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Increased Drying Rate Lowers the Critical Water Content for Survival in embryonic Axes of english Oak (Quercus robur L.) Seeds

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Journal of Integrative Plant Biology 2011年第4期53卷 270-280页

作者： Tobias M.Ntuli William e.finch-Savage Patricia Berjak Norman W.Pammenter Plant Germplasm Conservation Research School of Biological and Conservation SciencesUniversity of KwaZulu-NatalWestville CampusPrivate Bag X54001Durban 4000South Africa Department of Life and Consumer Sciences University of South AfricaPrivate Bag X6Florida 1710JohannesburgSouth Africa Warwick HRI Warwick UniversityWellesbourneWarwick CV35 9EFUK Plant Germplasm Conservation Research School of Biological and Conservation SciencesUniversity of KwaZulu-NatalWestville

The potential to cryopreserve embryonic axes of desiccation-sensitive（recalcitrant） seeds is limited by damage during the desiccation necessary for low temperature survival,but the basis of this injury and how to reduce it is not well *** effects of drying rate on the viability,respiratory metabolism and free radical-mediated processes were therefore investigated during dehydration of Quercus robur L embryonic ***,assessed by evidence of germination and tetrazolium staining,showed a sharp decline at 0.27 and 0.8 g/g during rapid（〈12 h） or slow（3d） dehydration,*** dehydration therefore lowered the critical water content for *** any given water content rapid dehydration was associated with higher activities of the free radical processing enzymes,superoxide dismutase,catalase and glutathione reductase and lower levels of hydroperoxide and membrane *** dehydration was also associated with lower malate dehydrogenase activity,and a reduced decline in phosphofructokinase activity and in levels of the oxidized form of nicotinamide *** may have contributed to increased damage during slow dehydration,since viability declined even in hydrated storage after 3 *** results presented are consistent with rapid dehydration reducing the accumulation of damage resulting from desiccation induced aqueous-based deleterious reactions.

关键词： Quercus robur L Seeds Figure NADH

Correspondence of bubble size and frother partitioning in flotation

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Journal of Central South University 2014年第6期21卷 2383-2390页

作者：张炜 Jan e.Nesset James A.finch Mining & Mineral Resources Division Department of Business AdministrationChinalco China Copper Corporation Limited Department of Mining and Materials engineering McGill UniversityMontrealQCH3A 0C5Canada

The size of bubbles created in the flotation process is of great importance to the efficiency of the mineral separation ***,it is believed that frother transport between phases is perhaps the most important reason for the interactive nature of the phenomena occurring in the bulk and froth phases in flotation,as frother adsorbed in the surface of rising bubbles is removed from the bulk phase and then released into the froth as a fraction of the bubbles *** causes the increased concentration in the froth compared to the bulk concentration,named as frother *** reflects the adsorption of frother on bubbles and how to influence bubble size is not *** currently exists no such a topic aiming to link these two key *** fill this vacancy,the correspondence between bubble size and frother partitioning was *** size was measured by sampling-for-imaging(SFI)*** total organic carbon(TOC)analysis to measure the frother partitioning between froth and bulk phases was *** have shown,with no exceptions including four different frothers,higher frother concentration is in the bulk than in the *** results also show strong partitioning giving an increase in bubble size which implies there is a compelling relationship between these two,represented by CFroth/CBulk and *** CFroth/CBulkand D32 curves show similar exponential decay relationships as a function of added frother in the system,strongly suggesting that the frother concentration gradient between the bulk solution and the bubble interface is the driving force contributing to bubble size reduction.

关键词： flotation frother bubble size frother partitioning total organic carbon (TOC) analysis concentration gradient

A novel approach to prevent bubble coalescence during measurement of bubble size in flotation

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Journal of Central South University 2014年第1期21卷 338-343页

作者：张炜 Jan e.Nesset James A.finch Mining and Mineral Resources Division Department of Business AdministrationChinalco China Copper Corporation Limited Department of Mining and Materials engineering McGill University

effect of frothers in preventing bubble coalescence during flotation of minerals has long been *** evaluate the performance of a frother,an apparatus to measure the bubble size is a basic *** Bubble Size Analyzer(MBSA) or bubble viewer that has been developed and completed by McGill University's Mineral Processing Group during the last decade is a unique instrument to serve this *** parameters which are thought to influence the bubble size measurements by McGill bubble viewer include water quality and frother concentration in the *** show that there is no difference in Sauter mean(D32) when tap or de-ionized water was used instead of process ***,the frother concentration,in this research DowFroth 250(DF250),inside the chamber exhibited a pronounced effect on bubble *** concentration below a certain point can not prevent coalescence inside the chamber and therefore caution must be taken in plant *** was also noted that the frother concentration which has been so far practiced in plant measurements(CCC75-CCC95) is high enough to prevent coalescence with the bubble viewer.

关键词： flotation frother bubble size bubble coalescence

Bubble size as a function of some situational variables in mechanical flotation machines

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Journal of Central South University 2014年第2期21卷 720-727页

The specific results of the work investigating the effect of gas density and water temperature on bubble size were *** were surrogate variables designed to investigate the effect of viscosity(varying water temperature) and altitude(varying gas density).The results show that there is a measurable but relatively small effect of gas density on bubble *** D32 is revealed to increase proportionally as(ρ0/ρg)*** projected impact on flotation kinetics at 4500 m versus sea level is small,of the order of 0.5% recovery loss for a bank of eight flotation *** effect of water temperature(4-40 °C) on bubble size is more significant than gas *** relationship correlates with water viscosity values quite closely.A finding that D32 increases proportionally as(μ/μ20)0.776 highlights the importance of accounting for viscosity effects if,for example,large process temperature fluctuations or deviation from design/test conditions are expected.

关键词： flotation frother bubble size viscosity altitude

effect of some operational variables on bubble size in a pilot-scale mechanical flotation machine

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Journal of Central South University 2014年第3期21卷 1077-1084页

作者：张炜 J.e.Nesset J.A.finch Mining and Mineral Resources Division Department of Business AdministrationChinalco China Copper Corporation Limited Department of Mining and Materials engineering McGill University

This work aims to provide a relationship of how the key operational variables of frother type and impeller speed affect the size of bubble （D32）. The study was performed using pilot-scale equipment （0.8 m^3） that is up to two orders of magnitude larger than equipment used for studies performed to date by others, and incorporated the key process variables of frother type and impeller speed. The results show that each frother family exhibits a unique CCC95-HLB relationship dependent on n （number of C-atoms in alkyl group） and m （number of propylene oxide group）. empirical models were developed to predict CCC95 from HLB associated with other two parameters a and ft. The impeller speed-bubble size tests show that D32 is unaffected by increased impeller tip speed across the range of 4.6 to 9.2 m/s （representing the industrial operating range）, although D32 starts to increase below 4.6 m/s. The finding is valid for both coalescing and non-coalescing conditions. The results suggest that the bubble size and bubble size distribution （BSD） being created do not change with increasing impeller speed in the quiescent zone of the flotation.

关键词： flotation bubble size operational variables critical coalescence concentration hydrophile-lipophile balance impellerspeed

Artificial intelligence and remote sensing for spatial prediction of daily air temperature:case study of Souss watershed of Morocco

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Geo-Spatial Information Science 2022年第2期25卷 244-258页

作者： Modeste Meliho Abdellatif Khattabi Driss Zejli Collins Ashianga Orlando caleb e.Dansou ecole Nationale des Sciences Appliquées Kénitra-Laboratoire Ingénierie des Systèmes Avancés(ISA) UniversitéIbn TofailKenitraMorocco ecole Nationale Forestière d’Ingénieurs SaléMorocco ecole Nationale des Sciences Appliquées Kénitra-Laboratoire Ingénierie des Systèmes Avancés(ISA) SaléMorocco Sciences de données École des sciences de l’information(ESI)RabatMorocco

Air temperature(Tair)is a fundamental variable in climate research and climate impact *** field observations do not accurately capture its spatial distribution due to the sparse and uneven distribution of weather stations,especially in remote areas where the local variability is *** circumvent this problem,in this study,remote sensing and weather station data were used to estimate Tair in the Souss watershed in *** statistical methods,including linear regression and partial least squares(PLS),and four machine learning algorithms,namely k-nearest neighbors,random forest(RF),extreme gradient boost,and Cubist,were used for modeling and predicting Tair and its performance were evaluated using random subsets and *** resolution imaging spectroradiometer predictors,including Terra band 32 emissivity,Terra nighttime land surface temperature,Terra local time of night observation,Aqua band 31 emissivity,Aqua daytime land surface tempera-ture,and Aqua nighttime land surface temperature(ALSTN),and auxiliary inputs,including sky-view,elevation,slope,and hillshade,were used as inputs for *** results showed that the Cubist and RF were the most accurate models(RMSe=2.09°C and 2.13°C,R2=0.91 and 0.90,respectively),while PLS had the lowest predictive power(RMSe=2.71°C;R2=0.83).The overall performance of the models for estimating Tair in the study area was generally satisfac-tory,with RMSe limited to less than 3°C for all ***,the station data reliability was still an issue,with only four of the seven stations marked by complete meteorological data.

关键词： Air temperature remote sensing machine learning Morocco

effect of solids on pulp and froth properties in flotation

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Journal of Central South University 2014年第4期21卷 1461-1469页

作者：张炜 James A.finch Mining & Mineral Resources Division Department of Business Administration Chinalco China Copper Corporation Limited Department of Mining and Materials engineering McGill University

Froth flotation is a widely used process of particle separation exploiting differences in surface properties. It is important to point out that overall flotation performance(grade and recovery) is a consequence of the quality and quantity of the solid particles collected from the pulp phase, transported into the froth phase, and surviving as bubble-particle aggregates into the overflow. This work will focus on studying these phenomena and will incorporate the effects of particle hydrophobicities in the 3-phase system. Solids are classed as either hydrophilic non-sulphide gangue(e.g. silica, talc), hydrophilic sulphide(e.g. pyrite), or hydrophobic sulphide(e.g. sphalerite). Talc is a surface-active species of gangue that has been shown to behave differently from silica(frother adsorbs on the surface of talc particles). Both are common components of ores and will be studied in detail. The focus of this work is to investigate the role of solids on pulp hydrodynamics, froth bubble coalescence intensity, water overflow rate with solids present, and in particular, the interactions between solids, frother and gas on the gas dispersion parameters. The results show that in the pulp zone there is no effect of solids on bubble size and gas holdup; in the froth zone, although hydrophilic particles solely do not effect on the water overflow rate, hydrophobic particles produce higher intensity of rates on water overflow and bubble coalescence, and many be attributed to the water reattachment.

关键词： flotation frothers bubble size coalescence gas holdup hydrophobicity

Alpine Activity Patterns of Mitopus morio(Fabricius, 1779) are Induced by Variations in Temperature and Humidity at Different Scales in Central Norway

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Journal of Mountain Science 2014年第3期11卷 644-655页

作者： Nils HeIN Roland PAPe Oliver-D. finch Jorg LOFFLeR Department of C-eography University of Bonn Meckenheimer AUee 166 D-53115 Bonn Germany Achtern Nordpol 8 D-26180 Rastede Germany

Our research addresses questions about how micro-climate affects activity abundance of a common and widespread harvestman in an alpine ecosystem. Activity patterns of the Harvestman Mitopus morio(Fabricius, 1779) were studied along different alpine gradients in the central Norwegian Scandes. Within a nested design, we surveyed 18 alpine habitats with pitfall traps and microclimatological equipment along oceanic-continental, two elevational, and(fine-scaled) microtopographic gradients. Sites in the oceanic region of the Scandes showed generally higher abundance of M. morio than sites in the continental region. Furthermore, along the elevational gradient, middle-alpine sites showed higher abundances than low-alpine sites. These general patterns are best explained by higher humidity in the oceanic region and in the middlealpine belt. Focusing at a finer scale, i.e. one elevational level within each region, revealed partly opposing activity patterns within relatively short distances. While in the western middle-alpine belt these patterns were best explained by humidityrelated measures but now with higher activity abundance during drier conditions, in the drier eastern middle-alpine belt heat sums rather than humidity were found to be the best explanatoryvariables for the observed patterns. Hence, our results imply a pronounced different reaction of the two populations towards climatic variables that partly even contradict the previously described general pattern. Regardless whether these differences in activity abundance in M. morio are a form of phenotypic plasticity or adaptation, our findings stress the importance of detailed autecological knowledge combined with fine-scaled climatic measurements when aiming at predictions about possible future ecosystem structures and spatiotemporal phenomena. M. morio proves to be an ideal biogeographic model organism for understanding spatio-temporal responses of alpine ecosystems under modified climatic conditions.

关键词： Climate gradients Opiliones Arctic-alpine ecosystems High mountains Scandinavia

Bioassays and proteomics as early detection tools in postharvest management of table grapes (Vitis vinifera L.) diseases-A Review

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FOOD BIOSCIeNCe 2023年第3期53卷 256-266页

作者： Kgang, Itumeleng e. Klein, Ashwil Husselmann, Lizex Nkomo, Andrew Mathabe, Patricia M. K. Belay, Zinash A. caleb, Oluwafemi James Univ Western Cape Dept Biotechnol ZA-7530 Bellville South Africa Royal Agr Univ Sch Agr Food & Environm Stroud Rd Cirencester GL7 6JS England Agr Res Council ARC Infruitec Nietvoorbij Postharvest & Agroproc Technol PHATs Private Bag X5026 ZA-7599 Stellenbosch South Africa Stellenbosch Univ Fac Agrisci Dept Food Sci ZA-7602 Matieland South Africa Stellenbosch Univ Africa Inst Postharvest Technol Fac Agrisci ZA-7602 Matieland South Africa

Postharvest diseases are a major concern to the table grapes (Vitis vinifera L.) industry, leading to huge economic losses worldwide. Monitoring postharvest disease and early detection of fruit pathogens are crucial to mitigate disease infestation and facilitate effective management practices. Over the years, traditional visual scouting for symptoms combined with biochemical assays, serological tests and/or DNA-based approach have been useful tools in fruit disease diagnosis. However, these tools have drawbacks in accurately detecting diseases during asymptomatic stage. Hence, these methods are not the most effective for disease confirmation and pathogen identification. In contrast, proteomics could provided instantaneous results that can be used to identify asymptomatic disease stages on table grapes. Therefore, this review provides an overview on the postharvest disease causing pathogens and associated symptoms on table grapes. Prospects of using changes in biochemical assays and proteomics as early response signal in postharvest disease management were discussed. This article proposed the need for continued advancement in the development of conventional tools, with emphasized on combining these tools with more robust and responsive novel approaches for better early disease diagnostic strategies.

关键词： Vitis vinifera L Ascorbate peroxidase assay Superoxide dismutase assay Malondialdehyde assay Food security