期刊文献+
共找到11篇文章
< 1 >
每页显示 20 50 100
Multiple responses optimization in the development of a headspace gas chromatography method for the determination of residual solvents in pharmaceuticals 被引量:8
1
作者 Carla M.Teglia Milagros Montemurro +1 位作者 María M.De Zan María S.Cmara 《Journal of Pharmaceutical Analysis》 SCIE CAS 2015年第5期296-306,共11页
An efficient generic static headspace gas chromatography (HSGC) method was developed, optimized and validated for the routine determination of several residual solvents (RS) in drug substance, using a strategy wit... An efficient generic static headspace gas chromatography (HSGC) method was developed, optimized and validated for the routine determination of several residual solvents (RS) in drug substance, using a strategy with two sets of calibration. Dimethylsulfoxide (DMSO) was selected as the sample diluent and internal standards were used to minimize signal variations due to the preparative step. A gas chroma- tograph from Agilent Model 6890 equipped with flame ionization detector (FID) and a DB-624 (30 m × 0.53 mm i.d., 3.00 μm film thickness) column was used. The inlet split ratio was 5:1. The influ- encing factors in the chromatographic separation of the analytes were determined through a fractional factorial experimental design. Significant variables: the initial temperature (IT), the final temperature (FT) of the oven and the carrier gas flow rate (F) were optimized using a central composite design. Response transformation and desirability function were applied to find out the optimal combination of the chromatographic variables to achieve an adequate resolution of the analytes and short analysis time. These conditions were 30 ℃ for IT, 158 ℃ for FT and 1.90 mL/min for F. The method was proven to be accurate, linear in a wide range and very sensitive for the analyzed solvents through a comprehensive validation according to the ICH guidelines. 展开更多
关键词 Headspace gas chromatographyResidual solventsPharmaceuticalsSurface response methodologyDesirabiliW function
下载PDF
Application of response surface methodology for optimization of purge gas recycling to an industrial reactor for conversion of CO_2 to methanol 被引量:2
2
作者 Hadiseh Khalilpourmeymandi Azadeh Mirvakili +1 位作者 Mohammad Reza Rahimpour Alireza Shariati 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第5期676-687,共12页
Nowadays, by the increasing attention to environment and high rate of fuel production, recycling of purge gas as reactant to a reactor is highly considered. In this study, it is proposed that the purge gases of methan... Nowadays, by the increasing attention to environment and high rate of fuel production, recycling of purge gas as reactant to a reactor is highly considered. In this study, it is proposed that the purge gases of methanol production unit, which are approximately15.018 t·h^(-1) in the largest methanol production complexes in the world, can be recycled to the reactor and utilized for increasing the production rate. Purge gas streams contain 63% hydrogen,20% carbon monoxide and carbon dioxide as reactants and 17% nitrogen and methane as inert. The recycling effect of beneficial components on methanol production rate has been investigated in this study. Simulation results show that methanol production enhances by recycling just hydrogen, carbon dioxide and carbon monoxide which is an effective configuration among the others. It is named as Desired Recycle Configuration(DRC) in this study. The optimum fraction of returning purge gas is calculated via one dimensional modeling of process and Response Surface Methodology(RSM) is applied to maximize the methanol flow rate and minimize the carbon dioxide flow rate. Simulation results illustrate that methanol flow rate increases by 0.106% in DRC compared to Conventional Recycle Configuration(CRC) which therefore shows the superiority of applying DRC to CRC. 展开更多
关键词 Methanol synthesis Recycling purge gas streams Novel configuration Response surface methodology
下载PDF
Role of CuO-ZnO Heterojunctions in Gas Sensing Response of CuO-ZnO Thick Films
3
作者 Madhavrao K. Deore Vishwas B. Gaikwad Gotan H. Jain 《Journal of Physical Science and Application》 2016年第2期51-60,共10页
The CuO-doped ZnO thick films were prepared by the screen printing technique. The CuO doped ZnO composite materials were obtained by mixing AR grade (99.9% pure) Zinc Oxide powder mechanochemically in acetone medium... The CuO-doped ZnO thick films were prepared by the screen printing technique. The CuO doped ZnO composite materials were obtained by mixing AR grade (99.9% pure) Zinc Oxide powder mechanochemically in acetone medium with various weight percentages of Copper Chloride (CulCI2.2H20) powder (1, 3, 5, 7 and 9wt.%). The prepared materials were sintered at 1,000 ℃ for 12 h in air ambience and ball milled to ensure sufficiently fine particle size. The films were characterized by different techniques with respect to their surface morphology and compositional property by means of SEM (scanning electron microscope) and EDXA (energy dispersive x-ray analysis). The surface morphology of the films was studied by SEM and it shows the films are porous in nature and petal-shaped grains of sizes varies from 220 nm to 250 nm were observed. The final composition of each film was determined by the EDXA analysis. The gas response of undoped ZnO and CuO doped ZnO films was studied for different gases such as CO, C12, NH3, Ethanol, H2S and LPG at operating temperature ranging from 50 ℃ to 400 ℃. The 7wt.% CuO-doped ZnO film shows good response to H2S gas (100 ppm) at 250 ℃. 展开更多
关键词 CuO-ZnO heterojunctions H2S thick film gas response SELECTIVITY response and recovery time.
下载PDF
Technical Analysis of Freshwater Use as Part of a Responsibly Sourced Gas ESG Strategy
4
作者 Finlay Carlson Huishu Li +2 位作者 Asma Hanif Josh Zier Kenneth Carlson 《Journal of Water Resource and Protection》 2022年第3期292-303,共12页
The Unconventional Oil and Gas industry has seen growth over the last ten years that has drastically transformed the domestic energy outlook while bringing up increased concerns over climate and environmental issues. ... The Unconventional Oil and Gas industry has seen growth over the last ten years that has drastically transformed the domestic energy outlook while bringing up increased concerns over climate and environmental issues. The rise of ESG and RSG can be seen as direct answers to these growing issues as communities and operators have both begun to demand better practices to limit the overall effects of UOG production. Few quantifiable metrics exist that holistically try to determine the overall effect UOG production has on local water resources. The FR2 metric/framework developed in this paper attempts to use commonly kept data such as water withdrawn and flowback volumes in conjunction with a new water stress index to quantify the effects operators are having on local water supplies. Testing this framework on a handful of operators from the Marcellus basin using open-source data revealed the value added by these methods as well as their use in a general RSG program. 展开更多
关键词 Responsible Sourced gas UOG Water Stewardship Water Stress Water Sustainability
下载PDF
Quantitative Method of the Structural Damage Identification of Gas Explosion Based on Case Study:The Shanxi “11. 23” Explosion Investigation
5
作者 Huanjuan Zhao Yiran Yan Xinming Qian 《Journal of Beijing Institute of Technology》 EI CAS 2018年第1期1-14,共14页
In order to present a retrospective analysis of exposition accidents using input data from investigation processes,data from a specific accident was examined,in which we analyzed possible involved gas species( liquef... In order to present a retrospective analysis of exposition accidents using input data from investigation processes,data from a specific accident was examined,in which we analyzed possible involved gas species( liquefied petroleum gas; nature gas) and computed their concentrations and distributions based on the interactions between the structures and the effects of the explosion. In this study,5 scenarios were created to analyze the impact effect. Moreover,a coupling algorithm was put into practice,with a practical outflow boundary and joint strength are applied. Finally,the damage effects of each scenario were simulated. Our experimental results showed significant differences in the 5 scenarios concerning the damage effects on the building structures. The results from scenario 3 agree with the accident characteristics,demonstrating the effectiveness of our proposed modeling method. Our proposed method reflects gas properties,species and the concentration and distribution,and the simulated results validates the root cause,process,and consequences of accidental explosions. Furthermore,this method describes the evolution process of explosions in different building structures. Significantly,our model demonstrates the quantatative explosion effect of factors like gas species,gas volumes,and distributions of gases on explosion results. In this study,a feasible,effective,and quantitative method for structure safety is defined,which is helpful to accelerate the development of safer site regulations. 展开更多
关键词 mechanics of explosion simulation dynamic response liquefied petroleum gas nature gas quantitative analysis
下载PDF
Shale Gas Characterization of Sembar Formation, Khipro Area, Pakistan
6
作者 Muhammad Sohail Khan Zainab Bibi 《International Journal of Geosciences》 2016年第8期1009-1019,共12页
This study pertains to the evaluation of shale gas and rock physics properties of this area with respect to its total organic content of Sember Formation, Khiproarea, Pakistan. We use well logs data for this study. Th... This study pertains to the evaluation of shale gas and rock physics properties of this area with respect to its total organic content of Sember Formation, Khiproarea, Pakistan. We use well logs data for this study. The Khipro area is prominent in the Lower Indus Basin for its hydrocarbon (oil and gas) structural traps. In shale gas evaluation, TOC of Sember Formation is estimated. The analysis has been done with the help of the wire line data of the well Bilal North-01. The presence of shale gas in the study area is analyzed with the help of different techniques. Rock physics and petrophysical analysis have been done in order to get the properties of the area related to the shale gas evaluation. 展开更多
关键词 Shale gas Reservoir Characterization Well Log Response in Shale gas Methods to Compute TOC Rock Physics Model for Shale gas
下载PDF
Air-stable,all-dry transferred ReS_(2)/GaSe heterostructure-based NO_(2)gas sensor
7
作者 A.Venkatesan Hyeyoon Ryu +2 位作者 Anupom Devnath Hyungyu Yoo Seunghyun Lee 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2024年第1期79-87,共9页
Two-dimensional(2D)materials have gained considerable attention in chemical sensing owing to their naturally high surface-to-volume ratio.However,the poor response time and incomplete recovery re-strict their applicat... Two-dimensional(2D)materials have gained considerable attention in chemical sensing owing to their naturally high surface-to-volume ratio.However,the poor response time and incomplete recovery re-strict their application in practical,high performance gas sensors.In this work,we fabricated air-stable ReS_(2)/GaSe heterostructure-based NO_(2)gas sensors with excellent gas sensing response,recovery,selectiv-ity and a low limit of detection(LOD)toward nitrogen dioxide(NO_(2)).The ReS_(2)/GaSe heterostructure was prepared via mechanical exfoliation and an all-dry transfer method.Before the sensing measurements,temperature-dependant transport measurements were carried out.The Schottky Barrier Height(SBH)of the ReS_(2)/GaSe heterostructure was calculated and the corresponding transport mechanisms were dis-cussed.The fabricated gas sensors showed a significant response enhancement with full reversibility to-ward ppm-level NO_(2)(response of∼17%at 3 ppm,a LOD of∼556 ppb)at an operating temperature of(33°C).In particular,the total response and recovery time of the ReS_(2)/GaSe was revealed to be less than 4 min(∼38 s and∼174 s,respectively)for the 250 ppm concentration,which is one of the best response and recovery time toward ppm-level NO_(2).The excellent sensing performances and recovery characteris-tics of the ReS_(2)/GaSe structure are attributed to its efficient charge separation,unique interlayer coupling and desirable band alignments.This atomically thin,ultrasensitive gas sensor that operates at room tem-perature is a strong technological contender to conventional metal oxide gas sensors,which often require elevated temperatures. 展开更多
关键词 2D materials All-dry transfer gas sensor Van der Waals heterostructure ReS_(2)/gase gas sensing response Transition metal dichalcogenide
原文传递
Response Surface Optimization of Nigella glandulifera Freyn Seed Oil Yield by Supercritical Carbon Dioxide Extraction 被引量:3
8
作者 ZHANG Jun-ping HOU Xi-lin +2 位作者 YU Tian LI Ying DONG Hai-yan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2012年第1期151-158,共8页
Supercritical carbon dioxide (SC-CO2) extraction was employed to extract oil from Nigella glandulifera Freyn seed in this study. Response surface methodology (RSM) was applied to evaluate the effects of the proces... Supercritical carbon dioxide (SC-CO2) extraction was employed to extract oil from Nigella glandulifera Freyn seed in this study. Response surface methodology (RSM) was applied to evaluate the effects of the process parameters (pressure, temperature, and CO2 flow rate) on oil yield of N. glandulifera seed. A Box-Behnken design was used to optimize the extraction parameters. The analysis of variance indicated that the linear coefficients of pressure and CO2 flow rate, the quadratic term coefficients of pressure and temperature and the interactions between pressure and temperature, as well as temperature and CO2 flow rate, had significant effects on the oil yield (P〈0.05). The optimal conditions to obtain the maximum oil yield from N. glandulifera seed were pressure 30.84 MPa, temperature 40.57°C, and CO2 flow rate 22.00 L h-1. Under these optimal conditions, the yield of oil was predicted to be 38.19%. The validation experiment results agreed with the predicted values. The fatty acid composition of N. glandulifera seed oil extracted using SC-CO2 was compared with that of oil obtained by Soxhlet method. The results showed that the fatty acid compositions of oil extracted by the two methods were similar. Identification of oil compounds with gas chromatography-mass spectrometry (GC-MS) showed that the contents of unsaturated fatty acids linoleic acid (48.30%), oleic acid (22.28%) and saturated fatty acids palmitic acid (16.65%), stearic acid (4.17%) were the most abundant fatty acids in seed oil from N. glandulifera. 展开更多
关键词 supercritical carbon dioxide extraction Nigella glandulifera Freyn seed oil response surface methodology gas chromatography-mass spectrometry fatty acids
下载PDF
Semiconductor metal oxide compounds based gas sensors: A literature review 被引量:6
9
作者 Sunil Jagannath PATIL Arun Vithal PATIL +5 位作者 Chandrakant Govindrao DIGHAVKAR Kashinath Shravan THAKARE Ratan Yadav BORASE Sachin Jayaram NANDRE Nishad Gopal DESHPANDE Rajendra Ramdas AHIRE 《Frontiers of Materials Science》 SCIE CSCD 2015年第1期14-37,共24页
This paper gives a statistical view about important contributions and advances on semiconductor metal oxide (SMO) compounds based gas sensors developed to detect the air pollutants such as liquefied petroleum gas (... This paper gives a statistical view about important contributions and advances on semiconductor metal oxide (SMO) compounds based gas sensors developed to detect the air pollutants such as liquefied petroleum gas (LPG), H2S, NH3, CO2, acetone, ethanol, other volatile compounds and hazardous gases. Moreover, it is revealed that the alloy/composite made up of SMO gas sensors show better gas response than their counterpart single component gas sensors, i.e., they are found to enhance the 4S characteristics namely speed, sensitivity, selectivity and stability. Improvement of such types of sensors used for detection of various air pollutants, which are reported in last two decades, is highlighted herein. 展开更多
关键词 gas sensor semiconductor metal oxide (SMO) sensitivity air pollutant gas response
原文传递
Gas selectivity of SILAR grown CdS nano-bulk junction
10
作者 R.Jayakrishnan Varun G Nair +1 位作者 Akhil M Anand Meera Venugopal 《Journal of Semiconductors》 EI CAS CSCD 2018年第3期8-13,共6页
Nano-particles of cadmium sulphide were deposited on cleaned copper substrate by an automated se- quential ionic layer adsorption reaction (SILAR) system. The grown nano-bulk junction exhibits Schottky diode behavio... Nano-particles of cadmium sulphide were deposited on cleaned copper substrate by an automated se- quential ionic layer adsorption reaction (SILAR) system. The grown nano-bulk junction exhibits Schottky diode behavior. The response of the nano-bulk junction was investigated under oxygen and hydrogen atmospheric condi- tions. The gas response ratio was found to be 198% for Oxygen and 34% for Hydrogen at room temperature. An increase in the operating temperature of the nano-bulk junction resulted in a decrease in their gas response ratio. A logarithmic dependence on the oxygen partial pressure to the junction response was observed, indicating a Temkin isothermal behavior. Work function measurements using a Kelvin probe demonstrate that the exposure to an oxy- gen atmosphere fails to effectively separate the charges due to the built-in electric field at the interface. Based on the benefits like simple structure, ease of fabrication and response ratio the studied device is a promising candidate for gas detection applications. 展开更多
关键词 Cu/CdS nano-bulk junction hydrogen work function gas response ratio
原文传递
High ammonia sensitive ability of novel Cu12Sb4S13 quantum dots@reduced graphene oxide nanosheet composites at room temperature 被引量:1
11
作者 Yueli Liu Binghua Sang +5 位作者 Haoran Wang Zijing Wu Yuxuan Wang Ziwei Wang Zhuoyin Peng Wen Chen 《Chinese Chemical Letters》 SCIE CAS CSCD 2020年第8期2109-2114,共6页
In the work,rGO nanosheet is synthesized using the typical Hummer’s method,then Cu12Sb4 S13 quantum dots@rGO composites are prepared by solvent thermal method,and Cu12Sb4 S13 quantum dots with the average size of 5 n... In the work,rGO nanosheet is synthesized using the typical Hummer’s method,then Cu12Sb4 S13 quantum dots@rGO composites are prepared by solvent thermal method,and Cu12Sb4 S13 quantum dots with the average size of 5 nm are densely distributed on the surface of rGO sheet.NH3 gas response of Cu12Sb4 S13quantum dots@rGO nanosheet composites at room te mperature of 25℃is enhanced compared with the pure Cu12Sb4 S13 quantum dots and rGO nanosheet,and the composites possess an excellent stability during the humidity range of 45%-80%with a low detection limit of 1 ppm,which is related with the intrinsic hydrophobicity characteristic of Cu12Sb4 S13 quantum dots.It also proves that Cu12Sb4 S13quantum dots@rGO nanosheet composites have a quite high selectivity towards ammonia compared with ethanol,methanol,acetone,toluene,hydrogen sulfide and nitrogen dioxide at room temperature.The gas sensing mechanism of the composites is discussed primarily. 展开更多
关键词 Cu12Sb4S13 quantum dots@rGO nanosheet COMPOSITES NH3 Room temperature gas response
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部