On the volumetric strain–time curve patterns of dredged clays during primary consolidation

Géotechnique ◽  
2015 ◽  
pp. 1-6 ◽  
Author(s):  
L.-L. Zeng ◽  
Z.-S. Hong ◽  
Y.-J. Cui
Géotechnique ◽  
2015 ◽  
Vol 65 (12) ◽  
pp. 1023-1028 ◽  
Author(s):  
L.-L. Zeng ◽  
Z.-S. Hong ◽  
Y.-J. Cui

2018 ◽  
Vol 192 ◽  
pp. 02029
Author(s):  
Takahiro Yoshidomi ◽  
Koichi Iinuma ◽  
Motohiro Sugiyama

In this study, we conducted a stage loading consolidation test with varying load increment ratio and investigated its effect. By adjusting the primary consolidation ratio of one-dimensional consolidation analysis with secondary consolidation taken into account, it is possible to reproduce the consolidation amount-time curve affected by the load increment ratio.


2007 ◽  
Vol 12 (3) ◽  
pp. 4-7
Author(s):  
Charles N. Brooks ◽  
Christopher R. Brigham

Abstract Multiple factors determine the likelihood, type, and severity of bodily injury following a motor vehicle collision and, in turn, influence the need for treatment, extent of disability, and likelihood of permanent impairment. Among the most important factors is the change in velocity due to an impact (Δv). Other factors include the individual's strength and elasticity, body position at the time of impact, awareness of the impending impact (ie, opportunity to brace, guard, or contract muscles before an impact), and effects of braking. Because Δv is the area under the acceleration vs time curve, it combines force and duration and is a useful way to quantify impact severity. The article includes a table showing the results of a literature review that concluded, “the consensus of human subject research conducted to date is that a single exposure to a rear-end impact with a Δv of 5 mph or less is unlikely to result in injury” in most healthy, restrained occupants. Because velocity incorporates direction as well as speed, a vehicular occupant is less likely to be injured in a rear impact than when struck from the side. Evaluators must consider multiple factors, including the occupant's pre-existing physical and psychosocial status, the mechanism and magnitude of the collision, and a variety of biomechanical variables. Recommendations based solely on patient history and physical findings (and, perhaps, imaging studies) may be ill-informed.


Author(s):  
Trần Thanh Nhàn

In order to observe the end of primary consolidation (EOP) of cohesive soils with and without subjecting to cyclic loading, reconstituted specimens of clayey soils at various Atterberg’s limits were used for oedometer test at different loading increments and undrained cyclic shear test followed by drainage with various cyclic shear directions and a wide range of shear strain amplitudes. The pore water pressure and settlement of the soils were measured with time and the time to EOP was then determined by different methods. It is shown from observed results that the time to EOP determined by 3-t method agrees well with the time required for full dissipation of the pore water pressure and being considerably larger than those determined by Log Time method. These observations were then further evaluated in connection with effects of the Atterberg’s limit and the cyclic loading history.


2020 ◽  
Author(s):  
Lungwani Muungo

Vaginal microbicides for the prevention of HIV transmission maybe an important option for protecting women from infection.Incorporation of dapivirine, a lead candidate nonnucleoside reversetranscriptase inhibitor, into intravaginal rings (IVRs) for sustainedmucosal delivery may increase microbicide product adherence andefficacy compared with conventional vaginal formulations. Twentyfourhealthy HIV-negative women 18–35 years of age were randomlyassigned (1:1:1) to dapivirine matrix IVR, dapivirine reservoir IVR,or placebo IVR. Dapivirine concentrations were measured in plasmaand vaginal fluid samples collected at sequential time points over the33-day study period (28 days of IVR use, 5 days of follow-up). Safetywas assessed by pelvic/colposcopic examinations, clinical laboratorytests, and adverse events. Both IVR types were safe and well toleratedwith similar adverse events observed in the placebo and dapivirinegroups. Dapivirine from both IVR types was successfully distributedthroughout the lower genital tract at concentrations over 4 logs greaterthan the EC50 against wild-type HIV-1 (LAI) in MT4 cells. Maximumconcentration (Cmax) and area under the concentration–time curve(AUC) values were significantly higher with the matrix than reservoirIVR. Mean plasma concentrations of dapivirine were ,2 ng/mL.These findings suggest that IVR delivery of microbicides is a viableoption meriting further study.Key Words: dapivirine, HIV, intravaginal ring, microbicide,pharmacokinetics, prevention


1992 ◽  
Vol 25 (10) ◽  
pp. 149-162 ◽  
Author(s):  
V. L. Pillay ◽  
C. A. Buckley

Cross-flow microfiltration (CFMF) has potentially wide application in the processing of industrial and domestic waste waters. Optimum design and operation of CFMF systems necessitates a knowledge of the characteristic system behaviour, and an understanding of the mechanisms governing this behaviour. This paper is a contribution towards the elucidation and understanding of the behaviour of a woven fibre CFMF operated in the turbulent flow regime. The characteristic flux-time curve and effects of operating variables on flux are presented for a limestone suspension cross-flow filtered in a 25 mm woven fibre tube. The phenomena contributing to the shape of the flux-time curve are discussed. A model of the mechanisms governing cake growth and limit is presented. Predicted steady-state fluxes show a notably good correspondence with experimentally measured values. It is also found that the flux may not be uniquely defined by the operating conditions, but may also be a function of the operating path taken to reach the operating point. This is of significance in the start-up and operation of CFMF units.


2020 ◽  
Vol 21 (6) ◽  
pp. 471-478
Author(s):  
Shenjia Huang ◽  
Qingqing Xu ◽  
Linsheng Liu ◽  
Yicong Bian ◽  
Shichao Zhang ◽  
...  

Background: Green tea can inhibit OATPs, so it may interact with the substrate of OATPs, such as rosuvastatin. Objective: This study aimed to investigate the effects of green tea on the pharmacokinetics of rosuvastatin and its mechanism. Methods: Male Sprague-Dawley rats received different doses of green tea extract (GTE) and (-)- epigallocatechin-3- gallate (EGCG). Caco-2 cells and OATP1B1-HEK293T cells were used in drug uptake and transport assay. The matrix concentrations of rosuvastatin and catechins were determined by ultra-performance liquid chromatographytandem mass spectrometry (UPLC-MS/MS). Results: GTE and EGCG were both found to increase the area under the plasma concentration-time curve (AUC0-∞) of rosuvastatin ((p<0.050). In the Caco-2 cell model, the uptake and transport of rosuvastatin in the GTE groups were 1.94-fold (p<0.001) and 2.11-fold (p<0.050) higher, respectively, than those of the control group. However, in the EGCG group, the uptake and transport of rosuvastatin were decreased by 22.62% and 44.19%, respectively (p<0.050). In the OATP1B1- HEK293T cell model, the OATP1B1-mediated rosuvastatin uptake was decreased by GTE to 35.02% of that in the control (p<0.050) and was decreased by EGCG to 45.61% of that in the control (p<0.050). Conclusion: GTE increased the systemic rosuvastatin exposure in rats. The mechanism may include an increase in rosuvastatin absorption and a decrease in liver distribution by inhibiting OATP1B1. EGCG may be the main ingredient of green tea that affects the pharmacokinetic parameters of rosuvastatin. Our results showed the importance of conducting green tea-rosuvastatin study.


2020 ◽  
Vol 17 (2) ◽  
pp. 140-147
Author(s):  
Karna B. Ghimirey ◽  
Kevin Ita

Objective: In vitro diffusion experiments were performed to assess the permeation of magnesium sulfate across pig skin. Method: The mean thickness of the dermatomed porcine skin was 648 ± 12 µm. Magnesium concentration was measured using inductively coupled plasma-optical emission spectroscopy. Transdermal flux of magnesium sulfate across MN-treated and untreated porcine skin was obtained from the slope of the steady-state linear portion of cumulative amount versus time curve. Results: Statistical analysis of the results was done with Student’s t-test. The transdermal flux of magnesium sulfate across microneedle-treated porcine skin was 134.19 ± 2.4 µg/cm2/h and transdermal flux across untreated porcine skin was 4.64 ± 0.05 µg/cm2/h. Confocal microscopy was used to visualize the microchannels created by a solid microneedle roller (500 µm). Conclusion: From our confocal microscopy studies, it was evident that the 500 μm long microneedles disrupted the stratum corneum and created microchannels measuring 191 ± 37 µm. The increase in transdermal flux across the microneedle-treated skin was statistically significant compared to that of controls, i.e., without the application of microneedles. With the application of microneedles, the transdermal flux of magnesium permeated over 12 h was approximately 33-fold higher in comparison to passive diffusion across an intact stratum corneum.


2019 ◽  
Vol 15 (4) ◽  
pp. 338-345
Author(s):  
Lijun Ni ◽  
Lu Ding ◽  
Liguo Zhang ◽  
Shaorong Luan

Background: Tong-Bi-Si-Wei-Fang (TBSWF) is a candidate formula of Traditional Chinese Medicine (TCM) for treating rheumatoid bone diseases, which is composed of rhizoma corydalis alkaloids, saponins of glycyrrhiza uralensis and panax notoginseng, flavonoids of rhizoma drynariae and glycyrrhiza uralensis. </P><P> Objective: Trahydropalmatine (THP), the main active ingredient of rhizoma corydalis alkaloids, was selected to study in vivo pharmacokinetics and druggability of TBSWF. Methods: The plasma concentration-time (C-T) profiles of THP and the pharmacokinetic property parameters after oral administration of THP monomer, extract of corydalis alkaloids (ECA) and TBSWF to rats, respectively were compared by a fully-validated HPLC method. Results: Compared to the THP monomer, the THP in TBSWF is absorbed faster, resides in the plasma longer and has a similar apparent volume of distribution Vz/F (10~20 L/kg). Compared to THP monomer and THP in TBSWF, the area under the concentration-time curve AUC 0-t of THP in ECA decreases two-third; Vz/F of THP in ECA (85.02 L/kg) is significantly higher than that of THP in TBSWF(p <0.05). Unlike THP monomer and THP in ECA, double peaks are observed in the C-T profile of THP after oral administration of TBSWF. THP in TBSWF exhibits slow release to a certain degree. Conclusion: The interactions among the ingredients of TBSWF promote the adsorption and prolong the residence time of THP in vivo, and provide an explanation for the advantages of TBSWF from the point of pharmacokinetics.


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