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Inline vertical separators are commonly employed on natural gas transmission facilities (e.g., receipt stations) to primarily filter out liquid contaminants such as compressor oil, glycol, free water, etc. However, these contaminants have been found invariably in the piping system downstream of these separators, indicating the separators are not performing as required. The potential consequences of not removing such contaminants includes lower gas quality, impaired gas metering accuracy, corrosion and damage to equipment/instrumentation and adverse impact on industrial or residential end users. Historically, separators’ performance claims and guarantees in terms of efficiency of liquid removal are often of the order 98–99% of liquid droplet sizes ≥ 8μm. However, there is a lack of ability to verify these claims due to difficulties in quantifying liquid injection rates and droplet characteristics vs. liquid collected while in operation. Extensive testing was undertaken at TC Energy’s Gas Dynamic Test Facility in Didsbury, Canada on three different separators from different manufacturers, two are mesh vane type (MV-1 and MV-2), and the third is dual cyclonic type (DC). The tests were conducted in the range of 4–5 MPa and flow velocity in the range of 1.3–13 m/s in the DN150 inlet nozzle to the separator, i.e., at 10:1 turn down ratio. The injected liquid was industrial compressor oil, typically used in the gas transmission industry, and was injected at a loading in the range of 0. 06–1.8%. Four different spray nozzles were used to atomize the injected oil to a range of particle size distributions (PSD), characterized by median diameter size, D50, in the range of 50–90 μm. Test results revealed that the performance of these separators varied between 90–99.8% independent of liquid loading. The effective Souders-Brown K factor also varied between 0.15–0.27 m/s. Tests were also conducted following a batch of solid injection to determine the effects on liquid separation efficiency on MV-2 separator. It was found that the separation efficiency decreased by approximately 9% following a 7.075 kg batch of solid injection, likely due to the accumulation of solids in the vane-pack.

Circulating Ly6Chi monocytes often undergo cellular death upon exhaustion of their antibacterial effector functions, which limits their capacity for subsequent macrophage differentiation. This shrouds the understanding on how the host replaces the tissue-resident macrophage niche effectively during bacterial invasion to avert infection morbidity. Here, we show that proliferating transitional premonocytes (TpMos), an immediate precursor of mature Ly6Chi monocytes (MatMos), were mobilized into the periphery in response to acute bacterial infection and sepsis. TpMos were less susceptible to apoptosis and served as the main source of macrophage replenishment when MatMos were vulnerable toward bacteria-induced cellular death. Furthermore, TpMo and its derived macrophages contributed to host defense by balancing the proinflammatory cytokine response of MatMos. Consequently, adoptive transfer of TpMos improved the survival outcome of lethal sepsis. Our findings hence highlight a protective role for TpMos during bacterial infections and their contribution toward monocyte-derived macrophage heterogeneity in distinct disease outcomes. Agency for Science, Technology and Research (A*STAR) National Research Foundation (NRF) Published version This research was funded by Singapore Immunology Network (SIgN) core funding and A*STAR, Singapore. F.G. is an EMBO YIP awardee and is supported by SIgN core funding and Singapore National Research Foundation Investigatorship (NRF2016NRF-NRF1001-02). L.G.N. is supported by SIgN core funding. S.Z.C. is supported by the Ministry of Health, Singapore’s National Medical Research Council under its Open Fund-Young Individual Research Grant (OFYIRG17may036), and A*STAR Career Development Award (192D8043). Y.C.T. is a graduate scholar supported by the Ministry of Education, Singapore. M.Y.C. is a graduate scholar supported by the SIgN-NTU-NUS scholarship, Singapore. SIgN Flow Cytometry facility is supported by National Research Foundation (NRF) Singapore under Shared Infrastructure Support (SIS) (NRF2017_SISFP09).

article i nfo Asignificant improvement in the photoluminescence of erbium doped amorphous carbon (a-C:H(Er)) is reported. The effects of the RF power on the anode and cathode a-C:H films were investigated in terms of the microstructural and local bonding features. It was determined that Er doped a-C:H fi lms should be placed on the anode to obtain wider bandgap and lower percentage of sp 2 carbon bonding. The metalorganic compound, tris(6,6,7,7,8,8,8- heptafluoro-2,2-dimethyl-3,5-octanedionate) Erbium(+III) or Er(fod)3, was incorporated in-situ into an a-C:H host by metalorganic rf plasma enhanced chemical vapor deposition. This technique provides the capability of doping Er in a vertically uniform profile. The high erbium concentration (3.9 at.%), partial fluorination of the surrounding ligands, and the large optical bandgap of the host a-C:H are the primary factors that enable enhancement of the photoluminescence.

In situ Yb-doped amorphous carbon thin films were grown on Si substrates at low temperatures (

Very high effective minority carrier lifetime (6.3 ms) and very low surface recombination velocity (2.6 cm/s) have been demonstrated on float-zone 1–2 Ω cm crystalline silicon (c-Si) wafers by depositing a-Si:H films using grid-biased remote radio-frequency plasma enhanced chemical vapor deposition (RF PECVD). This method employs a semi-transparent DC biased-grid within the conventional RF PECVD configuration. The DC-biased grid is positioned between the RF electrodes in order to develop a remote plasma and thus allow control of the flux and type of precursors involved in the growth of hydrogenated amorphous silicon (a-Si:H) film. It is shown that compared to conventional RF diode, the grid-biased remote RF PECVD method produces a-Si:H films with superior passivating properties as well as significantly lower concentrations of void and SiH 2 bonding and a lower overall hydrogen content, all of which contribute to a higher quality a-Si:H–c-Si heterostructure.

Selectively-transparent and conducting photonic crystals (STCPCs) made of alternating layers of sputtered indium-tin oxide (ITO) and spin-coated silica (SiO 2 ) nanoparticle films exhibit Bragg-reflectance peaks in the visible spectrum of 95% reflectivity and have a full width at half maximum that is greater than 200 nm. At the same time, their conductive properties are comparable to that of solid sputtered ITO films. Moreover, the average transmission of the STCPCs in the pass-band can be increased to ∼88%, or within 3.3% of the bare glass slide they are fabricated on. Furthermore, we also show that these STCPCs can readily be fabricated on textured surfaces similar to those used for micromorph solar cells. In this context wave optics analysis shows that these STCPCs can be utilized as intermediate reflectors that boost the relative photo-current generated in textured micromorph cells by more than 20% over a broad range of incident angles.

A novel low-emissive (low-E) coating based on plasma enhanced chemical vapor deposited hydrogenated diamond-like amorphous carbon (DLC) films has been developed. The coating is a three-layer structure comprised of a nano-thin Ag layer sandwiched between DLC layers. The tunable optical properties that the DLC layers afford make it extremely appealing for large-scale, low-cost manufacturing of low-E coatings. We have shown that the refractive index of DLC films can be precisely tuned between 1.55 and 2.15 at a wavelength of 550 nm, while the optical gap can be tuned between 1.7 and 4.0 eV. The tunable optical properties allow greater flexibility and provide an additional parameter for optimization of low-E coatings. The tunability also allows for simple fabrication of multi-layer or graded-layer low-E coatings. Initial results of the DLC based low-E coating have a mid-IR reflectance of approximately 95% and a transmittance of approximately 70% over the visible frequencies.

Hydrogenated amorphous silicon (a-Si H) films deposited on crystalline silicon substrates using the DC saddle field (DCSF) plasma enhanced chemical vapor deposition (PECVD) system have been investigated. We have determined the complex dielectric function, e(E) = e1(E) + ie2(E) for hydrogenated amorphous silicon (a-Si:H) thin films by spectroscopic ellipsometry (SE) in the 1.5–4.5 eV energy range at room temperature. The results indicate that there is a change in the structure of the a-Si:H films as the thickness is increased above 4 nm. This is attributed to either an increase in the bonded hydrogen content and, or a decrease of voids during the growth of a-Si:H films. The film thickness and deposition temperature are two important parameters that lead to both hydrogen content variation and silicon bonding change as well as significant variations in the optical band gap. The influence of substrate temperature during deposition on film and interface properties is also included.

The DC saddle-field (DCSF) glow discharge method was used to deposit intrinsic a-Si:H onto c-Si to passivate the c-Si surface. The effective minority carrier lifetime in the heterostructures as a function of the excess minority carrier density in the c-Si wafers was measured. The results were then analyzed in the context of recombination associated with interface defect states using three known recombination models. The defect density and the charge density at the interface are inferred. In addition subsequent annealing of the samples was studied. It is shown that for our intrinsic a-Si:H samples improvements in surface passivation are directly correlated with the reduction of interface defects and not the reduction of minority carrier concentration at the interface due to electric field. We have achieved excellent surface passivation with effective carrier lifetime >4 ms for an intrinsic a-Si:H sample deposited at a process temperature of 200 °C and thickness of about 30 nm. It is also demonstrated that subsequent annealing, at 240 °C, of the samples which were prepared at process temperatures

The integration of photonic materials into CMOS processing involves the use of new materials. A simple one-step metal-organic radio frequency plasma enhanced chemical vapor deposition system (RF-PEMOCVD) was deployed to grow erbium-doped amorphous carbon thin films (a-C:(Er)) on Si substrates at low temperatures (&lt, 200 °C). A partially fluorinated metal-organic compound, tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5- octanedionate) Erbium(+III) or abbreviated Er(fod)3, was incorporated in situ into a-C based host. Six-fold enhancement of Er room-temperature photoluminescence at 1.54 µm was demonstrated by deuteration of the a-C host. Furthermore, the effect of RF power and substrate temperature on the photoluminescence of a-C:D(Er) films was investigated and analyzed in terms of the film structure. Photoluminescence signal increases with increasing RF power, which is the result of an increase in [O]/[Er] ratio and the respective erbium-oxygen coordination number. Moreover, photoluminescence intensity decreases with increasing substrate temperature, which is attributed to an increased desorption rate or a lower sticking coefficient of the fluorinated fragments during film growth and hence [Er] decreases. In addition, it is observed that Er concentration quenching begins at ~2.2 at% and continues to increase until 5.5 at% in the studied a-C:D(Er) matrix. This technique provides the capability of doping Er in a vertically uniform profile.

The DC Saddle Field PECVD system was used to deposit hydrogenated amorphous silicon (a-Si:H) layers for high efficiency amorphous-crystalline silicon heterojunction (ACSHJ) solar cells. The plasma controlling parameters; including the chamber pressure, gas phase dopant concentration for the p-type a-Si:H (a-Si:H(p+)) emitter, and substrate temperature were varied. The substrate temperature was found to be a critical parameter for the deposition of intrinsic a-Si:H as epitaxial formation can occur with just a temperature increase of 10°C. The processing capabilities have been developed to construct ACSHJ solar cells with 15.5% conversion efficiency for a 4.2 cm2 area.

Silicon oxynitride (SiON) films have been found to possess extremely useful properties for optical applications. In optoelectronics, a major advantage of this material is the ability to tune the refractive index from 1.45 to 2.00, allowing designers the flexibility to custom tailor and optimize the refractive index value in the targeted optical device. In addition, its minimum allowable bending radius is much lower compared to other silica materials. This opens up the possibility of miniaturizing integrated photonic systems. Moreover, silicon oxynitride prepared using Plasma Enhanced Chemical Vapor Deposition (PECVD) can be deposited at high growth rates while exhibiting good homogeneity with wide refractive index tuning range making it a well-suited core layer for planar waveguide technologies and microphotonic devices. In this research work, the deposition process and the properties of SiON are discussed. The obtained refractive index as well as the X-ray photoelectron spectroscopy (XPS) analysis are highlighted. Furthermore, FTIR results as a function of the process parameters are presented and their influence on the film properties is discussed.

A new plasma deposition system was built with the capability of varying the electrode spacing in the DC Saddle Field plasma enhanced chemical vapor deposition system. An ion mass spectrometer was installed just below the substrate holder to sample the ion species travelling towards the substrate. Silane plasma and amorphous silicon film studies were conducted to shed light on the impinging ion species, ion energy distributions, and film properties with varying electrode spacing. The results indicate that decreasing the distance between the substrate and cathode leads to a reduction in the high energy ion bombardment.

Wave-optics analysis is performed to investigate the benefits of utilizing Bragg-reflectors and inverted ZnO opals as intermediate reflectors in micromorph cells. The Bragg-reflector and the inverted ZnO opal intermediate reflector increase the current generated in a 100 nm thick upper a-Si:H cell within a micromorph cell by as much as 20% and 13%, respectively. The current generated in the bottom muc-Si:H cell within the micromorph is also greater when the Bragg-reflector is used as the intermediate reflector. The Bragg-reflector outperforms the ZnO inverted opal because it has a larger stop-gap, is optically thin, and due to greater absorption losses that occur in the opaline intermediate reflectors.

Tritiated amorphous and crystalline silicon is prepared by exposing silicon samples to tritium gas (T2) at various pressures and temperatures. Total tritium content and tritium concentration depth profiles in the tritiated samples are obtained using thermal effusion and Secondary Ion Mass Spectroscopy (SIMS) measurements. The results indicate that tritium incorporation is a function of the material microstructure rather than the tritium exposure condition. The highest tritium concentration attained in the amorphous silicon is about 20 at.% on average with a penetration depth of about 50 nm. In contrast, the tritium occluded in the c-Si is about 4 at.% with a penetration depth of about 10 nm. The tritium concentration observed in a-Si:H and c-Si is higher than reported results from post-hydrogenation experiments. The beta irradiation appears to catalyze the tritiation process and enhance the tritium dissolution in silicon material.

The DC saddle field glow discharge method was used to deposit a-Si∶H in order to passivate c-Si surfaces. The process temperature and the thickness of the a-Si∶H films were varied. In addition subsequent annealing of the smaples were studied. Passivation quality of the a-Si∶H overlayers were studied by measuring the effective minority carrier lifetime in the heterostructures as a function of the minority carrier density in the c-Si wafer. These results are then used to model the surface recombination mechanism in our samples. The defect density and the charge density at the interface are inferred which helps us to distinguish between the effects of electric field and chemical passivation at the interface. It is shown that for our intrinsic a-Si∶H samples improvements in surface passivation are directly correlated with the reduction of interface defect density and field effect passivation is minimal. We have achieved surface passivation with effective carrier lifetime ≫ 5 ms for a 40 nm intrinsic a-Si∶H sample deposited at a process temperature of 200 °C. It is also demonstrated that subsequent annealing, at 240 °C, of the samples which were prepared at process temperatures ≪ 240 °C drastically increases the effective lifetime.

Hydrogenated amorphous silicon (a-Si:H) has been extensively investigated experimentally in the infrared spectral region via techniques such as Fourier Transform Infrared (FTIR) and Raman spectroscopy. Although spectroscopic ellipsometry has been proven to be an important tool for the determination of several parameters of a-Si:H films, including dielectric constant, surface roughness, doping concentration and layer thickness, the spectral range used in these studies has rarely covered the infrared region below 0.6 eV, and never over the complete spectral region of interest (0.04 – 0.3 eV). We have measured for the first time the dielectric function of a-Si:H films grown by the saddle field glow discharge technique by spectroscopic ellipsometry in the energy range from 0.04 eV to 6.5 eV, thus extending the analysis into the far infrared region. The a-Si:H films were deposited on germanium substrates for the ellipsometry studies, and on crystalline silicon substrates for the comparative FTIR analysis. Preparation parameters were chosen to obtain films with different hydrogen content. In this paper, we present the results of the ellipsometry analysis, evaluate different fitting techniques, and compare the results with the corresponding FTIR spectra. The similarities and differences between the spectra are discussed in terms of the a-Si:H properties.

Intrinsic hydrogenated amorphous silicon films were deposited by the DC saddle field system on crystalline silicon wafers. The substrate temperature of the amorphous film, crystalline silicon surface cleaning schemes, and the native oxide etchant were varied. The transport parameters of the amorphous-crystalline silicon heterostructures were evaluated by Photocarrier Radiometric (PCR) lifetime measurements. PCR bulk lifetime estimates were obtained using the quinhydrone in methanol solution to passivate the crystalline silicon surface. We present the effectiveness of the PCR system in evaluating different surface passivation schemes.

In the D.C. saddle field glow discharge deposition the transition from amorphous to microcrystalline silicon thin films occurs when the silane concentration in the gas phase drops below 10%. We report here the results of Raman spectroscopy, SEM, TEM, and HRTEM studies of the film morphology. We estimate the average crystallite size to be in the range of 5 to 7 nm and the crystalline volume fraction of 25 to 35%.

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

Wave-optics analysis is performed to show that selectively transparent and conducting photonic crystals (STCPCs) can be utilized as rear contacts to enhance the performance of building-integrated photovoltaics (BIPV). For instance, the current generated in an a-Si:H cell with an STCPC functioning as its rear contact is comparable to that of a similar cell with an optimized ZnO/Ag rear contact. However, the solar lumens (~3.5 klm/m2) and power (~430W/m2) transmitted through the cell with the STCPC rear contact can potentially provide indoor heating and lighting, respectively. Moreover, experimental results show that STCPC rear contacts could be used to control the color temperature of light transmitted through BIPV panels.

Experimental results on tritium effusion, along with the tritium depth profiles, from hydrogenated amorphous silicon (a-Si:H) and crystalline silicon (c-Si) tritiated in tritium (T2) gas at various temperatures and pressures are presented. The results indicate that tritium incorporation is a function of the material microstructure of the as-grown films, rather than the tritium exposure condition. The highest tritium concentration obtained is for a-Si:H deposited at a substrate temperature of 200°C. The tritium content is about 20 at. % on average with a penetration depth of about 50 nm. In contrast, tritium occluded in the c-Si is about 4 at. % with penetration depth of about 10 nm. The tritium concentration observed in a-Si:H and c-Si is much higher than the reported results for the post-hydrogenation process. β irradiation appears to catalyze the tritiation process and enhance tritium dissolution in the silicon matrix. The combination of tritium decay and β-induced ionizations results in formation of re...