Band gaps in the relaxed linear micromorphic continuum

In this note we show that the relaxed linear micromorphic model recently proposed by the authors can be suitably used to describe the presence of band-gaps in metamaterials with microstructures in which strong contrasts of the mechanical properties are present (e.g. phononic crystals and lattice structures). This relaxed micromorphic model only has 6 constitutive parameters instead of 18 parameters needed in Mindlin- and Eringen-type classical micromorphic models. We show that the onset of band-gaps is related to a unique constitutive parameter, the Cosserat couple modulus $\mu_{c}$ which starts to account for band-gaps when reaching a suitable threshold value. The limited number of parameters of our model, as well as the specific effect of some of them on wave propagation can be seen as an important step towards indirect measurement campaigns

Analisis Miskonsepsi Siswa Kelas XI SMA Pada Materi Larutan Penyangga Menggunakan Instrumen Tes Three Tier Multiple Choice

The research is aimed to analyze misconceptions of high school students of class XI on the buffer solution material using instruments Three Tier Multiple Choice Tests. Another purpose of this study was to determine the percentage of student misconceptions and location misconceptions on chemical material especially on the subject of buffer solution. The research method is descriptive, data collection by giving a 13 item multiple choice questions with closed reason and CRI index and then the results of each items students answer were analyzed. The results of this study are misconceptions in chemistry learning especially in a buffer solution dispersed in of all concepts. The most common misconceptions on the working principle of the buffer solution by 51% and the lowest on the properties of the buffer solution by 31%. Suggestions put forward is the need to hold further research to uncover misconceptions where they come from and how to overcome these misconceptions

Usulan Model Persediaan dengan Metode Hadley-Within dan Chiu Approximation dengan Mempertimbangkan Pengembalian pada Produk Farmasi di RSUD Kardinah

Keberadaan persediaan bagi suatu instansi merupakan hal yang penting dan tidak dapat dihindari, namun keberadaannya sering dianggap sebagai pemborosan. Oleh karena itu, pengendalian persediaan adalah hal yang penting untuk dilakukan agar kebutuhan akan suatu produk dapat terpenuhi secara optimal. Unit farmasi adalah instalasi pendukung bagi Rumah Sakit sebagai sarana penyedia obat. Obat merupakan salah satu produk yang memiliki masa kadaluwarsa. Pada kondisi manajemen unit logistik farmasi di RSUD Kardinah saat ini terdapat obat yang tidak mengalami penjualan selama 3 bulan berturut-turut atau deathstock akibat obat mengalami slow moving stock sehingga obat-obat tersebut menumpuk terlalu lama digudang dan menyebabkan biaya persediaan yang besar akibat biaya simpan yang besar. Obat-obat yang akan kadaluwarsa harus di lakukan return ke supplier dengan lead time rata-rata 5 bulan, hal ini menimbulkan resiko stockout dan opportunity lost yang tinggi atas penjualan obat-obat tersebut. Maka perlu dilakukan pengendalian persediaan dengan mempertimbangkan demand yang probabilistik, masa kadaluwarsa dan pengembalian produk agar total biaya persediaan minimum. Tujuan dari penelitian ini adalah menentukan kuantitas pemesanan obat yang optimal dan meminimalkan kuantitas obat kadaluwarsa yang di return. Dari hasil perhitungan numerik dapat disimpulkan bahwa metode yang digunakan dapat menyelesaikan masalah dari unit farmasi pada RSUD Kardinah yang memiliki suatu sistem persediaan dengan faktor demand probabilistik, kadaluwarsa dan pengembalian produk

Pengaruh Model Pembelajaran Probing Prompting Berbantuan Video Terhadap Hasil Belajar Dan Kemampuan Berpikir Kritis Peserta Didik

This research aim to examine the effect of probing prompting assisted video learning model for learning outcomes and critical thinking skill of student. This type of research is quasi experiment with untreated control group design with pretest and posttest. The research population was all students of X MIA MAN 2 Mataram. Sampling technique of this research use cluster random sampling so that there are two classes that is X MIA 1 as the experimental class and X MIA 3 as the control class. Type test used 20 choice question for learning outcomes and 5 essay for critical thinking skill. The posttest mean value for learning outcomes in experimental class and control class is 42,36 and 34,86. The posttest mean value for critical thinking skill in experimental class and control class is 54,86 and 46,08. Hypothesis testing of this research is MANOVA. The result of MANOVA test show a significant 0,004 so H0 is rejected and Ha is accepted. The conclusion of this research is there is the effect of  probing prompting learning model assisted video for learning outcomes and critical thinking skill of student.

Ultrasonic characterization and multiscale analysis for the evaluation of dental implant stability: a sensitivity study Biomedical Signal Processing and Control 42 (2018) 37-44

International audienceWith the aim of surgical success, the evaluation of dental implant long-term stability is an important task for dentists. About that, the complexity of the newly formed bone and the complex boundary conditions at the bone-implant interface induce the main difficulties. In this context, for the quantitative evaluation of primary and secondary stabilities of dental implants, ultrasound based techniques have already been proven to be effective. The microstructure, the mechanical properties and the geometry of the bone-implant system affect the ultrasonic response. The aim of this work is to extract relevant information about primary stability from the complex ultrasonic signal obtained from a probe screwed to the implant. To do this, signal processing based on multiscale analysis has been used. The comparison between experimental and numerical results has been carried out, and a correlation has been observed between the multifractal signature and the stability. Furthermore, a sensitivity study has shown that the variation of certain parameters (i.e. central frequency and trabecular bone density) does not lead to a change in the response

Galactic Binary Gravitational Wave Noise within LISA Frequency Band

Gravitational wave noise associated with unresolved binary stars in the Galaxy is studied with the special aim of determining the upper frequency at which it stops to contribute at the rms noise level of the proposed space-born interferometer (LISA). The upper limit to this background is derived from the statistics of SN Ia explosions, part of which can be triggered by binary white dwarf coalescences. The upper limiting frequency at which binary stochastic noise crosses LISA rms sensitivity is found to lie within the range 0.03-0.07 Hz, depending on the galactic binary white dwarf coalescence rate. To be reliably detectable by LISA, the energy density of relic cosmological background per logarithmic frequency interval should be Omega_{GW}h_{100}^2>10^{-8} at f>0.03 Hz.Comment: 16 pages with 1 eps figure, aasms4.sty, to appear in the ApJ vol. 494 February 20, 1998 issu

Sudden cardiac death in anabolic-androgenic steroid users: A literature review

Background and objectives: Anabolic-androgenic steroids (AASs) are a group of synthetic molecules derived from testosterone and its related precursors. AASs are widely used illicitly by adolescents and athletes, especially by bodybuilders, both for aesthetic uses and as performance enhancers to increase muscle growth and lean body mass. When used illicitly they can damage health and cause disorders affecting several functions. Sudden cardiac death (SCD) is the most common medical cause of death in athletes. SCD in athletes has also been associated with the use of performance-enhancing drugs. This review aimed to focus on deaths related to AAS abuse to investigate the cardiac pathophysiological mechanism that underlies this type of death, which still needs to be fully investigated. Materials and Methods: This review was conducted using PubMed Central and Google Scholar databases, until 21 July 2020, using the following key terms: “((Sudden cardiac death) OR (Sudden death)) AND ((androgenic anabolic steroid) OR (androgenic anabolic steroids) OR (anabolic-androgenic steroids) OR (anabolic-androgenic steroid))”. Thirteen articles met the inclusion and exclusion criteria, for a total of 33 reported cases. Results: Of the 33 cases, 31 (93.9%) were males while only 2 (61%) were females. Mean age was 29.79 and, among sportsmen, the most represented sports activity was bodybuilding. In all cases there was a history of AAS abuse or a physical phenotype suggesting AAS use; the total usage period was unspecified in most cases. In 24 cases the results of the toxicological analysis were reported. The most detected AASs were nandrolone, testosterone, and stanozolol. The most frequently reported macroscopic alterations were cardiomegaly and left ventricular hypertrophy, while the histological alterations were foci of fibrosis and necrosis of the myocardial tissue. Conclusions: Four principal mechanisms responsible for SCD have been proposed in AAS abusers: the atherogenic model, the thrombosis model, the model of vasospasm induced by the release of nitric oxide, and the direct myocardial injury model. Hypertrophy, fibrosis, and necrosis represent a substrate for arrhythmias, especially when combined with exercise. Indeed, AAS use has been shown to change physiological cardiac remodeling of athletes to pathophysiological cardiac hypertrophy with an increased risk of life-threatening arrhythmias