Investigation of metal-insulator like transition through the ab initio density matrix renormalization group approach

We have studied the Metal-Insulator like Transition (MIT) in lithium and beryllium ring-shaped clusters through ab initio Density Matrix Renormalization Group (DMRG) method. Performing accurate calculations for different interatomic distances and using Quantum Information Theory (QIT) we investigated the changes occurring in the wavefunction between a metallic-like state and an insulating state built from free atoms. We also discuss entanglement and relevant excitations among the molecular orbitals in the Li and Be rings and show that the transition bond length can be detected using orbital entropy functions. Also, the effect of different orbital basis on the effectiveness of the DMRG procedure is analyzed comparing the convergence behavior.Comment: 12 pages, 14 figure

Save Maryam: Islam, Toleration and Religious-Exclusivism in Social Media

Munginkan eksklusivisme agama bisa dihadapi di media sosial? Revolusi media yang sedemikian rupa telah membuka kemungkinan bagi lembaga-lembaga keagamaan untuk menjangkau pengikutnya dalam kisaran yang lebih luas. Makalah ini akan mengamati gagasan menghadapi eksklusivisme agama ini di media sosial dengan mempertimbangkan re-konseptualisasi gagasan konvensional toleransi di era media sosial. Untuk menilai argumen ini, secara hati-hati diuji tanggapan pemuda Indonesia terhadap video bermain pendek, berjudul bintang Maryam yang dapat didownload di media sosial, seperti Facebook, YouTube, Twitter, dan blog terkait lainnya. Dengan analisis semca ini, kami berpendapat bahwa toleransi dapat didefinisikan sebagai upaya budaya untuk menghadapi eksklusivisme agama

Calculation of the static and dynamical correlation energy of pseudo-one-dimensional beryllium systems via a many-body expansion

Low-dimensional beryllium systems constitute interesting case studies for the test of correlation methods because of the importance of both static and dynamical correlation in the formation of the bond. Aiming to describe the whole dissociation curve of extended Be systems we chose to apply the method of increments (MoI) in its multireference (MR) formalism. However, in order to do so an insight into the wave function was necessary. Therefore we started by focusing on the description of small Be chains via standard quantum chemical methods and gave a brief analysis of the main characteristics of their wave functions. We then applied the MoI to larger beryllium systems, starting from the Be6 ring. First, the complete active space formalism (CAS-MoI) was employed and the results were used as reference for local MR calculations of the whole dissociation curve. Despite this approach is well established for the calculation of systems with limited multireference character, its application to the description of whole dissociation curves still requires further testing. After discussing the role of the basis set, the method was finally applied to larger rings and extrapolated to an infinite chain

Fatigue Damage Accumulation Due to Complex Random Vibration Environments: Application to Single-Axis and Multi-Axis Vibration

A combination of experiments and modeling are used to address the vibration durability of structures subjected to different random vibration environments. Presented in this work are a set of experimental data comparing the rate of change of the first natural frequency and the measured time to failure, of simple structural members under repetitive shock (RS) vibration, single-axis electrodynamic (ED) vibration and multi-axis ED vibration. It was found that multi-axis testing is more severe than single-axis testing at the same level. In addition the RS system low frequency amplitude is often too weak to efficiently propagate the crack. Smoothing of the input power spectral density (PSD) or poor line resolution was also shown to change the time to failure of a test. A poor correlation was shown between the PSD and the rate of natural frequency change (RFC) over a wide frequency shift. The change in natural frequency caused the initial PSD to be ineffective in determining the total time to failure. A predictive, analytic methodology to quantify the RFC was developed to predict the fatigue life of a structure experiencing random vibration excitation. This method allows the estimation of fatigue life using the frequency domain, where only the input power spectral density, damping factor and structural information are required. The methodology uses linear elastic fracture mechanics for fatigue crack propagation and accounts for the frequency shifting that occurs due to fatigue crack evolution. The analytic model has been shown to compare favorably to both finite element analysis (FEA) and experimental results, for mild-steel cantilever beams. Monte Carlo simulations have been conducted to assess the sensitivity of the model predictions to uncertainties in the input parameters. In addition a semi-empirical model was developed whereby the input PSD and damping factor are measured from life tests, and the resulting time to failure and the acceleration factors between different vibration environments can be determined. The improved modeling methodology developed by this work are of value not only to structural designers who wish to design for dynamic environments, but also to test engineers who wish to qualify products through accelerated life testing, and to vibration engineers who wish to compare the relative severity of different random vibration environments, in terms of their potential to cause fatigue damage accumulation

Abort the Court? How abortion jurisprudence has highlighted questions surrounding the legitimacy of the Supreme Court

The Supreme Court is often viewed with awe and the justices treated with reverence. It is the highest court in the United States, tasked with interpreting the law. But is the Supreme Court the neutral arbiter of justice it purports to be? Most recently, the 2022 ruling on Dobbs v. Jackson Women’s Health Organization overturned the fifty-year precedent of Roe v. Wade, causing the Court to face increasing scrutiny and questions of its legitimacy. I conduct a philosophical analysis of the arguments made by the justices in the opinions on Roe v. Wade, Planned Parenthood v. Casey, and Dobbs v. Jackson Women’s Health Organization to understand the way abortion jurisprudence is argued. In the Court’s opinion on Casey, the plurality constructs an argument for the legitimacy of the Court. I take this argument and assess its logical validity, and then with the framework the argument presents, I examine if the Court can maintain its neutrality in the context of philosophical arguments. Then, using case law analysis from Melissa Murray about the impact of abortion and precedent, as well as Ronald Dworkin’s constitutional evaluation from Freedom’s Law, I discuss the role that legal principles play in abortion jurisprudence and apply political behavior research into motivated reasoning to better understand the Court’s political motivations. I find, on their own criteria, that the Court fails to maintain the neutrality they claim to have, meaning they are in fact a political body. I also find the Court’s political nature impacts its ability to decide on controversial topics and provide suggestions for what this means for the Court’s role in American government as we face increasing polarization

Tunable biohybrid hydrogels from coacervation of hyaluronic acid and PEO‐based block copolymers

Accurately tuning the macroscopic properties of biopolymer‐based hydrogels remains challenging due to the ill‐defined molecular architecture of the natural building blocks. Here, we report a biohybrid coacervate hydrogel, combining the biocompatibility and biodegradability of naturally occurring hyaluronic acid (HA) with the tunability of a synthetic polyethylene oxide (PEO) ‐based ABA‐triblock copolymer. Coacervation of the cationic ammonium or guanidinium‐functionalized copolymer A‐blocks with the anionic HA leads to hydrogel formation. Both mechanical properties and water content of the self‐healing hydrogels can be controlled independently by altering the copolymer structure. By controlling the strength of the interaction between the polymer network and small‐molecule cargo, both release rate and maximum release are controlled. Finally, we show that coacervation of HA and the triblock copolymer leads to increased biostability upon exposure to hyaluronidase. We envision that noncovalent crosslinking of HA hydrogels through coacervation is an attractive strategy for the facile synthesis of tunable hydrogels for biomedical applications