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Immediately after an earthquake a healthcare system within a city, comprising several hospitals, endures an extraordinary demand. This paper proposes a new methodology to estimate whether the hospital network has enough capacity to withstand the emergency caused by an earthquake. The ability of healthcare facilities and to provide a broad spectrum of emergency services immediately after a seismic event is assessed through a metamodel that assumes waiting time as main response parameter to assess the hospital network performance. The First Aid network of San Francisco subjected to a 7.2 Mw magnitude earthquake has been used as case study. The total number of injuries and their distributions among the six major San Francisco's Emergency Departments have been assessed and compared with their capacity that has been determined using a survey conducted by the medical staff of the hospitals. The numerical results have shown that three of the six considered San Francisco's hospitals cannot provide emergency services to the estimated injured. Two alternatives have been proposed to improve the performance of the network. The first one redistributes existing resources while the second one considers additional resources by designing a new Emergency Department. [ABSTRACT FROM AUTHOR]

In this paper, a multi-step etching method based on Bosch process was investigated to fabricate a slightly tapered via. The diameter of vias was scaled from 40 to 100 µm. Isotropic etching step was added into Bosch process to control the angle of the tapered vias. The slope angle could be adjusted by changing the time settings of isotropic etching step. The influence of the platen temperature was also studied. The passivation and etching steps are extremely sensitive to temperature. Silicon grass could be formed at low temperature. The two different processes of isotropic SF6 etching and Cl2/HBr etching were also compared. The wrinkles and cracks were observed on the surface after treatment with isotropic SF6 etching. The Cl2/HBr etching method is much better for removing the scallops. [ABSTRACT FROM AUTHOR]

Introduction: Ionizing radiation is widely used in industry and medicine; however, it causes a significant health hazard by making microscopic damage to living tissue. Various biological parameters, including cell survival fraction and relative biological effectiveness, are taken into account to assess the severity and extent of biological damages. Microdosimetry suffers from various shortcomings and limitations, but the development of some powerful simulation software has paved the way to resolve these problems in recent years. Material and Methods: In this study, the authors were looked for two keywords (Geant4 and radiobiology) in the title, abstracts, and keywords of Scopus and PubMed database articles. Results: More than 100 articles were found. The researchers extracted the articles that were devoted to the construction of different geometries for DNA, nucleus, and cells as simulate the parameters, such as relative biological effectiveness, SF, linear energy transfer, and single-strand breaks/double-strand breaks in the present study. Conclusion: Geant4 is one of the software commonly used to simulate biological factors. It has many properties, such as the ability to follow up physical processes in very low energy, open source code, and flexibility in complex geometries. In this paper, we reviewed some of the radiobiological parameters simulated with Geant4. [ABSTRACT FROM AUTHOR]

Aqueous silk fibroin (SF) sol is a colloidal solution. With the colloidal hydration layer and electrostatic repulsion, the SF sol can hardly make the efficient collision/assembly among micelles and perform like a following sol for a long time. In this paper, hydrophilic silk-based sequences (HSF) derived from SF molecules were obtained by immersing the dried SF condensates with water and extracting the dissolving fraction. The HSF was obtained by immersing the SF condensate dried at the temperature of 2 0 – 2 5 ∘ C and relative humid of 55–60% in water and collected the lixivium. The dissolving ratio was about 30%. The HSF sol (0.5%, w/v) self-assembled into the mesoscopic 3D nanofibrous network within 8 h. The obtained HSF nanofibers were 10–100 μ m in length and 50–100 nm in diameter. The HSF nanofiber possesses similar hierarchical structure consisting of nanofibrils bundles to the native silk fiber. There were significant aggregation structure transitions from random coil to β -sheet and amorphous chains to Silk II crystal aggregation during the formation of HSF nanofibers. The HSF nanofiber holds the potential to give further insight into the reconstruction of native silk in vitro and the fabrication of tough silk-based biomaterials. [ABSTRACT FROM AUTHOR]

To model the responses of electromagnetic surveys for geophysical subsurface sensing, a mixed total field/scattered field-based discontinuous Galerkin frequency-domain (TF/SF DGFD) method is proposed in this paper. The proposed TF/SF DGFD method is implemented at a subdomain level based on the domain decomposition technique. Different subdomains can employ either the TF DGFD framework or the SF DGFD framework, which are then coupled through the Riemann transmission condition. To balance the computation efficiency and accuracy for practical applications, the proposed method prefers to using the SF DGFD framework for subdomains with sources and using the TF DGFD framework for the remaining subdomains. At the interfaces between total field and scattered field subdomains, the Riemann transmission condition is slightly modified by incorporating the background fields due to the physically imposed sources in the background media. In this way, the proposed method only requires surface integrals of the background fields as extra overhead instead of elementwise integration of the scattering objects for the purely scattered field-based method, which can improve the computational efficiency. Also, it is more accurate than the purely TF DGFD method given the same mesh. Numerical examples are studied to examine the performance of the proposed method, which is proven to have better accuracy than the TF DGFD method. The TF/SF DGFD method will facilitate modeling of electromagnetic surveys under complicated geophysical environments for subsurface sensing. [ABSTRACT FROM AUTHOR]

In this paper, the results of experimental work on the strength and durability performances of self‐compacting mortars (SCMs) manufactured from silica fume (SF) and fly ash (FA) were presented. The cement was partially replaced with 5, 10, 15, 20, and 25% of FA and 5, 10, and 15% of SF as binary mixes. Also, ternary mixtures were prepared by the incorporation of FA and SF at different replacement dosages by weight. In total, 14 different combinations of mixes were studied at the ages of 7, 28, and 180 days. Prismatic samples of size 40 × 40 × 160 mm3 were produced and exposed to water curing to observe mechanical behavior of SCMs. The mechanical properties of SCMs were examined by the tests of compressive strength and flexural strength. Sorptivity, porosity, water absorption, and density were also measured. To evaluate fresh properties of SCMs, mini slump flow diameter and mini V‐funnel flow time tests were conducted. The results of the study reveal that increase in the dosage of FA increases SCMs flow but also reduce segregation resistance. The enhancement in flexural strength is the best in the binary mixes of SF10 and in binary mixes of FA. Ten percent replacement of FA shows the best flexural strength performance with a value of 10.21 MPa at the age of 180 days. Compressive and flexural strengths of mortars containing SF and FA reached up to about 86.14 and 10.50 MPa, respectively. [ABSTRACT FROM AUTHOR]

In the Bay Area of San Francisco, the earthquake contours are not easy to define: seismology is still a relatively recent science, and controversies around methods to evaluate the earthquake risk are constant. In this context, the invitation to think about the modes of citizen science is an opportunity to reflect on the modality of hybridized scientific practices as well as the process by which the plurality and complexity of the earthquake characteristics can be articulated, and sometime reconciled. Looking at different existences of the earthquake risk, the paper investigates different assemblages that question the clear-cut distinction between citizen science and science. I'll situate the question of the mode of citizen science within the larger framework of interdisciplinarity knowledge infrastructures and the work on 'mode of existence' initiated by Bruno Latour and Isabelle Stengers (2009). Expanding our understanding with regard to how CS is performed opens the possibility of reconsidering the specific types of assemblages and infrastructures from which these modes emerge and on their distinct trajectories. It is also an invitation to make visible the integration processes, the communities, and the imaginations that "make" science. [ABSTRACT FROM AUTHOR]

MgO‐based binders have been widely studied for decades. Recently, the MgO–SiO2–H2O system was developed as a novel construction material, however, its reaction mechanism remains unclear. This paper investigated the reaction products and kinetics of MgO/silica fume (SF) pastes with MgO calcinated at different temperatures. The results indicate that MgO presented larger grain size after calcination at higher temperature. Mg(OH)2 and magnesium silicate hydrate (M–S–H) gel were formed when using MgO calcined at 850, 950, and 1050°C. However, only M–S–H gel was formed when using MgO calcined at 1450°C. The reaction kinetics of MgO could be described using α = 1 − e−k*t. The reaction rate of MgO increased with decreasing calcination temperature, increasing SF dosage, and the addition of sodium hexametaphosphate. Only M–S–H gel was formed when the reaction rate of MgO was below the demarcation line (about 0.250 × 10−6 s−1), and the corresponding demarcation area was around 14 days. [ABSTRACT FROM AUTHOR]

Abstract The regeneration of load-bearing soft tissues has long driven the research and development of bioactive hydrogels. A major challenge facing the application of hydrogels to load-bearing tissues is the development of hydrogels with appropriate biological functionality and biomechanical stability that closely mimic the host tissue. In this paper, we describe a newly synthesized cell-laden interpenetrating polymer network (IPN) hydrogel based on gelatin methacrylate (GelMA) and silk fibroin (SF) that was formed via sequential sonication and photocrosslinking. The experimental results revealed that SF-GelMA IPN hydrogels exhibited high swelling ratios, excellent mechanical properties, resistance to enzymatic degradation by collagenase, and porous internal microstructures. Moreover, these properties could be tailored by changing the prepolymer components. MC3T3-E1 pre-osteoblasts attached to and subsequently proliferated on the IPN hydrogels, as demonstrated by fluorescein diacetate/propidium iodide (FDA/PI) staining and Cell Counting Kit-8 (CCK-8) analysis. In addition, the encapsulation of MC3T3-E1 pre-osteoblasts and a subsequent cell viability assay demonstrated that the entire IPN formation process was compatible with cells and that the growth of encapsulated cells could be tuned by adjusting the GelMA concentration, underlining their versatility for various load-bearing soft tissue engineering. Overall, this study introduces a class of mechanically robust and tunable cell-laden IPN hydrogels which have great potential as load-bearing soft tissue engineering scaffold. Graphical abstract Unlabelled Image Highlights • The IPN hydrogel based on methacrylated gelatin and silk fibroin was formed via sonication and photocrosslinking. • The physical and biological properties of the hydrogel could be tailored by changing the ratio of the prepolymer. • Cells or other growth factors can be encapsulated into the IPN hydrogel without any toxic crosslinking agent. [ABSTRACT FROM AUTHOR]

Abstract Tungsten-copper (WCu) contact materials are the core components of high-voltage electrical switches. However, significant arc ablation effect at high voltage and high current often leads to connection interruption and mechanical loss, which seriously affects the safe operation of appliances. In this paper, the failure mechanisms of tungsten-copper contact materials caused by significant arc ablation in the sulfur hexafluoride (SF 6) atmosphere were investigated. Results showed that the arc ablation of contact materials is mainly caused by the evaporation and splashing of copper component which has a low melting point, followed by the ablation and spallation of the tungsten (W) skeleton structure. All of these have roughened the surface of contact materials and then further accelerated the volatilization of copper (Cu) component and the reactions between the contact materials and arc extinguishing medium of SF 6. Finally, the contact materials lost their functions of arc extinguishing and current switching. Simulated experimental work has also been performed and it verified the above observed failure mechanisms of contact materials. Due to the instantaneously high temperature and high voltage generated during the arcing, both the Cu and W phases in the WCu alloy have suffered significant evaporation and mass losses. Highlights • The electric contact arc ablation failure after the service of the component was investigated. • A simulation experiment was performed. • The ablation mechanisms were discussed. [ABSTRACT FROM AUTHOR]

Abstract This paper first reports on the high-selective separation and recovery of Li(I) from Na(I) and K(I) using the polymer inclusion membrane (PIM) system containing both thenoyltrifluoroacetone (TTA) and trioctylphosphine oxide (TOPO) as the carrier molecules, and cellulose triacetate (CTA) as the base polymer. To characterize the PIM, we used Fourier Transform infrared (FT-IR) spectroscopy, scanning election microscopy (SEM) and thermogravimetric analysis (TGA). The optimized results of this work showed that initial flux ( J 0) of Li(I) that was as high as 1.04 × 10−2 mol m−2 h−1, corresponding to permeability (P) of 3.62 × 10−3 m h−1, were recorded using the PIM composed of 50 wt% CTA and 26.74 wt% TTA + 23.26 wt% TOPO from a feed phase containing Li(I), Na(I) and K(I) in an alkaline chloride solution into an acceptor phase containing 0.1 M HCl. Li(I) was transported successfully to the acceptor phase but Na(I) and K(I) barely passed in the first 20 h. The separation factor (S F) of Li(I) over the Na(I) and K(I) respectively (S F L i (I) / N a (I) ≒ 54.25, S F L i (I) / k (I) ≒ 50.60) demonstrated that Li(I) can be high-selectively separated. It is expected that this membrane can be applied for selective recovery of Li(I) from salt lakes or sea water that contains significant concentrations of Na(I) and K(I). Graphical abstract Image 1 Highlights • Promising functional PIM system for Li(I) recovery. • The carrier molecules including TTA and TOPO are adopted for PIM system. • Separation factors (SF): S F L i (I) / N a (I) & k (I) > 50. • Initial flux( J 0) of Li(I) is as high as 1.04 × 10−2 mol m−2 h−1. • Permeability(P) of Li(I) is 3.62 × 10−3 m h−1. [ABSTRACT FROM AUTHOR]

Abstract Cascading failures are emergent phenomena on interdependent networks and plenty of models have been proposed to explore the features of cascading failures. However, few of them focus on energy-supported dependence relations between interdependent networks including control nodes. In this paper, a load-based energy-supported cascading failure model is proposed on interdependent networks, where the energy control factor λ and control nodes are considered. According to the numerical simulations, it is found that as the energy control factor λ increases, both interdependent Erdős–Rényi (ER) networks and scale-free (SF) networks become more vulnerable. Meanwhile, with the increase of energy control factor λ , interdependent SF networks become more robust than ER networks against random failures. In addition, increasing the power exponent γ can improve the robustness of interdependent SF networks. Finally, although coupling preferences and control node setting strategies have few impacts on cascading failures on interdependent ER networks, the assortative coupling preference (AC) and betweenness control node setting strategy (BS) can improve the robustness of interdependent SF networks. Highlights • An energy-supported cascading failure model is proposed on interdependent networks. • Increasing factor λ makes interdependent SF networks more robust than ER networks. • Increasing exponent γ improves the robustness of interdependent SF networks. • The AC and BS can improve the robustness of interdependent SF networks. [ABSTRACT FROM AUTHOR]

Highlights • The performance of steel-concrete (SC) systems is enhanced through the use of hybrid fibers in the concrete core. • The hybrid fibers include a combination of macro and nano-scale fibers, steel fibers and carbon nanofibers respectively. • An overall fiber content percentage of 1.5% was deemed sufficient to alter the failure mode from brittle to ductile. • Experimental investigations on representative SC specimens confirmed the benefits gained from using hybrid fibers. Abstract Cementitious materials such as concrete are typically characterised as quasi-brittle with low tensile strength and low strain capacity, which hence affect the long-term durability of the structure. One of the most important issues in designing and maintaining massive concrete structures like offshore and nuclear power plants is concrete cracking, which is due to the low tensile strength of concrete. This can destroy the structural aesthetic and lead to deterioration of the structure. The addition of fibers to concrete has been proven to be a good mean to control its crack behaviour and maintain its ductility in tension. Further, since the discovery of carbon nanotubes/fibers (CNT/CNF), they have been also considered as efficient fibers for construction materials such as concrete. This study presents the structural performance of steel-concrete (SC) elements with a fiber reinforced concrete (FRC) core using both single and hybrid fibers (i.e. consisting of two types of fibers). For this study carbon nanofibers, and steel fibers which are conventionally used in practice, are used for the FRC. Static tests were conducted on eight SC beams with different concrete types. The paper reports on the experimental results obtained from four-point flexural loading of the SC beams. The study shows considerable improvement for both the strength and ductility of the tested specimens. The research laid the groundwork for additional in-depth studies on using carbon nanofiber reinforced concrete within structural members. [ABSTRACT FROM AUTHOR]

Currently available synthetic grafts demonstrate moderate success at the macrovascular level, but there are still challenges at small vascular scale (inner diameter of less than 6 mm). In this paper, silk fibroin (SF)/polyurethane (PU)/SF three-layer drug carrier nanofibrous tubes were developed for blood vessel repair with several advantages over existing designs. Our design consisted of a bionic three-layer microtube that was synthesized from the drug carrier SF and oligomeric proanthocyanidin nanofibers as the inner layer, PU nanofibers as the middle layer, and SF nanofibers as the outer layer. The results suggested that these three-layer tubes are attractive biocompatible materials for use as vascular grafts. [ABSTRACT FROM AUTHOR]

CF3I-N2 mixtures have garnered much attention as potential SF6-substitutes due to their excellent dielectric strengths, and the dielectric strength of SF6-N2 mixtures has a good synergy effect. This paper attempts to propose an approach of adding a small amount of SF6 to improve the dielectric strength of the CF3I-N2 mixture, by making an all-around consideration of dielectric strength, impact on the environment and the limitations of engineering pressure and the lowest ambient temperature. The influences of adding different amounts of SF6 on the electron energy distribution function, the reduced ionization, attachment and effective ionization coefficients, the critical reduced electric field strength and critical electron temperature of ternary SF6-CF3I-N2 mixtures are investigated by Boltzmann analysis. Then the relations of the critical electric fiend strength, mixed ratio and saturated vapor pressure of the ternary SF6-CF3I-N2 mixture are built and analyzed. The results demonstrate that an effective improvement of its dielectric strength can be obtained by adding a small amount of SF6 into the CF3I-N2 mixture, and that a proper choice of the mixed ratio and the gas pressure of the ternary SF6-CF3I-N2 mixture can provide a comparable dielectric strength to pure SF6. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of silica fume (SF), a slump-retaining polycarboxylate ether (PCE) dispersant, and their combinations, on the fresh and hardened properties of ordinary portland cement paste. The investigated properties include hydration kinetics, rheological properties (i.e., plastic viscosity and yield stress), setting time, and compressive strength. Cement was partially replaced by SF at mass substitution levels of 0%, 10%, 20%, and 30%. The PCE dosages included 0%, 0.6%, 1.2%, 1.8%, and 2.4%, by mass of the binder. The results indicate that SF accelerates cement hydration rates and reduces the time of initial/final setting in relation to its content in the paste. This is due to the provision of additional C-S-H nucleation sites on SF surfaces. However, when PCE is present, such enhancement induced by SF is suppressed. In addition to enhancing cement hydration rate, SF reduces inter-particle spacing, thus amplifying rheological properties. In contrast, PCE reduces viscosity and yield stress. Both SF and PCE reduce 1-day compressive strength due to the effects of cement dilution (caused by SF) and the suppression of early-age hydration kinetics of cement (caused by PCE). The 7-day compressive strength, however, are broadly the same among the binary pastes; this is because the acceleratory and retarding effects of SF and PCE, respectively, are less pronounced at later ages. Finally, robust correlations between hydration kinetics, rheological properties, and compressive strength evolution are established. Those correlations can provide a basis for optimizing binder formulation and proportioning of high/ultra-high performance concrete. [ABSTRACT FROM AUTHOR]

Highlights • The impact response of BSFRC under impact loads is investigated by SHPB device. • The effect of strain rate and BS and SF hybrid ratio on BSFRC are studied. • The impact behavior of BSFRC is significantly affected by strain rate. • Proper fiber hybrid ratio can improve the impact strength and toughness of BSFRC. • A damage dynamic constitutive model is derived for BSFRC. Abstract This paper experimentally studied the impact behavior of hybrid basalt-macro synthetic polypropylene fiber reinforced concrete under impact loads (101–102 /s) with a split Hopkinson pressure bar (SHPB) device. The fiber content of basalt fiber (BF) was 0.05%, 0.075% and 0.1% and that of macro synthetic polypropylene fiber (SF) was 0.15%, 0.25%, 0.35% and 0.5%. Both static and impact tests were conducted to investigate the effect of strain rate and fiber hybrid ratio on the dynamic performance of the hybrid FRC, i.e. impact strength, dynamic increase factor (DIF), impact strain and toughness. The test results indicate that the hybrid FRC is strain-rate sensitive and a proper fiber hybrid ratio can improve the impact performance of concrete. DIF and l g ε ̇ are linearly related, whereas the impact strain, toughness and strain rate present quadratic polynomial relationship. Both BF and SF can enhance the impact strength of concrete. However, BF has a better enhancement effect than SF in terms of improving impact strength but not as good as SF in improving impact toughness. Also, appropriate BF and SF hybrid ratio can enhance the impact strength and toughness of concrete but excess fiber content has a weakening effect. In this study, the optimal fiber hybrid ratio was 0.075%–0.35% (BF-SF) which had the best impact resistance. Finally, a damage dynamic constitutive model suitable for the hybrid FRC was proposed to fit the test curves from SHPB test based on Zhu-Wang-Tang (ZWT) constitutive model. [ABSTRACT FROM AUTHOR]

Highlights • Effect of steel fibres and recycled aggregate content on the shear behaviour of reinforced concrete beams. • Development of a mixing process considering the particular characteristics of RA. • The densified form of SF appears to exhibit a different behaviour compared to its original (dispersed) condition. • It is feasible to produce HPC without incorporating natural aggregates (NA). • Lack of appropriate formula to predict the behaviour of steel fibres recycled aggregate concrete beams. • Steel fibres can partially compensate the lack of transverse reinforcement in terms of shear behaviour. Abstract This paper mainly studies the shear characteristics of reinforced concrete beams manufactured by introducing coarse recycled aggregate (RA) and steel fibres. For that purpose, 27 concrete beams (15 cm, 20 cm and 150 cm of width, height and length, respectively) with dissimilar spacing of transverse reinforcement (TR) were produced. Additionally, the RA obtained from building demolition waste and introduced in the concrete mixes at 0%, 50% and 100%. Furthermore, the steel fibres (SF) were introduced in the beams at 0%, 1% and 2% to improve the flexural characteristics. Specimens underwent a 4 points bending test. In this test, the maximum deflection, shear capacity, at the mid-span of the beam and tension strain were obtained. The determination of the influence of SF and TR spacing and SF on RA reinforced concrete beams was the aim of this investigation. In addition, the results of this experiment and the requirements shown in the standards (e.g. CEB-fib model code, ACI and CSA) were compared. The results show that that SF improved the specimens' maximum strain and their use enhanced the shear behaviour of RA concrete beams relative to control specimens. [ABSTRACT FROM AUTHOR]

Highlights • A quantum chemistry analysis combining density functional theory (DFT) was used to study the complex decomposition process of SF 6. • A decomposition model of SF 6 with two typical zones was established. • SOF 2 and SO 2 are both mainly generated through hydrolysis reaction in the low-energy region. • SO 2 F 2 can be generated from oxidation reaction of SF 2 and hydrolysis reaction of SOF 4 , and the former is the main pathway. • SOF 2 and SO 2 F 2 are the most effective species to monitor the decay of SF 6 under corona discharge. Abstract SF 6 will decompose to several byproducts (including SOF 2 , SO 2 F 2 , SO 2 , etc.) under corona discharge. Macro features of SF 6 decomposition are closely linked with the micro decomposition process. A quantum chemistry analysis combining density functional theory (DFT) was used in this paper to study the complex decomposition process of SF 6 in detail. A decomposition model of SF 6 with two typical zones was then established. Electron distribution of low fluoride sulfides shows that (SF 2)* and (SF 4)* are relatively stable. Formation pathways, reaction rate constants, and reaction region of SOF 4 , SOF 2 , SO 2 F 2 , SO 2 were derived. SOF 4 mainly comes from dissociation of SF 5 OH generating by oxidation between (SF 5)* and OH*. SO 2 F 2 is mainly generated through the oxidation reaction between (SF 2)* and O* in the high-energy region. SOF 2 and SO 2 are both generated through hydrolysis reaction in the low-energy region. SOF 2 and SO 2 F 2 are the most effective species to monitor the decay of SF 6 under corona discharge. [ABSTRACT FROM AUTHOR]

Abstract Experimental investigation of inductively coupled plasma etching on cemented carbides was proposed in this paper. SF 6 /O 2 /Ar gases were selected as the etching gases. The effect of five etching parameters on the etching process was also analysed by laser scanning confocal microscope. Combined with the two indexes of etching rate and etched surface roughness, the optimal etching process parameters were obtained: SF 6 /O 2 /Ar gas flow ratio of 20/60/10 sccm, inductively coupled plasma power (ICP power) of 800 W, radio frequency power (RF power) of 250 W, gas pressure of 3 Pa, and substrate temperature of 60 °C. The results showed that etching rate significantly increased with the increase of RF power, ICP power, and substrate temperature, especially RF power. The etching rate slowly increased as oxygen flow rate in SF 6 /O 2 /Ar gas flow increased. The effect of gas pressure on etching rate showed a large fluctuation, which first increased and then decreased. Besides, substrate temperature and SF 6 /O 2 /Ar gas flow ratio had little effect on the etched surface roughness. However, the etched surface roughness significantly increased as ICP power and gas pressure increased. The effect of RF power on the etched surface roughness presented a fluctuating change, first increasing and then decreasing. Highlights • Inductively coupled plasma etching on cemented carbides was investigated. • Effect of different etching parameters on the etching process was analysed. • Based on two indexes, optimal etching process parameters were obtained. • Etching rate significantly increased with the increase of RF power. • Surface roughness significantly increased as ICP power and gas pressure increased. [ABSTRACT FROM AUTHOR]

• Thermodynamically consistent generalized modelling framework for vibro-thermography. • Simulation includes contact dynamics of ultrasonic actuator with the target structure during vibro-thermography. • Simulation scheme – resonance due to wavelength scale effect of structural feature. • Optimal relation between excitation frequency and dimensions of structural feature. • Optimal excitation frequency to maximize heat generation in structural feature. In this paper, a thermodynamically consistent generalized three-dimensional modeling scheme is developed to simulate vibro-thermography and subsequently perform a quantitative investigation on a test structure. Simulation results are analyzed considering a plate with Structural Features (SF) which are used in a gas turbine engine structural components to reduce structural mass and enhance cooling. The modeling framework includes (i) coupled thermo-elastic heat generation and (ii) effects of various sources of nonlinear vibration arising due to the amplitude of the excitation, the engagement force on the target structure due to the ultrasonic horn, and structural boundary conditions. Transient heat generation behavior in the target structure with SF is analyzed. Dynamic contact models are used to capture the nonlinear harmonics. The effects of engagement force on the dynamic response are analyzed. Simulation results are obtained by incorporating the model in a finite element scheme. The simulation results show that the thermographic inspection can be optimally designed using a relationship between the SF sizes with reference to wavelength based resonance phenomenon. The spectral components obtained at various locations in the SF reveals the presence of both sub- and super-harmonics. [ABSTRACT FROM AUTHOR]

It is common to identify the internal insulation conditions of Sulfur Hexafluoride (SF6) insulated equipment by monitoring the concentrations of SF6 decomposition products. Corona discharge can lead to the decomposition of SF6, and thus, a lot of reactions occur in the mixture of SF6 with the impurities H2O and O2. Even under the same strength of corona discharge, the reactions can cause the decomposition products to differ due to the different concentrations of H2O and O2. This paper systematically studies the effects of H2O and O2 on the formation mechanism of SF6 decomposition products from a theoretical perspective. Two coupled zero-dimensional chemical kinetic models were built to investigate the discharge mechanism of 50 Hz ac point-plane corona discharge. By calculating the related contributions of the pathways at different moisture and oxygen contents (from 200 ppm to 5000 ppm), the main chemical process and the influence of the moisture and oxygen contents on the main discharge mechanism are analyzed. [ABSTRACT FROM AUTHOR]

Star formation (SF) laws are fundamental relations between the gas content of a galaxy and its star formation rate (SFR) and play key roles in galaxy evolution models. In this paper, we present new empirical SF laws of disc galaxies based on volume densities. Following the assumption of hydrostatic equilibrium, we calculated the radial growth of the thickness of the gaseous discs in the combined gravitational potential of dark matter, stars, and gas for 12 nearby star-forming galaxies. This allowed us to convert the observed surface densities of gas and SFR into the deprojected volume densities. We found a tight correlation with slope in the range 1.3–1.9 between the volume densities of gas (HI+H2) and the SFR with a significantly smaller scatter than the surface-based (Kennicutt) law and no change in the slope over five orders of magnitude. This indicates that taking into account the radial increase of the thickness of galaxy discs is crucial to reconstruct their three-dimensional density profiles, in particular in their outskirts. Moreover, our result suggests that the break in the slope seen in the Kennicutt law is due to disc flaring rather than to a drop of the SF efficiency at low surface densities. Surprisingly, we discovered an unexpected correlation between the volume densities of HI and SFR, indicating that the atomic gas is a good tracer of the cold star-forming gas, especially in low density HI-dominated environments. [ABSTRACT FROM AUTHOR]

This paper describes the role of televised sports in married life. It documents how adults integrate televised sports into their relationship with their spouse and evaluate its impact on that relationship. Telephone interviews were conducted with 399 married adults residing in San Francisco and Indianapolis. Respondents were asked about their own TV sports viewing behaviors as well as those of their spouse. Televised sports appears to play a generally positive albeit small role in marital life. TV sports viewing often is a shared activity and does not appear to trigger many scheduling or TV viewing conflicts. And, when such conflicts occurs, they appear to be resolved amicably and easily. It may be that accommodations for differing interests in TV sports are resolved early in a marital relationship, along with other accommodations that marriage often dictates. [ABSTRACT FROM AUTHOR]

It is widely believed that unaffordable housing could drive businesses away and thus impede job growth. However, there is little evidence to support this view. This paper presents a simple model to clarify how housing affordability is linked to employment growth and why unaffordable housing could negatively affect employment growth. The paper then investigates this effect empirically using data on California municipalities. For various reasons, a simple correlation between unaffordable housing and employment growth cannot be interpreted as causal. Several empirical strategies are employed to identify the causal effect of unaffordable housing on employment growth. The estimation results provide consistent evidence that unaffordable housing indeed slows local employment growth. [ABSTRACT FROM PUBLISHER]

Which neighborhood conditions foster the growth of ethnic organizations? This paper explores how changing unemployment, homeownership, and immigration in neighborhoods shape the growth of ethnic organizations in San Francisco from 1940 to 1970. Using hierarchical linear modeling, this paper analyzes the growth of white ethnic and racial minority organizations as postwar neighborhood changes took form. Results indicate that white ethnic and racial minority organizations experience very different growth trajectories. Findings indicate that the growth of racial minority organizations was negatively affected as foreign-born population size grew and unemployment rose. White ethnic organizations, however, were impervious to these same neighborhood changes. These results suggest that social heterogeneity and economic uncertainty stall the growth of racial minority organizations, whereas white ethnic organizations are unaffected by these conditions. [ABSTRACT FROM AUTHOR]

San Francisco is engaged in a redevelopment project that could bring millions in investment and community benefits to a starved neighborhood-and yet the project is embedded in an urban development process that is displacing residents. In trying to unsettle these contradictions, this paper achieves two aims. First, I unearth a little known history of redevelopment activism that frames debate around the current project. Second, I use this history to argue for a reframing of the language of race. To wit: although the social construction of race and racism is well established, race is still deeply understood in everyday life as natural. This paper offers a theoretical fusing of race and class, 'race-class', to help us think race through a vital constructionist lens. Race-class makes present the economic dynamics of racial formation, and foregrounds that race is a core process of urban political economy. Race-class works both 'top-down' and 'ground-up.' While it is a vehicle for capital's exploitation of people and place, race-class also emerges as a mode of power for racialized working-class residents. [ABSTRACT FROM AUTHOR]

This paper advances the concept of 'waste formations' as a way of thinking together processes of race, space, and waste in brownfield redevelopment projects. Defined as formerly industrial and contaminated properties, in the 1990s brownfields emerged as the grounds for new forms of urbanization and an emerging environmental remediation industry. Through their redevelopment, the twentieth century's urban wastelands-environmentally degraded, economically divested, and often racially marked-have become sites of investment, resignification, and value formation. The concept of waste formations provides a critical framework on the ways these socio-ecological transformations rework twentieth century urban inequalities-in particular, the articulation of waste and toxic waste-and the ways they produce new geographies of environmental injustice through the displacement of toxic waste to newly waste-able spaces. This paper develops an analytic of waste formations and applies it to the process of brownfield redevelopment at the Hunters Point Shipyard in southeast San Francisco. [ABSTRACT FROM AUTHOR]

This paper evaluates through experimental testing a prototype of switchable insulated shading (SIS) systems suitable for windows to optimize solar heat gains in order to maintain indoor thermal comfort. Specifically, the paper describes a laboratory testing procedure and measurement results for SHGC values specific to various SIS designs and operation settings using a box calorimeter set-up. The SIS prototype can modulate continuously its optical and thermal properties including U-value and SHGC using rotating insulation layers controlled through an actuator to a specific slate angle setting. The results of the experimental testing confirm that SHGC value for the SIS prototype is correlated to the slate angle of the insulated layers. This correlation remains applicable for any SIS insulation thickness. The measured data are used to assess the potential energy efficiency benefits from SIS when applied to windows for US homes. In particular, a prototypical housing unit located in three US cities is considered to evaluate the energy efficiency potential for switchable opaque insulated shading systems. The results indicate that SIS systems can achieve up to 8.3%, 11.3%, and 11.4% in annual HVAC energy consumption compared to no-shading cases for dwellings located in Golden, CO (representing a cold climate), Phoenix, AZ (representing a hot climate), and San Francisco, CA (representing a mild climate), respectively. [ABSTRACT FROM AUTHOR]

• We examine the stakeholders and narratives which shaped TVP product development in the US in the 1960s to early 1980s. • The US Government supported TVP development through R&D funding and providing access to lucrative markets. • Several actors raised concerns, including about the nutritional content of products, and the use of captive markets. • Policymakers should ensure institutional markets are responsibly used when product innovation is at stake. This paper examines the interplay between government, industry and other stakeholders, and the key narratives shaping the development and regulation of alternative protein products in the US in the 1960s to early 1980s, paying particular attention to how the US National School Lunch Programme was used for the development of these products. Using internal food industry documents sourced from the University of California San Francisco (UCSF) Food Industry Documents Archive, we find that the US government proactively paved the way for industry to develop alternative protein products by: (a) providing government funding for textured vegetable protein product research and development; (b) opening the doors to lucrative markets; and (c) supporting a lenient regulatory environment for alternative protein products to be developed. A key market for textured vegetable protein products was the US National School Lunch Programme, which was treated as a captive market for developing new products and formulations. The motivations for introducing textured vegetable proteins in schools differed between government and industry, principally between: offering cost-savings and alleviating malnutrition and food insecurity versus developing profitable new food products. Industry actors actively sought to modify the regulatory environment to favour commercial interests, and the government was slow to regulate the alternative protein industry and relied on industry self-regulation. Our research is particularly relevant, because of what appears to be renewed interest in recent years in using school meal programs for the development of alternative-proteins, a phenomenon not limited to the US. [ABSTRACT FROM AUTHOR]

A high number of electric vehicles (EVs) in the transportation sector necessitates an advanced scheduling framework for e-mobility ecosystem operation to overcome range anxiety and create a viable business model for charging stations (CSs). The framework must account for the stochastic nature of all stakeholders' operations, including EV drivers, CSs, and retailers and their mutual interactions. In this paper, a three-layer joint distributionally robust chance-constrained (DRCC) model is proposed to plan day-ahead grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operations for e-mobility ecosystems. The proposed three-layer joint DRCC framework formulates the interactions of the stochastic behaviour of the stakeholders in an uncertain environment with unknown probability distributions. The proposed stochastic model does not rely on a specific probability distribution for stochastic parameters. An iterative process is proposed to solve the problem using joint DRCC formulation. To achieve computational tractability, the second-order cone programming reformulation is implemented for double-sided and single-sided chance constraints (CCs). Furthermore, the impact of the temporal correlation of uncertain PV generation on CSs operation is considered in the formulation. A simulation study is carried out for an ecosystem of three retailers, nine CSs, and 600 EVs based on real data from San Francisco, USA. The simulation results show the necessity and applicability of such a scheduling framework for the e-mobility ecosystem in an uncertain environment, e.g., by reducing the number of unique EVs that failed to reach their destination from 272 to 61. In addition, the choice of confidence level significantly affects the cost and revenue of the stakeholders as well as the accuracy of the schedules in real-time operation, e.g., for a low-risk case study, the total net cost of EVs increased by 247.3% compared to a high-risk case study. Also, the total net revenue of CSs and retailers decreased by 26.6% and 10.6%, respectively. • Mutual interactions between stochastic parameters of stakeholders are investigated. • PV temporal correlations has be formulated in the optimization problem. • An exact second-order cone programming reformulation is presented to improve accuracy. • By increasing the confidence level, the cost of EVs and charging stations increased. • Number of EVs with constraint violation decreased by increasing confidence level. [ABSTRACT FROM AUTHOR]

This paper presents the inclusion of path based pedestrian environment factors in the San Francisco's CHained Activity Modeling Process model. The factors capture environmental determinants of utility beyond travel time and cost for walking and transit modes with a level of accuracy not previously exhibited in a major agency travel demand model. The paper describes the method for generating the environment factors, discusses which environment factors were found to be significant predictors of walking and transit use, and offers sample interpretations of estimated coefficients using actual livability projects in San Francisco. [ABSTRACT FROM AUTHOR]

Information on several papers discussed at the 2013 Molecular Med Tri―Con international conference organized by the Cambridge Healthtech Institute (CHI) held in San Francisco, California in February. Topics include molecular diagnostics, digital pathology and cancer molecular markers. Several authors presented these papers in the conference including Richard Levinson, Keith Kaplan and Sushmitha Muhkerjee.

In the past 30 years, culture has been used as a means for revitalising neighbourhoods and branding the urban economy. Often, culture-led urban policies have had undesirable consequences in terms of rising rents, displacement of former residents and changes in the economic and retail landscape, i.e. gentrification. However, this process is not univocal, and displacement may not occur while disrupting community life. In this paper we explore the changes that have occurred in San Francisco, a working-class neighbourhood of Bilbao where the attraction of cultural industries has been used to revitalise the area and change the city image. We employ a framework that considers the built form, the cultural cluster organisation and the socioeconomic and demographic changes and we rely on different sources of evidence, including neighbourhood level socioeconomic data, personal interviews and a participatory evaluation, to capture the edges of this complex phenomenon. Our analysis suggests a less deterministic and more complex characterisation of culture-led neighbourhood transformations beyond the revitalisation/gentrification discourses, since conflicts may be driven not by economic transformations and social class replacement, but by the symbolic representation of space and the ‘right to the neighbourhood’. [ABSTRACT FROM AUTHOR]

The assumption of reflection symmetry is one of the major deficiencies for model-based decompositions. The introduction of helix scattering components can mitigate some of the impact of this assumption while simultaneously generating some new negative power problems. The helix mechanism has been developed in the Krogager coherent target decomposition where there is no negative power problem. Why do these problems happen in model-based decompositions? In this paper, we review the Krogager decomposition based on the coherency matrix form of the unified CTD model and come to the conclusion that the imaginary part of T23 is an overestimate of the helix contribution, which is the main cause of the problem. Furthermore, we review the techniques of symmetric scatterer transformation in the Cameron and Huynen decompositions and expand them to the multilook coherency matrix. Two new models of the nonlinear programming problem are proposed to get the transformed coherency matrix: 1) by subtracting the asymmetric component; and 2) by the procedure of con-diagonalization. A new parameter is established to measure the degree of reflection asymmetry of the coherency matrices. Experimental results in the L-band Airborne SAR (AIRSAR) San Francisco data show that the two new models can reduce the correlations between copolarized and cross-polarized channels significantly. In this case, the assumption of reflection symmetry is reasonable for the transformed coherency matrices, and negative power problems related to helix scattering no longer exist in the model-based decompositions; hence, the helix scattering component is not needed. Lastly, the Freeman and Durden decomposition has been applied to the transformed coherency matrices. Experimental results showed that the decomposition results can reflect the predominant characteristics of the ground objects. [ABSTRACT FROM PUBLISHER]

Over the past decade, carsharing has grown considerably in the United States, particularly in major metropolitan areas. This innovative business model offers individuals the opportunity to rent cars by the hour, providing them with greater flexibility for their mobility. Previous work on carsharing suggests that its adoption leads to a decline in household vehicle ownership, vehicle miles traveled, and associated greenhouse gas emissions. Utilizing representative data from the 2010–2012 California Household Travel Survey, this paper presents an analysis of travel behavior and vehicle ownership among carshare members versus non-members in the San Francisco Bay Area, focusing on a subsample of the population with access to carsharing at the U.S. census tract level. Consistent with previous findings on vehicle reduction, these results show that carsharing members own significantly fewer vehicles than non-members. However, lower levels of vehicle ownership are only found among households living in urban areas. In dense, urban neighborhoods, households with carsharing membership own 0.58 vehicles per household as compared with 0.96 vehicles of a control group. Suburban carshare members drive less than their non-carshare member counterparts – although the extent to which this difference can be attributed to self-selection it is unknown. This study also finds that among carsharing households that do own vehicles, a greater share of those vehicles are alternative vehicles (e.g., hybrid, plug-in hybrid electric, and battery electric). Among vehicles owned by the subsample examined in this study, electric drive vehicles represent 18.3% of those owned by carshare member households, as compared with 10.2% of the vehicles owned by non-carsharing households. This analysis finds that not only are urban carshare members likely to own fewer vehicles than the rest of the population, if they do own vehicles, they are more likely to own a vehicle with a smaller environmental footprint. [ABSTRACT FROM AUTHOR]

Critics often mourn a loss of publicness in cities due to the increased presence of antiterror security zones and related behavioral and access controls, although recent work suggests that security landscapes have shifted from the hard, intense, militarized architecture of the late 1990s-early 2000s to a softer, less obtrusive approach more commonly seen today. Nonetheless, these studies are mostly anecdotal in nature: few studies attempt to back these claims with empirical evidence and even fewer connect this physical security imposition with the policies and plans governing its implementation and operation. In this paper I describe results of site visits to Civic Centers and Financial Districts in New York City, Los Angeles, and San Francisco. In each neighborhood I catalog security landscapes using a simple tool to assess the intensity, duration, and location of individual security zones. I find that the security landscape covers between 3.4% and 35.7% of publicly accessible space in the districts studied, and that this landscape is most prevalent and intense in New York City. I also find that security zones governed by multistakeholder networks are more intense and militarized than zones managed by a single entity. By understanding how the policies impact physical security, albeit in a relatively small sample of cities and districts, we can better predict what the future of urban security measures might hold. This paper provides empirical grounding to more common theoretical speculations regarding the future of the urban security landscape in the global West. [ABSTRACT FROM AUTHOR]

Background: Poor communication between referring clinicians and specialists may lead to inefficient use of specialist services. San Francisco General Hospital implemented an electronic referral system (eReferral) that facilitates iterative pre-visit communication between referring and specialty clinicians to improve the referral process.Objective: The purpose of the study was to determine the impact of eReferral (compared with paper-based referrals) on specialty referrals.Design: The study was based on a visit-based questionnaire appended to new patient charts at randomly selected specialist clinic sessions before and after the implementation of eReferral.Participants: Specialty clinicians.Main Measures: The questionnaire focused on the self-reported difficulty in identifying referral question, referral appropriateness, need for and avoidability of follow-up visits.Key Results: We collected 505 questionnaires from speciality clinicians. It was difficult to identify the reason for referral in 19.8% of medical and 38.0% of surgical visits using paper-based methods vs. 11.0% and 9.5% of those using eReferral (p-value 0.03 and <0.001). Of those using eReferral, 6.4% and 9.8% of medical and surgical referrals using paper methods vs. 2.6% and 2.1% were deemed not completely appropriate (p-value 0.21 and 0.03). Follow-up was requested for 82.4% and 76.2% of medical and surgical patients with paper-based referrals vs. 90.1% and 58.1% of eReferrals (p-value 0.06 and 0.01). Follow-up was considered avoidable for 32.4% and 44.7% of medical and surgical follow-ups with paper-based methods vs. 27.5% and 13.5% with eReferral (0.41 and <0.001).Conclusion: Use of technology to promote standardized referral processes and iterative communication between referring clinicians and specialists has the potential to improve communication between primary care providers and specialists and to increase the effectiveness of specialty referrals. [ABSTRACT FROM AUTHOR]

Recently a “mobility turn” has entered critical geographic discourse. This mobility turn recognizes that mobility is at once physical movement and contains social meanings that are manifested in a politics of mobility. In this paper I contribute to this emerging line of inquiry by exploring how the politics of mobility is manifested in localized urban processes. Mobility, as with the broader localized urban process, is political and ideological, and this is particularly true with contemporary debates about automobiles and parking in cities. I explore parking as an example of the broader contestation of urban space, using a case study of San Francisco, California. There are three broad factions in San Francisco's parking debates—progressives that advocate for less parking, neoliberals that advocate that market-based pricing determine the amount of parking, and neoconservatives that advocate for more parking. Throughout the paper, I provide thoughts on the relationship between parking, space, ideology, and the broader urban process. [ABSTRACT FROM AUTHOR]

Abstract: This paper shows that a macroscopic fundamental diagram (MFD) relating average flow and average density must exist on any street with blocks of diverse widths and lengths, but no turns, even if all or some of the intersections are controlled by arbitrarily timed traffic signals. The timing patterns are assumed to be fixed in time. Exact analytical expressions in terms of a shortest path recipe are given, both, for the street’s capacity and its MFD. Approximate formulas that require little data are also given. For networks, the paper derives an upper bound for average flow conditional on average density, and then suggests conditions under which the bound should be tight; i.e., under which the bound is an approximate MFD. The MFD’s produced with this method for the central business districts of San Francisco (California) and Yokohama (Japan) are compared with those obtained experimentally in earlier publications. [Copyright &y& Elsevier]

Using data collected during a 4 year ethnography, this paper examines how the 1996 Personal Responsibility and Work Opportunity Reconciliation Act (PRWORA) has impacted homeless women in San Francisco who are also victims of domestic violence. Specifically this paper looks at how the behavior of abusive men prevents homeless women from successfully navigating the new welfare-to-work requirements and maintaining stable employment. Findings indicate that despite the discourse touting the success of welfare reform, the 1996 PRWORA has further disenfranchised an already devastated population systematically forcing them further onto the margins of society. [ABSTRACT FROM AUTHOR]