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Experimental study on the effect of porosity on the uniaxial compressive strength of sea ice in Bohai Sea

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Science China(Technological Sciences) 2011年第10期54卷 2429-2436页

作者： LI ZhiJun ZHANG LiMin LU Peng matti LEPPARANTA LI GuangWei State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China Department of Physics Helsinki University Helsinki FI-00014 Finland

For the abnormal ice condition in 2009–2010 winter,sea ice samples were collected in a tide ditch outside a port in the east coast of Liaodong Bay,and ice specimens were *** study was carried out with a temperature-control precision of 0.1°C,and 117 columnar-grained ice specimens were loaded along the direction parallel to ice surface under different test temperatures(-4,-7,-10,-13,-16°C)and strain rates ranging from 10-6 to 10-2 s-1 within which the ductile region,ductile-brittle transition and brittle region are *** uniaxial compressive strengths,density and salinity of the ice specimens were *** results support the curved-surface relationship between the uniaxial compressive strength and porosity within a wide range of strain *** curved-surface relationship gives a quantitative description about the variations of the mechanical behavior transition point with ice porosity,and supplies a uniform mathematical representation of uniaxial compressive strength under different failure ***,it is deduced that abnormal ice condition in 2009–2010 winter will not result in a change of the uniaxial compressive strength of sea ice in Bohai Sea.

关键词：单轴抗压强度渤海海冰孔隙率实验测试温度样品收集控制精度定量描述

Tectonics and architectonic quality in recently published Finnish log architecture:Corresponding architects’perceptions

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Frontiers of Architectural Research 2021年第4期10卷 741-757页

作者： matti Lakkala Janne Pihlajaniemi Oulu School of Architecture University of OuluOulu90570Finland

Due to the global increase in wood construction,it is crucial for architects to understand *** Finland,log building,a special subset of industrially manufactured massive timber construction materials is experiencing a *** aspects combined with newer technical developments make log a complex material from the viewpoint of architectonic *** inform practicing architects,the aim of this study is to explore how the tectonics of logs contribute to the architectonic quality of log *** interviews among architects of twelve recently published log buildings are *** results describe how architectonic quality is perceived among participants,and features of logs related to tectonics that they consider to be of importance in terms of architectonic *** features include the statics of log construction and log’s nature as a simultaneously insulating,load-bearing and visual *** between industrial and hand-hewn logs,as well as other architectural aspects of using logs in contemporary architecture are *** the“non-settling”log was perceived to have manifold implications for the architectonic possibilities of log *** results are of practical importance to designing architects and the log *** implications include tangible information on architectonic quality and tectonics of log building.

关键词： Log building Log architecture Architect perceptions Architectonic quality Tectonic theory in architecture Design ethnography

Predicting stand age in managed forests using National Forest Inventory field data and airborne laser scanning

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Forest Ecosystems 2020年第3期7卷 579-589页

作者： matti Maltamo Hermanni Kinnunen Annika Kangas Lauri Korhonen University of Eastern Finland School of Forest SciencesP.O.Box 11180101JoensuuFinland Natural Resources Institute Finland Bioeconomy and EnvironmentP.O.Box 6880100JoensuuFinland

Background: The aim of this study was to construct a nationwide stand age model by using National Forest Inventory(NFI) data and nationwide airborne laser scanning(ALS) data. In plantation forestry, age is usually *** this is not the case in boreal managed forests, age is still seldom predicted in forest management *** age accurately in situ is also very laborious. On the other hand, tree age is one of the accurately measured sample tree attributes in NFI field data. Many countries also have a nationwide coverage of airborne laser scanning(ALS) data. In this study, we merged these data sources and constructed a nationwide, area-based model for stand ***: While constructing the model, we omitted old forests from the data, since the correlation between ALS height metrics and stand age diminished at stands with age > 100 years. Additionally, the effect of growth conditions was considerable, so we also utilized different geographical and NFI variables such as site fertility and soil type in the modeling. The resultant nationwide model for the stand age of managed forests yielded a root mean square error(RMSE) of about 14 years. The model could be improved further by additional forest structure variables, but such information may not be available in ***: The results showed that the prediction of stand age by ALS, geographical and NFI information was challenging, but stil possible with moderate success. This study is an example of the joint use of NFI and nationwide ALS data and re-use of NFI data in research.

关键词： Forest stock age LiDAR NFI Nationwide model Growth conditions

The cost-effectiveness of hypertonic saline inhalations for infant bronchiolitis: a decision analysis

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World Journal of Pediatrics 2018年第1期14卷 26-34页

作者： Paula Heikkila Minna Mecklin matti Korppi Tampere Center for Child Health Research Universityof Tampere and Tampere University HospitalTampereFinland Department of Pediatrics Tampere University HospitalPOBOX200033521T ampereFinland

Background This study evaluated the cost-effectiveness of hypertonic saline (HS) inhalations for infant bronchiolitis, com-pared to normal saline inhalations or standard treatment without inhalations as controls. Methods The decision tree in the decision analysis was used to calculate the expected costs. Actual cost data were obtained from our retrospective case-control study on bronchiolitis treatment. The effectiveness of treatment, based on the hospitaliza-tion rate of those admitted to the emergency department and the length of stay (LOS) of those who were hospitalized, was collected from previous studies. For the effectiveness estimations, we made a meta-analysis summarizing the results of the meta-analysis of the Cochrane review in 2013 and the results of 10 studies published after it. Results The mean hospitalization rate was 24.7% in the HS inhalation group and 32.6% in the control group [risk ratio: 0.80, 95% confidence interval (CI) 0.67–0.96] and the mean LOS was 3.736 (HS group) and 4.292 (controls) days (mean difference: ? 0.55 days, 95% CI ? 0.96 to ? 0.15), respectively. The expected costs per patient, when both inpatients and outpatients were included, were €816 ($1111) in the HS inhalation group and €962 ($1310) in the control group. The expected costs per hospitalization, when only inpatients were included, were €2600 ($3540) in the HS inhalation group and €2890 ($3935) in the control group. Conclusions HS inhalations slightly reduced the expected hospitalization costs of infant bronchiolitis. However, the low effectiveness, rather than the cost, is the factor that will limit the use of HS inhalations in infant bronchiolitis.

关键词： Bronchiolitis Cost-effectiveness Decision analysis Hospitalization costs Hypertonic saline

On the potential to predetermine dominant tree species based on sparse-density airborne laser scanning data for improving subsequent predictions of species-specific timber volumes

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Forest Ecosystems 2016年第2期3卷 95-111页

作者： Janne Raty Jari Vauhkonen matti Maltamo Timo Tokola University of Eastern Finland School of Forest Sciences Yliopistokatu 7 P.O.Box 111FI-80101 Joensuu Finland

Background： Tree species recognition is the main bottleneck in remote sensing based inventories aiming to produce an input for species-specific growth and yield models. We hypothesized that a stratification of the target data according to the dominant species could improve the subsequent predictions of species-specific attributes in particular in study areas strongly dominated by certain species. Methods： We tested this hypothesis and an operational potential to improve the predictions of timber volumes, stratified to Scots pine, Norway spruce and deciduous trees, in a conifer forest dominated by the pine species. We derived predictor features from airborne laser scanning （ALS） data and used Most Similar Neighbor （MSN） and Seemingly Unrelated Regression （SUR） as examples of non-parametric and parametric prediction methods, respectively Results： The relationships between the ALS features and the volumes of the aforementioned species were considerably different depending on the dominant species. Incorporating the observed dominant species inthe predictions improved the root mean squared errors by 13.3-16.4 % and 12.6-28.9 % based on MSN and SUR, respectively, depending on the species. Predicting the dominant species based on a linear discriminant analysis had an overall accuracy of only 76 % at best, which degraded the accuracies of the predicted volumes. Consequently, the predictions that did not consider the dominant species were more accurate than those refined with the predicted species. The MSN method gave slightly better results than models fitted with SUR. Conclusions： According to our results, incorporating information on the dominant species has a clear potential to improve the subsequent predictions of species-specific forest attributes. Determining the dominant species based solely on ALS data is deemed challenging, but important in particular in areas where the species composition is otherwise seemingly homogeneous except being dominated by certain species

关键词： Forest inventory Light Detection and Ranging (LiDAR) Area-based approach Nearest neighbor estimation,Crown base height Intensity Volume model

Tonsillitis in children: unnecessary laboratory studies and antibiotic use

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世界儿科杂志:英文版 2016年第1期12卷 114-117页

作者： Antti Kunnamo matti Korppi Merja Helminen Pediatric Research Centre Tampere University and Univesity HospitalTampereFinland

Background:The Finnish Current Care Guidelines on diagnostics and treatment of sore throat recommend the treatment of only group A streptococcus(GAS)positive cases with *** aim of the study was to evaluate how these guidelines are followed in the pediatric emergency ***:We analyzed retrospectively the data on microbiological studies and blood tests done,and data on prescribing of antibiotics,of 200 children admitted for febrile exudative ***:After the clinical diagnosis of exudative tonsillitis,antigen test and/or culture for GAS identifi cation was done in>95%of *** the 32(16%)children with GAS infection,but also 52(38%)of the 137 children without any evidence of bacterial infection received *** laboratory studies were done in 96%of *** C-reactive concentrations or white blood cell counts were not able to separate streptococcal from non-streptococcal *** serious bacterial infection was ***:The Finnish Current Care Guidelines lead to over-treatment with *** of the 200 children returned after discharge,suggesting that undertreatment did not happen.

关键词： exudative tonsillitis streptococcal antigen test streptococcal culture

Inflammatory Biomarkers in Elite Cross-Country Skiers After a Competition Season:A Case-Control Study

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Journal of Science in Sport and Exercise 2023年第3期5卷 254-262页

作者： Raakel Luoto Olli Ruuskanen Johanna K.Ihalainen Satu Pekkala Jukka Hintikka Noora Kanerva matti Waris Olli J.Heinonen Maarit Valtonen Department of Paediatrics and Adolescent Medicine Turku University Hospital and University of TurkuPL 5220521 TurkuFinland Faculty of Sport and Health Sciences University of JyväskyläJyväskyläFinland Department of Food and Nutrition University of HelsinkiHelsinkiFinland Institute of Biomedicine Department of Clinical VirologyUniversity of TurkuTurku University HospitalTurkuFinland Paavo Nurmi Centre and Unit for Health and Physical Activity University of TurkuTurkuFinland Finnish Institute of High Performance KIHURautpohjankatu640700 JyväskyläFinland

Purpose Whether elite athletes,who have been exposed to vigorous-intensity exercise combined with other stressors,have elevated systemic low-grade inflammation,remains largely *** address this question,we studied the levels of six inflammatory cytokines as potential biomarkers of a low-grade inflammatory state in elite athletes after an 11-month train-ing and competition *** We collected sera from 27 Finnish elite cross-country skiers and 27 gender-and age-matched,moderately-exer-cising *** serum concentrations of C-reactive protein(CRP),interleukin 6(IL-6),tumor necrosis factor alpha(TNF-α),glycoprotein acetyls(GlycA),interleukin 10(IL-10),and interferon gamma(IFN-γ)cytokines were quantified as surrogate markers of low-grade *** The athletes were found to have significantly lower concentrations of CRP(P=0.0232)and higher concentrations of IL-10,TNF-α,and IFN-γ(P=0.0097,P=0.0256,and P=0.0185,respectively)than the *** significant differences between athletes and controls were detected in the concentrations of IL-6 and *** inflammatory score(IS)did not differ significantly between athletes and *** The results of this study argued against the hypothesis of a significant chronic low-grade inflammation in response to prolonged high-performance exercise among elite endurance athletes.

关键词： Athlete Biomarker Chronic low-grade inflammation Exercise GlycA Inflammation

Cadmium in insects after ash fertilization

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Insect Science 2009年第1期16卷 93-98页

作者： Martin Lodenius Jussi Josefsson Kari Heliovaara Esa Tulisalo matti Nummelin Department of Biological and Environmental Sciences Department of Forest Ecology University of Helsinki Finland

Ash fertilization of forests returns nutrients to forest ecosystems and has a positive effect on soil pH, but it also may elevate Cd concentrations of forest biota. Cadmium concentrations of some forest insects （Formica ants, carabids and Coleopteran larvae from decaying wood） were investigated in southern Finland, where two plots were fertilized with wood ash, while two other plots represented unfertilized control plots. In ants, mean Cd concentration was 3.6 ± 1.4 mg/kg, with nest workers having significantly higher concentrations than workers trapped in pitfall traps. Concentrations at fertilized and unfertilized plots were similar. In carabid beetles, the average Cd concentration of Carabus glabratus was 0.44 ±0.36 mg/kg, with no significant difference between control plots and fertilized plots. In another carabid beetle, Pterostichus niger, mean Cd concentration was higher at fertilized plots compared to control plots. We conclude that the variation of Cd concentrations in the insects studied is more efficiently controlled by species-specific differences than fertilization history of the forest floor.

关键词： bioaccumulation cadmium Carabidae Coleoptera fertilization Formica,wood ash

Compression curve analysis and compressive strength measurement of brittle granule beds in lieu of individual granule measurements

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Particuology 2016年第6期14卷 60-68页

作者： matti Jairvelainen Aaretti Kaleva Annikka Kaitajairvi ,Jarmo Laakso Ulla Kanerva Erkki Levanen Department of Materials Science Tampere University of Technology PO Box 589 FIN-33101 Tampere Finland VTT Technical Research Centre of Finland Sinitaival 6 PO Box 1300 FI33101 Tampere Finland

Powders in granulated form are used in various processes to facilitate convenient usage. The durability of the formed granules is a crucial parameter, typically evaluated by the compressive strength of the gran- ules. However, especially for granules with a diameter in the order of tens of microns, statistically relevant testing of individual granules is not a feasible alternative, and in such cases uniaxial bed compression is required. There has not been consensus on whether uniaxial compression of a granule bed can be used to study the fracture of micron size or brittle granules. In our case study of a bed of sintered kaolinite granules with diameters under 100 μm, we show how the compressive strength of individual granules can be obtained from the compressive measurement of the entire bed by plotting the relative density versus the logarithmic pressure scale. We compressed the kaolinite powder with different loads; microscopy confirmed that below the ana- lyzed strength the granules are intact, though the granules start to fracture in the curved region on the compression curve. We found that angle-fitting can be used to locate the average compressive strength on the compression curve and to follow the evolution of strength with sintering temperature. The experi- ments in unison demonstrate that compression curve analysis is applicable for strength analysis of brittle granules.

关键词： GranuleMechanical characterization Pressing Compressive strength Sintering Compression curves