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Evaluation of a Wireless Solar Powered Personal Weather Station

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Automated retrofit targeting of heat exchanger networks

Agricultural Sciences（农业科学） 2024年第1期

作者： Robert j.Lascano timothy S.Goebel Dennis C.Gitz III john E.Stout

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Frontiers of Chemical Science and Engineering 2018年第4期12卷 630-642页

作者： timothy G.Walmsley Nathan S.Lal Petar S.Varbanov jiri j.Klemes Sustainable Process Integration Laboratory -SPIL NETME CentreFaculty of Mechanical Engineering Bmo University of TechnologyBmo 60190Czech Republic Energy Research Centre School of EngineeringUniversity of WaikatoHamilton 3240New Zealand

The aim of this paper is to develop a novel heat exchanger network (HEN) retrofit method based on a new automated retrofit targeting (ART) algorithm. ART uses the heat surplus-deficit table (HSDT) in combination with the Bridge Retrofit concepts to generate retrofit bridges option, from which a retrofit design may be formulated. The HSDT is a tabular tool that shows potential for improved re-integration of heat source and sink streams within a HEN. Using the HSDT, retrofit bridges—a set of modifications that links a cooler to a heater to save energy—may be identified, quantified, and compared. The novel retrofit method including the ART algorithm has been successfully implemented in Microsoft ExcelTM to enable analysis of large-scale HENs. A refinery case study with 27 streams and 46 existing heat exchangers demonstrated the retrofit method’s potential. For the case study, the ART algorithm found 68903 feasible unique retrofit opportunities with a minimum 400 kW·unit−1 threshold for heat recovery divided by the number of new units. The most promising retrofit project required 3 new heat exchanger units to achieve a heat savings of 4.24 MW with a favorable annualised profit and a reasonable payback period.

关键词： process retrofit pinch analysis heat exchanger network heat recovery

Déjàvu:Might Future Eruptions of Hunga Tonga-Hunga Ha'apai Volcano be a Repeat of the Devastating Eruption of Santorini,Greece(1650 BC)?

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journal of Earth Science 2022年第2期33卷 229-235页

作者： timothy M.Kusky Center for Global Tectonics Three Gorges Research Center for Geo-HazardsChina University of GeosciencesWuhan 430074China

The remote Pacific islands nation of Tonga(about 170 islands,with a population of 105000),and surrounding countries,are suffering from the damage from one of the largest,most explosive volcanic eruptions in at least several decades,at least since the 1991 eruption of Pinatubo in the *** data is still coming in from the jan.15,2022 *** reports show(remarkably)few casualties,but the islands are still(as of this writing)inaccessible because of thick volcanic ash coverings。

关键词： volcanic eruption thick

Seasonal Variations of CH_4 Emissions in the Yangtze River Delta Region of China Are Driven by Agricultural Activities

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Advances in Atmospheric Sciences 2021年第9期38卷 1537-1551页

作者： Wenjing HUANG timothy jGRIFFIS Cheng HU Wei XIAO Xuhui LEE Yale-NUIST Center on Atmospheric Environment International Joint Laboratory on Climate and Environment Change(ILCEC)Nanjing University of InformationScience and TechnologyNanjing 210044China Department of Soil Waterand ClimateUniversity of MinnesotaTwin CitiesSt.PaulMN 55108USA College of Biology and the Environment Joint Center for sustainable Forestry in Southern ChinaNanjing Forestry UniversityNanjing 210037China School of the Environment Yale UniversityNew HavenCT 06511USA

Developed regions of the world represent a major atmospheric methane(CH_4) source,but these regional emissions remain poorly *** Yangtze River Delta(YRD) region of China is densely populated(about 16% of China's total population) and consists of large anthropogenic and natural CH_4 ***,atmospheric CH_4 concentrations measured at a 70-m tall tower in the YRD are combined with a scale factor Bayesian inverse(SFBI) modeling approach to constrain seasonal variations in CH_4 *** indicate that in 2018 agricultural soils(AGS,rice production) were the main driver of seasonal variability in atmospheric CH_4 *** was an underestimation of emissions from AGS in the a priori inventories(EDGAR—Emissions Database for Global Atmospheric Research v432 or v50),especially during the growing *** CH_4 emissions from AGS accounted for 39%(4.58 Tg,EDGAR v432) to 47%(5.21 Tg,EDGAR v50) of the total CH_4 *** posteriori natural emissions(including wetlands and water bodies) were1.21 Tg and 1.06 Tg,accounting for 10.1%(EDGAR v432) and 9.5%(EDGAR v50) of total emissions in the YRD *** show that the dominant factor for seasonal variations in atmospheric concentration in the YRD was AGS,followed by natural *** summer,AGS contributed 42%(EDGAR v432) to 64%(EDGAR v50) of the CH_4 concentration enhancement while natural sources only contributed about 10%(EDGAR v50) to 15%(EDGAR v432).In addition,the newer version of the EDGAR product(EDGAR v50) provided more reasonable seasonal distribution of CH_4 emissions from rice cultivation than the old version(EDGAR v432).

关键词： CH_4 emissions WRF-STILT seasonal variations Yangtze River Delta

Evaluation of cone fishways to facilitate passage of small-bodied fish

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Aquaculture and Fisheries 2021年第2期6卷 125-134页

作者： Ivor G.Stuart timothy j.Marsden Arthur Rylah Institute for Environmental Research Department of EnvironmentLandWater and Planning123 Brown StreetHeidelbergVictoria 3084Australia Australasian Fish Passage Services 6 Spinifex StreetFern BayNew South Wales 2295Australia

Fishways are being provided more regularly than ever before and new designs are needed to provide passage for whole fish *** recent progress,fishways have frequently performed poorly,especially for small-bodied fish(i.e.10-100 mm long),which can form large aggregations below stream *** was the genesis for the development of the cone fishway design,a new style of technical fishway which consists of a series of pre-fabricated cone-shaped concrete baffles installed laterally within a concrete *** cone design arose from the need to install rock ramp fishways at remote sites where rock was unavailable and where maintenance would be *** objective of the present study was to evaluate the suitability of the new cone fishway design to provide passage for small-bodied diadromous species(i.e.jor ecological *** fishways provide a useful and novel option to improve passage of small-bodied fish,at appropriate sites,and contribute to a contemporary vision of restoration of whole fish communities.

关键词： fishway fish migration fish communities Australia tidal barrier Fitzroy River Norman River Maribyrnong River

A note on the estimation of variance for big BAF sampling

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Forest Ecosystems 2020年第4期7卷 819-832页

作者： jeffrey H.Gove timothy G.Gregoire Mark j.Ducey Thomas B.Lynch USDA Forest Service Northern Research Station271 Mast RoadDurham NH03824USA. School of Forestry&Environmental Studies Yale University360 Prospect StNew Haven CT06511USA. Department of Natural Resources and the Environment University of New Hampshire114 James HallDurham NH03824USA. Professor Emeritus Department of Natural Resource Ecology and ManagementOklahoma State UniversityAg Hall Room 008CStillwater OK74078USA.

Background:The double sampling method known as“big BAF sampling”has been advocated as a way to reduce sampling effort while still maintaining a reasonably precise estimate of volume.A well-known method for variance determination,Bruce’s method,is customarily used because the volume estimator takes the form of a product of random ***,the genesis of Bruce’s method is not known to most foresters who use the method in ***:We establish that the Taylor series approximation known as the Delta method provides a plausible explanation for the origins of Bruce’s *** were conducted on two different tree populations to ascertain the similarities of the Delta method to the exact variance of a ***,two alternative estimators for the variance of individual tree volume-basal area ratios,which are part of the estimation process,were compared within the overall variance estimation ***:The simulation results demonstrate that Bruce’s method provides a robust method for estimating the variance of inventories conducted with the big BAF *** simulations also demonstrate that the variance of the mean volume-basal area ratios can be computed using either the usual sample variance of the mean or the ratio variance estimators with equal accuracy,which had not been shown previously for Big BAF ***:A plausible explanation for the origins of Bruce’s method has been set forth both historically and mathematically in the Delta *** most settings,there is evidently no practical difference between applying the exact variance of a product or the Delta method—either can be used.A caution is articulated concerning the aggregation of tree-wise attributes into point-wise summaries in order to test the correlation between the two as a possible indicator of the need for further covariance augmentation.

关键词： Bitterlich sampling Delta method Double sampling Forest inventory Horizontal point sampling Variance of a product

An approximate point-based alternative for the estimation of variance under big BAF sampling

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Forest Ecosystems 2021年第3期8卷 439-457页

作者： Thomas B.Lynch jeffrey H.Gove timothy G.Gregoire Mark j.Ducey Professor Emeritus Department of Natural Resource Ecology and ManagementOklahoma State UniversityAg Hall Room 008CStillwater 74078OKUSA USDA Forest Service Northern Research Station271 Mast RoadDurham 03824NHUSA Yale School of Environment Yale University360 Prospect StNew Haven 06511CTUSA Department of Natural Resources and the Environment University of New Hampshire114 James HallDurham 03824NHUSA

Background:A new variance estimator is derived and tested for big BAF(Basal Area Factor)sampling which is a forest inventory system that utilizes Bitterlich sampling(point sampling)with two BAF sizes,a small BAF for tree counts and a larger BAF on which tree measurements are made usually including DBHs and heights needed for volume ***:The new estimator is derived using the Delta method from an existing formulation of the big BAF estimator as consisting of three sample *** new formula is compared to existing big BAF estimators including a popular estimator based on Bruce’s ***:Several computer simulation studies were conducted comparing the new variance estimator to all known variance estimators for big BAF currently in the forest inventory *** simulations the new estimator performed well and comparably to existing variance ***:A possible advantage of the new estimator is that it does not require the assumption of negligible correlation between basal area counts on the small BAF factor and volume-basal area ratios based on the large BAF factor selection trees,an assumption required by all previous big BAF variance estimation *** this correlation was negligible on the simulation stands used in this study,it is conceivable that the correlation could be significant in some forest types,such as those in which the DBH-height relationship can be affected substantially by density perhaps through *** derived a formula that can be used to estimate the covariance between estimates of mean basal area and the ratio of estimates of mean volume and mean basal *** also mathematically derived expressions for bias in the big BAF estimator that can be used to show the bias approaches zero in large samples on the order of 1n where n is the number of sample points.

关键词： Bitterlich sampling Delta method Double sampling Estimator bias Forest inventory Horizontal point sampling Variance of a product Volume basal area ratio Covariance estimation

4D imaging of void nucleation,growth,and coalescence from large and small inclusions in steel under tensile deformation

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journal of Materials Science & Technology 2022年第28期123卷 168-176页

作者： Yi Guo timothy L.Burnett Samuel A.McDonald Michael Daly Andrew H.Sherry Philip j.Withers Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Henry Royce Institute Department of MaterialsUniversity of ManchesterM139PLUK European Synchrotron Radiation Facility(ESRF) 6 rue J Horowitz38000 GrenobleFrance National Nuclear Laboratory Chadwick HouseBirchwood ParkWarringtonWA36AEUK

Samples of SA508 grade 3 nuclear pressure vessel ferritic steel were subjected to tensile straining whilst being simultaneously imaged in 3D in real time using high resolution,high frame rate time-lapse synchrotron computed tomography(CT).This enabled direct observation of void development from nucleation,through growth to coalescence and final failure validating many inferences made post-mortem or by theoretical models,as well as raising new *** sparse,large inclusions were found to nucleate voids at essentially zero plastic strain(consistent with zero interfacial strength);these became increasingly elongated with *** contrast,a high density of small spherical voids were found to nucleate from the sub-micron cementite particles at larger strains(>200%)only in the centre of the necked(high triaxiality)*** interfacial strength approaching 2100 MPa was inferred and soon after their nucleation,these small voids coalesce to form internal microcracks that lead to the final failure of the *** surprisingly,under these conditions of generally low triaxial constraint the large voids are simply cut across and appear to play no significant role in determining the final *** implications of these results are discussed in terms of ductile fracture behaviour and the Gurson model for ductile fracture.

关键词： Void growth Ductile fracture Synchrotron X-ray tomography 4D imaging Bainitic steel

Implementation of a Prototype VoIP System

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journal of Computer Science & Technology 2000年第5期15卷 480-484页

作者：刘喜成李仲同 CentreforCommunicationsSystemsResearch UniversityofCambridgeUK NetworkingandComputingSystemsGroup MotorlaSemiconductorProductsSector

VoIP (Voice over IP) is a rapidly growing area with great market potential. To promote it for both commercial and research purposes, a prototype VoIP system based on state-of-the-art Motorola communication techniques has been developed. It is a gateway system integrating a PBX and a VoIP module. All components that H.323 defines to support VoIP are implemented in the VoIP module, though in a simplified manner. As an embedded system, the system features real timeness and task distributiveness. A number of additional techniques are used to improve the performance, including noise suppression, zero copy, and buffer structure optimization. When refined in interoperability, the system will also readily serve as a product.

关键词： VoIP gateway gatekeeper communication common platform embedded system voice processing H.323