Laser-generated stress waves and their effects on the cell membrane

High-power lasers can generate well characterized stress (pressure) waves. The characteristics of the stress waves can be controlled by the appropriate choice of the laser parameters and the properties of the target material. Laser-generated stress waves can alter the structure and function of cells in vitro. Furthermore, they render the cell membrane permeable. Molecules present in the extracellular medium diffuse into the cytoplasm under the concentration gradient. Subsequently, the plasma membrane reseals, keeping the exogenous molecules inside the cell. Laser-generated stress waves can provide a potentially powerful tool for drug delivery     

On the design and fabrication by two-photon polymerization of a readily assembled micro-valve

This paper reports on the conceptual design and fabrication of a complex shape, readily assembled micro check valve using the two-photon polymerization technique. The material used for the fabrication of the valve is a zirconium containing organic–inorganic hybrid photosensitive sol-gel known to exhibit negligible distortion during photopolymerization. A preliminary computational fluid dynamics study has been carried out in order to evaluate the flow performance of the valve under blood pressures exhibited in healthy human veins. The fabricated micro-valves exhibit good dimensional accuracy when compared to the CAD-created valve design and the capability of an internal moving component to perform its intended function.     

Numerical studies on the effect of plan irregularities in the progressive collapse of steel structures

This research examines the effect of plan irregularities on the progressive collapse of four steel structures located in regions with different seismic activity. The plans of the first and second structure are irregular, whilst those of the third and fourth structures are regular. The collapse patterns of the four buildings are examined and compared under seven loading scenarios using non-linear dynamic and static analyses. In the non-linear dynamic analyses, node displacements above the removed columns and the additional force on the columns adjacent to them are discussed. Furthermore, the strength and capacities of the columns are compared to determine their susceptibility to collapse. In the non-linear static analyses, the pushdown curve and yield load factor of the structures are obtained after column removal. The results indicate that an irregular structure designed in site class C seismic zone, collapses in most of the column-removal scenarios. Moreover, when comparing regular and irregular structures designed in site class E seismic zone, the demand force to capacity ratio (D/C) of the columns in the irregular structures is on average between 1.5 and 2 times that of the regular ones.     

Sustainable energy technologies in Israel under the CDM: Needs and prospects

The complexities related to the Clean Development Mechanism (CDM) are considered quite high and only a relatively low percentage of the existing potential has been exploited in the developing world. Israel obtains a significant unexploited potential, especially regarding Renewable Energy Sources (RESs) and Energy Efficiency (ENEF). In order to be able to identify potential CDM projects and to formulate a series of possible investment strategies with a CDM component, it is crucial to establish a clear understanding of the host country's needs and priorities, the suitable sustainable energy technologies, as well as their related potential benefits and barriers. The paper presents results obtained from an elaborated stakeholders' assessment on potential of sustainable energy technologies under the CDM conducted in Israel.     

Interactions between bacterial isolates from modified-atmosphere-packaged artisan-type cooked ham in view of the development of a bioprotective culture

Growth and metabolite production of three dominant bacterial isolates (Carnobacterium divergens 3M14, Leuconostoc carnosum 3M42, and Brochothrix thermosphacta RMS6) from modified-atmosphere-packaged (MAP), artisan-type cooked ham were assessed for their interactions in view of the development of a bioprotective culture. During monoculture experiments in cooked ham simulation medium, Leuc. carnosum 3M42 converted the available glucose into lactic acid and ethanol, whereas the two other strains produced additional metabolites such as acetic acid and 3-methyl-1-butanol. When grown in co-culture, Leuc. carnosum 3M42 suppressed the growth and metabolism of B. thermosphacta RMS6. In contrast, a co-culture of the latter bacterium with C. divergens 3M14 led to a variety of spoilage-related metabolic compounds. Subsequently, experiments with a commercial cooked ham product indicated that Leuc. carnosum 3M42 dominated the meat matrix and improved acceptability of the product over time, hence acting as a bioprotective culture for MAP, artisan-type cooked ham.     

拱桥的平面内屈曲性能研究

对系杆拱桥进行有限元建模,分析拱的平面内屈曲长度系数,并将其与EC3中推荐的数值进行比较。首先简要介绍了EC3中针对拱的平面内屈曲性能提出的分析方法。随后说明了系杆拱桥的模型、桥梁特性和计算方法,并进行了参数分析。同时也对拉索损坏的情况进行了讨论。最后归纳了研究结论。     

A Small Area Charge Sensitive Readout Chain with a Dual Mode of Operation

A charge sensitive readout chain has been designed and fabricated in acommercially available 0.8 m CMOS technology. The readout chain is optimizedfor pixel detectors measuring soft X-ray energies up to 20 KeV. In the first modean analog signal proportional to input charge is generated and processed in realtime. In the second mode a peak-and-hold operation is enabled and therelevant signal is processed in later time. This dual mode of operation iscontrolled by an external digital signal. The readout chain consists of a chargeamplifier, a shaper, an operational amplifier which can either operate as avoltage amplifier or a peak detector and an output buffer. Its area is . The gain at the shaper output is 378 mv/fC, theENC is 16 rms at 160 nsec shaping time. The overall gainis 557 mV/fC, the ENC is rms with 240 nsec peaking timeand 1.4 sec recovery time. The overall power dissipation is 1.5 mWatt with aload capacitance of 25 pF.     

Automatic derivation of BPEL4WS from IDEF0 process models

Integration definition for function modelling (IDEF0) is one of the most popular notations for modelling business processes. It employs a rather simple and intuitive modelling construct, consisting of boxes representing functions and arrows connecting them signifying flow of information and materials. Web services on the other hand are an emerging technology for implementing distributed systems. Web service orchestration languages, such as Business Process Execution Language for Web Services (BPEL4WS), are the emerging approach for describing processes as networks of coordinated web services. Business processes as captured in IDEF0 models, however, may contain both web services as well as other types of activities which need to be coordinated. By automatically analysing the Extensible Markup Language (XML) definition of an IDEF0 model, we can identify how web services interact with other activities and at runtime generate code to support the orchestration of web services with the overall business process. The approach proposed is independent of the orchestration language and ensures an implementation independent model for specifying web service orchestrations. This approach also enables the top-down analysis of a business process to its constituent web services and avoids any misalignment problems during design time between the two.     

Linear micropolar elastic crack-tip fields under mixed mode loading conditions

Micropolar elasticity laws provide a possibility to describe constitutive properties of materials for which internal length scales may become important. They are characterized by the presence of couple stresses and nonsymmetric Cauchy stress tensor. Beyond the classical displacement field, the kinematical variables are augmented by a so-called microrotation field and its gradient, the latter introducing an internal length scale in the theory. For an isotropic, linear micropolar elastic material, the near-tip asymptotic field solutions for mode I and mode II cracks are derived. It is shown that these solutions behave similar to those according to the so-called couple stress theory, which has been investigated by Huang et al. (1997a), or similar to those derived for cellular materials by Chen et al. (1998). In particular, the singular fields have an order of singularity r ^–1/2 and are governed by some amplitude factors, having the meaning of stress intensity factors as in the classical linear elastic theory. The effect of material parameters on the stress intensity factors is studied by applying the finite element method to calculate the values of the stress intensity factors for an edge-cracked specimen of finite width.