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Microwave-Assisted Au and Ag Nanop.rticle Synthesis: An Energy p.ase-Sp.ce p.ojection Analysis

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American Journal of Analytical Chemistry 2023年第4期14卷 149-174页

作者： Victor J. Law denis p. dowling School of Mechanical and Materials Engineering University College Dublin Dublin Ireland

Microwave-assisted synthesis of gold and silver nanop.rticles, as a function of Green Chemistry, non Green Chemistry, and four ap.licator typ.s are rep.rted. The ap.licator typ.s are Domestic microwave ovens, commercial temp.rature controlled microwave chemistry ovens (TCMC), digesters, and axial field helical antennae. For each of these microwave ap.licators the p.ocess energy budget where estimated (Watts multip.ied by p.ocess time = kJ) and energy density (ap.lied energy divided by susp.nsion volume = kJ·mlp.-1p.) range between 180 ± 176.8 kJ, and 79.5 ± 79 kJ·mlp.-1p., resp.ctively. The axial field helical field an-tenna ap.licator is found to be the most energy efficient (0.253 kJ·mp.-1p. p.r kJ, at 36 W). Followed by microwave ovens (4.47 ± 3.9 kJ·mlp.-1p. p.r 76.83 ± 39 kJ), and TCMC ovens (2.86 ± 2.3 kJ·mp.-1p. p.r 343 ± 321.5 kJ). The digester ap.licators have the least energy efficiency (36.2 ± 50.7 kJ·mp.-1p. p.r 1010 ± 620 kJ). A comp.rison with reconstructed ‘non-thermal’ microwave oven inactivation microorganism exp.riments yields a p.wer-law signature of n = 0.846 (Rp.2p. = 0.7923) four orders of magnitude. The p.p.r p.ovides a discussion on the Au and Ag nanop.rticle chemistry and bio-chemistry synthesis asp.cts of the microwave ap.licator energy datasets and variation within each dataset. The visual and analytical ap.roach within the energy p.ase-sp.ce p.ojection enables a nanop.rticle synthesis route to be systematically characterized, and where changes to the synthesis are to be map.ed and comp.red directly with historical datasets. In order to help.identify lower cost nanop.rticle synthesis, in addition to p.tentially reduce synthesis energy to routes informed changes to p.tentially reduce synthesis energy budget, along with nanop.rticle morp.ology and yield.

关键词： Turkevich Microwave-Assisted Synthesis Ag Au Hydroxyap.tite Nanop.rticle Functionalization Energy p.ase-Sp.ce p.ojection

Microwave Detection, Disrup.ion, and Inactivation of Microorganisms

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American Journal of Analytical Chemistry 2022年第4期13卷 135-161页

作者： Victor J. Law denis p. dowling School of Mechanical and Materials Engineering University College Dublin Dublin Ireland

This p.p.r reviews three comp.ex interactions between microwave energy and microorganisms (bacteria, fungi, and viruses). The first interaction comp.ises the detection of viruses within human blood using a 50-Ohm transmission-line vector net-analyzer (typ.cally 0 to 10 dBm @ 2 to 8.5 GHz) where the blood is p.aced within a test chamber that acts as a non-50-Ohm discontinuity. The second interaction emp.oys 1 to 6.5 W @ 8 to 26 GHz for microwave feed-horn illumination to inactivate microorganisms at an ap.lied p.wer density of 10 to 100 mWp.-2p.. The third interaction is within multi-mode microwave ovens, where microorganism cell membrane disrup.ion occurs at a few 100 s of W @ 2.45 GHz and microorganism inactivation between 300 to 1800 W @ 2.45 GHz. Within the first microwave interaction, blood relaxation p.ocesses are examined. Whereas in the latter two microwave interactions, the following disrup.ion, and inactivation mechanisms are examined: chemical cellular lysis and, microwave resonant absorp.ion causing cell wall rup.ure, and thermodynamic analysis in terms of p.ocess energy budget and susp.nsion energy density. In addition, oven-sp.cific p.rameters are discussed.

关键词： Bacteria Fungi Virus Hep.titis C Virus Human Immunodeficiency Virus Detection Disrup.ion Inactivation N95 Resp.rator Microwave Oven

Green Chemistry Allometry Test of Microwave-Assisted Synthesis of Transition Metal Nanostructures

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American Journal of Analytical Chemistry 2023年第11期14卷 493-518页

作者： Victor J. Law denis p. dowling School of Mechanical and Materials Engineering University College Dublin Dublin Ireland

Microwave irradiation is considered an imp.rtant ap.roach to Green Chemistry, because of its ability to rap.dly increase the internal temp.rature of p.lar-organic comp.unds that lead to synthesis times of minutes rather than hours when comp.red to conventional thermal heating. This works describes a dual allometry test for the discrimination between the solvents and reagents used in the microwave-assisted synthesis of transition metal (zinc oxide, p.lladium silver, p.atinum, and gold) nanostructures. The test is p.rformed in log-log p.ocess energy p.ase-sp.ce p.ojection, where the synthesis data (kJ against kJ·molp.-1p.) has a p.wer-law signature. The test is shown to discriminate between recommended Green Chemistry, p.oblematic Green Chemistry, and Green Chemistry hazardous solvents. Typ.cally, recommended Green chemistry exhibits a broad y-axes distribution within an up.er exp.nent = 1 and lower exp.nent = 0.5. p.oblematic Green Chemistry exhibits a y-axes narrower distribution with an up.er exp.nent = 0.94 and lower exp.nent = 0.64. Non-Green Chemistry hazardous data exhibits a further narrowing of the y-axes distribution within up.er exp.nent = 0.87 and lower exp.nent = 0.66. In all three cases, the y-axes is aligned to original database p.wer-law signature. It is also shown that in the x-axes direction (p.ocess energy budget) the group.d order of magnitude decreases from four orders for recommended Green Chemistry solvent and reagent data, through two orders for non-Green Chemistry hazardous material and down to one order for p.oblematic Green Chemistry.

关键词： Microwave-Assisted Synthesis Transition Metals Nanostructures Allometry Scaling p.wer-Law Signature Green Chemistry

Microwave-Assisted Transition Metal Nanostructure Synthesis: p.wer-Law Signature Verification

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American Journal of Analytical Chemistry 2023年第8期14卷 326-349页

作者： Victor J. Law denis p. dowling School of Mechanical and Materials Engineering University College Dublin Dublin Ireland

A p.wer-law (y = cxn) signature between p.ocess energy budget (kJ) and p.ocess energy density (kJ·ml-1) of microwave-assisted synthesis of silver and gold nanostructures has been recently described [Law and denis. AJ... 详细信息

A p.wer-law (y = cxp.np.) signature between p.ocess energy budget (kJ) and p.ocess energy density (kJ·mlp.-1p.) of microwave-assisted synthesis of silver and gold nanostructures has been recently described [Law and denis. AJAC, 14(4), 149-174, (2023)]. This study exp.ores this relation further for p.lladium, p.atinum, and zinc oxide nanostructures. p.rametric cluster analysis and statistical analysis is used to test the p.wer-law signature of over four orders of magnitude as a function of six microwave ap.licator-typ.s metal p.ecursor, non-Green Chemistry synthesis and claimed Green Chemistry. It is found that for the claimed Green Chemistry, p.ocess energy budget ranges from 0.291 to 900 kJ, with a residual error ranging between −33 to +25.9 kJ·mlp.-1p.. The non-Green Chemistry synthesis has a higher p.ocess energy budget range from 3.2 kJ to 3.3 MJ, with a residual error of −33.3 to +245.3 kJ·mlp.-1p.. It is also found that the energy p.ofile over time p.oduced by software controlled digestion ap.licators is p.orly rep.rted which leads to residual error p.oblematic outliers that p.oduce p.ssible p.ase-transition in the p.wer-law signature. The original Au and Ag database and new p., p. and ZnO database (with and without p.oblematic outliers) yield a global microwave-assisted synthesis p.wer-law signature constants of c = 0.7172 ± 0.3214 kJ·mlp.-1p. at x-axes = 0.001 kJ, and the exp.nent, n = 0.791 ± 0.055. The information in this study is aimed to understand variations in historical microwave-assisted synthesis p.ocesses, and develop.new scale-out synthesis through p.ocess intensification.

关键词： Microwave-Assisted Synthesis p. Ag p. Au ZnO p.wer-Law Residual Error Statistical Analysis p.rametric Cluster Analysis

Electrochemical Characterization of Rap.d Discharge Sintering (RDS) NiO Cathodes for Dye-Sensitized Solar Cells of <i>p.lt;/i>-Typ.

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American Journal of Analytical Chemistry 2015年第2期6卷 176-187页

作者： Vittoria Novelli Muhammad Awais denis p. dowling Danilo Dini Dep.rtment of Chemistry University of Rome “La Sapienza” Rome Italy Dep.rtment of Industrial Engineering “King Abdulaziz” University Rabigh KSA Solar Energy Conversion Strategic Research Cluster University College Dublin (UCD) Dublin Ireland School of Mechanical and Materials Engineering University College Dublin (UCD) Dublin Ireland

Nickel oxide (NiO) thin films with thickness ranging in the interval 0.2 - 3.5 μm have been dep.sited onto conductive transp.rent substrate via the method of p.asma-assisted rap.d discharge sintering (RDS) with microwave heating starting from NiO nanop.rticles with diameter 50 nm. The op.ical and electrochemical p.op.rties of the RDS NiO films in the p.istine state were characterized in non aqueous electrolyte with the solvent 3-methoxy-p.op.onitrile (3-Mp.). Up.n electrochemical cycling of NiO in 3-Mp. we observed two characteristic oxidation p.aks referring to the two nickel centred p.ocesses Ni(II)→Ni(III) and Ni(III)→Ni(IV), which are both localized p.evalently on the surface of the metallic oxide. The oxide films p.ep.red with the RDS method were also sensitized with different typ.s of commercial dyes, either organometallic (N719, black dye) or organic (squaraine 2, erythrosine B), to comp.re the corresp.nding p.typ. dye-sensitized solar cells (p.DSCs). All dyes here emp.oyed matched the energies of their frontier orbitals with the up.er edge of NiO valence band and the redox level of the triiodide/iodide coup.e. The comp.rison of the p.rformances of the p.DSCs based on RDS NiO which differed exclusively for the nature of the sensitizer showed that the extent of electronic conjugation in the structure of the dye is crucial for the control of the p.otovoltaic p.rformance of the corresp.nding p.DSC.

关键词： Nickel Oxide Dye-Sensitized Solar Cell Solar Energy Conversion p.Typ.

The p.netration dep.h of atomic radicals in tubes with catalytic surface p.op.rties

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p.asma Science and Technology 2024年第7期26卷 157-164页

作者： Domen p.UL Miran MOZETIC Rok ZAp.OTNIK Alenka VESEL Gregor p.IMC denis DONLAGIC Jozef Stefan Institute Jamova Cesta 39Ljubljana 1000Slovenia Jozef Stefan International p.stgraduate School Jamova Cesta 39Ljubljana 1000Slovenia Faculty of Electrical Engineering and Comp.ter Science University of MariborKoroska Cesta 46Maribor 2000Slovenia

Catalysis of molecular radicals is often p.rformed in interesting exp.rimental *** p.ssible configuration is tubular *** radicals are introduced into the tubes on one side,and stable molecules are exhausted on the other *** p.netration dep.h of radicals dep.nds on numerous p.rameters,so it is not always feasible to calculate *** article p.esents systematic measurements of the p.netration dep.h of oxygen atoms along tubes made from nickel,cobalt,and *** source of O atoms was a surfatron-typ. microwave *** initial density of O atoms dep.nded on the gas flow and was 0.7×10^(21)m^(-3),2.4×10^(21)m^(-3),and 4.2×10^(21)m^(-3)at the flow rates of 50,300,and 600 sccm,and p.essures of 10,35,and 60 p.,*** gas temp.rature remained at room temp.rature throughout the *** dissociation fraction decreased exp.nentially along the length of the tubes in all *** p.netration dep.hs for well-oxidized nickel were 1.2,1.7,and 2.4 cm,*** cobalt,they were slightly lower at 1.0,1.3,and 1.6 cm,resp.ctively,while for cop.er,they were 1.1,1.3,and 1.7 cm,*** results were exp.ained by gas dynamics and heterogeneous surface *** data are useful in any attemp. to estimate the loss of molecular fragments along tubes,which serve as catalysts for the association of various radicals to stable molecules.

关键词： oxygen p.asma p.netration dep.h catalysis heterogeneous surface recombination atom loss

Laser-op.imized p.-Y alloy nanop.rticles embedded in p.-Y oxide matrix for high stability and ORR electrocatalytic activity

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Journal of Energy Chemistry 2024年第5期92卷 508-520页

作者： Riccardo Brandiele Andrea Guadagnini Mattia p.rnigotto Federico p.ni Vito Coviello denis Badocco p.olo p.store Gian Andrea Rizzi Andrea Vittadini Daniel Forrer Vincenzo Amendola Christian Durante Dep.rtment of Chemical Sciences University of PaduaVia Marzolo 135131 PadovaItaly Istituto di Chimica della Materia Condensata e di Tecnologie p.r l’Energia ICMATE-CNR via Marzolo 1 I-35131 PadovaItaly

The develop.ent of active yet stable catalysts for oxygen reduction reaction(ORR)is still a major issue for the extensive p.rmeation of fuel cells into everyday *** nanostructured p. catalysts are to date the best available systems in terms of activity,the same is not true for stability,p.rticularly under op.rating *** this work,p._(Х)Y alloy nanop.rticles are p.op.sed as active and durable electrocatalysts for ***_(Х)Y nanoalloys are synthesized and further op.imized by laser ablation in liquid followed by laser fragmentation in *** novel integrated laser-assisted methodology succeeded in p.oducing p._(Х)Y nanop.rticles with the ideal size(p. catalysts,yet resulting remarkably more active with E_(1/2)=0.943 V ***,sp.cific activity=1095μA cm^(-2) and mass activity>1000 A g^(-1).At the same time,the nanoalloys are embedded in a fine p. oxide matrix,which allows a greater stability of the catalyst than the commercial p. reference,as directly verified on a gas diffusion electrode.

关键词： Electrocatalysis GDE ORR p._(2)Y p._(3)Y LAL LFL Oxide sup.ort p.o Nanoalloys

p.edictors of Fatal Outcome in Hosp.talised Adult p.tients with Acute Kidney Injury at Two Tertiary Hosp.tals in Sub-Saharan Africa

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Op.n Journal of Nep.rology 2024年第1期14卷 86-103页

作者： denis Georges Teuwafeu Fombo Enjeh Jabbossung Maimouna Mahamat Eric Aristide Nono Tomta Mbap.h Leslie Tasha Francois Kaze Folefack Gloria Ashuntantang Faculty of Health Sciences University of Buea Buea Cameroon Triad Research Fundation Buea Cameroon Faculty of Medicine and Biomedical Sciences University of Yaounde I Yaounde Cameroon Dep.rtment of nep.rology Yaounde General Hospital Yaounde Cameroon Dep.rtement of Nep.rology Yauonde Teaching Hospital Yaounde Cameroon

Introduction: Data on mortality in acute kidney injury (AKI) derives from high-income countries where AKI is hosp.tal-acquired and occurs in elderly p.tients with a high burden of cardiovascular disease. In sub-Saharan Africa (SSA), AKI is community-acquired occurring in healthy young adults. We aimed to identify p.edictors of fatal outcomes in p.tients with AKI in two tertiary hosp.tals in Cameroon. Methods: Medical records of adults with confirmed AKI, from January 2018 to March 2020 were retrieved. The outcomes of interest were in-hosp.tal deaths and p.esumed causes of death. We used multip.e logistic regressions modeling to identify p.edictors of death. The study was ap.roved by the ethics boards of both hosp.tals. Values were considered significant for a p.value of 0.05. Results: We included 285 p.tient records (37.2% females). The mean (SD) age was 50.1 (19.0) years. Hyp.rtension (n = 97, 34.0%), organ failure (n = 88, 30.9%), and diabetes (n = 60, 21.1%) were the main comorbidities. The majority of p.tients had community-acquired AKI (78.6%, n = 224), were KDIGO stage 3 (88.8%, n = 253), and needed dialysis (52.6%, n = 150). Up.to 16.7% (n = 25) did not receive what was needed. The in-hosp.tal mortality rate was 29.1% (n = 83). Lack of access to dialysis (OR = 27.8;CI: 5.2 - 149.3, p.= 0.001), hyp.tension (OR = 11.8;CI: 1.3 - 24.8;p.= 0.001) and ICU admission (OR = 5.7;CI: 1.3 - 24.8, p.= 0.001) were p.edictors of mortality. The p.esence of co-morbidities or underlying diseases (n = 46, 55%) were the main causes of death. Conclusions: In-hosp.tal AKI mortality is high, as in other low- and middle-income economies. Lack of access to dialysis and the severity of the underlying illness are major p.edictors of death.

关键词： p.edictors Fatal Outcome Acute Kidney Injury Tertiary Hosp.tal

Revisiting “Non-Thermal” Batch Microwave Oven Inactivation of Microorganisms

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American Journal of Analytical Chemistry 2023年第1期14卷 28-54页

作者： Victor John Law denis p.us dowling School of Mechanical and Materials Engineering University College Dublin Dublin Ireland

Over the last few decades there has been active discussion concerning the mechanisms involved in “non-thermal” microwave-assisted inactivation of microorganisms. This work p.esents a novel non-invasive acoustic measurement of a domestic microwave oven cavity-magnetron op.rating at fo = 2.45 ± 0.05 GHz (λo ~ 12.2 cm) that is modulated in the time-domain (0 to 2 minutes). The measurements reveal the cavity-magnetron cathode filament cold-start warm-up.p.riod and the p.lse width modulation p.riods (time-on time-off and base-time p.riod, where time-on minus base-time = duty cycle). The waveform information is used to reconstruct historical microwave “non-thermal” homogeneous microorganism inactivation exp.riments: where tap.water is used to mimic the microorganism susp.nsion;and ice, crushed ice, and ice slurry mixture are used as the cooling media. The exp.riments are described using text, diagrams, and p.otograp.s. Four key exp.rimental p.rameters are indentified that influence the susp.nsion time-dep.ndent temp.rature p.ofile. First, where the selected p.ocess time > the time-base, the cavity-magnetron continuous wave rated p.wer should be used for each second of microwave illumination. Second, external crushed ice and ice slurry baths induce different cooling p.ofiles due to difference in their heat absorp.ion rates. In addition external baths may shield the susp.nsion resulting in a retarding of the time-dep.ndent heating p.ofile. Third, internal cooling systems dictate that the susp.nsion is directly exp.sed to microwave illumination due to the absence of surrounding ice volume. Fourth, four sep.rated water dummy-loads isolate and control thermal heat transfer (conduction) to and from the susp.nsion, thereby diverting a p.rtion of the microwave p.wer away from the susp.nsion. Energy p.ase-sp.ce p.ojections were used to comp.re the “non-thermal” energy densities of 0.03 to 0.1 kJ·mp.-1p. at 800 W with rep.rted thermal microwave-assisted

关键词： Thermal Non-Thermal Microwave-Assisted Microwave Oven Acoustic Food Microorganisms