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the great catastrophe: causes of the Permo-triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： paul B.Wignall David P.G.Bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

the marine losses during the Permo-triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. the ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(the overwhelming evidence for rapid warming during the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern Boreal latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

Comparative study of Exhaust Emissions from Diesel and Syngas Powered 3.5 kW Compression Ignition Engine with and without Load

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Journal of Power and Energy Engineering 2024年第8期12卷 30-46页

作者： Benson Kariuki paul Njogu Joseph Kamau robert Kinyua Sameer Bachani Institute of Energy and Environmental technology Jomo Kenyatta University of Agriculture & Technology Nairobi Kenya Department of Mechanical and Automotive Engineering Technical University of Mombasa Mombasa Kenya

Despite diesel engines being highly efficient, with low fuel consumption and reduced carbon dioxide emissions, they emit relatively high levels of particulate matter and oxides of nitrogen (NOx) due to high exhaust gas temperatures. Engine emissions show the quality and completeness of combustion. this paper aims to present the results of a study comparing exhaust emissions from a diesel and syngas powered engine. Syngas was produced from co-firing coal and biomass in a gasifier then cleaned, cooled and applied as an alternative fuel in an engine operated from 0 - 100% load. Exhaust-emissions were monitored at this load conditions. the exhaust-temperature was measured using thermocouples and the emission gases were analyzed using testo 350. the emissions were lower and decreased as the engine load increased, except for sulphur dioxide and NOx. the study shows that levels of carbon monoxide, were higher in a range of 46.5 - 80.2%, while carbon dioxide was 3.3 - 18% higher compared to those from diesel. Hydrocarbon emissions were 480 and 1250 ppm for diesel and syngas respectively. the study reveals that the engine operates optimally at higher loads since hydrocarbons and oxides of carbon are low due to complete combustion at higher temperatures. Exhaust gas temperature was higher in the syngas fuel and increased as the engine load increased in the range of 455.83 - 480.03˚C which influenced the formation of NOx. NOx from diesel was found to be higher, ranging from 32.5 - 40.5%, compared to those from syngas with an engine load of 75%. the study observed that relative to diesel, the emissions of sulfur dioxide at 50% engine load were lower in a range of 23.7 - 57.1%. Emissions of hydrocarbons depended on the degree of substitution of diesel and engine load. the study therefore shows that, relative to diesel, emissions decreased when syngas was used with upgraded syngas from Prosporis juliflora presenting as the best alternative followed by Hyphanae compressa, and last

关键词： Emissions Engine Load temperature Neat-Diesel Syngas

Smart contract applications in the built environment: How prepared are Nigerian construction stakeholders?

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Frontiers of Engineering Management 2024年第1期11卷 50-61页

作者： Andrew EBEKOZIEN Clinton AIGBAVBOA Samuel Adeniyi ADEKUNLE mohamad Shaharudin SAMSURIJAN John ALIU Bernard Martins ARtHUR-AIDOO Godpower Chinyeru AMADI Department of Construction Management and Quantity Surveying University of JohannesburgJohannesburg 2006South Africa School of Social Sciences Universiti Sains MalaysiaGelugor11800 USM PenangMalaysia Department of Quantity Surveying Auchi PolytechnicAuchiNigeria Institute for Resilient Infrastructure Systems College of EngineeringUniversity of GeorgiaAthensGA 30602USA Department of Building technology Faculty of Built EnvironmentAccra Technical UniversityAccraGhana Nigerian Institute of Management Port HarcourtNigeria

studies have demonstrated that advanced technology,such as smart contract applications,can enhance both pre-and post-contract administration within the built environment *** contract technology,exemplifying blockchain technologies,has the potential to improve transparency,trust,and the security of data transactions within this ***,there is a dearth of academic literature concerning smart contract applications within the construction industries of developing countries,with a specific focus on ***,this study seeks to explore the relevance of smart contract technology and address the challenges impeding its adoption,offering strategies to mitigate the obstacles faced by smart contract *** investigate the stakeholders,this research conducted 14 virtual interview sessions to achieve data *** interviewees encompassed project management practitioners,senior management personnel from construction companies,experts in construction dispute resolution,professionals in construction software,and representatives from government construction *** data obtained from these interviews underwent thorough analysis employing a thematic *** study duly recognizes the significance of smart contract applications within the *** the 12 identified barriers,issues such as identity theft and data leakage,communication and synchronization challenges,high computational expenses,lack of driving impetus,excessive electricity consumption,intricate implementation processes,absence of a universally applicable legal framework,and the lack of a localized legal framework were recurrent impediments affecting the adoption of smart contract applications within the *** study also delves into comprehensive measures to mitigate these *** conclusion,this study critically evaluates the relevance of smart contract applications within the built environment,with a specific focus on promoting their *** may serve

关键词： built environment industry digitalization Nigeria smart contract technological revolution

the concept of gene therapy for glaucoma:the dream that has not come true yet

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Neural Regeneration Research 2024年第1期19卷 92-99页

作者： robert Sulak Xiaonan Liu Adrian Smedowski Department of Physiology Faculty of Medical Sciences in KatowiceMedical University of Silesia in KatowiceKatowicePoland Institute of Biotechnology HiLIFEUniversity of HelsinkiHelsinkiFinland Glaucotech Co. KatowicePoland

Gene therapies,despite of being a relatively new therapeutic approach,have a potential to become an important alternative to current treatment strategies in *** glaucoma is not considered a single gene disease,the identified goals of gene therapy would be rather to provide neuroprotection of retinal ganglion cells,especially,in intraocular-pressure-independent *** most commonly reported type of vector for gene delivery in glaucoma studies is adeno-associated virus serotype 2 that has a high tro pism to retinal ganglion cells,res ulting in long-term expression and low immunogenic *** gene thera py studies recruit inducible and genetic animal models of optic neuropathy,like DBA/2J mice model of high-tension glaucoma and the optic nerve *** gene therapy-based neuroprotection of retinal ganglion cells is targeting specific genes translating to growth factors(i.e.,brain derived neurotrophic factor,and its receptor trkB),regulation of apoptosis and neurodegeneration(i.e.,Bcl-xl,Xiap,FAS system,nicotinamide mononucleotide adenylyl transferase 2,Digit3 and Sarm1),immunomodulation(i.e.,Crry,C3 complement),modulation of neuroinflammation(i.e.,e rythropoietin),reduction of excitotoxicity(i.e.,Com KIlα)and transcription regulation(i.e.,Max,Nrf2).On the other hand,some of gene therapy studies focus on lowering intra ocular pressure,by impacting genes involved in both,decreasing aqueous humor production(i.e.,aquaporin 1),and increasing outflow facility(i.e.,COX2,prostaglandin F2a receptor,RhoA/RhoA kinase signaling pathway,MMP1,Myocilin).the goal of this review is to summarize the current stateof-art and the direction of development of gene therapy strategies for glaucomatous neuropathy.

关键词： adeno-associated virus gene editing gene therapy glaucoma IOP lowering IOP-independent mechanisms neuroprotection optic nerve optic neuropathy retinal ganglion cells

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Prediction of Bandwidth of Metamaterial Antenna Using Pearson Kernel-Based techniques

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Computers, Materials & Continua 2024年第3期78卷 3449-3467页

作者： Sherly Alphonse S.Abinaya Sourabh paul School of Computer Science and Engineering Vellore Institute of TechnologyChennai600127India School of Electronics Engineering Vellore Institute of TechnologyChennai600127India

the use of metamaterial enhances the performance of a specific class of antennas known as metamaterial *** radiation cost and quality factor of the antenna are influenced by the size of the *** antennas allow for the circumvention of the bandwidth restriction for small *** parameters have recently been predicted using machine learning algorithms in existing *** learning can take the place of the manual process of experimenting to find the ideal simulated antenna *** accuracy of the prediction will be primarily dependent on the model that is *** this paper,a novel method for forecasting the bandwidth of the metamaterial antenna is proposed,based on using the Pearson Kernel as a standard *** with these new approaches,this paper suggests a unique hypersphere-based normalization to normalize the values of the dataset attributes and a dimensionality reduction method based on the Pearson kernel to reduce the dimension.A novel algorithm for optimizing the parameters of Convolutional Neural Network(CNN)based on improved Bat Algorithm-based Optimization with Pearson Mutation(BAO-PM)is also presented in this *** prediction results of the proposed work are better when compared to the existing models in the literature.

关键词： Antenna pearson optimization bandwidth metamaterial

Improving Heat transfer in Parabolic trough Solar Collectors by Magnetic Nanofluids

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Energy Engineering 2024年第4期121卷 835-848页

作者： Ritesh Singh Abhishek Gupta Akshoy Ranjan paul Bireswar paul Suvash C.Saha Department of Applied Mechanics Motilal Nehru National Institute of Technology AllahabadPrayagrajIndia Department of Mechanical and Mechatronic Engineering University of Technology SydneySydneyAustralia

A parabolic trough solar collector(PtSC)converts solar radiation into thermal ***,low thermal efficiency of PtSC poses a hindrance to the deployment of solar thermal power *** performance of PtSC is enhanced in this study by incorporating magnetic nanoparticles into the working *** circular receiver pipe,with dimensions of 66 mm diameter,2 mm thickness,and 24 m length,is exposed to uniform temperature and velocity *** working fluid,therminol-66,is supplemented with Fe3O4 magnetic nanoparticles at concentrations ranging from 1%to 4%.the findings demonstrate that the inclusion of nanoparticles increases the convective heat transfer coefficient(HtC)of the PtSC,with higher nanoparticle volume fractions leading to greater heat transfer but increased pressure *** thermal enhancement factor(tEF)of the PtSC is positively affected by the volume fraction of nanoparticles,both with and without a magnetic ***,the scenario with a 4%nanoparticle volume fraction and a magnetic field strength of 250 G exhibits the highest tEF,indicating superior thermal *** findings offer potential avenues for improving the efficiency of PtSCs in solar thermal plants by introducing magnetic nanoparticles into the working fluid.

关键词： Parabolic trough solar collector(PtSC) magnetic nanofluid(MNF) heat transfer convective heat transfer coefficient(HtC) thermal enhancement factor(tEF)

Exploring innovative synthetic solutions for advanced polymer-based electrochromic energy storage devices:Phenoxazine as a promising chromophore

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Journal of Energy Chemistry 2024年第4期91卷 433-452页

作者： Catalin-paul Constantin Mihaela Balan-Porcarasu Gabriela Lisa “Petru Poni”Institute of Macromolecular Chemistry Electroactive Polymers&Plasmochemistry Laboratory41A Grigore Ghica Voda AlleyIasi 700487Romania “Gh.Asachi”technical University Iasi Faculty of Chemical EngineeringBd.Mangeron 71Iasi 700050Romania

the current investigation offers an innovative synthetic solution regarding electrochromic(EC)and energy storage applications by exploring phenoxazine(POZ)***,three POZ-based polymers(polyimide,polyazomethine,and polyamide)were synthesized to ascertain the superior *** polyamide exhibited remarkable attributes,including high redox stability during 500 repetitive CVs,optical contrast of 61.98%,rapid response times of 1.02 and 1.38 s for coloring and bleaching,EC efficiency of 280 cm^(2)C^(-1).and decays of the optical density and EC efficiency of only 12.18%and 6.23%after 1000 ***,the energy storage performance of polyamide PA was tested,for which the following parameters were obtained:74.7 F g^(-1)(CV,scan rate of 10 mV s^(-1))and 118 F g^(-1)(GCD,charging current of 0.1 A g^(-1)).then,the polyamide was tested in EES devices,which yielded the following EC parameters:an optical contrast of 62.15%,response times of 9.24 and 5.01 s for coloring and bleaching,EC efficiency of 178 cm^(2)C^(-1),and moderate decays of 20.25%and 23.24%for the optical density and EC efficiency after 500 *** energy storage performance included a capacitance of 106 F g^(-1)(CV,scan rate of 0.1 mV s^(-1))and 9.23 F g^(-1)(GCD,charging current of 0.1 A g^(-1)),capacitance decay of 11.9%after500 cycles,and 1.7 V retention after 2 ***,two EES devices connected in series powered a 3 V LED for almost 30 s.

关键词： Polymers Phenoxazine Electrochromic Energy storage Electrochromi cenergy storage devices

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Optimization of product characteristics of porous carbon agglomerates using a design of experiments in fluidized bed agglomeration

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Particuology 2024年第6期89卷 258-269页

作者： Martin Oelofse robert Rack Marcelle Hilden Peter Langguth Department of Pharmaceutical technology and Biopharmaceutics Johannes Gutenberg UniversityMainzGermany Carbon Advanced Solutions GmbH HeuchelheimGermany

Spraying parameters during particle agglomeration processes can affect the agglomeration kinetics and particle *** study was conducted to better understand the influence of the spraying parameters in a fluidized bed wet agglomeration process,and the influence on the stability characteristics of carbon tablets.A formulation based on fine carbon and peroxide powder,as well as carboxymethyl cellulose as a binder,was used to produce agglomerates in a first production *** in a second production step carbon tablets with a high porosity were molded for the customer goods *** optimization of the compressive strength of these carbon tablets was the goal of the *** agglomerates were produced with a laboratory scale granulator called“ProCell”and were compressed with a five-cavity mechanical *** screening of the agglomeration process parameters and their influence on the agglomerates quality,as well as the performance characteristics of the carbon tablets,were investigated using a multilevel factorial *** experimental runs were done by varying atomized air pressure and feed rate of the *** was determined by the design *** findings of the statistical trials showed that low atomized air pressure and a low feed rate lead to a higher tablet compressive strength.

关键词： Wet agglomeration Fluidized bed Design of experiments Carbon agglomerates and tablets

Assessment of portable FtIR and Raman spectroscopy for the detection of 2,3-dimethyl-2,3-dinitrobutane(DMDNB)in plastic explosives

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Defence technology（防务技术） 2024年第4期34卷 11-18页

作者： Jacky Cailes robert Dunsmore Kathryn L.Linge ChemCentre PO Box 1250PerthAustralia

the Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of ***,to-date,laboratory testing remains the internationally accepted practice for identifying and quantifying the taggants stipulated in the *** this project,portable FtIR and Raman instruments were tested for their ability to detect 2,3-dimethyl-2,3-dinitrobutane(DMDNB),the chemical marker incorporated in plastic explosives that are manufactured within *** both FtIR and Raman instruments detected solid DMDNB(98%purity),field analysis of plastic explosives at an Australian Defence establishment showed that both FtIR and Raman spectra were matched the relevant explosive(RDX or PEtN),rather than the DMDNB *** all three plastic explosives tested,the concentration of DMDNB was measured by SPME-GC-MS to be between 1.8 and 2%,greater than the minimum 1%concentration stipulated by the Marplex *** testing with a plastic explosive analogue confirmed that the minor absorption peaks that would characterize low concentrations of DMDNB were masked by absorption bands from other compounds within the ***,while both FtIR and Raman spectroscopy are suitable for detection of plastic explosives,neither rely on the presence of DMDNB for *** is likely that similar results would be found for other taggants stipulated by the Marplex Convention,given they are also present in concentrations less than 1%.

关键词： Explosive ICAO taggants 2,3-Dimethyl-2,3-dinitrobutane(DMDNB) Fourier transform infrared(FtIR) Raman

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