Documents disponibles écrits par cet auteur

Ozonation combined with sonolysis for degradation and detoxification of m-nitrotoluene in aqueous solution / Zhiqiao He in Industrial & engineering chemistry research, Vol. 48 N° 12 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 12 (Juin 2009) . - pp. 5578–5583 Titre : Ozonation combined with sonolysis for degradation and detoxification of m-nitrotoluene in aqueous solution Type de document : texte imprimé Auteurs : Zhiqiao He, Auteur ; Runye Zhu, Auteur ; Xing Xu, Auteur Année de publication : 2009 Article en page(s) : pp. 5578–5583 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Sonolytic  ozonation  Nitroaromatic  compound  m-nitrotoluene  Toxicity  Aqueous  solution Résumé : Sonolytic ozonation (US/O3 oxidation) is an advanced oxidation process that has become a focus of intense investigation. In this study, the nitroaromatic compound m-nitrotoluene (MNT) was chosen as a model substrate for degradation experiments in which pH, initial concentration of MNT, ozone dose, and US density were varied. At pH 10.0, initial concentration of MNT 400 mg/L, ozone dose 2.4 g/h, and US energy density 88 W/L, the efficiency of MNT removal reached 98% after 120 min. Of the initial degradation rate of MNT abatement, 9.8, 4.1, and 1.1 mg/(L min) were observed with US/O3, O3, and US, respectively. The variation of the concentrations of related anions (oxalate, acetate, formate, and nitrate ion) during the reaction process was ascertained by ion chromatography (IC). The major intermediates detected by gas chromatography/mass spectrometry (GC/MS) were 3-nitrobenzaldehyde, 3-nitrobenzoic acid, nitrobenzene, benzene, butene diacid, oxalic acid, and acetic acid. A degradation pathway is proposed on the basis of these findings. The acute toxicity of the reaction solution to zebra fish (Danio rerio) was estimated after US/O3 treatment. According to the decreasing lethal rate during the US/O3 process, it could be deduced that US/O3 is a powerful tool with which to achieve effective reduction of the toxicity of MNT. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801566z [article] Ozonation combined with sonolysis for degradation and detoxification of m-nitrotoluene in aqueous solution [texte imprimé] / Zhiqiao He, Auteur ; Runye Zhu, Auteur ; Xing Xu, Auteur . - 2009 . - pp. 5578–5583. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 12 (Juin 2009) . - pp. 5578–5583 Mots-clés : Sonolytic  ozonation  Nitroaromatic  compound  m-nitrotoluene  Toxicity  Aqueous  solution Résumé : Sonolytic ozonation (US/O3 oxidation) is an advanced oxidation process that has become a focus of intense investigation. In this study, the nitroaromatic compound m-nitrotoluene (MNT) was chosen as a model substrate for degradation experiments in which pH, initial concentration of MNT, ozone dose, and US density were varied. At pH 10.0, initial concentration of MNT 400 mg/L, ozone dose 2.4 g/h, and US energy density 88 W/L, the efficiency of MNT removal reached 98% after 120 min. Of the initial degradation rate of MNT abatement, 9.8, 4.1, and 1.1 mg/(L min) were observed with US/O3, O3, and US, respectively. The variation of the concentrations of related anions (oxalate, acetate, formate, and nitrate ion) during the reaction process was ascertained by ion chromatography (IC). The major intermediates detected by gas chromatography/mass spectrometry (GC/MS) were 3-nitrobenzaldehyde, 3-nitrobenzoic acid, nitrobenzene, benzene, butene diacid, oxalic acid, and acetic acid. A degradation pathway is proposed on the basis of these findings. The acute toxicity of the reaction solution to zebra fish (Danio rerio) was estimated after US/O3 treatment. According to the decreasing lethal rate during the US/O3 process, it could be deduced that US/O3 is a powerful tool with which to achieve effective reduction of the toxicity of MNT. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801566z

Performance comparison of R410A and R32 in vapor injection cycles / Xing Xu in International journal of refrigeration, Vol. 36 N° 3 (Mai 2013) 

Public ISBD [article]  in International journal of refrigeration > Vol. 36 N° 3 (Mai 2013) . - pp. 892–903 Titre : Performance comparison of R410A and R32 in vapor injection cycles Titre original : Comparaison de la performance du R410A et du R32 dans des cycles à injection de vapeur Type de document : texte imprimé Auteurs : Xing Xu, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur Année de publication : 2013 Article en page(s) : pp. 892–903 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : R410A;  R32;  Vapor;  Injection;  Heat  pump Résumé : As global warming has raised more critical concerns in recent years, refrigerants with high global warming potentials (GWP) are facing the challenges of being phased out. R410A, with a GWP of 2088, has been widely used in residential air-conditioner and heat pump systems. A potential substitute for R410A is R32, which has a GWP of 675. This paper investigates the performance difference using R410A and R32 in a vapor-injected heat pump system. Through experimentation, it was found that the capacity and coefficient of performance (COP) improvements using R32 can reach up to 10% and 9%, respectively, as compared to an identical cycle using R410A. It is concluded that R32 is an excellent alternative to replace R410A in terms of performance and can be further enhanced by component optimization. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712003532 [article] Performance comparison of R410A and R32 in vapor injection cycles = Comparaison de la performance du R410A et du R32 dans des cycles à injection de vapeur [texte imprimé] / Xing Xu, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur . - 2013 . - pp. 892–903. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 36 N° 3 (Mai 2013) . - pp. 892–903 Mots-clés : R410A;  R32;  Vapor;  Injection;  Heat  pump Résumé : As global warming has raised more critical concerns in recent years, refrigerants with high global warming potentials (GWP) are facing the challenges of being phased out. R410A, with a GWP of 2088, has been widely used in residential air-conditioner and heat pump systems. A potential substitute for R410A is R32, which has a GWP of 675. This paper investigates the performance difference using R410A and R32 in a vapor-injected heat pump system. Through experimentation, it was found that the capacity and coefficient of performance (COP) improvements using R32 can reach up to 10% and 9%, respectively, as compared to an identical cycle using R410A. It is concluded that R32 is an excellent alternative to replace R410A in terms of performance and can be further enhanced by component optimization. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712003532

Refrigerant injection for heat pumping/air conditioning systems: Literature review and challenges discussions / Xing Xu in International journal of refrigeration, Vol. 34 N° 2 (Mars 2011) 

Public ISBD [article]  in International journal of refrigeration > Vol. 34 N° 2 (Mars 2011) . - pp. 402-415 Titre : Refrigerant injection for heat pumping/air conditioning systems: Literature review and challenges discussions Titre original : Injection du frigorigène dans les systèmes à pompe à chaleur et de conditionnement d'air : passage en revue de la littérature et discussion sur les défis Type de document : texte imprimé Auteurs : Xing Xu, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur Année de publication : 2011 Article en page(s) : pp. 402-415 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Liquid  Vapor  Separation  Injection  Tank  Heat  exchanger Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper reviews the major research on refrigerant injection techniques in detail. Liquid and vapor refrigerant injection techniques are discussed and compared. The current research on refrigerant injection techniques falls into two categories: system level research and component level research. The system level research is focused on low ambient temperature heating, heat pump water heating, high ambient temperature cooling, cycle comparison, and control strategy development. Internal heat exchanger and flash tank cycles are the two typical cycles for refrigerant injection. These two cycles are discussed and compared in detail. The component level research is focused on employing different types of compressors, variable speed compressors, the injection process, and the flash tank. Different types of compressors employing refrigerant injection are presented. Based on the literature study, the potential future research directions are presented and discussed. The flash tank cycle control strategy and refrigerant charge management strategy are worth further research efforts. Compressor design can be improved in order to optimize the performance with refrigerant injection. The appropriate design of flash tanks plays a vital role in achieving appropriate two-phase flow patterns in the flash tank. Computational Fluid Dynamics (CFD) modeling can be a useful tool to facilitate the design of the flash tank. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002239 [article] Refrigerant injection for heat pumping/air conditioning systems: Literature review and challenges discussions = Injection du frigorigène dans les systèmes à pompe à chaleur et de conditionnement d'air : passage en revue de la littérature et discussion sur les défis [texte imprimé] / Xing Xu, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur . - 2011 . - pp. 402-415. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 2 (Mars 2011) . - pp. 402-415 Mots-clés : Liquid  Vapor  Separation  Injection  Tank  Heat  exchanger Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper reviews the major research on refrigerant injection techniques in detail. Liquid and vapor refrigerant injection techniques are discussed and compared. The current research on refrigerant injection techniques falls into two categories: system level research and component level research. The system level research is focused on low ambient temperature heating, heat pump water heating, high ambient temperature cooling, cycle comparison, and control strategy development. Internal heat exchanger and flash tank cycles are the two typical cycles for refrigerant injection. These two cycles are discussed and compared in detail. The component level research is focused on employing different types of compressors, variable speed compressors, the injection process, and the flash tank. Different types of compressors employing refrigerant injection are presented. Based on the literature study, the potential future research directions are presented and discussed. The flash tank cycle control strategy and refrigerant charge management strategy are worth further research efforts. Compressor design can be improved in order to optimize the performance with refrigerant injection. The appropriate design of flash tanks plays a vital role in achieving appropriate two-phase flow patterns in the flash tank. Computational Fluid Dynamics (CFD) modeling can be a useful tool to facilitate the design of the flash tank. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002239

Transient and steady-state experimental investigation of flash tank vapor injection heat pump cycle control strategy / Xing Xu in International journal of refrigeration, Vol. 34 N° 8 (Décembre 2011) 

Public ISBD [article]  in International journal of refrigeration > Vol. 34 N° 8 (Décembre 2011) . - pp. 1922–1933 Titre : Transient and steady-state experimental investigation of flash tank vapor injection heat pump cycle control strategy Titre original : Etude expérimentale en régime transitoire et permanent de la stratégie de régulation appliquée à un cycle à pompe à chaleur avec injection de vapeur du réservoir intermédiaire Type de document : texte imprimé Auteurs : Xing Xu, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur Année de publication : 2012 Article en page(s) : pp. 1922–1933 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Tank  Injection  Transient  state  Steady  state  Control Résumé : Recent research on vapor injection technique has been mostly focused on performance improvement using different system configurations. The flash tank cycle typically shows better performance than the internal heat exchanger cycle. However, the flash tank cycle control strategy is not yet clearly defined. In this study, a novel cycle control strategy is proposed for an R-410A vapor injection flash tank heat pump system and its feasibility was experimentally investigated. The proposed novel cycle control strategy utilized an electronic expansion valve (EEV) for the upper-stage expansion and a thermostatic expansion valve for the lower-stage expansion, and applied an electric heater in the vapor injection line to introduce superheat to the injected vapor by providing a control signal to the upper-stage EEV. Both transient and steady-state system behaviors were studied. The proposed cycle control strategy was found to be able to provide reliable control to the system. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001927# [article] Transient and steady-state experimental investigation of flash tank vapor injection heat pump cycle control strategy = Etude expérimentale en régime transitoire et permanent de la stratégie de régulation appliquée à un cycle à pompe à chaleur avec injection de vapeur du réservoir intermédiaire [texte imprimé] / Xing Xu, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur . - 2012 . - pp. 1922–1933. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 8 (Décembre 2011) . - pp. 1922–1933 Mots-clés : Tank  Injection  Transient  state  Steady  state  Control Résumé : Recent research on vapor injection technique has been mostly focused on performance improvement using different system configurations. The flash tank cycle typically shows better performance than the internal heat exchanger cycle. However, the flash tank cycle control strategy is not yet clearly defined. In this study, a novel cycle control strategy is proposed for an R-410A vapor injection flash tank heat pump system and its feasibility was experimentally investigated. The proposed novel cycle control strategy utilized an electronic expansion valve (EEV) for the upper-stage expansion and a thermostatic expansion valve for the lower-stage expansion, and applied an electric heater in the vapor injection line to introduce superheat to the injected vapor by providing a control signal to the upper-stage EEV. Both transient and steady-state system behaviors were studied. The proposed cycle control strategy was found to be able to provide reliable control to the system. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001927#