Objectives:Near-infra red(NIR)spectroscopy is a rapid technique able to assess meat quality even if its capability to determine the shelf life of chicken fresh cuts is still debated,especially for portable devices.The...Objectives:Near-infra red(NIR)spectroscopy is a rapid technique able to assess meat quality even if its capability to determine the shelf life of chicken fresh cuts is still debated,especially for portable devices.The aim of the study was to compare bench-top and portable NIR instruments in discriminating between four chicken breast refrigeration times(RT),coupled with multivariate classifier models.Materials and Methods:Ninety-six samples were analysed by both NIR tools at 2,6,10 and 14 days post mortem.NIR data were subsequently submitted to partial least squares discriminant analysis(PLS-DA)and canonical discriminant analysis(CDA).The latter was preceded by double feature selection based on Boruta and Stepwise procedures.Results:PLS-DA sorted moderate separation of RT theses,while shelf life assessment was more accurate on application of Stepwise-CDA.Bench-top tool had better performance than portable one,probably because it captured more informative spectral data as shown by the variable importance in projection(VIP)and restricted pool of Stepwise-CDA predictive scores(SPS).Conclusions:NIR tools coupled with a multivariate model provide deep insight into the physicochemical processes occurring during storage.Spectroscopy showed reliable effectiveness to recognise a 7-day shelf life threshold of breasts,suitable for routine at-line application for screening of meat quality.展开更多
The main objective of this study was to determine the consolidation behaviour of clay slurries.A finegrained clay with high consistency limits(W_L = 180%,w_P= 120%) was investigated using conventional oedometer and be...The main objective of this study was to determine the consolidation behaviour of clay slurries.A finegrained clay with high consistency limits(W_L = 180%,w_P= 120%) was investigated using conventional oedometer and bench-top centrifuge tests.Results indicated that the slurry had an apparent preconsolidation(due to initial conditions,electrochemical interactions,tortuous drainage,and thixotropic strength) from e = 5.7 to e = 5.5 followed by virgin compression.Likewise,the low hydraulic conductivity(10^(-10)-10^(-12) m/s) was due to low porosity(small pore throats) and high tortuosity(long flow paths).Unlike consolidation of soils,the c_v and m_v decreased with increasing σ' but increased with increasing e and k.The data from the two tests correlated well in the range of σ' = 10-65 kPa,e = 5.5-3.86,k= 1.7 × 10^(-10)-5×10^(-11) m/s,F_c = 1-40 MN.New equations were developed to correlate the consolidation parameters(e,σ',k) with F_c.The deviation of k beyond 40 MN(e = 4.65) was due to deviation from the initial straight line portion of the settlement curve in the centrifuge test.展开更多
The bench top test is one of the most important and effective methods to evaluate the total thermal protective performance(TPP) of firefighters' protective clothing,which is greatly influenced by the air gaps entr...The bench top test is one of the most important and effective methods to evaluate the total thermal protective performance(TPP) of firefighters' protective clothing,which is greatly influenced by the air gaps entrapped.In this paper,to investigate the effect of air gap width on TPP,a new improved apparatus with two height changeable buttons to hold the thermal sensor was developed to get a series of air gap sizes from 0 mm to 40 mm.The TPP of two types of flame-resistant outer fabrics was measured with TPP test apparatus respectively.Analysis of temperature rise with each air gap width was made to determine the effects of different air gaps on protective performance.It was indicated that air gap size had great effect on TPP of fabrics in the bench top test.An air gap width above 8 mm was suggested for the thermal protective clothing design.展开更多
台式微生物培养反应器由于体积小、生物膜采样过程简单、培养生物膜用水量不大等优点被广泛应用,而CDC台式反应器作为典型的台式反应器,其内部的采样片通常被当作平行样本来对待,但实际上它的微生物空间分布是有差异的。为了探究CDC台...台式微生物培养反应器由于体积小、生物膜采样过程简单、培养生物膜用水量不大等优点被广泛应用,而CDC台式反应器作为典型的台式反应器,其内部的采样片通常被当作平行样本来对待,但实际上它的微生物空间分布是有差异的。为了探究CDC台式反应器微生物群落空间分布差异性,尝试提出该模拟装置的适用条件和适用的研究目的,故依托建设于实际管网试验大厅的CDC台式反应器平台开展研究。采用实时荧光定量PCR法计数生物膜中细菌总数、高通量16S r DNA测序分析微生物群落种类和含量。研究结果表明,对于不同水力停留时间的CDC台式反应器,细菌总数和可培养菌数量均呈现上部最少,中部和下部最大的分布规律;在不同水力停留时间不同空间位置处的优势菌门(属)和条件致病菌存在一定差异的。因此,针对不同水力停留时间的CDC台式反应器,微生物采样方式也是不同的;要培养不同类型的菌门(属)时,所选择的反应器类型也是不一样的。展开更多
基金supported by FONDAZIONE CARIVERONA(projects Tre Poli 4,6,call 2012,2016)University of Padova(2019 SID assignment),Italy.
文摘Objectives:Near-infra red(NIR)spectroscopy is a rapid technique able to assess meat quality even if its capability to determine the shelf life of chicken fresh cuts is still debated,especially for portable devices.The aim of the study was to compare bench-top and portable NIR instruments in discriminating between four chicken breast refrigeration times(RT),coupled with multivariate classifier models.Materials and Methods:Ninety-six samples were analysed by both NIR tools at 2,6,10 and 14 days post mortem.NIR data were subsequently submitted to partial least squares discriminant analysis(PLS-DA)and canonical discriminant analysis(CDA).The latter was preceded by double feature selection based on Boruta and Stepwise procedures.Results:PLS-DA sorted moderate separation of RT theses,while shelf life assessment was more accurate on application of Stepwise-CDA.Bench-top tool had better performance than portable one,probably because it captured more informative spectral data as shown by the variable importance in projection(VIP)and restricted pool of Stepwise-CDA predictive scores(SPS).Conclusions:NIR tools coupled with a multivariate model provide deep insight into the physicochemical processes occurring during storage.Spectroscopy showed reliable effectiveness to recognise a 7-day shelf life threshold of breasts,suitable for routine at-line application for screening of meat quality.
基金the University of Regina for providing laboratory space and the Natural Science and Engineering Research Council of Canada for financial assistance
文摘The main objective of this study was to determine the consolidation behaviour of clay slurries.A finegrained clay with high consistency limits(W_L = 180%,w_P= 120%) was investigated using conventional oedometer and bench-top centrifuge tests.Results indicated that the slurry had an apparent preconsolidation(due to initial conditions,electrochemical interactions,tortuous drainage,and thixotropic strength) from e = 5.7 to e = 5.5 followed by virgin compression.Likewise,the low hydraulic conductivity(10^(-10)-10^(-12) m/s) was due to low porosity(small pore throats) and high tortuosity(long flow paths).Unlike consolidation of soils,the c_v and m_v decreased with increasing σ' but increased with increasing e and k.The data from the two tests correlated well in the range of σ' = 10-65 kPa,e = 5.5-3.86,k= 1.7 × 10^(-10)-5×10^(-11) m/s,F_c = 1-40 MN.New equations were developed to correlate the consolidation parameters(e,σ',k) with F_c.The deviation of k beyond 40 MN(e = 4.65) was due to deviation from the initial straight line portion of the settlement curve in the centrifuge test.
基金National Natural Science Foundation of China (No. 50876019)the Research Fund for the Doctoral Program of Higher Education of China (No. 200802550009)Fundamental Research Funds for the Central Universities,China
文摘The bench top test is one of the most important and effective methods to evaluate the total thermal protective performance(TPP) of firefighters' protective clothing,which is greatly influenced by the air gaps entrapped.In this paper,to investigate the effect of air gap width on TPP,a new improved apparatus with two height changeable buttons to hold the thermal sensor was developed to get a series of air gap sizes from 0 mm to 40 mm.The TPP of two types of flame-resistant outer fabrics was measured with TPP test apparatus respectively.Analysis of temperature rise with each air gap width was made to determine the effects of different air gaps on protective performance.It was indicated that air gap size had great effect on TPP of fabrics in the bench top test.An air gap width above 8 mm was suggested for the thermal protective clothing design.
文摘台式微生物培养反应器由于体积小、生物膜采样过程简单、培养生物膜用水量不大等优点被广泛应用,而CDC台式反应器作为典型的台式反应器,其内部的采样片通常被当作平行样本来对待,但实际上它的微生物空间分布是有差异的。为了探究CDC台式反应器微生物群落空间分布差异性,尝试提出该模拟装置的适用条件和适用的研究目的,故依托建设于实际管网试验大厅的CDC台式反应器平台开展研究。采用实时荧光定量PCR法计数生物膜中细菌总数、高通量16S r DNA测序分析微生物群落种类和含量。研究结果表明,对于不同水力停留时间的CDC台式反应器,细菌总数和可培养菌数量均呈现上部最少,中部和下部最大的分布规律;在不同水力停留时间不同空间位置处的优势菌门(属)和条件致病菌存在一定差异的。因此,针对不同水力停留时间的CDC台式反应器,微生物采样方式也是不同的;要培养不同类型的菌门(属)时,所选择的反应器类型也是不一样的。
