ANALISIS DAN PERANCANGAN APLIKASI KATALOG PRODUK BERBASISKAN MULTIMEDIA PADA PT. TIGERSON PHILTI

ANALISIS DAN PERANCANGAN APLIKASI KATALOG PRODUK BERBASISKAN MULTIMEDIA PADA PT. TIGERSON PHILT

Vers une pluralité des échelles de fourniture des services urbains : quels impacts d'une décentralisation des techniques sur la mise en œuvre des services publics en termes de gestion, suivi et prise de décision ?

Concerning urban services, the decentralized techniques have known a growing interest partly due to the increasing environmental concern. These new techniques with recognized benefits are favorably considered by public authorities even though their ability to last may occasionally be questioned. These local techniques are also part of a broader and complex existing framework which it is important to understand. From a historical point of view in Western countries, the foundations of the model of the urban services’ contribution rest upon two prevailing principles: an awareness of the reality of public service and of anability to be part of a network. The study of these characteristics in the light of the feedback from the Urban Community of Nantes has brought up a number of questions as to the ways to integrate such decentralized techniques into an already existing system. Now, the action of the public services is not limited to ensuring that the network is operational: the role of public authority, separate from the management organization, appears to be the essential center that ensures the necessary knowledge and global consistency of the system. Many potential structures of management and financing can be set on foot and the tools available for taking decisions have started being adapted by renewed actors and issues.Dans le cadre de la fourniture des services urbains, le recours à des techniques décentralisées connaît un regain d’intérêt en grande partie lié à la montée des préoccupations environnementales. Ces nouvelles techniques ne sont pas dénuées d’avantages et séduisent a priori les pouvoirs publics même si leur durabilité propre est parfois questionnée. Bien que d’échelle souvent locale, ces techniques s’insèrent dans un cadre existant complexe plus global qu’il convient de bien appréhender. Les soubassements du modèle de fourniture des services urbains occidentaux se sont construits, au cours de l’histoire, en intégrant deux composantes principales : la notion de service public et la technique en réseau. À travers l’étude de ces deux caractéristiques éclairée par le retour d’expérience de la communauté urbaine de Nantes Métropole, certaines pistes de réflexion concernant les modalités d’intégration des techniques décentralisées au système existant sont soulevées. Les services publics ne se limitent plus à assurer le fonctionnement de services en réseau : le rôle de la puissance publique, distinct de celui de l’entité organisatrice du service ressort comme étant central et indispensable pour garantir la connaissance et la cohérence globale du système. De multiples formes de structures de gestion et de financement peuvent potentiellement être mises en place et les instruments de prise de décision commencent à être remodelés par de nouveaux acteurs et enjeux

A metric-affine version of the Horndeski theory

© 2020 World Scientific Publishing Company. We study the metric-affine versions of scalar-tensor theories whose connection enters the action only algebraically. We show that the connection can be integrated out, resulting in an equivalent metric theory. Specifically, we consider the metric-affine generalisations of the subset of the Horndeski theory whose action is linear in second derivatives of the scalar field. We determine the connection and find that it can describe a scalar-tensor Weyl geometry without a Riemannian frame. Still, as this connection enters the action algebraically, the theory admits the dynamically equivalent (pseudo)-Riemannian formulation in the form of an effective metric theory with an extra K-essence term. This may have interesting phenomenological applications

Varying the Horndeski Lagrangian within the Palatini approach

© 2020 IOP Publishing Ltd and Sissa Medialab. We analyse what happens when the Horndeski Lagrangian is varied within the Palatini approach by considering the metric and connection as independent variables. Assuming the connection to be torsionless, there can be infinitely many metric-affine versions LP of the original Lagrangian which differ from each other by terms proportional to the nonmetricity tensor. After integrating out the connection, each LP defines a metric theory, which can either belong to the original Horndeski family, or it can be of a more general DHOST type, or it shows the Ostrogradsky ghost. We analyse in detail the subclass of the theory for which the equations are linear in the connection and find that its metric-affine version is ghost-free. We present a detailed classifications of homogeneous and isotropic cosmologies in these theories. Taking into consideration other pieces of the Horndeski Lagrangian which are non-linear in the connection leads to more complex metric-affine theories which generically show the ghost. In some special cases the ghost can be removed by carefully adjusting the non-metricity contribution, but it is unclear if this is always possible. Therefore, the metric-affine generalisations of the Horndeski theory can be ghost-free, but not all of them are ghost-free, neither are they the only metric-affine theories for a gravity-coupled scalar field which can be ghost-free

A metric-affine version of the Horndeski theory

International audienceWe study the metric-affine versions of scalar-tensor theories whose connection enters the action only algebraically. We show that the connection can be integrated out, resulting in an equivalent metric theory. Specifically, we consider the metric-affine generalisations of the subset of the Horndeski theory whose action is linear in second derivatives of the scalar field. We determine the connection and find that it can describe a scalar-tensor Weyl geometry without a Riemannian frame. Still, as this connection enters the action algebraically, the theory admits the dynamically equivalent (pseudo)-Riemannian formulation in the form of an effective metric theory with an extra K-essence term. This may have interesting phenomenological applications

Varying the Horndeski Lagrangian within the Palatini approach

International audienceWe analyse what happens when the Horndeski Lagrangian is varied within the Palatini approach by considering the metric and connection as independent variables. Assuming the connection to be torsionless, there can be infinitely many metric-affine versions LP of the original Lagrangian which differ from each other by terms proportional to the non-metricity tensor. After integrating out the connection, each LP defines a metric theory, which can either belong to the original Horndeski family, or it can be of a more general DHOST type, or it shows the Ostrogradsky ghost. We analyse in detail the subclass of the theory for which the equations are linear in the connection and find that its metric-affine version is ghost-free. We present a detailed classifications of homogeneous and isotropic cosmologies in these theories. Taking into consideration other pieces of the Horndeski Lagrangian which are non-linear in the connection leads to more complex metric-affine theories which generically show the ghost. In some special cases the ghost can be removed by carefully adjusting the non-metricity contribution, but it is unclear if this is always possible. Therefore, the metric-affine generalisations of the Horndeski theory can be ghost-free, but not all of them are ghost-free, neither are they the only metric-affine theories for a gravity-coupled scalar field which can be ghost-free

ANALISIS ALIRAN UDARA MELINTASI SILINDER SIRKULAR DENGAN PENAMBAHAN BODI PENGGANGGU YANG TERSUSUN TANDEM DENGAN VARIASI RASIO (d/D = 0,05, 0,07 dan 0,11)

Silinder sirkular adalah salah satu bentuk yang sering digunakan pada struktur mekanikal, seperti pada struktur penyangga anjungan lepas pantai. Struktur penyangga tersebut menerima beban, baik beban aerodynamics maupun hydrodynamics, resultan beban-beban tersebut adalah gaya drag. Gaya drag yang dialami oleh tiang penyangga ini harus benar-benar di investigasi, dan diminimalkan pengaruhnya pada struktur tiang penyangga anjungan lepas pantai, karena berpotensi menimbulkan kegagalan struktur. Salah satu cara untuk meminimalkan pengaruh gaya drag adalah dengan meletakkan bodi pengganggu didepan silinder utama. Bagaimana hubungan antara rasio diameter bodi pengganggu dengan silinder utama, terhadap beban yang diterima oleh silinder utama, hal ini menarik untuk di investigasi. Oleh karena itu pada penelitian ini dilakukan riset, untuk mengetahui seberapa besar pengaruh pengurangan gaya drag atas rasio diameter tersebut. Penelitian ini dilakukan secara eksperimen dan simulasi numerik CFD, dengan variasi rasio diameter bodi pengganggu dan diameter silinder uatama (d/D = 0.05, 0.07, 0.11), L/D = 2,0 konstan dan bilangan Reynolds 5,3 x 104. Hasil yang didapat adalah koefisien drag (CD) untuk silinder utama tanpa pengganggu sebesar 0,85. Dengan adanya peletakan bodi pengganggu dapat menurunkan koefisien drag sebesar 0,67, 0,62 dan 0,56, untuk masing-masing d/D 0,05, 0,07 dan 0,11. Dengan adanya penempatan bodi pengganggu didepan silinder utama, dapat menurunkan nilai koefisien drag pada silinder utama. Kata kunci : Silinder utama, bodi pengganggu, koefisien tekanan (Cp), koefisien drag (CD), komputasi dinamika fluida (CFD)