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Selection of a gas sensor requires consideration of environmental effects that can significantly affect performance and cause false alarms. Metal‐oxide sensors have high sensitivity due to the specific interactions of gas molecules with thin metal‐oxide films, however, the films can also be sensitive to variations in temperature and humidity and some oxidizing and deoxidizing gases. The purpose of this paper is to evaluate the environmental effect on metal‐oxide nitrogen dioxide (NO₂) sensors quantitatively.

Three commercial metal‐oxide NO₂ sensors and one electrochemical sensor were tested simultaneously under controlled gas concentrations and various environmental conditions. For this test, a customized sensor testing setup was prepared including a gas mixer, heating module, gas chamber, electronics, and data acquisition units.

Based on the test results for NO₂ gas concentrations ranging from 0 to 10 ppm, the metal‐oxide sensors showed significant signal variations at elevated temperatures and humidity. The results provide overall sensor performance. Linearity, repeatability, selectivity and sensitivity of the metal‐oxide sensors were measured and compared to an electrochemical sensor.

A systematic evaluation to characterize metal‐oxide NO₂ sensors is presented, and their comparison regarding sensitivity, selectivity, linearity, and dependence on humidity and temperature is reported. The result provides sensor performance data and guideline for sensor evaluation.

May 5, 1972 Factory — Statutory duty — Breach — Fume — Prolonged inhalation of low concentration — Chronic lung illness — Employer's actual or constructive knowledge of health hazard — Whether to be determined up to time when action brought — Limits of statutory duty — Whether need to act on expert speculation unaccompanied by hazard warning — Factories Act, 1961 (9 & 10 Eliz. II, c.34), ss. 4(1), 63(1).

PART IV Inorganic chemistry textbooks. Seventeen textbooks of inorganic chemistry are considered in this part of the review, and the inorganic sections of the syllabuses of the three GCE Boards previously discussed are analysed.

Transport of people and goods has always been associated with the generation of some form of pollution, whether atmospheric, sound or visual. Managing the urban environment presents a major challenge: preserving environmental resources and also ensuring decent living conditions for the current population and for future generations. In the era of motorized and carbonized transport, vehicles are the main source of emission of atmospheric pollutants, mainly in large urban centers and important precursors of ozone. An important advance in minimizing vehicle emissions was the introduction of cleaner and additive fuels into the Brazilian market. The purpose of this paper is to study the effect of the Dienitro additive on the NO_x and CO emissions in buses of collective transport, Diesel S-50 exhaust gas recirculation (EGR) and S-10 with selective catalytic reduction (SCR) and EGR systems. Measurements of CO and NO_x gas emissions were carried out using a gas analyzer in S50 and S10 diesel buses with an EGR and SCR systems from a company operating in the collective transport of Biguaçu.

In this study, 20 measurements were performed without additives and 20 measurements with additivation in each bus, making it possible to calculate the average emission rate of CO and NO_x, pollutant gases with toxic effect.

The usage of Dienitro additive in diesel engines resulted in a significant reduction in the emission of polluting gases, carbon monoxide (CO) and nitrogen oxide (NO_x), thus being efficient in reducing the emissions of these gases.

The Dienitro additive was first tested on diesel engines by public transport buses, and there is great potential for reducing the emission of toxic gases.

Incineration strengths of hazardous (2.8×10⁸μg/s) and nonhazardous (6.31×10⁸μg/s) materials were found from the quantities to be incinerated, chemical formulas, and the incineration time. The smoke stack geometry, exhaust dynamics, and different atmospheric stability conditions were used in the Gaussian model to predict the maximum concentration distances of 0.5 to about 6 km at the ground level in the downwind direction. However, trailing edges of some of exhaust distributions were found to extend beyond 120 km under some atmospheric stability conditions. The counties of Jefferson, Lonoke, Pulaski, Dallas, Cleveland, Calhoun, and Grant in the state of Arkansas are more likely to be affected than others. The possible major products in the hazardous incineration exhaust are chlorinated compounds. The results of this study are important to know the areas that fall under comparatively higher concentrations of incineration exhaust for further observations because of its inherent impact upon living beings, crop production, and environmental conditions.

The purpose of this paper is to investigate the ability of transition metals (TMs) of iron-, nickel- and zinc-doped graphene nanosheet for adsorption of toxic gas of nitric oxide (NO). The results of this paper have provided a favorable understanding of the interaction between TM-doped graphene nanosheet and NO molecule.

A high performance of TM-doped graphene nanosheet as a gas sensor is demonstrated by modeling the material’s transport characteristics by means of the Langmuir adsorption and three-layered ONIOM/ density functional theory method. The Langmuir adsorption model has been done with a three-layered ONIOM using CAM-B3LYP functional and LANL2DZ and 6–311G (d, p) basis sets by Gaussian 16 revision C.01 program towards the formation of of NO→TM(Mn, Co, Cu)-doped on the Gr nanosheet.

The changes of charge density for Langmuir adsorption of NO on Mn-, Co- and Cu-doped graphene nanosheet orderly have been achieved as: ΔQ_Co-doped = +0.309 >> ΔQ_Mn-doped = −0.074 > ΔQ_Cu-doped = −0.051. Therefore, the number of changes of charge density have concluded a more remarkable charge transfer for Mn-doped graphene nanosheet. However, based on nuclear magnetic resonance spectroscopy, the sharp peaks around Cu doped on the surface of graphene nanosheet and C19 close to junction of N2 and Co17 have been observed. In addition, Cu-doped graphene sheet has a large effect on bond orbitals of C8–Cu 17, C15–Cu 17 and C16–Cu17 in the adsorption of NO on the Cu-doped/Gr which has shown the maximum occupancy. The amounts of ΔGads,NO→Mn−Co through IR computations based on polarizability have exhibited that ΔGads,NO→Mn−Co has indicated the most energy gap because of charge density transfer from the nitrogen atom in NO to Mn-doped graphene nanosheet, though ΔG(NO→Cu−C)0> ΔG(NO→Co−C)0>ΔG(NO→Mn−C)0.

This research aims to explore the adsorption of hazardous pollutant gas of “NO” by using carbon nanostructure doped by “TM” of iron, nickel and zinc to evaluate the effectiveness of adsorption parameters of various TM-doped graphene nanosheets.

Gas exposure cabinet Wentworth Instruments Ltd., U.K. representatives of Atlas Electric Devices Company of Chicago, U.S.A. can now make available a Gas Exposure Cabinet for use in material testing. Material degradation and failure is commonly caused by the polluting gases such as ozone, sulphur dioxide, oxides of nitrogen found in our atmosphere. The Atlas Gas Exposure Cabinet is a versatile instrument designed to meet specifications calling for concentrations of gas under controlled conditions of temperature and humidity. Models are available for testing with ozone only, with gas from a pressure cylinder only or with controls for both ozone and one cylinder gas. While much attention is being focused on sulphur dioxide and the nitrogen oxides, most gases available in pressure cylinders may be used in the cabinet. Complete information is available in bulletin 1315 from Wentworth Instruments Ltd., North Green, Datchet, Slough, SL3 9JH.

The aim of this paper is to better understand the impact of petroleum production facilities on ambient air quality of host airshed.

Field measurements were taken daily for four consecutive months around petroleum production facilities in the Niger Delta area, of Nigeria, one of the world's important petroleum producing areas. Statistical analysis tool and air quality analytical tool known as the air quality index (AQI) were applied on the field data obtained.

The mean measured daily concentrations of both carbon monoxide (CO) and nitrogen dioxide (NO₂) between distances 50 and 500 m of petroleum flow stations were of the range 140 – 3400 μg/m3 and 23 – 1250 μg/m3 respectively. The AQI from measured CO concentrations in the study area ranged between 1 and 44, an indication of good AQI category with no known health effects but a need for cautionary statement. Similarly, over 97 percent of the measured concentrations of NO₂ were below 0.60 ppm which implies that the AQI of the host environment of the flow stations were below 200 with respect to NO₂ thus indicating a good category of air with no health alarm. However, at the 60 m distance around a flow station, the AQI was 210 thus the quality of available air at this point could be described as very unhealthy. Generally the concentrations of CO were higher than NO₂ in all the distances from the flow stations and were corroborated with their significant T‐test values. The T‐test results of the relationship between the concentrations of the air pollutants per time of the day, showed that their T‐test values were not significant, indicating that concentrations of these air pollutants were independent of the sampling time. A strong and positive correlation existed between the two air pollutants signifying common sources.

The paper highlights that at 60 m distance around petroleum production facilities, people with respiratory or heart disease, the elderly and children should be prevented from gaining access in the morning without taking necessary precautionary measures against the inhalation of air pollutants.

In the first part of the paper, which outlines the laboratory and field investigations on corrosion by flue gases from solid fuel combustion carried out by the British Coal Utilisation Research Association, the effects of different flue gas constituents on corrosion phenomena are discussed. Laboratory studies of the effects of fuel type and method of combustion on the sulphuric acid content of combustion gases are described. The second part presents the results of measurements of the condensation characteristics of flue gases from water‐tube boilers in power stations and from various industrial boilers and furnaces; investigations into the use of additives are described briefly. The final section is concerned with some theoretical considerations of effects of fuel type, burning rate, etc., on the amounts of sulphuric acid likely to be present in the combustion products from domestic appliances.