Carbon Monoxide Gas Research Articles

Polydopamine‐Mediated Interfacial Functionalization of Implants for Accelerating Infected Bone Repair through Light‐Activatable Antibiosis and Carbon Monoxide Gas Regulated Macrophage Polarization

AbstractCurrent treatments for implant‐associated infection remain unsatisfactory due to secondary infection and excessive inflammation, which impairs osseointegration. Herein, an interfacial functionalization strategy is proposed by the integration of a carbon monoxide gas (CO) nanogenerator on titanium implants, followed by covalently grafting arginine‐glycine‐aspartic acid (RGD) polypeptide. Under near‐infrared light (NIR) irradiation, the designed surface displays great light‐activatable antibiosis through CO‐potentiated mild photothermal therapy. Interestingly, the functionalized surface exerts a CO‐mediated anti‐inflammatory effect by activating the expression of heme oxygenase (HO‐1), and inducing the down‐regulation of p38 mitogen‐activated protein kinase (MAPK) and nuclear factor kappa B (NFκB) (p50/p65). More importantly, the combination of CO delivery and RGD immobilization drives the polarization of lipopolysaccharide (LPS)‐stimulated M1‐phenotype macrophages towards anti‐inflammatory M2‐phenotype through a potential Janus kinase 1/signal transducer and activator of transcription 6 (JAK1/STAT6) pathway, thereby remodeling the damaged microenvironment into a pro‐regenerative microenvironment. In a rat model of implant‐associated infection, the designed surface effectively eliminates the residual bacteria, alleviates the accompanying inflammation and mediates macrophage‐mediated immunomodulation, resulting in good osteogenesis. Together, these findings are a first report on the therapeutic potential of CO signal in the cascade of immunomodulation‐osteogenic differentiation. The functionalized implant may serve as a promising candidate in implant replacement surgeries.

A model of FeN-decorated BeO layer particle for CO gas adsorption

Carbon monoxide (CO) is known as a deathful gas produced by burning of hydrocarbons in a lack of enough oxygen, in which breathing CO leads to serious issues on human life health quality. Therefore, adsorption of CO gas is an essential task for diagnosis or removal of this dreadful gas in environment. To do this, a HEME-like model of iron-nitrogen-doped beryllium oxide (FeNBeO) monolayer was investigated for adsorbing CO gas by performing density functional theory (DFT) calculations. Two models were obtained for this process, in which relaxation of CO with C-head or O-head towards Fe region of monolayer. The results indicated that the formation of FeNBeO-CO model could be achieved more favorable than the formation of FeNBeO-OC model. The obtained optimized geometers and energies all approved this achievement for favorability of FeNBeO-CO model formation. Moreover, molecular orbital based electronic features indicated variations of such features for the models upon adsorption of CO substance, in which the models could be detectable in a sensor function for the existence of CO gas in the environment. As a consequence, the investigated FeNBeO monolayer could be proposed useful for adsorption of CO gas at least for the CO deathful gas diagnosis purposes.

Highly Selective and Low-Power Carbon Monoxide Gas Sensor Based on the Chain Reaction of Oxygen and Carbon Monoxide to WO3.

Carbon monoxide (CO) poisoning can easily occur in industrial and domestic settings, causing headaches, loss of consciousness, or death from overexposure. Commercially available CO gas sensors consume high power (typically 38 mW), whereas low-power gas sensors using nanostructured materials with catalysts lack reliability and uniformity. A low-power (1.8 mW @ 392 °C), sensitive, selective, reliable, and practical CO gas sensor is presented. The sensor adopts floated WO3 film as a sensing material to utilize the unique reaction of lattice oxide of WO3 with CO gas. The sensor locally modulates the electron concentration in the WO3 film, allowing O2 and CO gases to react primarily in different sensing areas. Electrons generated by the CO gas reaction can be consumed for O2 gas adsorption in a remote area, and this promotes the additional reaction of CO gas, boosting sensitivity and selectivity. The proposed sensor exhibits a 39.5 times higher response than the conventional resistor-type gas sensor fabricated on the same wafer. As a proof of concept, sensors with In2O3 film are fabricated, and the proposed sensor platform shows no advantage in detecting CO gas. Fabrication of the proposed sensor is reproducible and inexpensive due to conventional silicon-based processes, making it attractive for practical applications.

Understanding on the hydrogen detection of plasma sprayed tin oxide/tungsten oxide (SnO2/WO3) sensor

The plasma spray technique was well proven in producing metal oxide based gas sensors in the last two decades using different powder feedstocks. However, limited research was made to fabricate hydrogen gas sensor from tin oxide layer coated over tungsten oxide layer. This paper attempts to interpret the hydrogen gas sensing performances of plasma sprayed coating derived by depositing tin oxide layer over tungsten oxide (SnO2/WO3) layer. Plasma sprayed SnO2/WO3 sensor showed maximum response of 90% at 150 °C in contrast to stand-alone WO3 (89% at 350 °C) and stand-alone SnO2 (89% at 250 °C). The lower operating temperature of SnO2/WO3 sensor without compromising gas response was attributed to the WO3–SnO2 hetero-junction. SnO2/WO3 sensor showed selective sensing towards hydrogen with respect to carbon monoxide and methane gases. This sensor also possessed repeatable characteristics after 39 days from the initial measurement. In a nut-shell, plasma spayed SnO2/WO3 sensor showed stability of base resistance, repeatability after successive response and recovery cycles, selective sensing towards 500 ppm H2 with significant magnitude of gas response of 90%, response time of 35 s and recovery time of 269 s at a temperature of 150 °C.

Strategies for Reduced Engine-Out HC, CO, and NOx Emissions in Diesel-Natural Gas and POMDME-Natural Gas Dual-Fuel Engine

<div class="section abstract"><div class="htmlview paragraph">Dual-fuel engines employ precisely metered amounts of a high reactivity fuel (HRF) such as diesel at high injection pressures to burn a low reactivity fuel (LRF) such as natural gas, which is typically fumigated into the intake manifold. Dual fuel engines have demonstrated the ability to achieve extremely low engine-out oxides of nitrogen (NOx) emissions compared to conventional diesel combustion at the expense of unburned hydrocarbon (HC) and carbon monoxide (CO) emissions. At low engine loads, due to low in-cylinder temperatures, oxidation of HC and CO is very challenging. This results in both compromised combustion and fuel conversion efficiencies. The experimental campaign discussed in this paper involved a set of six engine control parameters that were strategically varied to find the best possible efficiency-emissions trade-offs for both diesel- and poly-oxy methylene dimethyl ether (POMDME)-natural gas dual fuel combustion on the University of Alabama single-cylinder research engine (SCRE) based on a PACCAR MX-11 heavy-duty engine platform. The control parameters investigated include: ((1)) Start of Injection (SOI1) of HRF, ((2)) percentage energy substitution (PES) of LRF, ((3)) introduction of the second HRF injection (SOI2), ((4)) split ratio, i.e., ratio of the duration of the first injection to the duration of the second injection, ((5)) rail pressure, and (6) intake pressure. At a fixed gross indicated mean effective pressure (IMEPg) of 5 bar (representative of typical low load operation) and an engine speed of 1339 rpm (“B speed” of the SCRE), SOI1 was varied to determine the lowest engine-out NOx point. Using that SOI1 as baseline and not-to-exceed (NTE) limits of: ((1)) Indicated specific NOx < 1 g/kWh, ((2)) maximum pressure rise rate (MPRR) < 10 bar/deg, and ((3)) coefficient of variation (COV) of IMEPg < 10%, the rest of the five control parameters were systematically varied. Based on HC and CO vs NOx emissions trade-offs, the best PES, SOI2, and split ratio were determined to achieve the lowest possible HC emissions. Subsequently, rail pressure sweeps showed minimal impact on performance and emissions between 500 bar and 1500 bar. Finally, reducing the intake pressure significantly reduced CO emissions to achieve the best overall set of operating parameters. Compared to the baseline diesel-natural gas case, HC and CO were reduced by ~88% and ~82%, respectively, in addition to ~21% improvement in the indicated fuel conversion efficiency. Whereas for POMDME-natural gas dual fuel combustion, HC and CO were reduced by ~85% and ~92%, respectively, in addition to ~20% improvement in the indicated fuel conversion efficiency. Furthermore, due to the high oxygen content of POMDME (47% m/m), engine-out soot emissions were reduced to zero measurable filter smoke number (FSN) for all conditions investigated.</div></div>

Effects of Oxygen-Enhanced Combustion Methods on Combustion Characteristics of Non-Premixed Swirling Flames

The objective of the present study was to experimentally investigate and compare the characteristics of three oxygen-enhanced combustion (OEC) methods; premix enrichment (PE), air-oxy/fuel combustion (AO), and additionally also oxygen lancing (OL) method. The overall oxygen concentration varied from 21% to 38%. Combustion tests were carried out using the gas burner with the thermal input of 750 kW fired by natural gas. The characteristics of OEC methods, such as the concentration of nitrogen oxides and carbon monoxide in flue gas, in-flame temperatures distribution in the horizontal symmetry plane of the combustion chamber, heat flux to the combustion chamber wall, flue gas temperature, and the stability of flame were investigated. NOx emissions increased by more than 40 times and by 20 times for the PE method. The tests using the AO and OL methods with NOx emissions below 150 mg/Nm3 at all oxygen concentrations showed significantly better results. For all OEC methods, radiative heat transfer increased with increasing oxygen concentration. The available heat was 20% higher at 38% O2 than at 21% O2. The flue gas temperature decreased with increasing oxygen concentration, which was affected by a decrease in N2 concentration in the oxidizer and a simultaneous increase in radiant heat flux.

Heme Oxygenase-1: An Anti-Inflammatory Effector in Cardiovascular, Lung, and Related Metabolic Disorders.

The heme oxygenase (HO) enzyme system catabolizes heme to carbon monoxide (CO), ferrous iron, and biliverdin-IXα (BV), which is reduced to bilirubin-IXα (BR) by biliverdin reductase (BVR). HO activity is represented by two distinct isozymes, the inducible form, HO-1, and a constitutive form, HO-2, encoded by distinct genes (HMOX1, HMOX2, respectively). HO-1 responds to transcriptional activation in response to a wide variety of chemical and physical stimuli, including its natural substrate heme, oxidants, and phytochemical antioxidants. The expression of HO-1 is regulated by NF-E2-related factor-2 and counter-regulated by Bach-1, in a heme-sensitive manner. Additionally, HMOX1 promoter polymorphisms have been associated with human disease. The induction of HO-1 can confer protection in inflammatory conditions through removal of heme, a pro-oxidant and potential catalyst of lipid peroxidation, whereas iron released from HO activity may trigger ferritin synthesis or ferroptosis. The production of heme-derived reaction products (i.e., BV, BR) may contribute to HO-dependent cytoprotection via antioxidant and immunomodulatory effects. Additionally, BVR and BR have newly recognized roles in lipid regulation. CO may alter mitochondrial function leading to modulation of downstream signaling pathways that culminate in anti-apoptotic, anti-inflammatory, anti-proliferative and immunomodulatory effects. This review will present evidence for beneficial effects of HO-1 and its reaction products in human diseases, including cardiovascular disease (CVD), metabolic conditions, including diabetes and obesity, as well as acute and chronic diseases of the liver, kidney, or lung. Strategies targeting the HO-1 pathway, including genetic or chemical modulation of HO-1 expression, or application of BR, CO gas, or CO donor compounds show therapeutic potential in inflammatory conditions, including organ ischemia/reperfusion injury. Evidence from human studies indicate that HO-1 expression may represent a biomarker of oxidative stress in various clinical conditions, while increases in serum BR levels have been correlated inversely to risk of CVD and metabolic disease. Ongoing human clinical trials investigate the potential of CO as a therapeutic in human disease.

Formic Acid Dehydrogenation Using Noble-Metal Nanoheterogeneous Catalysts: Towards Sustainable Hydrogen-Based Energy

The need for sustainable energy sources is now more urgent than ever, and hydrogen is significant in the future of energy. However, several obstacles remain in the way of widespread hydrogen use, most of which are related to transport and storage. Dilute formic acid (FA) is recognized asa a safe fuel for low-temperature fuel cells. This review examines FA as a potential hydrogen storage molecule that can be dehydrogenated to yield highly pure hydrogen (H2) and carbon dioxide (CO2) with very little carbon monoxide (CO) gas produced via nanoheterogeneous catalysts. It also present the use of Au and Pd as nanoheterogeneous catalysts for formic acid liquid phase decomposition, focusing on the influence of noble metals in monometallic, bimetallic, and trimetallic compositions on the catalytic dehydrogenation of FA under mild temperatures (20–50 °C). The review shows that FA production from CO2 without a base by direct catalytic carbon dioxide hydrogenation is far more sustainable than existing techniques. Finally, using FA as an energy carrier to selectively release hydrogen for fuel cell power generation appears to be a potential technique.

Study on the effect of long-term high temperature irradiation on TRISO fuel

In the core of the WWR-K reactor, a long-term irradiation of tristructural isotopic (TRISO)-coated fuel particles (CFPs) with a UO2 kernel was carried out under high-temperature gas-cooled reactor (HTGR)-like operating conditions. The temperature of this TRISO fuel during irradiation varied in the range of 950–1100 °C. A fission per initial metal atom (FIMA) of uranium burnup of 9.9% was reached. The release of gaseous fission products was measured in-pile. The release-to-birth ratio (R/B) for the fission product isotopes was calculated. Aspects of fuel safety while achieving deep fuel burnup are important and relevant, including maintaining the integrity of the fuel coatings. The main mechanisms of fuel failure are kernel migration, silicon carbide corrosion by palladium, and gas pressure increase inside the CFP. The formation of gaseous fission products and carbon monoxide leads to an increase in the internal pressure in the CFP, which is a dominant failure mechanism of the coatings under this level of burnup. Irradiated fuel compacts were subjected to electric dissociation to isolate the CFPs from the fuel compacts. In addition, nondestructive methods, such as X-ray radiography and gamma spectrometry, were used. The predicted R/B ratio was evaluated using the fission gas release model developed in the high-temperature test reactor (HTTR) project. In the model, both the through-coatings of failed CFPs and as-fabricated uranium contamination were assumed to be sources of the fission gas. The obtained R/B ratio for gaseous fission products allows the finalization and validation of the model for the release of fission products from the CFPs and fuel compacts. The success of the integrity of TRISO fuel irradiated at approximately 9.9% FIMA was demonstrated. A low fuel failure fraction and R/B ratios indicated good performance and reliability of the studied TRISO fuel.

Mechanism insights into CO oxidation over transition metal modified V2O5/TiO2 catalysts: A theoretical study

The V2O5/TiO2 based selective catalytic reduction (SCR) catalysts possess not only promising capability on the denitrification of nitrogen oxides (NOx), but also certain effects on the oxidation of carbon monoxide (CO) in the flue gas. Modification of traditional SCR catalysts with certain transition metals can further improve their catalytic oxidation ability of CO. Therefore, it is of great significance to reveal the catalytic oxidation mechanism of CO for developing modified SCR catalysts to achieve the co-removal of CO and NOx. Theoretical calculations based on density functional theory (DFT) were performed to probe the comprehensive reaction mechanism of CO oxidation on M doped V2O5/TiO2 catalysts (M = Mo, Fe, and Co). The whole CO oxidation cycles include three stages, i.e., the first CO oxidation, the re-oxidation of the surface, and the second CO oxidation. The terminal oxygen and the surface oxygen formed by the adsorbed O2 all play vital roles in the whole CO oxidation cycles. The activation barriers of the rate-determining steps for CO oxidation on Fe–V2O5/TiO2 and Co–V2O5/TiO2 are much lower than that of Mo–V2O5/TiO2, which indicates Fe and Co dopants can apparently promote the CO oxidation activities of the modified SCR catalysts. Meanwhile, the electronic structure analysis confirms that Fe and Co dopants can cause electron distribution change with strong oxidation ability at the active oxygen sites.

Sources of Carbon Monoxide (CO) Pollution in the Niger Delta area of Nigeria

The Niger Delta in the Southern part of Nigeria had been captioned ‘a region of environmental degradation’ including carbon monoxide (CO) pollution in the World Bank study of the region in 1995 and in the UNEP Environmental assessment of Ogoniland in 2011. The objective of the study was to ascertain the sources of CO production in the Niger Delta, the availability of Nigerian national guidelines on CO pollution, Nigerian national and regional register of CO poisoning and air quality check for CO in the region. A mixed method study (observational-descriptive and systemic review was carried out. Sources of CO production were visited, guidelines on environmental protection, CO and its register and data on daily air monitoring were looked for in Rivers State and the Nigerian Federal Ministries of Environment, Health and Justice. The result showed that there were no guidelines on environmental protection against CO pollution, no register of its poisoning and no monitoring of its ambient and indoor air concentrations in the Niger Delta. Sources of its pollution were tobacco fumes, generator, firewood, kerosene, bush and refuse burning, fire out-brake, barbecues, burning of fossil fuels in old vehicles, crude oil and gas industry (three refineries, oil wells, flow stations and gas flaring, crude oil and condensate spills, vapours from crude and refined oil storage, processing and transportation facilities, petrochemical plants and gas liquefaction plants). In conclusion the Niger Delta was plagued with numerous sources of CO emission and ineffective environmental protection laws. There was therefore urgent need for revival of regional and national environmental laws, maintenance of registers for CO poisoning and conduct of daily air quality check for CO and other gases in the Niger Delta and in Nigeria at large.

IoT Based Gas Leakage Detection and Alarming System using Blynk platforms

Gas or liquefied petroleum gas (LPG) is a chemical substance resultant from petroleum and could be dangerous in industrial places or those that deal with this substance. Gas leakage causes many health issues. So, to prevent such catastrophes and in order to maintain a clean air environment, the workspace atmosphere should be frequently monitored and controlled. The proposed monitoring gas leakage detector system is based on Internet of Things (IoT) technology. NodeMCU ESP8266 Wi-Fi is used to be the microcontroller for the whole system. The combustible gas sensor (MQ2) is used in order to detect the presence of methane (CH4) and carbon monoxide gas (CO). MQ2 sensor will detect the concentration of the gas according to the voltage output of the sensor and the ESP8266 will send the data reading from the gas sensor to Blynk IoT platform over an IOS phone; data visualization is done using Thingspeak IoT Platform. Besides, a fan will immediately work upon the leakage occurs along with an alarming buzzer.

CO recovery from blast furnace gas by vacuum pressure swing adsorption process: Experimental and simulation approach

This paper presents experimental and numerical approaches to use a four-bed, six-step CO vacuum-pressure-swing adsorption (VPSA) process with CuCl/boehmite adsorbent to extract carbon monoxide (CO) gas from a simulated blast furnace gas (BFG; N2:CO:CO2 = 60:20:20 mol %) at setting temperature Tset = 60 °C and adsorption pressure 2.5 bar ≤ Pad ≤ 6.4 bar. The cyclic adsorption isotherms of pure CO2 and CO on CuCl/boehmite pellets were measured at temperature range, 20 °C ≤ Tset ≤ 60 °C using a volumetric method. At Tset = 60 °C, the CO-adsorption capacity was stable during cyclic operation, with negligible hysteresis between adsorption and desorption processes. A mathematical model of four-bed, six-step CO-VPSA was developed; this model successfully reproduced the bench-scale experimental data. A sensitivity analysis of the effect of feed flowrate, rinse flowrate, and desorption pressure on CO purity and recovery was conducted to improve the efficiency of the CO enrichment. Simulations show that 79.9–87.4 mol % of CO recovery could be attained with >90 mol % purity of CO, and 71.8–81.8% CO recovery could be achieved with >99 mol % purity of CO at Tset = 60 °C and 2.5 bar ≤ Pad ≤ 6.4 bar. This method to recover CO from emissions by the steel-making industry can detoxify them, and the CO can be used in syntheses of value-added chemical products.

Design of control system for the gas engine with an electronic control unit and sequential fuel injection

This paper reports the results of studying the electronic control system designed for a gas internal combustion engine with spark ignition operated on liquefied petroleum gas. A new feature in the control system is the possibility to provide the most effective sequential type of gas fuel injection, in which fuel is injected in a sequence corresponding to the order of operation of the cylinders. The special feature of the designed control system is that a movable voltage distributor (ignition distributor) of the ignition system was modified to ensure sequential injection. The ignition distributor modification involves installing an additional setting disc with one integrated permanent magnet on its drive shaft and an additional Hall sensor on the body of the ignition distributor. This makes it possible to ensure that the electronic control unit receives a signal about the angular position of the camshaft, thereby enabling consistent fuel injection. The principle of operation of the gas engine control system provided by the electronic control unit has been described. The structure of the modified ignition distributor is shown. Tests of the gas engine with a new control system involving the designed electronic control unit Avenir Gaz 37 "B" and the software module "B2" were carried out. The tests confirmed the feasibility of the designed electronic control system, which implies consistent injection of gas fuel. In addition, idling tests have shown that the carbon monoxide and hydrocarbon content in exhaust engine gases is significantly lower than the maximum allowable for motors without catalysts. The control system designed could be used for converting the diesel vehicles in operation into gas engines. The use of this control system ensures their safe operation.

Toxic and metabolic leukoencephalopathies in emergency department patients: a primer for the radiologist.

One of the most common chief complaints in the emergency department (ED) is altered mental status (AMS). Imaging plays a critical role in triaging patients and identifying the etiology of AMS. Toxic and metabolic etiologies are one of the primary differential categories for AMS, leading to toxic leukoencephalopathies. Toxic leukoencephalopathies are white matter disorders that result from either exogenous or endogenous sources. Common exogeneous causes of toxic leukoencephalopathy include drugs of abuse (heroin and cocaine), alcohol, inhaled gases (carbon monoxide), industrial agents (pesticides, toluene, ethylene glycol), and neurotoxic medications (methotrexate, metronidazole, vigabatrine, etc.); endogenous causes include hyper- and hypoglycemia, hyperammonemia, hyponatremia, and uremia. The imaging findings of toxic leukoencephalopathies manifest through a combination of vasogenic and cytotoxic edema, resulting in white matter patterns. These white matter patterns have been found to be pathognomonic. In the ED setting, it is imperative to develop a diagnosis based off of the imaging due to the lack of history and context that is typically provided with a chief complaint of altered mental status (AMS). To offer expeditious and accurate diagnosis, we present the classic imaging features of toxic leukoencephalopathies and correlate these imaging findings with pathophysiology.

Visualizing the gas channel of a monofunctional carbon monoxide dehydrogenase

Carbon monoxide dehydrogenase (CODH) plays an important role in the processing of the one‑carbon gases carbon monoxide and carbon dioxide. In CODH enzymes, these gases are channeled to and from the Ni-Fe-S active sites using hydrophobic cavities. In this work, we investigate these gas channels in a monofunctional CODH from Desulfovibrio vulgaris, which is unusual among CODHs for its oxygen-tolerance. By pressurizing D. vulgaris CODH protein crystals with xenon and solving the structure to 2.10 Å resolution, we identify 12 xenon sites per CODH monomer, thereby elucidating hydrophobic gas channels. We find that D. vulgaris CODH has one gas channel that has not been experimentally validated previously in a CODH, and a second channel that is shared with Moorella thermoacetica carbon monoxide dehydrogenase/acetyl-CoA synthase (CODH/ACS). This experimental visualization of D. vulgaris CODH gas channels lays groundwork for further exploration of factors contributing to oxygen-tolerance in this CODH, as well as study of channels in other CODHs. We dedicate this publication to the memory of Dick Holm, whose early studies of the Ni-Fe-S clusters of CODH inspired us all.

Spatio-Temporal Characteristics of Air Quality Index (AQI) over Northwest China

In recent years, air pollution has become a serious threat, causing adverse health effects and millions of premature deaths in China. This study examines the spatial-temporal characteristics of ambient air quality in five provinces (Shaanxi (SN), Xinjiang (XJ), Gansu (GS), Ningxia (NX), and Qinghai (QH)) of northwest China (NWC) from January 2015 to December 2018. For this purpose, surface-level aerosol pollutants, including particulate matter (PMx, x = 2.5 and 10) and gaseous pollutants (sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3)) were obtained from China National Environmental Monitoring Center (CNEMC). The results showed that fine particulate matter (PM2.5), coarse particulate matter (PM10), SO2, NO2, and CO decreased by 28.2%, 32.7%, 41.9%, 6.2%, and 27.3%, respectively, while O3 increased by 3.96% in NWC during 2018 as compared with 2015. The particulate matter (PM2.5 and PM10) levels exceeded the Chinese Ambient Air Quality Standards (CAAQS) Grade II standards as well as the WHO recommended Air Quality Guidelines, while SO2 and NO2 complied with the CAAQS Grade II standards in NWC. In addition, the average air quality index (AQI), calculated from ground-based data, improved by 21.3%, the proportion of air quality Class I (0–50) improved by 114.1%, and the number of pollution days decreased by 61.8% in NWC. All the pollutants’ (except ozone) AQI and PM2.5/PM10 ratios showed the highest pollution levels in winter and lowest in summer. AQI was strongly positively correlated with PM2.5, PM10, SO2, NO2, and CO, while negatively correlated with O3. PM10 was the primary pollutant, followed by O3, PM2.5, NO2, CO, and SO2, with different spatial and temporal variations. The proportion of days with PM2.5, PM10, SO2, and CO as the primary pollutants decreased but increased for NO2 and O3. This study provides useful information and a valuable reference for future research on air quality in northwest China.

Analysis of downdraft low rank coal performance gasification by variations coal to syngas product

Coal resources are inclusive (reserves are part of the resource), of which 48% is located in South Sumatra, with 70% of the deposits being brown or low-quality coal. With the high amount available, the direct use of coal has several shortcomings, one of which is that coal releases gases (CO2, N2O, NOx, SOx and Hg) which cause global warming. Coal gasification is a process for converting solid coal into a gas mixture that has a fuel value. Coal gasification will yield producer gas in the form of synthetic gas (syngas) with the main components consisting of carbon monoxide (CO), hydrogen (H2), and methane gas (CH4). By converting coal using gasification as a clean energy producer, a blower as a regulator of air flow, a cyclone as a tar separator and a gas cooler. Based on the results of testing the variation of coal used, the variation of 5515 kcal /kg coal has a rapid rise in temperature and is able to produce a flame for 115 minutes. with the composition of Syngas CO and CH4 of 12.4% an 1.2%, while the coal variation of 4640 kcal/kg produces the highest H2 of 6.9%. Coal 5515 kcal/kg produces the largest percentage of syngas conversion, carbon conversion, Low Heating Value, power output and stove efficiency, namely 13.46%, 70.397%, 2.427 MJ/kg, 18.403 kW and 31.23%.

Comparison of emissions and engine performance of safflower and commercial biodiesels

Safflower oilseed needs to be studied in detail in relation to the production of biodiesel and its application in engines to be an alternative to commercial biodiesel used around the world. The aim of this study is to compare safflower biodiesel with commercial biodiesel in terms of emissions and performance of an engine using blends biodiesel (B11, B15, B30, and B100). Commercial biodiesel consists of soybean oil and fat. The tests were performed on a single-cylinder, four-stroke, naturally aspirated, and direct-injection diesel engine at four engine loads with a constant engine speed of 3000 rpm. The comparison shows that safflower biodiesel has relatively closer fuel properties to commercial biodiesel than those of diesel oil. The engine power was less affected by increasing engine loads and increasing safflower biodiesel blends compared to commercial biodiesel. Safflower B11 reduced the specific consumption by 2% in relation to diesel (D100) at a load of 3000 W. Safflower biodiesel B11 showed lower carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxide (NOx), and exhaust gas temperature (EGT) compared to commercial biodiesel at high engine loads. The use of safflower biodiesel and commercial biodiesel blend B11 reduced NOx emissions by 15% at a high load of 3000 W. Therefore, safflower biodiesel is a promising alternative to diesel, although it has a higher production cost.

First-principles study of CO gas adsorption on pristine and Fe-doped H[formula omitted]-graphyne

Due to the advantages of high surface volume ratio, stable structure and easy modification, two-dimensional carbon materials have received extensive attention in recent years. In order to find suitable materials for detecting or storing toxic carbon monoxide (CO) gas, first-principles calculations are used to systematically investigate the adsorption performance of pristine H4,4,4-graphyne (H4,4,4-G) and Fe-doped H4,4,4-graphyne (Fe-H4,4,4-G) for CO. The calculation results show that only weak physical adsorption occurs between CO and H4,4,4-G. On the contrary, in the Fe-H4,4,4-G system, the substrate interacts strongly with CO and chemical adsorption occurs. Fe-H4,4,4-G has excellent adsorption performance for CO and the charge transfer is more obvious. Its adsorption energy and charge transfer are -1.601 eV and -0.167 e, respectively. Therefore, Fe-H4,4,4-G can be used as a candidate material for storage or detection of CO. In addition, the applied electric field can effectively control the gas sensitivity of Fe-H4,4,4-G, and further enhance the adsorption performance of CO on the substrate. It is expected that CO can be captured or released by Fe-H4,4,4-G. The results of this research will help advance the study of the adsorption characteristics of H4,4,4-G, and the Fe-doped H4,4,4-G will provide a new idea for the application of gas sensors.