Diversity in Shareholder Protection in Common Law Countries

Aktionär, Anlegerschutz, Common Law, Shareholders, Investor protection

FRAP Analysis: Accounting for Bleaching during Image Capture

The analysis of Fluorescence Recovery After Photobleaching (FRAP) experiments involves mathematical modeling of the fluorescence recovery process. An important feature of FRAP experiments that tends to be ignored in the modeling is that there can be a significant loss of fluorescence due to bleaching during image capture. In this paper, we explicitly include the effects of bleaching during image capture in the model for the recovery process, instead of correcting for the effects of bleaching using reference measurements. Using experimental examples, we demonstrate the usefulness of such an approach in FRAP analysis.Molecular and Cellular Biolog

Non-linear mechanical behavior of polydimethylsiloxane (PDMS): application to the manufacture of microfluidic devices

Soft-lithography is a low-cost and convenient microfabrication technique that is becoming increasingly popular in the manufacture of microfluidic devices. A typical elastomer used in soft-lithography is polydimethylsiloxane (PDMS), an organic polymer that is commercially available, inexpensive, optically transparent, permeable to gases, and nontoxic. For soft-lithography to become a viable microfabrication technique for the commercial manufacture of microfluidic devices, several issues concerning the mechanical behavior of this material must be considered and addressed. We are currently working on the following materials-related issues that are critical to the development of this process for mass production: •Multilayer microfluidic devices are made by layering thin films having alternating ratios of monomer to curing agent, in order to facilitate bonding between the layers. Common mixing ratios of monomer to curing agent are 5:1, 10:1, and 20:1. Characterization of the mechanical behavior of these materials with different compositions is necessary in the design of these devices. We have conducted uniaxial tension tests at the macroscale and found that the monomer-to-curing agent ratio contributes significantly to the non-linear stress-strain behavior of PDMS (see adjoining figure). We are working on uniaxial tension tests on microscale specimens which are approximately 10 µm thick and have a gauge width of 1 mm; this smaller scale is representative of actual dimensions in microfluidic devices. •The fabrication of microfluidic devices involves curing the mixture of PDMS monomer and curing agent on a mold. Currently, a cast layer is peeled off the mold slowly by hand, being careful not to tear the material. We shall work on modeling the PDMS-substrate interface decohesion response to facilitate the design of an automated demolding process. To simulate the demolding of the PDMS during fabrication, we plan to conduct peel experiments of PDMS at various stages of cure from silicon, plastic, glass and other substrates that are commonly used; and using the experimental results, determine parameters for interface constitutive models for use in failure prediction during demolding. •We shall conduct experimental and numerical studies to optimize the design parameters, like the thickness of different layers, composition of materials used, and geometry of microchannels for microfluidic devices. The layers within a multilayer microfluidic device appear to bond irreversibly, but the strength of the bond is not understood. We plan to conduct peel experiments to test the bond between different PDMS layers of different compositions. The channels within the microfluidic devices are usually pressurized during actuation, so we also plan to conduct blister tests to understand the interface failure behavior between the different layers of a device. •Reliability of these devices is an issue that has not been addressed. All devices are currently made in a laboratory environment, and the limits of pressure magnitude and cyclic frequency of these devices have not been explored. We plan to experimentally study the fatigue behavior of these devices, and develop appropriate guidelines for reliable use of these devices.Singapore-MIT Alliance (SMA

Stacking faults in double hexagonal close-packed crystals

Possible deviations in the regular ....ABACA.... sequence of stacking (0004) close-packed planes in the double hexagonal close-packed (d.h.c.p.) structure have been considered. Six intrinsic and one extrinsic type stacking faults have been suggested. The schemes of stacking sequences have been usefully considered in terms of the configurational symbols suggested by Jagodzinski. Extending the Hirth and Lothe procedure, estimates of theoretical fault energies are given in terms of the number of pairs of planes of separation N which are not in the shceme of perfect structure sequence. Relative fault energies have been arrived at reckoning only the first and second nearest neighbour interactions for three ideal situations: (a) the transformation energy of d.h.c.p. structure to either f.c.c. or h.c.p. structure is the same; (b) d.h.c.p. ⇌ f.c.c. transformation occurs; and (c) d.h.c.p. ⇌ h.c.p. transformation occurs

Colloidal diffusion and hydrodynamic screening near boundaries

The hydrodynamic interactions between colloidal particles in small ensembles are measured at varying distances from a no-slip surface over a range of inter-particle separations. The diffusion tensor for motion parallel to the wall of each ensemble is calculated by analyzing thousands of particle trajectories generated by blinking holographic optical tweezers and by dynamic simulation. The Stokesian Dynamics simulations predict similar particle dynamics. By separating the dynamics into three classes of modes: self, relative and collective diffusion, we observe qualitatively different behavior depending on the relative magnitudes of the distance of the ensemble from the wall and the inter-particle separation. A simple picture of the pair-hydrodynamic interactions is developed, while many-body-hydrodynamic interactions give rise to more complicated behavior. The results demonstrate that the effect of many-body hydrodynamic interactions in the presence of a wall is much richer than the single particle behavior and that the multiple-particle behavior cannot be simply predicted by a superposition of pair interactions

Enhancement of reactivity and increased usage of low lime class -F-fly ash-possible avenues

The low lime class-F fly ash available in the country shows high degree of variability in the quality, higher content of crystallites , lower glassy phase which accounts for lower of usage in cement and concrete . The time reactivity test used for assessing the pozzolanicity of fly ash did not always correlate with its observed reactivity in Blended cements . An alternative rapid alkali reactivity rest developed at the authors ' laboratory is illustrated in the paper. The paper also discusses the possibility of increasing the reactivity of fly ash and effect of the reactive fly ash on characteristics of PPC and concrete. The paper further discusses other avenues of fly ash utilisation, which could be categorised as low, medium and high value applications. One of such applications developed at the authors ' laboratory that merits special interest, is the Hydrogel process of clinkerisation , which has a potential for utilisation of 20-30% fly ash as a raw material in cement manufacture

Role of pressure diffusion in non-homogeneous shear flows

A non-local model is presented for approximating the pressure diffusion in calculations of turbulent free shear and boundary layer flows. It is based on the solution of an elliptic relaxation equation which enables local diffusion sources to be distributed over lengths of the order of the integral scale. The pressure diffusion model was implemented in a boundary layer code within the framework of turbulence models based on both the kappa-epsilon-(bar)upsilon(exp 2) system of equations and the full Reynolds stress equations. Model computations were performed for mixing layers and boundary layer flows. In each case, the pressure diffusion model enabled the well-known free-stream edge singularity problem to be eliminated. There was little effect on near-wall properties. Computed results agreed very well with experimental and DNS data for the mean flow velocity, the turbulent kinetic energy, and the skin-friction coefficient

Non-descent vaginal hysterectomy in women with previous caesarean section scar: our experience

Background: Hysterectomy is one of the common gynaecological major surgeries performed worldwide. In spite of technological advancement with laparoscopic and robotic hysterectomy conventional hysterectomy through vaginal route of nonprolapse uterus popularly known as, Non-Descent Vaginal Hysterectomy (NDVH) remains a justifiable cost effective, cosmetically appealing option especially in resource-crunched developing country. NDVH in post caesarean scarred uterus too a technically challenged procedure requiring skills and expertise.Assessment of technical feasibility and safety of non-descent vaginal hysterectomy in women with previous caesarean section scar were studied.Methods: The study was a prospective observational study of 72 patients with LSCS scar requiring hysterectomy for benign conditions were selected based on the inclusion and exclusion criteria carried out from June 2012 to May 2017. Operating time, blood loss, surgical techniques, intra/postoperative challenges, conversion to laparotomy or laparoscopic assistance and length of hospital stay were recorded for each case. Patients were followed up till 03 months of surgery.Results: Vaginal hysterectomy was successful in all cases. Morcellation, bisection or myomectomy, were done in 86% cases. Two patients had bladder injury, which was repaired vaginally, two cases required support of laparoscopy.  No patients needed blood transfusion. None of the patients were converted to laparotomy.Conclusions: Vaginal hysterectomy is a safe and effective procedure for benign non-prolapsed uteri in women with previous caesarean section scar when uterine size is less than 14 weeks. Standby operating laparoscopy provides added advantages to surgeon in doubtful or difficult cases to avoid conversion laparotomy

Evaluation of Noise Radiation Mechanisms in Turbulent Jets

Data from the direct numerical simulation (DNS) of a turbulent, compressible (Mach = 1.92) jet has been analyzed to investigate the process of sound generation. The overall goals are to understand how the different scales of turbulence contribute to the acoustic field, and to understand the role that linear instability waves play in the noise produced by supersonic turbulent jets. Lighthill’s acoustic analogy was used to predict the radiate sound from turbulent source terms computed from the DNS data. Preliminary computations (for the axisymmetric mode of the acoustic field) showgood agreement between the acoustic field determined from DNS and acoustic analogy. Further work is needed to refine the calculations and investigate the source terms. Work was also begun to test the validity of linear stability wave models of sound generation in supersonic jets. An adjoint-based method was developed to project the DNS data onto the most unstable linear stability mode at different streamwise positions. This will allow the evolution of the wave and its radiated acoustic field, determined by solving the linear equations, to be compared directly with the evolution of the near and far-field fluctuations in the DNS