Physical Properties Of Gas Research Articles

Visualization of Gas Diffusion-Sorption in Coal: A Study Based on Synchrotron Radiation Nano-CT

Gas diffusion-sorption is a critical step in coalbed methane (CBM) exploitation and carbon dioxide sequestration. Because of the particularity of gas physical properties, it is difficult to visualize the gas diffusion-sorption process in coal by experimental methods. Due to the limitation of experimental approaches to image the three-dimensional coal pore structure, it is impossible to obtain the three-dimensional pore structure images of coal. As a result, the visualization of gas diffusion-sorption in coal pore structure by numerical ways is impossible. In this study, gas diffusion coefficients were firstly estimated by experiments. Then, a gas diffusion-sorption coupled model was developed which can be applied to the nanoscale geometry imaged by synchrotron radiation nano-CT. The dynamic process of gas diffusion and ad-/desorption in the nanoscale microstructure of coal was visualized by the developed gas diffusion-adsorption coupled model and the numerical simulation based on MATLAB. The simulation results show a good agreement with the experimental results. The gas diffusion-sorption coupled model and numerical method can help to investigate the effect of microstructure on gas diffusion and ad-/desorption and provides a possibility to investigate the multiscale gas transportation and adsorption in coal pore-fracture system.

Chemodynamics of green pea galaxies – I. Outflows and turbulence driving the escape of ionizing photons and chemical enrichment

ABSTRACT We investigate the ionized gas kinematics, physical properties, and chemical abundances of Sloan Digital Sky Survey J142947, a Green Pea galaxy at redshift z∼ 0.17 with strong, double-peak Ly α emission and indirect evidence of Lyman continuum (LyC) leakage. Using high-dispersion spectroscopy, we perform a multicomponent analysis of emission-line profiles. Our model consistently fits all lines as a narrow component with intrinsic velocity dispersion σ ∼ 40 km s−1, and two broader blue-shifted components with σ ∼ 90 and ∼ 250 km s−1. We find electron densities and temperatures, ionization conditions, and direct O/H and N/O abundances for each component. A highly ionized, metal-poor, young and compact starburst dominates narrow emission, showing evidence of hard radiation fields and elevated N/O. The blue-shifted broader components are consistent with highly turbulent, possibly clumpy ionized gas at the base of a strong photoionized outflow, which accounts for ≳50 per cent of the integrated emission-line fluxes. The outflow is dense and metal-enriched compared to the H ii regions, with expansion velocities larger than those obtained from UV interstellar absorption lines under standard assumptions. Some of these metals may be able to escape, with outflows loading factors comparable to those found in high-z galaxies of similar SFR/Area. Our findings depict a two-stage starburst picture; hard radiation fields from young star clusters illuminate a turbulent and clumpy ISM that has been eroded by SNe feedback. Whilst UV data suggest an extended Ly α halo with high average H i column density, LyC photons could only escape from SDSS J142947 through low H i density channels or filaments in the ISM approaching density-bounded conditions, traced by outflowing gas.

The Research and Well Performance Simulation under Conditions of West Siberia

The paper proposes a new method of calculating the pressure at the pump intake, taking into account changes in the density of the gas-liquid mixture in the well depth. An algorithm for performing the pressure calculation is presented. Graphs of pressure distribution in the well depth with different gas content in comparison with the traditional method for calculating pressure are given. The importance of taking into account the physical properties of gas depending on the depth was proved.

A critical analysis of transport models for refueling of MOF-5 based hydrogen adsorption system

This work presents a critical analysis of 2D model of refueling a hydrogen storage tank containing MOF-5 adsorbent under cryogenic and room temperature conditions. Three isotherm models, viz. Unilan, modified Dubinin–Astakhov DA and Tóth, were fitted with experimental data of hydrogen adsorption from the literature, and their effect on refueling of adsorbent bed is analyzed. The choice of isotherm has the greatest impact on predicting refueling behavior, for both flow-through and end-flow (i.e., batch) systems. A comparison between the ideal gas assumption and virial equation of state indicates that the former reasonably captures the overall behavior at lower computational cost. Analysis of the role of momentum balance, solved as full Navier–Stokes model and with Darcy’s approximation, indicates same hydrogen uptake in the adsorbent bed and only a minor difference in the predicted velocity profiles. Finally, effect of temperature-dependent physical properties of gas, adsorbent and walls is analyzed.

The effect of hydrogen on the physical properties of natural gas and the metrological characteristics of its metering systems

Given the promise of the concept of using a mixture of hydrogen and natural gas as an energy source, studies were conducted in the following areas:
 
 determination of the effect of hydrogen impurities on the physical properties of natural gas;
 study of the effect of adding hydrogen to natural gas on the metrological characteristics of its consumption metering systems.
 
 To solve these problems, the following was carried out:
 
 determination of the dependence of the physical parameters of natural gas on the percentage of hydrogen in its composition:
 determination of the permissible fraction (permissible concentration) of hydrogen in natural gas in modern gas transmission and gas consuming systems.
 study of the effect of hydrogen additions on the metrological characteristics of measuring instruments and gas commercial metering systems.
 
 To conduct objective research and modeling, natural gas samples having different component composition were prepared. An analysis of the physical properties of these gases was carried out — their physical parameters were calculated: adiabatic index and sound velocity, density, compressibility factor, higher calorific value and Wobbe number. Based on these samples, modeling was performed — the physical parameters of the gases were calculated by adding hydrogen at different concentrations (from 2 to 23 %).
 Based on the research results, the following conclusions are made:
 
 When hydrogen is added to natural gas in an amount of from 2 to 10 %, the physical parameters of the resulting mixture change slightly (within acceptable limits), therefore, the addition of hydrogen to natural gas in an amount of up to 10 % allows the use of existing gas transmission and gas-consuming systems without any reconstructions, improvements, changes in algorithms for calculating the physical parameters of the gas mixture and calculating (volume) volumetric flow for commercial accounting. The impact on gas meters of consumers will be within the acceptable ranges of accuracy and repeatability and, therefore, will not require the cost of updating the meters.
 The addition of up to 25 % hydrogen by volume does not require a radical new technology of burners and gas transmission systems. Safety will not be compromised by adding 25 % hydrogen by volume to the natural gas network. Changes in the physical properties in the gas mixture have a number of disadvantages, but, in the aggregate, they do not pose any additional safety risk.
 The addition of hydrogen in a volume of more than 25 %, as well as the use of the mixture at high pressures, requires additional research and the development of new algorithms.

Modeling of the modes of natural gas transportation by main gas pipelines in the conditions of underloading

The current state of transit of natural gas through the Ukrainian gas transmission system (GTS) is estimated in the paper. The prerequisites for further reduction of the GTS load in the coming years are considered, in particular in the direction of Europe through the gas measuring station "Orlivka" (south direction), taking into account the construction of alternative bypass gas pipelines. On the basis of the review of literature sources on the problem of efficient operation of gas pipelines under conditions of underloading, a method for determining the capacity and energy consumption of the gas pipeline for a given combination of working gas pumping units (GPU) was developed. The Ananyev-Tiraspol-Izmail gas pipeline at Tarutino-Orlivka section was selected as the object of research. The methodology includes the calculation of the physical properties of gas by its composition, the calculation of gas compression, the calculation of the linear part, the gas flow to the compressor station's own needs, and the calculation of the total power of the gas-pumping units under the specified technological limitations. With the help of the original software developed in the MATLAB programming language, cyclical multivariate calculations of the capacity and energy consumption of the gas pipeline were carried out and the operating modes of the compressor shop were optimized in the load range from 23 ... 60 million m3/day. Optimization criterion is the minimum total capacity of the GPU. Variable parameters at the same time are the speeds of the superchargers, different combination of working GPU, load factor. According to the results of the optimization graphical dependences were constructed: the optimum frequency of the rotor of the supercharger on the performance of the pipeline; changes in power and pressure depending on the performance of the pipeline when operating a different combination of superchargers. Recommendations have been developed to minimize fuel gas costs at the compressor station.

Study on strip-shaped liquid film in the corrugated plate dryer

Corrugated plate is an important steam-water separation device in steam generator of a nuclear power plant. Liquid film rupture and subsequent re-entrainment phenomenon are important factors affecting steam-water separation efficiency. The strip-shaped liquid film generated by rupture of film on corrugated plate wall under horizontal shear of airflow is studied. When airflow speed increases to a certain extent, one strip-shaped film suddenly becomes two strip-shaped films. When two strip-shaped films fly away from the mainstream, their fly direction will form a certain angle, which is called the angle formed by two strip-shaped liquid films. LIF method is used to measure this angle. A fitting equation of the angle with good applicability is obtained. Results reveal that the angle is related to corrugated plate structure parameters, physical properties of gas and liquid, relatively. Additionally, breakdown position of two strip-shaped liquid films is measured and its prediction is future research direction.

배기가스 조성에 따른 활성탄의 수은 흡착 특성

Activated carbon injection upstream of a particulate matter control device is a widely applied method for the control of mercury emission from the coal-fired plant and waste incinerator. Performance of activated carbon in mercury control depends on various factors such as flue gas composition, physical and chemical properties of fly ash and activated carbon, etc. This study was designed to investigate the effect of flue gas composition on the mercury adsorption efficiency of activated carbon. Commercial activated carbon was obtained, and a fixed-bed reactor system was used for the tests of its mercury adsorption at various simulated flue gas conditions. A baseline gas consists of 12% carbon dioxide (CO₂), 5% oxygen (O₂), 7% water vapor (H₂O), 60∼70 μg mercury (Hg)/m³ and balance nitrogen (N₂). Each of acidic gases such as sulfur dioxide (SO₂), nitrogen monoxide (NO) and hydrogen chloride (HCl) was added to the baseline gas and injected for the test to investigate the effect of each acidic gas on the mercury adsorption efficiency of activated carbon. In addition, the mercury adsorption efficiency of activated carbon was examined at the conditions of simulated flue gas (1) before air pollution control (2) after desulfurization and (3) after nitrogen oxides (NOx) control.

Discovery of intergalactic bridges connecting two faint z ∼ 3 quasars

We used the Multi-Unit Spectroscopic Explore (MUSE) on the Very Large Telescope (VLT) to conduct a survey of z ∼ 3 physical quasar pairs at close separation (<30″) with a fast observation strategy (45 min on source). Our aim is twofold: (i) to explore the Lyα glow around the faint-end of the quasar population; and (ii) to take advantage of the combined illumination of a quasar pair to unveil large-scale intergalactic structures (if any) extending between the two quasars. In this work we report the results for the quasar pair SDSS J113502.03−022110.9 – SDSS J113502.50−022120.1 (z = 3.020, 3.008; i = 21.84, 22.15), separated by 11.6″ (or 89 projected kpc). MUSE reveals filamentary Lyα structures extending between the two quasars with an average surface brightness of SBLyα = 1.8 × 10−18 erg s−1 cm−2 arcsec−2. Photoionization models of the constraints in the Lyα, He IIλ1640, and C IVλ1548 line emissions show that the emitting structures are intergalactic bridges with an extent between ∼89 kpc, the quasars’ projected distance, and up to ∼600 kpc. Our models rule out the possibility that the structure extends for ∼2.9 Mpc, that is, the separation inferred from the uncertain systemic redshift difference of the quasars if the difference was only due to the Hubble flow. At the current spatial resolution and surface brightness limit, the average projected width of an individual bridge is ∼35 kpc. We also detect one strong absorption in H I, N V, and C IV along the background sight-line at higher z, which we interpret to be due to at least two components of cool (T ∼ 104 K), metal enriched (Z > 0.3 Z⊙), and relatively ionized circumgalactic or intergalactic gas surrounding the quasar pair. Two additional H I absorbers are detected along both quasar sight-lines at ∼−900 and −2800 km s−1 from the system; the latter has associated C IV absorption only along the foreground quasar sight-line. The absence of galaxies in the MUSE field of view at the redshifts of these two absorbers suggests that they trace large-scale structures or expanding shells in front of the quasar pair. Combining longer exposures and higher spectral resolution when targeting similar quasar pairs has the potential to firmly constrain the physical properties of gas in large-scale intergalactic structures.

Simultaneous sulfur hexafluoride and nitrogen multiple-breath washout (MBW) to examine inherent differences in MBW outcomes.

Multiple-breath washout (MBW) can be performed with different gases (sulfur hexafluoride (SF6­) and nitrogen (N2)) and different devices, all of which give discrepant results. This study aimed to confirm previously reported differences and explore factors influencing discrepant results; equipment factors or the physical properties of gases used.MethodsHealthy controls (HCs) and participants with cystic fibrosis (CF) completed MBW trials on two commercially available devices (Exhalyzer D (N2) and Innocor (SF6)). Simultaneous washout of both gases at the same time on the commercial equipment and simultaneous washouts using a respiratory mass spectrometer (RMS) were completed in subsets. Primary outcomes were lung clearance index (LCI), breath number and time required to washout.ResultsBreath number was higher with N2 washout than SF6 in both HCs and patients with CF, whether washouts were completed individually or simultaneously. The difference was greater in more advanced disease, largely caused by differences in the final part of the washout. Results from commercial devices were similar to those obtained with the RMS.ConclusionsN2 MBW results were higher than SF6 MBW, with some of the largest differences reported to date being observed. The biggest impact was at the end of the washout and this was even the case when gases were washed out simultaneously. N2 and SF6 MBW results are inherently different and should be considered as independent measurements.

Structure and Density Comparison of Noble Gas Hydrates Encapsulating Xenon, Krypton and Argon.

Understanding the effect of guest species on the host framework is important for the development of structure-based properties of inclusion compounds. Herein, the crystal structures of the noble gas hydrates encapsulating Xe, Kr, and Ar were studied by powder X-ray diffraction measurements. The crystal structures and hydration numbers of these noble gas hydrates were solved by Rietveld refinements using optimized models with the direct-space technique. It was revealed that host cage size of these hydrates changed depending on the type of guest species even though their unit-cell parameters were the same. Based on the structure models obtained, the densities of Xe, Kr, and Ar gas hydrates were also determined to be 1.837, 1.445 and 1.097 g/cm3 at 93 K, respectively. Our findings, from a crystallographic point of view, may give insight into further understanding the thermodynamic stability and physical properties of gas hydrates encapsulating small guests.

Pressurized IntraPeritoneal Aerosol Chemotherapy vs. intravenous chemotherapy for unresectable peritoneal metastases secondary to platinum resistant ovarian cancer - study protocol for a randomized control trial.

BackgroundDespite optimal surgery and appropriate first-line chemotherapy, ∼70–80 % of patients with epithelial ovarian cancer will develop disease relapse. The prognosis is poor especially for women with Platinum resistant ovarian cancer. The standard treatment for these groups of patients is non-platinum-containing chemotherapy like taxanes, anthracyclines, gemcitabine, topotecan, and trabectedin. These drugs in various combinations and sequences provide modest survival or symptomatic benefit but with significant side effects. Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) is a minimally-invasive drug-delivery technique specifically addressing limited tissue penetration and poor drug distribution with promising results. PIPAC is a novel method of delivering normothermic chemotherapy into the abdominal cavity as an aerosol under pressure. This concept seems to enhance the effectiveness of intra peritoneal chemotherapy by taking advantage of the physical properties of gas and pressure by generating an artificial pressure gradient and enhancing tissue uptake and distributing drugs homogeneously within the closed and expanded peritoneal cavity. Thus, due to the high local bioavailability during PIPAC, the chemotherapy dosage can be reduced which in turn largely prevents systemic side effects and organ toxicity.MethodsThe study aims to investigate the therapeutic efficacy measured as objective tumour response according to Response Evaluation Criteria in Solid Tumours (RECIST) criteria, of PIPAC in comparison with conventional Intravenous chemotherapy for women with recurrent platinum resistant ovarian cancer with peritoneal metastasis (PM). Consecutive patients diagnosed with PM secondary to platinum-resistant ovarian cancer will be randomized to PIPAC group or IV chemotherapy group. The primary objective of this study is to determine the efficacy after three cycles of PIPAC with cisplatin and doxorubicin in comparison with six cycles of systemic chemotherapy. The secondary outcome measures include morbidity and mortality, overall survival and disease specific survival. Analysis is by intention to treat.AimAssess the objective tumour response of PIPAC in comparison with systemic intravenous chemotherapy for women with platinum-resistant ovarian cancer.Study typeProspective randomized control intervention trial.Intervention modelIV Chemotherapy group (Control group) PIPAC group (Experimental group)MaskingOpen label.Primary purposeTreatment.Sample sizeCalculated sample size is 97 and rounded to 100. For each treatment group sample size of 50 will be considered.Primary outcome criteriaObjective tumour response according to Response Evaluation Criteria in Solid Tumours (RECIST) criteria version 1.1.Secondary outcome criteriaMorbidity;Disease-specific survival (months between inclusion and death due to ovarian cancer);OS (months between inclusion and death due to any cause);CA 125 levels.DiscussionPIPAC in women with platinum resistant ovarian PM has good response owing to superior tissue penetration and better drug distribution. The procedure is safe and well tolerated owing it to its minimal invasiveness. Typical side-effects of systemic chemotherapy, such as alopecia, peripheral neurotoxicity, nausea and myelosuppression are absent. We expect reduction of ascites with symptomatic relief and CA 125 levels. PIPAC is a novel technique for selected patients with platinum resistant ovarian PM and further investigation in comparative clinical trials with conventional chemotherapy will establish its role as a good palliative treatment option.Ethics committee approvalObtained.StatusRecruiting.Trial registration numberREF/2018/08/021223 Registered on Clinical Trials Registry – India (CTRI); www.ctri.nic.in

A model for prediction of maximum-efficiency inlet velocity in a gas-solid cyclone separator

A new model for determining maximum-efficiency inlet velocity in the gas-solid cyclone separator was developed analytically in this study. Previous maximum-efficiency inlet velocity (VMEIV) models are derived at normal temperature and do not function properly under high-temperature conditions. The new model not only accounts for gas physical properties and cyclone structure dimensions, but also various particle characteristics as well as temperature; it can be applied to predict VMEIV at both normal and high temperatures. Based on Yang’s model, a hard sphere analogy of the soft sphere model was used to directly manage particle-wall collision as per the flow field of the cyclone. This model yields more accurate downward flow region width information than previously proposed models. If the radial displacement of a rebounded particle after collision is equal to the width of the downward flow region, then the corresponding inlet velocity is defined as the maximum-efficiency inlet velocity. Comparisons among different experimental results and other models’ results indicate that the proposed model more accurately predicts maximum-efficiency inlet velocity.

H2/CO2 Gas Transport Performance in Poly (Ethylene Oxide) Reverse-selective Membrane with Star-like Structures

A series of poly (ethylene oxide) (PEO) membranes with star-like structures for CO2/ H2 separation were prepared by the photo-polymerization method. The structure of PEO membrane was characterized by Fourier transform infrared spectroscopy (FTIR). The thermal property and inter-segmental distance of polymer chain were investigated by differential scanning calorimetry and wide-angle X-ray diffraction, respectively. The density was determined by hydrostatic weighing method. The gas permeability, solubility and diffusivity of CO2 and H2 were investigated in the star-like PEO membranes. The relationship between gas permeation performances and physical properties was also discussed. The membrane exhibits outstanding CO2 permeability (about 9.7×10-11 cm3 (STP) cm/cm2/s/Pa) and CO2/H2 selectivity (about 11) compared with other membranes.

Study of Flow Characteristics of Gas Mixtures in a Rectangular Knudsen Pump.

A Knudsen pump operates under the thermal transpiration effect or the thermal edge effect on the micro-scale. Due to the uneven temperature distribution of the walls in the channel axis direction or the constant temperature of the tips on the walls, directional thermally-induced flow is generated. In this paper the Direct Simulation Monte Carlo (DSMC) method is applied for N2–O2 gas mixtures in the ratios of 4:1, 1:1, and 1:4 with different Knudsen numbers in a classic rectangular Knudsen pump to study the flow characteristics of the gas mixtures in the pump. The results show that the changing in the gas physical properties does not affect the distribution of the velocity field, temperature fields, or other fields in the Knudsen pump. The thermal creep effect is related to the molecular mass of the gas. Even in N2 and O2 gas mixtures with similar molecular masses, N2 can be also found to have a stronger thermal creep effect. Moreover, the lighter molecular weight gas (N2) can effectively promote the motion of the heavier gas (O2).

Discrimination and concentration measurement of different binary gas mixtures with a simple resonator through viscosity and mass density measurements

Compared to physical microsensors based on the measurement of physical properties of gases, chemical microsensors are attractive for detection of gas due to their selectivity and relatively high sensitivity. However, most of the time they present a considerable drift in their output which either requires recalibration or makes them unsuitable for several applications. Physical gas microsensors used for chemical detection on the other hand lack of selectivity which makes them unsuitable for applications where more than one gas concentration is susceptible to change. In this paper, a new method is exposed, that allows physical microsensors to discriminate different binary gas mixtures in applications such as industrial gas monitoring, where the viscosity and mass density of the gases prone to manifest are known. The method is based on the measurement of both the resonant frequency and the quality factor in microresonators. The small variations of such signals are interpreted in terms of viscosity and mass density variations with respect to a reference gas such as nitrogen (N2). This method allows the discrimination of the gases mixtures as well as the determination of the gas concentration.

High polarization degree of the continuum of comet 2P/Encke based on spectropolarimetric signals during its 2017 apparition

Context.Spectropolarimetry is a powerful technique for investigating the physical properties of gas and solid materials in cometary comae without mutual contamination, but only a few spectropolarimetric studies have been conducted to extract each component.Aims.We attempt to derive the continuum (i.e., scattered light from dust coma) polarization degree of comet 2P/Encke, free of the influence of molecular emissions. The target is unique in that its orbit is dynamically decoupled from Jupiter, like the main-belt asteroids, but it ejects gas and dust like ordinary comets.Methods.We observed the comet using the Hiroshima Optical and Near-Infrared Camera attached to the Cassegrain focus of the 150 cm Kanata telescope on UT 2017 February 21 when the comet was at the solar phase angle ofα= 75°.7.Results.We find that the continuum polarization degree with respect to the scattering plane isPcont, r= 33.8 ± 2.7% at the effective wavelength of 0.82μm, which is significantly higher than those of cometary dust in a high-Pmaxgroup at similar phase angles. Assuming that an ensemble polarimetric response of the dust of 2P/Encke as a function of phase angle is morphologically similar with those of other comets, its maximum polarization degree is estimated toPmax≳ 40% atαmax≈ 100°. In addition, we obtain the polarization degrees of the C2swan bands (0.51–0.56μm), the NH2αbands (0.62–0.69μm), and the CN-red system (0.78–0.94μm) in a range of 3–19%, which depend on the molecular species and rotational quantum numbers of each branch. The polarization vector is aligned nearly perpendicularly to the scattering plane with an average of 0°.4 over a wavelength range of 0.50–0.97μm.Conclusions.From the observational evidence, we conjecture that the high polarization degree of 2P/Encke might be attributable to a dominance of large dust particles around the nucleus, which have remained after frequent perihelion passages near the Sun.

India National Gas Hydrate Program Expedition-02: Operational and technical summary

Abstract The India National Gas Hydrate Program is being steered by the government of India's Ministry of Petroleum and Natural Gas (MoPNG) with participation of Directorate General of Hydrocarbons (DGH), Oil and Natural Gas Corporation Limited (ONGC), and the National Oil Companies and Research Institutes of India. The India National Gas Hydrate Program Expedition 01 (NGHP-01) established the presence of gas hydrate in the Krishna Godavari (KG) and Mahanadi Basins and in the offshore area of the Andaman Sea Basin. However, the gas hydrates discovered during NGHP-01 were mainly distributed as fracture-filling material in fine-grained clay-rich sediments. The India National Gas Hydrate Program Expedition 02 (NGHP-02) was carried out with an objective to discover gas hydrate in sand-rich sediment along the eastern offshore margin of India. ONGC planned and executed NGHP-02 on the behalf of the MoPNG. NGHP-02 started on March 3, 2015 and was completed on July 28, 2015 (total 147 days) using the Japanese scientific Drilling Vessel Chikyu (D/V Chikyu). During NGHP-02, 42 holes at 25 sites were drilled, cored, and/or surveyed with downhole logging tools. These sites were located in four areas along the eastern margin of India and formally named Area A (Mahanadi Basin, three sites), Area B (northern part of the KG-Basin, twelve sites), Area C (central part of the KG-Basin, six sites), and Area E (southern part to the KG-Basin, four sites). All 25 sites established during NGHP-02 were first drilled and logged with logging-while-drilling (LWD) tools and an additional 17 holes were then drilled and/or cored with conventional coring tools (HPCS/ESCS) or pressure coring tools (PCTB). Wireline logging was conducted in 10 holes and formation tests using a dual packer Modular Formation Dynamics Tester (MDT) tool were carried out in two holes. The onboard science team used the laboratory facilities on the D/V Chikyu to examine and analyse the physical properties, geochemistry, and sedimentology of all the cores collected during the expedition. Core samples were also analysed in additional post-expedition shore-based studies conducted in numerous domestic and international gas hydrate research laboratories. The NGHP-02 sediment cores were archived at the National Gas Hydrate Core Repository in Mumbai (India), which is associated with the ONGC Gas Hydrate Research and Technology Centre (GHRTC). The necessary data for characterizing the occurrence of gas hydrate, such as interstitial water chlorinities, core-derived gas chemistry, physical and sedimentological properties, thermal images of the recovered cores, pressure core and downhole measured logging data (LWD and/or conventional wireline log data), were obtained from most of the drill sites established during NGHP-02. Almost all the drill sites yielded evidence for the occurrence of gas hydrate; however, the inferred in situ concentration of gas hydrate varied substantially from site to site. For the most part, the interpretation of downhole logging data, core thermal images, interstitial water analyses, and pressure core images from the sites established during NGHP-02 indicate that the occurrence of concentrated gas hydrate is mostly associated with coarser grained (sand-rich) sediments. This paper presents the operational and technical summary of NGHP-02.

Randomized control trial comparing quality of life of patients with end-stage peritoneal metastasis treated with pressurized intraperitoneal aerosol chemotherapy (PIPAC) and intravenous chemotherapy.

BackgroundPeritoneal metastasis (PM) is a common occurrence in gynaecological and gastrointestinal cancers and is associated with poor survival. Patients typically present with ascites, abdominal pain, malnutrition, nausea, emesis, and bowel obstruction which significantly compromise the quality of life (QoL). The treatment remains a particular challenge, with palliative systemic chemotherapy being the standard of care. However, the efficacy of systemic chemotherapy is poor but with high potential for side effects and complications. QoL plays an important role in patients with PM and is deteriorating continuously until death. Thus, there is an obvious medical need for better therapeutic options in PM for prolonging survival and preserving QoL by reducing both disease-related symptoms and therapy side effects. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel technique for delivering pressurized normothermic chemotherapy into the abdominal cavity as an aerosol. This concept seems to enhance the effectiveness of intraperitoneal chemotherapy by taking advantage of the physical properties of gas and pressure by generating an artificial pressure gradient and enhancing tissue uptake and distributing drugs homogeneously within the closed and expanded peritoneal cavity.MethodsThe primary objective of this study is to assess QoL and symptoms in a consecutive cohort of patients with PM treated with PIPAC procedure in comparison with conventional systemic intravenous chemotherapy. QoL is assessed prospectively using European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30(Version 3.0) questionnaire. QLQ-C30 is a 30-question self-administered questionnaire inquiring about global health status, 9 individual symptoms, and 5 functional scales. Baseline QoL is measured using the global physical health functional score, and symptom scores derived from EORTC QLQ30 questionnaire before starting therapy, followed by at 60, 120, and 180 days after the first intervention. Calculated sample size is 119 and rounded to 120. For each treatment group, sample size of 60 will be enrolled; Intervention model: IV chemotherapy group (control group) and PIPAC group (experimental group); Study type: prospective randomized control intervention trialDiscussionAll consecutive patients diagnosed with advanced end-stage PM are randomized to be treated with PIPAC or IV chemotherapy. The primary objective of this study is to determine the QoL after three cycles of PIPAC in comparison with six cycles of systemic chemotherapy. The secondary outcome measures include morbidity and mortality. Analysis is by intention to treat.ResultsThe effect of systemic chemotherapy remains limited on the peritoneum due to poor vascularization and low penetration. Side effects after systemic chemotherapy for PM are relatively frequent. QoL plays an important role in these patients and is deteriorating continuously due to the disease or therapy related. Thus, there is need for better therapeutic options for prolonging survival and preserving QoL by reducing both disease-related symptoms and therapy side effects. PIPAC is a novel minimally invasive repeatable treatment modality which demonstrated potentially encouraging tumour response and only minimal toxicity in patients with PM of various origins. It can optimize local drug delivery and improve clinical outcome due to superior pharmacological properties as compared to systemic chemotherapy.Trial registrationREF/2018/08/021225 Registered on Clinical Trials Registry-India (CTRI); www.ctri.nic.in

Combustion interactions of blended coals in an O2/CO2 mixture in a drop-tube furnace: Experimental investigation and numerical simulation

Interactions, known as the ignition promotion and burnout inhibition, exist during the combustion of blended coals in the air. The oxy-fuel conditions influence these interactions due to the change of the gas physical properties and the gasification reaction. However, little research has focused on the oxy-fuel combustion interactions of blended coals. To investigate the combustion interactions of blended coals in an O2/CO2 atmosphere, experimental and numerical studies of the mixed combustion of less- and more-volatile coals are performed in a drop tube furnace. The results show that the more-volatile coal combustion brings the promotive effect on the devolatilization of the less-volatile coal and the inhibitive effect on the char combustion of the less-volatile coal. Compared with that in the air, the promotive effect is weaker, but the inhibitive effect is stronger in the 21%O2/79%CO2 environment due to the different physical properties of the gases. In the O2/CO2, increasing the oxygen concentration increases the promotive effect but weakens the inhibitive effect owing to the change of the physical properties of gases and the reactivity improvement of the less-volatile coal char. In addition, the promotive and inhibitive effects achieve a level similar to that in the air when the oxygen concentration is increased to approximately 30–35%. Furthermore, the char-CO2 gasification reaction in the O2/CO2 has little impact on the promotive effect but weakens the inhibitive effect. Increasing the reactor wall temperature weakens both the promotive effect and the inhibitive effect.