstill in Experiment 2. The system interface that minimized cognitive demand was operated more quickly and was easier to learn. Its system delays increased static task times, which still predicted 58% of variance in display glance times compared with even 76% for the second system. The ease of learning to use an IVIS interface and the decrease in attentional demand with training can be assessed at standstill. Fitting the power law of practice to static task times yields parameters that predict display glance times while driving, which makes it possible to compare interfaces with regard to ease of learning.

Measurement of creep of optical fiber by a low coherent white light double interferometer system

The creep properties of optical fiber used in fiber optical sensors were studied in this paper. A low coherent white light double interferometer system was designed and calibrated and the creep deformations of optical fibers under static and cyclic loadings were measured with this device. The research results showed that polymer coated optical fibers crept at the beginning when they were under static or cyclic load. As the number of the cyclic loading or the static loading times increased the creep tended to stop. Thus to ensure that the optical fiber keeps pre-stress for long time in pressure transducer, it is recommended that the optical fiber should be tensioned cyclically before being fixed into the sensor device.

Uncertainty analysis in statics corrections obtained by tomographic inversion: Application in a mountainous zone in Catatumbo (Colombia)

Seismic tomography techniques are frequently used to obtain velocity models of the weathering layer, which are then used to calculate static corrections times. The main idea in tomography is to use the misfit between synthetic and observed first-arrival (refraction) times to correct an initial velocity model. Due to the nature of the seismic method where, in general, sources and receivers are placed on only one edge of the medium, the Earth surface, it can be shown that inverting for velocities using the observed times does not give a unique solution. Instead, a family of solutions is obtained that explains the same data set. To give a meaning to a nonunique solution, uncertainty analysis techniques are necessary. They can give information about the family of solutions such as which zones have a larger error, which zones are better resolved, is there a dispersion measurement (such as variance) associated with the solution model family, and is there a more probable solution model. To give clues to the answ...

Carotenoid extraction from the gonad of the scallop Nodipecten nodosus (Linnaeus, 1758) (Bivalvia: Pectinidae)

In marine bivalve mollusks, unsaturated molecules called carotenoids are present in the natural diet and play an important role in different biological process, especially in reproduction. In order to gain more insights into these compounds in Nodipecten nodosus it was necessary to develop a suitable protocol for extraction of carotenoids from the gonads. Female gonads of cultured scallops (75 mm length) were lyophilized and macerated in liquid N2. To verify the effect of composition in organosolvents on the extracting solutions, two organic solvents were tested: acetone and hexane (Ac = O:Hex) at four ratios, 1:1, 1:3, 1:5, and 2:3, in four static extraction times: 0, 5, 10, and 15 minutes. Total carotenoids and astaxanthin contents were determined in the crude extracts by UV-visible spectrophotometry and high performance liquid chromatography (HPLC), respectively. Triplicate aliquots of 50 mg were used for each treatment. The results indicated that the best single extraction (0.312 +/- 0.016 microg carotenoids/mg) was attained with Ac = O: Hex 1:3, for 15 minutes. Through exhaustive extraction methodology (10x), a superior yield (0.41 +/- 0.001 microg carotenoids/mg) was obtained from a gonad sample in comparison to the highest value found for a single extraction. Astaxanthin content was reduced by 8.6% in carotenoid extract preservation assay, i.e., -18 degrees C, 26 days incubation, under N2 atmosphere.

Effect of Various Parameters on the Selective Extraction of Main Components from Hyssop Using Supercritical Fluid Extraction (SFE)

The essential oil from the aerial parts of hyssop (Hyssopus officinalis L.) from Iran was extracted using both hydrodistillation (HD) and supercritical fluid extraction (SFE) methods. SFE was performed at various pressures, temperatures, extraction (dynamic and static) times and modifier (methanol) concentrations using an orthogonal array design with an OA25(55) matrix conditions. Using GC-MS, 22 components were characterized in the oil extracted by HD. The data obtained from this study suggest that hyssop collected from Iran could be a special chemotype with a high sabinene concentration (11.04%). Major compounds identified when using SFE were sabinene, pinocamphene and iso-pinocamphene, which were extracted at different levels when applying different operational conditions. The highest selectivity of sabinene was obtained at 100 atm, 55°C, with 1.5 µL (0.05%, w/w) methanol, dynamic extraction time of 30 min and static extraction time of 35 min. Also, the highest selectivity of pinocamphene and iso-pinocamphene were obtained at 100 atm, 45°C, with 4.5 µL (0.14%, w/w) methanol, dynamic extraction time of 20 min and static extraction time of 25 min.

A remark about static space times

We discuss a differential equation, whose unknowns are a function and a Riemannian metric. This equation occurs both in general relativity (static space times) and in the study of the space of Riemannian metrics on a manifold (singularities of the map from the space of metrics into the space of functions, which assigns to any metric its scalar curvature).

Waiting and Buffering Strategies for the Dynamic Pickup and Delivery Problem with Time Windows

We investigate the impact of two strategies for dynamic pickup and delivery problems on the quality of solutions produced by insertion heuristics: (a) a waiting strategy that delays the final assignment of vehicles to their next destination, and (b) a request buffering strategy that postpones the assignment of some non-urgent new requests to the next route planning. In this study, the strategies are tested in a constructive-deconstructive heuristic for the dynamic pickup and delivery problem with hard time windows and random travel times. Comparisons of the solution quality provided by these strategies to a more conventional approach were performed on randomly generated instances up to 100 requests with static and dynamic (time-dependent) travel times and different degrees of dynamism. The results indicate the advantages of the strategies both in terms of lost requests and number of vehicles.

Determination of 252–302 Da and tentative identification of 316–376 Da polycyclic aromatic hydrocarbons in Standard Reference Materials 1649a Urban Dust and 1650b and 2975 Diesel Particulate Matter by accelerated solvent extraction–HPLC-GC-MS

We have assessed and compared the extraction recoveries of polycyclic aromatic hydrocarbons (PAHs) with molecular weights of 252, 276, 278, 300 and 302 from diesel particulate matter (PM) and urban air particles using ultrasonically assisted extraction and accelerated solvent extraction methods, and evaluated the effects of sample and treatment parameters. The results show that accelerated solvent extraction can extract PAHs more efficiently from diesel PM than ultrasonically assisted extraction. They also show that PAHs are more difficult to extract from diesel PM than from urban air particles. Using toluene and maximum instrumental settings (200 degrees C, 3,000 psi and five extraction cycles) with 30-min static extraction times > 85% of the analytes were estimated to be extracted from the diesel particles, but four extraction cycles with just 5-min static extraction times under these conditions seem to be sufficient to extract > 95% of the analytes from the urban air particles. The accelerated solvent extraction method was validated using the Standard Reference Materials (SRM) 1649a, Urban Dust, and SRM 2975 and SRM 1650a, Diesel Particulate Matter, from the US National Institute of Standards and Technology (NIST). PAH concentrations determined by on-line high-performance liquid chromatography-gas chromatography-mass spectrometry (HPLC-GC-MS) following the developed accelerated solvent extraction method were generally higher than the certified and reference NIST values and concentrations reported in the literature (e.g. the estimated concentration of benzo[a]pyrene in SRM 2975 was 15-fold higher than the NIST-certified value), probably because the extraction recoveries were higher than in previous studies. The developed accelerated solvent extraction method was used to analyse high molecular (HMW) weight PAHs (MW > 302) in the investigated SRMs, and more than 170 (SRM 1649a), 80 (SRM 1650b) and 60 (SRM 2975) potential high molecular weight PAHs were tentatively identified in them, with molecular weights (depending on the SRM sample analysed) of 316, 326, 328, 340, 342, 350, 352, 366, 374 and 376. This is, to our knowledge, the first study to tentatively report PAHs with molecular weights of 316, 326, 328, 342, 350, 352, 366 and 376 in diesel particulate matter. GC-MS chromatograms obtained in selected ion monitoring mode (extracted ions for the abovementioned m/z) and full-scan mass spectra of tentatively identified high molecular weight PAHs are shown in the Electronic supplementary material.

Ricci Symmetries of Static Space-Times with Maximal Symmetric Transverse Spaces

In the paper [M. Akbar and R.G. Cai, Commun. Theor. Phys. 45 (2006) 95], a complete classification is provided with at least one component of the vector field V is zero. In this paper, I consider the vector field V with all non-zero components and the static space times with maximal symmetric transverse spaces are classified according to their Ricci collineations. These are investigated for non-degenerate Ricci tensor det R ≠ 0. It turns out that the only collineations admitted by these spaces can be ten, seven, six or four. It also covers our previous results as a spacial case. Some new metrics admitting proper Ricci collineations are also investigated.