Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences最新文献

{"title":"Direct measurement of non-thermal microwave effects on bacterial growth and redox dynamics using a novel high-throughput waveguide applicator.","authors":"Angharad Miles, Adrian Porch, Heungjae Choi, Steve Cripps, Helen Brown, Catrin Williams","doi":"10.1098/rsta.2024.0073","DOIUrl":"10.1098/rsta.2024.0073","url":null,"abstract":"<p><p>A high-throughput microwave applicator has been designed and characterized to investigate microwave interactions with biological systems. When operated in the TE₁₀ mode, this rectangular waveguide enabled simultaneous exposure of 96 biological samples to a quantifiable electric field (<i>E</i> field) at 2.45 GHz. Optimized electric probe transitions efficiently couple power (up to 50 W) into and out of the waveguide, achieving a voltage transmission coefficient (S₂₁) near unity (0 dB) and a voltage reflection coefficient (S₁₁) below 0.01 ( less than -20 dB). The growth dynamics of <i>Staphylococcus aureus</i> bacteria were analysed after non-thermal, microsecond-pulsed microwave exposure at 25 W r.m.s. of microwave power for 24 h. Post-exposure, <i>S. aureus</i> exhibited significantly higher optical density measurements and growth rates than thermal controls. Fluorescent probes directed towards key redox indicators revealed that microwave exposure altered the cellular redox state. This study provides new insights into the non-thermal effects of pulsed 2.45 GHz microwaves on <i>S. aureus</i> growth dynamics and characterizes a novel high-throughput platform for further exploration of fundamental microwave effects on biological systems.This article is part of the theme discussion meeting issue 'Microwave science in sustainable technologies'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"383 2297","pages":"20240073"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12096104/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microwave power sources for industrial, scientific and medical applications.","authors":"Steve Cripps","doi":"10.1098/rsta.2024.0069","DOIUrl":"10.1098/rsta.2024.0069","url":null,"abstract":"<p><p>The industrial, scientific and medical (ISM) sector has been a growth area in recent years for applications of microwave engineering. These applications include various forms of heating and more controversial uses that exploit so-called 'non-thermal' effects of microwave exposure on biological and chemical samples. Given the non-thermal nature of these effects, the microwave power source may be adequate in pulsed, rather than continuous form. This paper will not attempt to address the questions surrounding the provenance of such effects but will discuss the challenges presented to the microwave circuit designer in delivering substantial amounts of microwave power, both continuous and pulsed, to targets that vary in size and microwave impedance properties. ISM applications may represent a large new market for radio frequency power amplifier (RFPA) products that may utilize alternative technologies and design approaches over those that have evolved for the conventional microwave applications such as telecommunications and radar.This article is part of the discussion meeting issue 'Microwave science in sustainability'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"383 2297","pages":"20240069"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12096102/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microwaves in clean energy technologies.","authors":"Samuel Hefford, Michael Barter, M Usman Azam, Bhupinder Singh, Georgios Dimitrakis, Xiangyu Jie, Peter Edwards, Daniel R Slocombe","doi":"10.1098/rsta.2024.0394","DOIUrl":"10.1098/rsta.2024.0394","url":null,"abstract":"<p><p>Energy in the microwave spectrum is increasingly applied in clean energy technologies. This review discusses recent innovations using microwave fields in hydrogen production and synthesis of new battery materials, highlighting the unique properties of microwave heating. Key innovations include microwave-assisted hydrogen generation from water, hydrocarbons and ammonia and the synthesis of high-performance anode and cathode materials. Microwave-assisted catalytic water splitting using Gd-doped ceria achieves efficient hydrogen production below 250°C. For hydrocarbons, advanced microwave-active catalysts Fe-Ni alloys and ruthenium nanoparticles enable high conversion rates and hydrogen yields. In ammonia synthesis, microwaves reduce the energy demands of the Haber-Bosch process and enhance hydrogen production efficiency using catalysts such as ruthenium and Co₂Mo₃N. In battery technology, microwave-assisted synthesis of cathode materials like LiFePO₄ and LiNi_0.5Mn_1.5O₄ yields high-purity materials with superior electrochemical performance. Developing nanostructured and composite materials, including graphene-based anodes, significantly improves battery capacities and cycling stability. The ability of microwave technology to provide rapid, selective heating and enhance reaction rates offers significant advancements in clean energy technologies. Ongoing research continues to bridge theoretical understanding and practical applications, driving further innovations in this field. This review aims to highlight recent advances in clean energy technologies based upon the novel use of microwave energy. The potential impact of these emerging applications is now being fully understood in areas that are critical to achieving net zero and can contribute to the decarbonization of key sectors. Notable in this landscape are the sectors of hydrogen fuel and battery technologies. This review examines the role of microwaves in these areas.This article is part of the discussion meeting issue 'Microwave science in sustainability'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"383 2297","pages":"20240394"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12096106/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low to near-zero CO₂ production of hydrogen from fossil fuels: critical role of microwave-initiated catalysis.","authors":"Xiangyu Jie, Daniel R Slocombe, Adrian Porch, Tiancun Xiao, Sergio González-Cortés, Saud Aldrees, Jon R Dilworth, Benzhen Yao, Martin-Owen Jones, Vladimir Kuznetsov, Peter P Edwards","doi":"10.1098/rsta.2024.0061","DOIUrl":"10.1098/rsta.2024.0061","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Presently, there is no single, clear route for the near-term production of the huge volumes of CO&lt;sub&gt;2&lt;/sub&gt;-free hydrogen necessary for the global transition to any type of hydrogen economy. All conventional routes to produce hydrogen from hydrocarbon fossil fuels (notably natural gas) involve the production-and hence the emission-of CO&lt;sub&gt;2&lt;/sub&gt;, most notably in the steam methane reforming (SMR) process. Our recent studies have highlighted another route; namely, the critical role played by the microwave-initiated catalytic pyrolysis, decomposition or deconstruction of fossil hydrocarbon fuels to produce hydrogen with low to near-zero CO&lt;sub&gt;2&lt;/sub&gt; emissions together with high-value solid nanoscale carbonaceous materials. These innovations have been applied, firstly to wax, then methane, crude oil, diesel, then biomass and most recently Saudi Arabian light crude oil, as well as plastics waste. Microwave catalysis has therefore now emerged as a highly effective route for the rapid and effective production of hydrogen and high-value carbon nanomaterials co-products, in many cases accompanied by low to near-zero CO&lt;sub&gt;2&lt;/sub&gt; emissions. Underpinning all of these advances has been the important concept from solid state physics of the so-called Size-Induced-Metal-Insulator Transition (SIMIT) in mesoscale or mesoscopic particles of catalysts. The mesoscale refers to a range of physical scale in-between the micro- and the macro-scale of matter (Huang W, Li J and Edwards PP, 2018, Mesoscience: exploring the common principle at mesoscale, &lt;i&gt;Natl. Sci. Rev&lt;/i&gt;. &lt;b&gt;5&lt;/b&gt;, 321-326 (doi:10.1093/nsr/nwx083)). We highlight here that the actual physical size of the mesoscopic catalyst particles, located close to the SIMIT, is the primary cause of their enhanced microwave absorption and rapid heating of particles to initiate the catalytic-and highly selective-breaking of carbon-hydrogen bonds in fossil hydrocarbons and plastics to produce clean hydrogen and nanoscale carbonaceous materials. Importantly, also, since the surrounding 'bath' of hydrocarbons is cooler than the microwave-heated catalytic particles themselves, the produced neutral hydrogen molecule can quickly diffuse from the active sites. This important feature of microwave heating thereby minimizes undesirable side reactions, a common feature of conventional thermal heating in heterogeneous catalysis. The low to near-zero CO&lt;sub&gt;2&lt;/sub&gt; production of hydrogen via microwave-initiated decomposition or cracking of abundant hydrocarbon fossil fuels may be an interim, viable alternative to the conventional, widely-used SMR, that a highly efficient process, but unfortunately associated with the emission of vast quantities of CO&lt;sub&gt;2&lt;/sub&gt;. Microwave-initiated catalytic decomposition also opens up the intriguing possibility of using distributed methane in the current natural gas structure to produce hydrogen and high-value solid carbon at either central or distributed sites. That approach will","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"383 2297","pages":"20240061"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12096099/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A reactor for <i>in situ</i>, time-resolved neutron diffraction studies of microwave-induced rapid solid-state chemical reactions.","authors":"Ross George Bell McFadzean, Ronald Smith, Timothy David Drysdale, Duncan H Gregory","doi":"10.1098/rsta.2024.0065","DOIUrl":"10.1098/rsta.2024.0065","url":null,"abstract":"<p><p>Utilizing direct microwave- (MW)-induced heating in solid-state synthesis yields the clear benefits of greatly reduced reaction times and lower energy requirements as compared with conventional methods. Here, we describe a bespoke single-mode cavity (SMC) MW reactor designed to operate within a neutron beamline that allowed powder diffraction data to be collected from materials <i>in situ</i> as they were heated using MWs. The unique set-up was used to investigate the rapid solid-state synthesis of the binary metal chalcogenide thermoelectric (TE) materials Bi₂Se₃, Bi₂Te₃, Sb₂Se₃ and Sb₂Te₃. The resultant time-resolved diffraction data from each synthesis were time-sliced post-reaction into segments covering periods of tens of seconds, enabling the reaction progression to be visualized as colourmap plots. This technique enabled the accurate tracking of polycrystalline structure formation and a quantitative analysis of phase fractions during the accelerated heating and subsequent cooling stages of each reaction. Our investigations have also revealed some of the present limitations of rapid <i>in situ</i> neutron diffraction techniques and how these might be remedied.This article is part of the discussion meeting issue 'Microwave science in sustainability'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"383 2297","pages":"20240065"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12096107/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the potential of microwave heating to convert waste into added-value chemicals and materials: a review.","authors":"Emmanuel Dan, Alan J McCue, Davide Dionisi, Claudia Fernández Martín","doi":"10.1098/rsta.2024.0071","DOIUrl":"10.1098/rsta.2024.0071","url":null,"abstract":"<p><p>Microwave (MW) heating represents a superior alternative to conventional heating techniques due to its unique ability for rapid, selective, uniform and volumetric heating. However, challenges such as temperature non-uniformity, especially in certain materials and processing conditions, can limit its widespread application. Nevertheless, this heating method can enhance the physicochemical properties and performance of materials produced, making it a vital tool in sustainable material processing to produce valuable porous carbons for CO₂ capture, essential for climate change mitigation through carbon capture, utilization and storage (CCUS) strategies. MW heating significantly reduces processing time, energy consumption and operational costs, providing an efficient, green and cost-effective processing option. In this review we explore the use of MW heating in converting biomass, plastics and materials such as tyres and electronic waste into biofuels, bioenergy and hydrogen through biological and thermochemical processes. We highlight MW heating for producing solid adsorbents such as activated carbons from waste, their role in carbon capture and regeneration after CO₂ exposure. We also examine the principles of MW heating, its unique processing advantages and diverse applications across fields. In addition, we emphasize the life cycle assessment (LCA) of MW-assisted treatment for biomass and plastics while addressing the limitations of MW processing in material applications.This article is part of the discussion meeting issue 'Microwave science in sustainability'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"383 2297","pages":"20240071"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12096103/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rapid anchoring of iron-carbon nanoparticles on carbon spheres using microwave heating.","authors":"Suguang Yang, Minghui Lyu, Xiaxin Jiao, Na Wang, Kai Liu, Hong Li, Zhenyu Zhao, Xin Gao","doi":"10.1098/rsta.2024.0070","DOIUrl":"https://doi.org/10.1098/rsta.2024.0070","url":null,"abstract":"<p><p>Despite excellent performance of iron/carbon materials in microwave absorbing field, the synthesis of these composites faces challenges, involving prolonged processing times and the aggregation of iron nanoparticles. Here, an efficient microwave-induced preparation method is proposed to overcome this problem. First, carbon spheres with uniform particle size were synthesized as support for iron deposition. By employing ultrafast pyrolysis of ferrocene, iron nanoparticles were anchored on the surface of carbon spheres, where a comparative analysis of the microstructure and composition of Fe/C materials synthesized via microwave heating and conventional heating was conducted, alongside a quantitative investigation into the correlation between ferrocene addition and complex dielectric constant. The mechanism of microwave enhancing dispersion of iron particles was elucidated, indicating that microwave induced local overheating of carbon spheres rapidly decomposes ferrocene, facilitating uniform deposition of iron nanoparticles on the carbon sphere surfaces. Consequently, compared with Fe/C materials synthesized via conventional methods, microwave heating improves the dispersion of supported iron nanoparticles, reducing reaction time from hours to 2 min. In addition, an optimal multi-step strategy for promoting the efficient deposition of iron nanoparticles was developed, where a variety of different absorbing materials, the highest real and imaginary parts of which, obtained at 2.45 GHz, were 87.15 and 68.81, respectively.This article is part of the discussion meeting issue 'Microwave science in sustainability'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"383 2297","pages":"20240070"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highly efficient and rapid dechlorination of polyvinyl chloride via microwave pyrolysis.","authors":"Chai Siah Lee, Mohamed Adam, John P Robinson, Eleanor R Binner","doi":"10.1098/rsta.2024.0064","DOIUrl":"10.1098/rsta.2024.0064","url":null,"abstract":"<p><p>Polyvinyl chloride (PVC) waste recycling is challenging due to its high chlorine content, which generates hazardous chlorinated pollutants if treated improperly. A safe and promising PVC dechlorination method is urgently needed to address this issue. Several dechlorination methods have been reported at the laboratory scale; however, each method has its downsides, and none has been proven at the commercial scale. We present, for the first time in the literature, an effective microwave pyrolysis process that can dechlorinate PVC rapidly without the requirement of a solvent/microwave absorber. High dechlorination efficiency up to 99.6% was achieved within 96 s. This process releases hydrogen chloride and generates hydrocarbon-containing liquid and a dechlorinated residue. Dielectric analysis revealed that the untreated PVC was readily heated under microwaves due to the polar chlorine group in its structure. Thermogravimetric analysis confirmed that there were two pyrolysis stages and dechlorination was achieved after the first pyrolysis stage. Fourier-transform infrared (IR) analysis showed that all the bands corresponding to the stretching of C-Cl bonds were not detected in the dechlorinated residue. All these results prove that microwave pyrolysis is a promising process for PVC dechlorination, and it could be the game changer that makes PVC recycling commercially viable.This article is part of the discussion meeting issue 'Microwave science in sustainability'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"383 2297","pages":"20240064"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12096105/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preface to 'Microwave science in sustainability'.","authors":"Daniel R Slocombe, Adrian Porch","doi":"10.1098/rsta.2024.0075","DOIUrl":"10.1098/rsta.2024.0075","url":null,"abstract":"","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"383 2297","pages":"20240075"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12096100/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diamond thin films: a twenty-first century material. Part 2: a new hope.","authors":"Paul W May, Ramiz Zulkharnay","doi":"10.1098/rsta.2023.0382","DOIUrl":"https://doi.org/10.1098/rsta.2023.0382","url":null,"abstract":"<p><p>Nearly a quarter of a century ago, we wrote a review paper about the very new technology of chemical vapour deposition (CVD) of diamond thin films. We now update this review and bring the story up to date by describing the progress made-or not made-over the intervening years. Back in the 1990s and early 2000s, there was enormous excitement about the plethora of applications that were suddenly possible now that diamonds could be fabricated in the form of thin films. Diamond was hailed as the ultimate semiconductor, and it was believed that the few remaining problems would be quickly solved, leading to a new 'diamond age' of electronics. In reality, however, difficulty in making large-area diamond wafers and the elusiveness of a useful <i>n</i>-type dopant slowed progress substantially. Unsurprisingly, over the following decade, the enthusiasm and funding for diamonds faded, while competing materials forged ahead. But in the early 2010s, several new game-changing applications for diamonds were discovered, such as electrochemical electrodes, the nitrogen-vacancy (NV) centre defect that promised room-temperature quantum computers, and methods to grow large single-crystal gemstone-quality diamonds. These led to a resurgence in diamond research and a new hope that diamond might <i>finally</i> live up to its promise.This article is part of the theme issue 'Science into the next millennium: 25 years on'.</p>","PeriodicalId":19879,"journal":{"name":"Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","volume":"383 2296","pages":"20230382"},"PeriodicalIF":4.3,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12059586/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144037449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}