A Bipotential Method Coupling Contact, Friction and Adhesion

International audience– The paper is related to the analysis and the modeling of structural interface behaviors when unilateral contact, friction and adhesion interact. Among the contact models in literature, the model developed by Raous, Cangémi, Cocou and Monerie (RCCM model) is retained. It consists to include strict unilateral contact to avoid interpenetration, initial adhesion progressively decreases when the load increases, and Coulomb's friction which is progressively activated when adhesion decreases. Because of its implicit character, the Coulomb friction law with adhesion is non-associated, and the notion of superpotential with normality rule cannot be used anymore. In the present work, to overcome this non-associated character, a specific potential adapted to coupling unilateral contact, friction and adhesion is build and named bipotential. A numerical model is proposed and improved to solve the boundaries values problem. The algorithm is implemented in the finite element code SYMEF which has been developed at the University of Bechar (Algeria). A comparative study is made between the bipotential model and the previously developed RCCM model. The numerical results show that, this approach is robust and efficient in terms of numerical stability, precision convergence and CPU time compared to the RCCM model

Spatio-temporal patterns of beaked whale echolocation signals in the North Pacific.

At least ten species of beaked whales inhabit the North Pacific, but little is known about their abundance, ecology, and behavior, as they are elusive and difficult to distinguish visually at sea. Six of these species produce known species-specific frequency modulated (FM) echolocation pulses: Baird's, Blainville's, Cuvier's, Deraniyagala's, Longman's, and Stejneger's beaked whales. Additionally, one described FM pulse (BWC) from Cross Seamount, Hawai'i, and three unknown FM pulse types (BW40, BW43, BW70) have been identified from almost 11 cumulative years of autonomous recordings at 24 sites throughout the North Pacific. Most sites had a dominant FM pulse type with other types being either absent or limited. There was not a strong seasonal influence on the occurrence of these signals at any site, but longer time series may reveal smaller, consistent fluctuations. Only the species producing BWC signals, detected throughout the Pacific Islands region, consistently showed a diel cycle with nocturnal foraging. By comparing stranding and sighting information with acoustic findings, we hypothesize that BWC signals are produced by ginkgo-toothed beaked whales. BW43 signal encounters were restricted to Southern California and may be produced by Perrin's beaked whale, known only from Californian waters. BW70 signals were detected in the southern Gulf of California, which is prime habitat for Pygmy beaked whales. Hubb's beaked whale may have produced the BW40 signals encountered off central and southern California; however, these signals were also recorded off Pearl and Hermes Reef and Wake Atoll, which are well south of their known range

Growth characteristics of American Ginseng (Panax quinquefolius L.) woods and field - cultivated at Northern Europe

Received: February 19th, 2022 ; Accepted: May 15th, 2022 ; Published: May 16th, 2022 ; Correspondence: [email protected] Latvia, Northern Europe, American ginseng was grown in three forest types with different dominant species, as well as in agricultural field conditions - cultivated under artificial shade with three different types of mulches. Field cultivation yielded higher yields, root length, and root weight than wood cultivation under dominant species Corylus avellana, Betula pendula, and Picea abies. Mulching had a positive impact on ginseng growth in the field. Mulching with straw and buckwheat hulls resulted in longer and heavier roots. In American ginseng roots, the contents of six ginsenosides were determined: Rg1, Re, Rb1, Rc, Rb2, and Rd. Re was the most abundant ginsenoside, followed by Rb1 > Rd > Rg1 = Rb2 > Rd. The total content of ginsenosides in our study did not reach the 4 percent threshold set by US Pharmacopeia. These findings show that Panax quinquefolium can be grown in Northern Europe at 57°N, but it takes more than four years to achieve adequate yields and ginsenoside content

Pengaruh Kualitas Produk,Harga, dan Word of Mouth Terhadap Proses Keputusan Pembelian (Studi pada Konsumen Martabak Jayaraga Jalan Terusan Buahbatu Bandung)

Bandung merupakan salah satu kota di Indonesia yang memiliki beragam objek wisata alam maupun objek wisata sejarah, maka dari itu banyak wisatawan yang berkunjung ke Kota Bandung untuk menikmati tempat wisata maupun berwisata kuliner yang ada di Kota Bandung hal ini dibuktikan dengan adanya peningkatan jumlah kunjungan dikota bandung pada tahun 2014 yaitu sebesar 5.807.565 dari jumlah 3.897.429. Seiring dengan jumlah kunjungan yang begitu besar ternyata berimbas pada tumbuhnya industri kuliner makanan dan minuman dibandung pada tahun 2014 yang mencapai 10.455 unit usaha dari 10.448 unit. Salah satunya adalah usaha makanan Martabak Jayaraga. Dari hasil survey awal yang peneliti lakukan bahwa kualitas produk harga dan word of mouth merupakan hal yang paling sering dipertimbangkan dalam proses keputusan pembelian, Oleh karena itu penelitian ini dilakukan bertujuan untuk mengetahui pengaruh dari Kualitas Produk, Harga, dan word of Mouth secara parsial dan simultan terhadap Proses Keputusan Pembelian pada Martabak Jayaraga di Jalan Terusan Buahbatu Bandung. Metode penelitian ini menggunakan metode kuantitatif dengan jenis penelitian deskriptif dan kausal. Populasi dalam penelitian ini adalah seluruh konsumen yang melakukan pembelian minimal satu kali di Martabak Jayaraga. Sampel yang diambil sebanyak 100 responden dengan menggunakan teknik pengambilan sampel accidental sampling. penelitian menggunakan metode analisis regresi linier berganda dan uji hipotesis (uji statistik t, uji statistik F, dan koefisien determinasi) dengan menggunakan software SPSS IBM 20. Hasil penelitian secara simultan menunjukan bahwa kualitas produk, harga, dan word of mouth berpengaruh signifikan terhadap proses keputusan pembelian. Namun secara parsial menunjukan bahwa kualitas produk dan harga tidak berpengaruh signifikan terhadap proses keputusan pembelian. Dan word of mouth mempunyai pengaruh secara parsial terhadap proses keputusan pembelian. Nilai koefisien determinasi diperoleh sebesar 0,396. Hal ini menunjukan bahwa pengaruh variabel independen (kualitas produik, harga, dan word of mouth) terhadap proses keputusan pembelian sebesar 36.9% sedangkan sisanya 60,4% dipengaruhi oleh faktor lain yang tidak diteliti dalam peneltian ini. Perusahaan harus terus meningkatkan mutu kualitas produk agar dapat bersaing dengan kualitas produk martabak lain, dengan menyesuaikan kualitas produk terhadap berbagai inovasi baru dengan menciptakan menu rasa yang baru sesuai dengan kebutuhan yang diinginkan konsumen sehingga konsumen dapat saling menyebarkan informasi tersebut bahwa Jayaraga telah membuat variasi rasa yang baru. Kata Kunci : Kualitas Produk, Harga, Word Of Mouth, Proses Keputusan Pembelian

Teaching an insurance model: An interactive exercise

In this paper we present a tutorial exercise where advanced undergraduate students can solve a problem of insurance demand using Excel Solver, and explore the main features of this problem. We also present an interactive Excel file that contains the graphical analysis of different attitudes toward risk using some well-known utility functions. The interactive Excel includes scroll bars that can be used to perform both comparative static and interactive graphical analyses, with the aim to improve students´ understanding of the model

A variational formulation for constitutive laws described by bipotentials

Inspired by the algorithm of Berga and de Saxce for solving the discretisation in time of the evolution problem for an implicit standard material, we propose a general variational formulation in terms of bipotentials