Topology Optimization of Deformable Bodies with Linear Dynamic Impact and Frictionless Contact Condition

There has been an increasing demand for the design of an optimum topological layout in several engineering fields for a simple part, along with a system that considers the relative behaviors between adjacent parts. This paper presents a method of designing an optimum topological layout to achieve a linear dynamic impact and frictionless contact conditions in which relative behaviors can be observed between adjacent deformable parts. The solid isotropic method with penalization (SIMP) method is used with an appropriate filtering scheme to obtain an optimum topological layout. The condensed mortar method is used to handle the non-matching interface, which inevitably occurs in the impact and contact regions, since it can easily apply the existing well-known topology optimization approach even in the presence of a non-matching interface. The validity of the proposed method is verified through a numerical example. In the future, the proposed optimization approach will be applied to more general and highly nonlinear non-matching interface problems, such as friction contact and multi-physics problems.

Casting of complex structures in aluminum using gypsum molds produced via binder jetting

Purpose The purpose of present paper is to enlarge the knowledge about the performance of gypsum powder to realize complex molds or cores for aluminum casting. Design/methodology/approach The research was divided into two activities: simple; and complex-part production capability. In the simple-part step, the performance of gypsum powder and the minimum mold thickness that would withstand the casting process. In the complex-part step, the authors first investigated the powder removability as a function of geometry complexity and then binder jetting performance was evaluated for the case of lattice-structure fabrication. Findings All the geometries tested withstand the casting process demonstrating the benefits in terms of complexity part design; however, the process suffers of all the typical defect of casting as misrun, porosity and cold shut. Originality/value The results found in this research improve the benefits related to additive manufacturing application in industrial environment and in particular to the binder jetting technology and the rapid casting approach.

Stoic Ethics as a Guide to the Political Life in Marcus Aurelius

Marcus Aurelius reigned from 161 A.D. to 180 A.D., and he ranks among the most successful emperors of the antonine dynasty. The success of his administration may be attributed to his philosopher personality and, more than that, to his stoic character. Meditations presents thoughts of a stoicism devotee, which reflects in moments of intimacy on the challenges that he faced throughout his life as an emperor. It is in the practice of the ethical precepts of stoicism that he finds his refuge. The text consists of a series of spiritual exercises which reaffirm the indifference to pleasures, contempt for fame, detachment from riches and abnegation for political power. This paper is a study of Meditations, and its main purpose is to elucidate how the stoic way of life is incorporated in the figure of the philosopher emperor; this, as a military function, as he was a commander of the Roman army in the war against the Nordics, where political virtue was tested. Amid the chaos of an insane struggle for the survival of Rome, he found in stoicism a precious source of inspiration. Marcus Aurelius was not dazzled by the cult of the emperor's personality; he acted for the natural right to freedom and guided his political actions for the common good. His stoic perseverance reveals itself in a harmonious conduct with the city, the rational and cosmic organism from which the emperor is a simple part.

HoT Turning Operation in Finite Element Analysis

There is a requirement for materials of high hardness and protection from cutting. As we probably aware the machining of these materials has dependably been an incredible test. Machining of these composites and materials required for cutting high-quality, which now and again isn't prudent and in some cases even illogical. Also, even the non-ordinary procedures are by and large constrained to the perspective of efficiency. The benefits of simple part assembling of exorbitant hard materials can be considerable as far as decreasing expenses and lead times machined contrasted with the customary one includes the warmth treatment, granulating and manual completing/cleaning. In the hot working at a temperature of work piece is expanded in order to decrease its shear quality. This paper will centre around hot working of high manganese steel with oil fuel. A few parameters, for example, cutting pace, feed, profundity of cut and the temperature of the work piece are taken. An investigation was led. Indeed, even the machining process was reproduced in ANSYS and Disfigure 2D to discover relating distortion, rate of hardware wear, cutting power and the temperature dissemination.

Traveling Waves As a De-Powdering Process for Additively Manufactured Parts

Steady-state traveling waves in structures have been previously investigated for a variety of purposes including propulsion of objects and agitation of a surrounding medium. In the field of additive manufacturing, powder bed fusion (PBF) is a commonly used process that uses heat to fuse regions of metallic or polymer powders within a loose bed. PBF processes require post-process removal of loose powder, which can be difficult when blind holes or complex internal geometry are present in the fabricated part. Here, a preliminary investigation of a simple part is conducted examining the use of traveling waves for post-process de-powdering of additively manufactured specimens. The generation of steady-state traveling waves in a structure is accomplished through excitation at a frequency between two adjacent resonant frequencies of the structure, resulting in two-mode excitation. This excitation can be generated by bonded piezoceramic elements actuated by a sinusoidal voltage signal. The response of the structure is affected by the parameters of the excitation, such as the particular frequency of the voltage signal, the placement of the piezoceramic actuators, and the phase difference in the signals applied to different actuators. Careful selection of these parameters allows adjustment of the quality, wavelength, and wave speed of the resulting traveling waves. In this work, open-top rectangular box specimens composed of sintered nylon powder and coated with fine sand are used to represent freshly fabricated parts yet-to-be cleaned of un-sintered powder. Steady-state traveling waves are excited in the specimens while variations in the frequency content and phase differences between actuation points of the excitation are used to affect the characteristics of the dynamic response. The effectiveness of several response types for the purpose of moving un-sintered nylon powder within the specimens is investigated.

Operational Risk in Both Conventional and Islamic Banking Perceptions: Differences and Similarities

While risks in conventional banks have been meticulously discussed in the literature, they remain a fresh research area in Islamic banks. In this context, operational risk has long been considered a simple part of “other” risks outside the dominion of credit risk and market risk, before it made its way to the forefront of banking. In fact, with the rise and enlargement of the Islamic banking industry and its unique contractual features and legal environment, operational risk has become more wide-ranging in Islamic banks compared to conventional banks. In this sense, the following work aims to provide a comparison of operational risk perceptions in both conventional and Islamic banks, with the objective of determining the fundamental similarities and differences of this risk within each system, which can be seen as a boosting step meant to help creating a good risk management tactics in both banks. This work showed a difference regarding the two definitions of operational risk. It also demonstrated that the conventionnal and Islamic banking systems are similar while presenting some differences in terms of components and factors of opeational risk.

Edge Reconstruction of the Ihara Zeta Function

We show that if a graph $G$ has average degree $\overline d \geq 4$, then the Ihara zeta function of $G$ is edge-reconstructible. We prove some general spectral properties of the edge adjacency operator $T$: it is symmetric for an indefinite form and has a "large" semi-simple part (but it can fail to be semi-simple in general). We prove that this implies that if $\overline d>4$, one can reconstruct the number of non-backtracking (closed or not) walks through a given edge, the Perron-Frobenius eigenvector of $T$ (modulo a natural symmetry), as well as the closed walks that pass through a given edge in both directions at least once.

The semantic-syntactical structure of the apposition phrase

The article is devoted to the semantic-syntactical structure of the appositive phrase in the Ukrainian language. The term “double name”is used for the demonstration of semantical parameteres of the apposition phrase. Two levels of syntactic analysis are considered: abstract-grammatical level (internal structure of the appositive word-combinations) and concrete-grammatical level (the function in sentence structure). The concrete-grammatical analysis indicates that appositional phrases in the sentence are: syntactically indivisible components that serve as a simple part of the sentence (subject, object). The conflict arises between formal analyticity and functional syntheticity. This conflict is caused by nominative features of double name (compound nouns indicates the same subject of objective reality). Therefore they can be referred to as the type of lexical (stable) word-combinations. Abstract-grammatical analysis leads to the conclusion that internal structure of the appositional phrase can express different semantic-syntactical relations between nouns: appositional relations or mutual appositional relations. The mutual appositional relations are peculiar to the majority of stylistically neutral double names. O. Peshkovskiy wrote about mutual relations between nouns. The differentiation of two relation types was done with the help of the semantic principle and predicate transformation method.

The algebra of parallel endomorphisms of a pseudo-Riemannian metric: semi-simple part

On a (pseudo-)Riemannian manifold (${\mathcal M}$, g), some fields of endomorphisms i.e. sections of End(T${\mathcal M}$) may be parallel for g. They form an associative algebra $\mathfrak e$, which is also the commutant of the holonomy group of g. As any associative algebra, $\mathfrak e$ is the sum of its radical and of a semi-simple algebra $\mathfrak s$. Here we study $\mathfrak s$: it may be of eight different types, including the generic type $\mathfrak s$ = ${\mathbb R}$ Id, and the Kähler and hyperkähler types $\mathfrak s$ ≃ ${\mathbb C}$ and $\mathfrak s$ ≃ ${\mathbb H}$. This is a result on real, semi-simple algebras with involution. For each type, the corresponding set of germs of metrics is non-empty; we parametrize it. We give the constraints imposed to the Ricci curvature by parallel endomorphism fields.