Penetration Limit Research Articles

Retrieval of local surface wave velocities from traffic noise – an example from the La Barge basin (Wyoming)

ABSTRACTIn regions where active source seismic exploration is constrained by limitations of energy penetration and recovery, cost and logistical concerns, or regulatory restrictions, analysis of natural source seismic data may provide an alternative. In this study, we investigate the feasibility of using locally‐generated seismic noise in the 2–6 Hz band to obtain a subsurface model via interferometric analysis. We apply this technique to three‐component data recorded during the La Barge Passive Seismic Experiment, a local deployment in south‐western Wyoming that recorded continuous seismic data between November 2008 and June 2009. We find traffic noise from a nearby state road to be the dominant source of surface waves recorded on the array and observe surface wave arrivals associated with this source up to distances of 5 kms. The orientation of the road with respect to the deployment ensures a large number of stationary points, leading to clear observations on both in‐line and cross‐line virtual source‐receiver pairs. This results in a large number of usable interferograms, which in turn enables the application of standard active source processing methods like signal processing, common offset stacking and traveltime inversion. We investigate the dependency of the interferograms on the amount of data, on a range of processing parameters and on the choice of the interferometry algorithm. The obtained interferograms exhibit a high signal‐to‐noise ratio on all three components. Rotation of the horizontal components to the radial/transverse direction facilitates the separation of Rayleigh and Love waves. Though the narrow frequency spectrum of the surface waves prevents the inversion for depth‐dependent shear‐wave velocities, we are able to map the arrival times of the surface waves to laterally varying group and phase velocities for both Rayleigh and Love waves. Our results correlate well with the known geological structure. We outline a scheme for obtaining localized surface wave velocities from local noise sources and show how the processing of passive data benefits from a combination with well‐established exploration seismology methods. We highlight the differences with interferometry applied to crustal scale data and conclude with recommendations for similar deployments.

An integrated assessment of Super & Smart Grids.

By Elena Claire Ricci Fondazione Eni Enrico Mattei (FEEM), Centro Euro-Mediterraneo sui Cambiamenti Climatici (CMCC) elena.ricci@cmcc.it SUMMARY We assess the optimality of investments in power grid innovation, under both technological options of Super and Smart Grids, using the WITCH model in the version that includes Super-Grids. Super Grids allow to produce and trade electricity generated by large scale concentrated solar power (CSP) plants in highly productive areas that are connected to the demand centres through High Voltage Direct Current (HVDC) cables. We extend the model to include also Smart-Grids that allow: i) to increase the share of renewable power manageable by the power network, ii) to reduce the costs of customer relationships via Smart Meters; iii) residential consumer to generate electricity via micro-photovoltaic plants, and iv) residential consumer to generate virtual electricity via consumption management. We find that it becomes optimal to invest in grid innovation, in order to start gaining the management benefits and taking advantage of consumer generating opportunities (of electricity and “nega-watts”), starting in 2010 and to exploit the increased possible penetration of renewable energy sources from 2035. Long-distance CSP generation becomes optimal only from 2040, and trade from 2050; but it reaches very high shares in the second half of the century, especially when penetration limits are imposed on nuclear power and on carbon capture and storage operations (CCS). On the whole, climate policy costs can be reduced by large percentages, up to 48%, 34%, 24% for the USA, Western Europe, Eastern Europe, respectively, with respect to corresponding scenarios without the grid innovation via Super and Smart Grid option and with limits on nuclear power, CCS, and CSP import. The analysis is then extended to compare these options considering, at least qualitatively, the differentiated impacts on the environment, technology, organization, society, local and national economies and geopolitics.

Probabilistic approach for optimal planning of distributed generators with controlling harmonic distortions

In this study, a probabilistic planning approach is proposed for optimally allocating different types of distributed generator (DG) (i.e. wind-based DG, solar DG and non-renewable DG) into a harmonic polluted distribution system so as to minimise the annual energy losses and reduce the harmonic distortions. The proposed planning methodology takes into consideration the intermittent nature of the renewable resources, load profile and the technical constraints of the system. The objective function is the total system annual power loss. The constraints include voltage limits at different buses (slack and load buses) of the system, feeder capacity, total harmonic distortion (THD) limits and maximum penetration limit of DG units. The optimisation process is achieved using the genetic algorithm optimisation method. This proposed approach has been applied to a typical rural distribution system with different scenarios including all possible combinations of distributed energy resources. The simulation results using Matlab programming environment show that significant reductions in the energy losses and THD are achieved for all the proposed scenarios. Also simulation results depict that the proposed method is robust and computationally efficient.

General and Simple Decision Method for DG Penetration Level in View of Voltage Regulation at Distribution Substation Transformers

A distribution system was designed and operated by considering unidirectional power flow from a utility source to end-use loads. The large penetrations of distributed generation (DG) into the existing distribution system causes a variety of technical problems, such as frequent tap changing problems of the on-load tap changer (OLTC) transformer, local voltage rise, protection coordination, exceeding short-circuit capacity, and harmonic distortion. In view of voltage regulation, the intermittent fluctuation of the DG output power results in frequent tap changing operations of the OLTC transformer. Thus, many utilities limit the penetration level of DG and are eager to find the reasonable penetration limits of DG in the distribution system. To overcome this technical problem, utilities have developed a new voltage regulation method in the distribution system with a large DG penetration level. In this paper, the impact of DG on the OLTC operations controlled by the line drop compensation (LDC) method is analyzed. In addition, a generalized determination methodology for the DG penetration limits in a distribution substation transformer is proposed. The proposed DG penetration limits could be adopted for a simplified interconnection process in DG interconnection guidelines.

Low-velocity impact response of woven Kevlar/epoxy laminated composites reinforced with multi-walled carbon nanotubes at ambient and low temperatures

In this article, the low-velocity impact response of woven Kevlar/epoxy laminated composites enhanced with different weight percentages (⩽1%) of multi-walled carbon nanotubes (MWCNTs), was investigated under ambient (27°C) and low temperature (−40°C) conditions. Energy profile diagrams (EPDs) were employed to determine the penetration threshold of Kevlar/epoxy laminated composites. In addition, the effect of MWCNTs on laminate composites was evaluated by subjecting all specimens to the same level of energy, 45J. The time history of absorbed energy, deflection and velocity are measured and some parameters such as stiffness bending, penetration limit and maximum deflection, for both composites and nanocomposites at ambient and low temperatures are reported. Results showed a remarkable dependency of damage formation on temperature and contents of MWCNTs. It was concluded that the MWCNTs was improved the impact response and was restricted the damage size in the woven Kevlar fiber composites at ambient and low temperature. The addition of 0.5% MWCNTs resulted in about 35% increase in energy absorption at ambient temperature, and the addition of 0.3% MWCNTs increased the absorbed energy capability about 34% at low temperature.

Additive manufactured textiles for high‐performance stab resistant applications

PurposeThe purpose of this paper is to ascertain the stab resistance characteristics of a series of planar and articulated laser sintered (LS) samples, in accordance with the United Kingdom Home Office Scientific Development Branch (HOSDB) Body Armour Standard – Publication 39/07.Design/methodology/approachA series of LS planar samples were manufactured using an EOS P100 Formiga system, manufactured from 100 per cent virgin or a 50:50 mix of recycled and virgin Nylon (PA2200), ranging in thickness from 1‐10 mm. All planar samples were stab tested to the HOSDB knife‐resistance (KR) level one impact energy of 24 Joules, using an in‐house manufactured HOSDB guided rail drop test impact rig and standardised knives. Penetration through the underside of each sample was measured and recorded. These results were then used to develop an articulated, additive manufactured (AM) scale textile – LS from a 50:50 mix of recycled and virgin PA2200 powder. These samples were then tested using the aforementioned impact rig and stab impact energy.FindingsThe research demonstrated that while virgin PA2200 sample required a minimum thickness of 8 mm to achieve stab‐resistance below the HOSDB maximum penetration limit of 7 mm, this figure can be reduced to 5.6 mm when manufacturing LS planar samples from a 50:50 mix of virgin and recycled PA2200. Results from stab testing the articulated samples indicated a successful AM textile‐like design, with a maximum knife penetration of 1.6 mm – below the 7 mm HOSDB limit.Originality/valueThe paper describes a unique application of AM technologies for the manufacture of high‐performance stab resistant AM textiles.

How much wind energy will be curtailed on the 2020 Irish power system?

This paper describes a model of the 2020 Irish electricity system which was developed and solved in a mixed integer programming, unit commitment and economic dispatch tool called PLEXOS®. The model includes all generators on the island of Ireland, a simplified representation of the neighbouring British system including proposed wind capacity and interconnectors between the two systems. The level of wind curtailment is determined under varying levels of three influencing factors. The first factor is the amount of offshore wind, the second is the allowed limit of system non-synchronous penetration (SNSP) and the third is inclusion or exclusion of transmission constraints. A binding constraint, resulting from the 2020 EU renewable energy targets, is that 37% of generation comes from wind. When the SNSP limit was increased from 60% to 75% there was a reduction in wind curtailment from 14% to 7%, with a further reduction when the proportion of wind capacity installed offshore was increased. Wind curtailment in the range of SNSP limit of 70–100% is influenced primarily by the inclusion of transmission constraints. Large changes in the dispatch of conventional generators were also evident due to the imposition of SNSP limits and transmission constraints.

An Integrated Assessment of Super & Smart Grids

We assess the optimality of investments in power grid innovation, under both technological options of Super and Smart Grids, using the WITCH model in the version that includes Super-Grids. Super Grids allow producing and trading of electricity generated by large scale concentrated solar power (CSP) plants in highly productive areas that are connected to the demand centres through High Voltage Direct Current (HVDC) cables. We extend the model to include also Smart-Grids that allow: i) to increase the share of renewable power manageable by the power network, ii) to reduce the costs of customer relationships via Smart Meters; iii) residential consumer to generate electricity via micro-photovoltaic plants, and iv) residential consumer to generate virtual electricity via consumption management. We find that it becomes optimal to invest in grid innovation, in order to start gaining the management benefits and taking advantage of consumer generating opportunities (of electricity and “nega-watts”), starting in 2010 and to exploit the increased possible penetration of renewable energy sources from 2035. Long-distance CSP generation becomes optimal only from 2040, and trade from 2050; but it reaches very high shares in the second half of the century, especially when penetration limits are imposed on nuclear power and on carbon capture and storage operations (CCS). On the whole, climate policy costs can be reduced by large percentages, up to 48%, 34%, 24% for the USA, Western Europe, Eastern Europe, respectively, with respect to corresponding scenarios without the grid innovation via Super and Smart Grid option and with limits on nuclear power, CCS, and CSP import. The analysis is then extended to compare these options considering, at least qualitatively, the differentiated impacts on the environment, technology, organization, society, local and national economies and geopolitics.

Calcium hydroxide nanosols for the consolidation of porous building materials - results from EU-STONECORE

The main idea of the European STONECORE R&D project (2008 to 2011) was to develop and evaluate nano materials for the use in refurbishment and conservation of historic monuments. A set of different calcium hydroxide (“lime”) nanoparticles dispersed in alcohols (CaLoSiL®) available on the market were tested. The general advantages attributed to alcoholic lime dispersions were: compatibility of the consolidant with the original building material, no limitation of penetration due to the particle size, and no mobilisation of soluble salts. The paper mainly reports the evaluation of lime nanosols for consolidation of lime mortar, gypsum stucco, and mural painting layers. In order to achieve a penetration behaviour which is adequate to the pore structure of the substrate, the composition of the nanosol as well as its application procedure had to be adjusted. This could be achieved by dilution, additives, or after-treatment of the surface. Apart from structural strengthening of porous structures the lime nanosols were tested for treatment of larger defects such as fissures, cracks, detachment, and delamination. For this purpose the nanosols were modified with additives, fillers, and aggregate. The developed lime nanosol formulations were applied to test sites at three historic monuments with promising results. A ‘modular system’ was developed to meet all these conservation needs. These materials showed sufficient adhesive strength. They proved applicable for the consolidation of severely cracked limestone as well.

Fatco Sendromlu Immunsağlıklı Bir Çocukta Aspergillus flavus Nedenli Osteomyelit Due to Aspergillus flavus in an: Bir Olgu Sunumu ve Literatürün Gözden Geçirilmesi

Invasive aspergillosis usually affects the lungs, and osteomyelitis due to Aspergillus spp. is a rare manifestation of invasive aspergillosis. Generally, there are underlying immunosuppressive conditions such as prolonged granulocytopenia, immunosuppressive therapy, and chronic granulomatous disease. Although amphotericin B is one of the most preferred agents for invasive aspergillosis management, its poor bone penetration and renal toxicity limit its use for the treatment of osteomyelitis, especially in pediatric ages. Case Report / Olgu Sunumu

The penetration limit of poly(4-vinyl phenol) thin films for etching via holes by inkjet printing

This paper reports the penetration limit of via holes through dissolving dielectric polymer thin films by inkjet printing. It was found that both the outer diameter of via holes and the polymer thickness affect the penetration depth from the experimental results. Based on this finding, a more accurate relationship between the inner diameter of via holes and the diameter of in-flight droplets for different polymer thicknesses is obtained.

What Is The Upper Limit Of Cement Penetration For Different Femoral Hip Resurfacing Components?

We used a validated femoral resurfacing model to obtain measurements of pressure and temperature and quantify cement distribution as a function of inner geometry and cementing technique of five different femoral hip resurfacing components. The purpose was to investigate if manufacture cementing recommendations are reliable. ASR showed only with the recommended manual cementing technique low cement pressures of 58.0±50.2kPa and low interface temperatures of 33.3±4.1°C. BHR had large cement defects of 10.4±1.1mm. Conserve Plus caused the smallest cement penetration depths of 2.9±0.6mm. Durom was tolerant against changes of the cementing technique but showed the widest spread of temperature data 42.8±7.0°C. ReCap showed the highest risk for incomplete seating with a cement mantle thickness of 4.3±0.9mm. Polymerization heat did not exceed the threshold of 45°C with a cement penetration depth of less than 4.2mm in any circumstances of this study.

Overview on Key Technologies of Grid-Connected Wind Power Based on Energy Storage

In order to promote the development of wind power and accelerate the efficient use of new energy sources, countries have brought energy storage systems into grid-connected wind farms to achieve efficient and stable operation of the wind power plant. This paper recounts the latest development status and trend of wind power at home and abroad, and introduces the principle of power conversion between energy storage system and wind farm. Based on the existing research results, it analyses power system stability related to wind power, low voltage ride-through ability of wind turbine, wind power penetration limit, as well as power quality issues. It also describes the new ideas about how to use energy storage technologies to solve the problems faced by the wind power.

Evaluation of the Wind Power Penetration Limit and Wind Energy Penetration in the Mongolian Central Power System

This paper describes evaluation results of the wind power penetration limit (WPPL) and the wind energy penetration (WEP) in the Mongolian central power system (MCPS). A wind power plant (WPP) in a power system possesses an output power limit because the power system must maintain a balance between the generation and consumption of electricity at all times in order to achieve an adequate level of quality. The instantaneous penetration limit (IPL) of wind generation at a load is determined as the minimum of the three technical constraints: the minimum output, the ramp rate capability, and the spinning reserve of the conventional generating units. In this paper, a WPPL is defined as the maximum IPL divided by the peak load. A maximal variation rate (VR) of wind power is a major factor in determining the IPL, WPPL, and WEP. This paper analyzes the effects of the maximal VR of wind power on the WPPL, WEP, and capacity factor (CF) in the MCPS. The results indicate that a small VR can facilitate a large amount of wind energy while maintaining a high CF with increased wind power penetration.

Analysis of Voltage Profile Problems Due to the Penetration of Distributed Generation in Low-Voltage Secondary Distribution Networks

This paper presents a comprehensive analysis of the possible impacts of different penetration levels of distributed generation (DG) on voltage profiles in low-voltage secondary distribution networks. Detailed models of all system components are utilized in a study that performs hundreds of time-domain simulations of large networked distribution systems using the Electromagnetic Transients Program (EMTP). DGs are allocated in a probabilistic fashion to account for the uncertainties of future installations. The main contribution of this paper is the determination of the maximum amount of DG that secondary distribution networks can withstand without exhibiting undervoltage and overvoltage problems or unexpected load disconnections. This information is important for network planning engineers to facilitate the extension of the maximum penetration limit. The results show that depending on the location, type, and size of the installed DGs, small amounts of DG may cause overvoltage problems. However, large amounts of DG may not cause any voltage problems when properly selected.

Use of NIR light and upconversion phosphors in light-curable polymers

ObjectiveLight-curable polymers are commonly used in restorative surgery, prosthodontics and surgical procedures. Despite the fact of wide application, there are clinical problems due to limitations of blue light penetration: application is restricted to defects exposed to the light source, layered filling of defect is required. MethodsCombining photo-activation and up conversion allows efficient polymer hardening by deep penetrating near-infrared (NIR) light. The prerequisite 450nm blue light to polymerize dental resins could be achieved by filler particles, which absorb the incident NIR irradiation and convert it into visible light. ResultsThe on spot generated blue light results in uniform polymer hardening. Composite samples of 5mm thickness were cured two times faster than pure polymer cured by blue light (30 and 60s, respectively). Overall degree of monomer conversion resulted in higher values of more than 40%. The enhanced transmission of NIR light was confirmed by optical analysis of dentin and enamel. The NIR transmittance surge in the 800–1200nm window could improve sealing of complex and deep caries lesions. SignificanceWe demonstrate faster curing and an improved degree of polymerization by using upconversion filler particles as multiple light emission centers. This study represents an alternative approach in curing dental resins by NIR source.

A Simple Method for Imaging <em>Arabidopsis</em> Leaves Using Perfluorodecalin as an Infiltrative Imaging Medium

The problem of acquiring high-resolution images deep into biological samples is widely acknowledged1. In air-filled tissue such as the spongy mesophyll of plant leaves or vertebrate lungs further difficulties arise from multiple transitions in refractive index between cellular components, between cells and airspaces and between the biological tissue and the rest of the optical system. Moreover, refractive index mismatches lead to attenuation of fluorophore excitation and signal emission in fluorescence microscopy. We describe here the application of the perfluorocarbon, perfluorodecalin (PFD), as an infiltrative imaging medium which optically improves laser scanning confocal microscopy (LSCM) sample imaging at depth, without resorting to damaging increases in laser power and has minimal physiological impact2. We describe the protocol for use of PFD with Arabidopsis thaliana leaf tissue, which is optically complex as a result of its structure (Figure 1). PFD has a number of attributes that make it suitable for this use3. The refractive index of PFD (1.313) is comparable with that of water (1.333) and is closer to that of cytosol (approx. 1.4) than air (1.000). In addition, PFD is readily available, non-fluorescent and is non-toxic. The low surface tension of PFD (19 dynes cm-1) is lower than that of water (72 dynes cm-1) and also below the limit (25 - 30 dyne cm-1) for stomatal penetration4, which allows it to flood the spongy mesophyll airspaces without the application of a potentially destructive vacuum or surfactant. Finally and crucially, PFD has a great capacity for dissolving CO2 and O2, which allows gas exchange to be maintained in the flooded tissue, thus minimizing the physiological impact on the sample. These properties have been used in various applications which include partial liquid breathing and lung inflation5,6, surgery7, artificial blood8, oxygenation of growth media9, and studies of ice crystal formation in plants10. Currently, it is common to mount tissue in water or aqueous buffer for live confocal imaging. We consider that the use of PFD as a mounting medium represents an improvement on existing practice and allows the simple preparation of live whole leaf samples for imaging.

Development of PSO-based robust controller for maximising wind penetration

In this paper, a new robust controller has been proposed for attaining the maximum safe instantaneous wind penetration. Particle swarm optimisation (PSO)-based algorithm has been developed to obtain the maximum safe instantaneous penetration by the optimisation of grid parameters. The developed algorithm has been tested on modified IEEE 14-bus system. The effectiveness of the proposed methodology has been shown in terms of maximum instantaneous safe wind energy penetration limit, in percentage and also maximum safe bus loading point, explicitly beyond which system drives into instability.

풍력발전기 출력제한을 고려한 풍력한계용량 산정에 관한 연구

The wind energy is one of the most prospective resources in renewable energy. However, the WTGS shouldn`t be installed indiscriminately because the power system can be negatively influenced by a variable and uncertain nature of the wind energy. It is the reason why it has to be limited to install the WTGS thoughtlessly mentioned above that support the importance of the maximum penetration limit of wind power. It may required that power system operators suggests a new way of power system operation as percentage of the WTGS increase in the existing power system. The wind power is fixed in a limited area, so using rate of the wind power will be increased by installing additional WTGS. In this paper, we have studied on economic evaluation of the wind capacity increased by restricting the output of the WTGS as the way to increase the wind capacity.

Motility is critical for effective distribution and accumulation of bacteria in tumor tissue

Motile bacteria can overcome the penetration limitations of cancer chemotherapeutics because they can actively migrate into solid tumors. Although several genera of bacteria have been shown to accumulate preferentially in tumors, the spatiotemporal dynamics of bacterial tumor colonization and their dependence on bacterial motility are not clear. For effective tumor regression, bacteria must penetrate and distribute uniformly throughout tumors. To measure these dynamics, we used an in vitro model of continuously perfused tumor tissue to mimic the delivery and systemic clearance of Salmonella typhimurium strains SL1344 and VNP20009, and Escherichia coli strains K12 and DH5α. Tissues were treated for 1 hour with 10(5) or 10(7) CFU ml(-1) suspensions of each strain and the location and extent of bacterial accumulation were observed for 30 hours. Salmonella had 14.5 times greater average swimming speed than E. coli and colonized tissues at 100 times lower doses than E. coli. Bacterial motility strongly correlated (R(2) = 99.3%) with the extent of tissue accumulation. When inoculated at 10(5) CFU ml(-1), motile Salmonella formed colonies denser than 10(10) CFU/(g-tissue) and less motile E. coli showed no detectable colonization. Based on spatiotemporal profiles and a mathematical model of motility and growth, bacterial dispersion was found to be necessary for deep penetration into tissue. Bacterial colonization caused apoptosis in tumors and apoptosis levels correlated (R(2) = 98.6%) with colonization density. These results show that motility is critical for effective distribution of bacteria in tumors and is essential for designing cancer therapies that can overcome the barrier of limited tumor penetration.