Elastic Buckling of Infinitely Long Specially Orthotropic Plates on Tensionless Foundations

1991 ◽  
Vol 113 (4) ◽  
pp. 396-403 ◽  
Author(s):  
K. W. Shahwan ◽  
A. M. Waas
Keyword(s):  
Growth Models ◽  
Elastic Buckling ◽  
Rigid Foundation ◽  
Orthotropic Plates ◽  
Near Surface ◽  
Simply Supported ◽  
Epoxy Material ◽  
Delamination Buckling ◽  
Materials Used ◽  
The One

The results of an analytical study on the elastic buckling of long narrow orthotropic plates resting on a tensionless foundation are reported. The motivation for the present study stems from the importance of delamination buckling as a viable mode of failure in fibrous laminated composites. When near surface delaminations undergo buckling, the buckled displacements are of one sign, because the remainder of the laminate (parent sublaminate) essentially acts like a rigid foundation. The results of the present study can be incorporated into developing delamination growth models for various loading conditions. Example results are presented for five different types of plates where one is of the isotropic type and the remaining four are of the laminated orthotropic type. Example results for two types of Graphite/Epoxy material systems (IM7/8551-7 and T300/BP907) are reported. In the laminates considered, the stacking is sequenced so that the bending constitutive constants D16 and D26 vanish. Extensive parametric analysis was performed and it was found that for the case of a simply supported plate and in the limiting case of a rigid foundation, conforming to buckled displacements of one sign, the increase in the buckling load over that of a simply supported plate but with no foundation varies between 22 and 33 percent, depending on the plate stacking sequence. On the other hand, for the clamped-free case this number was found to vary between 24 and 36 percent for all types of materials used in this study. Previous studies that addressed similar issues did not pay particular attention to the one sided buckling constraint that is placed due to physical considerations.

Linking climate, gross primary productivity, and site index across forests of the western United States

2011 ◽  
Vol 41 (8) ◽  
pp. 1710-1721 ◽  
Author(s):  
Aaron R. Weiskittel ◽  
Nicholas L. Crookston ◽  
Philip J. Radtke
Keyword(s):  
Climate Change ◽  
Growth Models ◽  
Gross Primary Production ◽  
Site Index ◽  
Nonparametric Model ◽  
Climate Change Scenarios ◽  
Geographic Scale ◽  
Potential Productivity ◽  
The One ◽  
The Relationship

Assessing forest productivity is important for developing effective management regimes and predicting future growth. Despite some important limitations, the most common means for quantifying forest stand-level potential productivity is site index (SI). Another measure of productivity is gross primary production (GPP). In this paper, SI is compared with GPP estimates obtained from 3-PG and NASA’s MODIS satellite. Models were constructed that predict SI and both measures of GPP from climate variables. Results indicated that a nonparametric model with two climate-related predictor variables explained over 68% and 76% of the variation in SI and GPP, respectively. The relationship between GPP and SI was limited (R2 of 36%–56%), while the relationship between GPP and climate (R2 of 76%–91%) was stronger than the one between SI and climate (R2 of 68%–78%). The developed SI model was used to predict SI under varying expected climate change scenarios. The predominant trend was an increase of 0–5 m in SI, with some sites experiencing reductions of up to 10 m. The developed model can predict SI across a broad geographic scale and into the future, which statistical growth models can use to represent the expected effects of climate change more effectively.

scholarly journals Heritage Building Stones from Évora, Portugal

2020 ◽  
Author(s):  
Luis Lopes
Keyword(s):  
Analytical Techniques ◽  
The Other ◽  
World Heritage Site ◽  
Raw Material ◽  
Other Hand ◽  
Heritage Site ◽  
Ancient Rock ◽  
Materials Used ◽  
The One ◽  
The City

<p>The city of Évora, a World Heritage Site recognized by UNESCO in 1986, also owes this recognition to the stones that built its monuments and preserve them until today.</p><p>This work brings together the contributions that we have gathered over the past three decades and allow us to have a very complete idea, not only about the materials used in the hundreds of monuments and historic buildings but also about their provenance. If some materials are so emblematic that they allow an immediate identification with the naked eye, others needed more sophisticated and precise techniques so that there was no doubt about their origin.</p><p>The igneous rocks and gneisses of granite composition are part of the “Massif of Évora” on which the city is built. Thus, and quite naturally they are by far the most represented group in monuments from all historical periods. Its function is essentially structural, but there are also functional, ornamental and decorative objects. For example, the oldest megalithic structures found in the vicinity of the city are made up of large granite blocks that often had to be transported to their locations.</p><p>On the other hand, many gargoyles and statues that decorate the churches are also made up of these granite rocks. On these, the natural erosion of centuries of exposure to the environment has led to a state of alteration, sometimes very accentuated, which would justify its replacement by replicas sculpted in similar rocks. Provenance studies have made it possible to identify old quarries in the vicinity of the city where, on the one hand, the ancient rock extraction techniques can be observed and on the other hand, they allow the obtaining of the raw material necessary for these restoration and conservation works. In any case, they are places that need to be inventoried and protected, with the municipality already aware of their existence.</p><p>As well as the monuments of the Roman Period, also the structures of the Medieval Period, such as the city walls, the Cathedral (started to be built in 1186 AD) and all the great churches, were also built with these granitoids.</p><p>In addition to these rocks, many others of multiple varieties and origins are present. The marbles, especially the Estremoz Marbles (Global Heritage Stone Resource), are ubiquitous in the city, but there are also emblematic marbles from other places, some easily identifiable (ie Viana do Alentejo, Escoural, Trigaches, Serpa and Vila Verde de Ficalho, for presenting mineralogy, textures, colors and patterns which, together with more recent analytical techniques, have confirmed its provenance.</p><p>Sedimentary rocks, with emphasis on Portuguese Mesozoic limestones, ie Lioz - GHSR and Brecha da Arrábida - GHSR candidate, among others more rare and with very specific use in ornamental details, are also present and contribute to enrich a heritage in stone that makes this city so special and very popular with tourists of all nationalities.</p><p>Acknowledgments: the authors thank to FCT for funding the ICT (UID/GEO/04683/2019), as well as COMPETE POCI-01-0145-FEDER-007690.</p>

Conceptual and Methodological Issues in the Analysis of Data from Dyads and Groups

2012 ◽  
pp. 208-238 ◽  
Author(s):  
Deborah A. Kashy ◽  
M. Brent Donnellan
Keyword(s):  
Social Relations ◽  
Growth Models ◽  
Cross Sectional ◽  
Personality Psychology ◽  
Psychological Science ◽  
Actor Partner Interdependence Model ◽  
Group Research ◽  
The Social ◽  
The One ◽  
Spss Syntax

This chapter provides a detailed introduction to the analysis of nonindependent data from dyads and groups. We begin the chapter by examining current practices regarding dyadic and group research in social and personality psychology. We then present a set of basic definitions, as well as a brief introduction to multilevel modeling (MLM). Throughout the chapter we present SPSS syntax that can be used to specify the models we describe using variants of MLM. The remainder of the chapter is broken into two sections—the first focuses on dyadic contexts, and the second focuses on group contexts. For dyads we discuss both cross-sectional and longitudinal designs, and we provide a detailed discussion of the actor-partner interdependence model (APIM), dyadic growth models, and lagged models. For groups we limit our presentation to methods for cross-sectional research; we describe the APIM for groups, the one-with-many design, and we provide a brief introduction to the social relations model. Examples of how these methods have been used to advance social and personality psychological science are given throughout.

Data Sets

2013 ◽  
Author(s):  
James B. Elsner ◽  
Thomas H. Jagger
Keyword(s):  
Model Building ◽  
Careful Analysis ◽  
Logical Structure ◽  
Fortran Program ◽  
Data Sets ◽  
Data Set ◽  
Near Surface ◽  
Wind Speeds ◽  
The North ◽  
The One

Hurricane data originate from careful analysis of past storms by operational meteorologists. The data include estimates of the hurricane position and intensity at 6-hourly intervals. Information related to landfall time, local wind speeds, damages, and deaths, as well as cyclone size, are included. The data are archived by season. Some effort is needed to make the data useful for hurricane climate studies. In this chapter, we describe the data sets used throughout this book. We show you a work flow that includes importing, interpolating, smoothing, and adding attributes. We also show you how to create subsets of the data. Code in this chapter is more complicated and it can take longer to run. You can skip this material on first reading and continue with model building in Chapter 7. You can return here when you have an updated version of the data that includes the most recent years. Most statistical models in this book use the best-track data. Here we describe these data and provide original source material. We also explain how to smooth and interpolate them. Interpolations are needed for regional hurricane analyses. The best-track data set contains the 6-hourly center locations and intensities of all known tropical cyclones across the North Atlantic basin, including the Gulf of Mexico and Caribbean Sea. The data set is called HURDAT for HURricane DATa. It is maintained by the U.S. National Oceanic and Atmospheric Administration (NOAA) at the National Hurricane Center (NHC). Center locations are given in geographic coordinates (in tenths of degrees) and the intensities, representing the one-minute near-surface (∼10 m) wind speeds, are given in knots (1 kt = .5144 m s−1) and the minimum central pressures are given in millibars (1 mb = 1 hPa). The data are provided in 6-hourly intervals starting at 00 UTC (Universal Time Coordinate). The version of HURDAT file used here contains cyclones over the period 1851 through 2010 inclusive. Information on the history and origin of these data is found in Jarvinen et al (1984). The file has a logical structure that makes it easy to read with a FORTRAN program. Each cyclone contains a header record, a series of data records, and a trailer record.

scholarly journals PENGARUH PENYAMAKAN ZIRKONIUM TERHADAP UJI KEKUATAN TARIK, UJI KEKUATAN SOBEK, UJI KEMULURAN DAN UJI SUHU KERUT PADA BERBAGAI JENIS KULIT IKAN (The Effect of Zirconium Tanning Against Tensile Strength Test, Strength Test of Tear, Glide Test, and Wrinkle Temperature Test on Different Fish Types)

2018 ◽  
Vol 13 (2) ◽  
pp. 105
Author(s):  
Rokhmah Hergiyani ◽  
Y. S. Darmanto ◽  
Lukita Purnamayati
Keyword(s):  
Tensile Strength ◽  
Negative Impact ◽  
Strength Test ◽  
Collagen Fibers ◽  
Raw Material ◽  
Tear Strength ◽  
Complex Processes ◽  
Materials Used ◽  
The One ◽  
Physical Changes

Kulit ikan merupakan limbah perikanan yang dapat memberikan dampak negatif pada lingkungan. Salah satu cara untuk menanggulangi limbah tersebut adalah dengan proses penyamakan kulit. Penyamakan kulit adalah rangkaian proses yang sangat kompleks terjadi banyak perubahan fisik dan kimia di satu sisi, bagian yang tidak berguna dihilangkan dari kulit mentah untuk mendapatkan serat kolagen murni dan membuka struktur serat kolagen. Proses penyamakan yang tidak baik mengakibatkan kulit menjadi rusak, lemas, dan kebusukan, sehingga penanganannya dapat dengan cara menambah bahan penyamak untuk menguatkan dan menghindari kebusukan. Bahan penyamak yang digunakan yaitu zirconium. Tujuan penelitian ini adalah untuk mengetahui pengaruh penyamakan zirkonium terhadap uji kekuatan tarik, uji kekuatan sobek, uji kemuluran dan uji suhu kerut pada berbagai jenis ikan. Bahan baku yang digunakan adalah kulit ikan nila, kakap dan bandeng. Metode penelitian yang digunakan adalah experimental laboratories menggunakan Rancangan Acak Lengkap (RAL) dengan tiga kali ulangan dan  menggunakan analisa ragam ANOVA. Hasil uji menunjukan penggunaan zirkonium 7,5% terhadap kulit ikan nila, kakap, dan bandeng berpengaruh nyata (p<0,05) pada kekuatan tarik, kekuatan sobek, kemuluran dan suhu kerut pada karakteristik penyamakan. Penggunaan bahan penyamak zirkonium 7,5% terbaik dihasilkan oleh kulit ikan kakap pada uji kekuatan tarik 1675,84 N/cm2, kekuatan sobek 163,92 N/cm2 dan uji suhu kerut 103,45˚C sedangkan kemuluran untuk hasil terbaik pada kulit bandeng sebesar 28,74%, jadi setiap ikan mempunyai ciri kulit tersendiri pada setiap parameter uji. The skin of the fish waste is a fishery that can give a negative impact on the environment. One way of tackling the waste is by the process of tanning leather. Tanning is a very complex processes occur many chemical and physical changes on the one hand, the useless removed from rawhide to get pure collagen fibers and the open structure of the collagen fibers. The process of tanning is not a good result in the skin becomes broken, buckled, and corruption, so that responses can be with how to add ingredients to strengthen Tanner and avoid corruption. On the research of materials used i.e. Tanners used are zirconium.. The purpose of this research is to know the influence of zirconium tanning against test tensile strength, tear strength test, test and test temperature wrinkle elongation on various types of fish. The raw material used is leather fish tilapia, milkfish and snapper. Research methods used are experimental laboratories using Complete Random Design (RAL) with three-time repeats and a range of analysis using ANOVA. Test results showed the use of zirconium 7.5% against the skin of the fish, snapper, tilapia and milkfish influential real (p < 0.05) on the tensile strength, tear strength, elongation and wrinkle on temperature characteristics of tanning. The use of zirconium Tanner 7.5% best produced by skin test on a snapper 1675.84 tensile strength N/cm2, the strength of RIP 163.92 N/cm2 and test the temperature of the wrinkle 103,45 ˚ C while elongation for the best results on the skin of the banding of 28.74%, so each fish has its own skin characteristics on each test parameter.

scholarly journals Addressing the Insufficiencies of the Traditional Development Aid Model by Utilizing the One Belt, One Road Initiative to Sustain Development in Afghanistan

2019 ◽  
Vol 11 (2) ◽  
pp. 312 ◽  
Author(s):  
Yanzhe Zhang ◽  
Xiao Yu ◽  
Huizhi Zhang
Keyword(s):  
Economic Development ◽  
Growth Models ◽  
Social Economy ◽  
Development Aid ◽  
Policy Model ◽  
One Belt One Road ◽  
Political Communities ◽  
The One ◽  
Conflict Affected States ◽  
Economic Growth Models

This paper investigated the use of the One Belt One Road initiative (BRI) as a policy model that might address the insufficiencies of the traditional development aid model in reconstructing and developing Afghanistan. Afghanistan has emerged as one of the world’s most fragile and conflict-affected countries, and it has gained the attention of both academic and political communities since the early 2000s. The materials for this article are based partly on a thorough analysis of the available documentation. The authors also conducted interviews with high-ranking political elites and policy officials in the Afghan government and international organizations. The study employed a purposive sampling method to identify people with firsthand information on how to sustain economic development in Afghanistan. This paper provides new insights by comparing the traditional development aid model and the BRI in terms of social economy, local security and regional economic development. The aim of this research is to evaluate whether the BRI can remedy the insufficiencies of the traditional development aid model in order to sustain development in Afghanistan. The findings provide a better understanding of the BRI in promoting the internal dynamism required to develop the regional economy, and fill a gap in the literature with regard to the applied and theoretical economic growth models for stabilizing and sustaining the development of fragile and conflict-affected states.

scholarly journals Mesoporous Activated Carbon Supported Ru Catalysts to Efficiently Convert Cellulose into Sorbitol by Hydrolytic Hydrogenation

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4394
Author(s):  
Fatima-Zahra Azar ◽  
M. Ángeles Lillo-Ródenas ◽  
M. Carmen Román-Martínez
Keyword(s):  
Carbon Materials ◽  
Activated Carbons ◽  
One Pot ◽  
Cellulose Conversion ◽  
Hydrolytic Hydrogenation ◽  
Ru Nanoparticles ◽  
Two Samples ◽  
Materials Used ◽  
The One ◽  
By Products

Catalysts consisting of Ru nanoparticles (1 wt%), supported on mesoporous activated carbons (ACs), were prepared and used in the one-pot hydrolytic hydrogenation of cellulose to obtain sorbitol. The carbon materials used as supports are a pristine commercial mesoporous AC (named SA), and two samples derived from it by sulfonation or oxidation treatments (named SASu and SAS, respectively). The catalysts have been thoroughly characterized regarding both surface chemistry and porosity, as well as Ru electronic state and particle size. The amount and type of surface functional groups in the carbon materials becomes modified as a result of the Ru incorporation process, while a high mesopore volume is preserved upon functionalization and Ru incorporation. The prepared catalysts have shown to be very active, with cellulose conversion close to 50% and selectivity to sorbitol above 75%. The support functionalization does not lead to an improvement of the catalysts’ behavior and, in fact, the Ru/SA catalyst is the most effective one, with about 50% yield to sorbitol, and a very low generation of by-products.

scholarly journals Experimental Testing of Reinforced Concrete Deep Beams Designed by Strut-And-Tie Method

2020 ◽  
Vol 10 (18) ◽  
pp. 6217
Author(s):  
Anka Starčev-Ćurčin ◽  
Andrija Rašeta ◽  
Mirjana Malešev ◽  
Danijel Kukaras ◽  
Vlastimir Radonjanin ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Experimental Testing ◽  
Deep Beams ◽  
Simply Supported ◽  
Strut And Tie ◽  
The Third ◽  
Variation Parameter ◽  
The One

The aim of the research presented in this paper is the experimental confirmation of the numerically defined shapes of the Strut-and-Tie models, designed according to the EN 1992-1-1 recommendations, and obtained from the software “ST method”. Three reinforced concrete deep beams with openings were tested. Each of them had the same dimensions and quality of the material characteristics. The specimens, constructed as simply supported beams, were loaded with two concentrated forces and were tested for bending until failure. Each specimen was reinforced with different reinforcement layout determined by variation parameter β, incorporated in the software “ST method”. For the determination of the Strut-and-Tie models, all of the reinforcement layouts were equally favored in the first specimen (β = 1.0 for 0°, 45°, and 90°), only the horizontal direction was favored in the second (β = 1.0 for 0°), while in the third specimen the one at the angle of 45° (β = 1.0 for 45°). Based on the results of experimental research, it was concluded that the behavior of loaded members was in agreement with the proposed shapes of the Strut-and-Tie models that were used for their design, and it was confirmed that the program “ST method” can be used for obtaining Strut–and-Tie models.

Sign in / Sign up

Export Citation Format

Share Document