Dual sourcing inventory management with nonconsecutive lead times from a supply chain perspective: a numerical study

We study a stochastic multi-period two-echelon dual sourcing inventory system where the buyer can source a product from two different suppliers: a regular and an expedited supplier. The regular supplier is a low-cost offshore supplier, whereas the expedited supplier is a responsive nearshore supplier. Such dual sourcing inventory systems have been well studied in the literature, mostly being solely evaluated from the buyer’s perspective. Since the buyer’s decisions have an impact on the supply chain profit, we adopt the perspective of the entire supply chain, i.e., by taking the suppliers explicitly into consideration. In addition, we study this system for general (nonconsecutive) lead times for which the optimal policy is unknown or very complex. We numerically compare the performance of two different policies in a two-echelon setting: the Dual-Index Policy (DIP) and the Tailored Base-Surge Policy (TBS). From earlier studies we know that when the lead time difference is one period, DIP is optimal from the buyer’s perspective, but not necessarily from the supply chain perspective. On the other hand, when the lead time difference grows to infinity, TBS becomes optimal for the buyer. In this paper, we evaluate the policies numerically (under various conditions) and we show that from a supply chain perspective, TBS typically outperforms DIP at a limited lead time difference of a few time periods. Based on data collected from 51 manufacturing firms, the results of our paper imply for many supply chains with a dual sourcing setting that TBS quickly becomes a beneficial policy alternative, especially given its simple and appealing structure

1-Decyl-6-nitro-1H-benzimidazol-2(3H)-on

The title mol­ecule, C17H25N3O3, is built up from fused six- and five-membered rings linked to a –C10H21 chain. The fused-ring system is essentially planar, the largest deviation from the mean plane being 0.009 (2) Å. The chain is roughly perpendic­ular to this plane, making a dihedral angle of 79.5 (2)°. In the crystal, N—H[cdots, three dots, centered]O hydrogen bonds build infinite chains along [010]. There are channels in the structure containing disordered hexane. The contribution of this solvent to the scattering power was suppressed using the SQUEEZE option in PLATON [Spek (2009 [triangle]). Acta Cryst. D65, 148–155]

Choc anaphylactique au cours de la chirurgie de kyste hydatique du foie : à propos d’un cas

Nous rapportons l’observation d’un choc anaphylactique survenue au cours d’une chirurgie de kystes hydatiques hépatiques multiples. Il s’agit d’un enfant de 13 ans, de sexe féminin, sans antécédents pathologiques notables, en particulier allergique, programmé pour cure chirurgicale de kystes hydatiques hépatiques multiples. L’examen préopératoire est strictement normal. La patiente est classée ASA (American Society of Anaesthesiologists) I. L’intervention est réalisée sous anesthésie générale. Au moment de la manipulation du deuxième kyste, une augmentation des pressions d’insufflation apparaît, avec des râles sibilants au niveau des deux champs pulmonaires et une désaturation, suivi d’un collapsus vasculaire avec hypotension artérielle 50/30. La prise en charge est débutée aussitôt par un remplissage vasculaire par du sérum salé 9%, suivi par des bolus d’adrénaline de 0,1mg à trois reprises, puis d’une perfusion continue à raison. L’adrénaline est arrêtée au bout de 48 heures et la patiente est adressée au service de chirurgie à j+4 de l’intervention. Le choc anaphylactique est une complication connue de la rupture intra péritonéale spontanée ou post-traumatique du kyste hydatique du foie. Sa survenue en peropératoire est devenue exceptionnelle, grâce aux mesures de prévention chirurgicale entretenues en peropératoire par l’éviction de manipulation du kyste, de le vider avant d’injecter le scolicide, et de ne pas l’administrer sous forte pression

Effect of Rockfall Spatial Representation on the Accuracy and Reliability of Susceptibility Models (The Case of the Haouz Dorsale Calcaire, Morocco)

Rockfalls can cause loss of life and material damage. In Northern Morocco, rockfalls and rock avalanche-deposits are frequent, especially in the Dorsale Calcaire morpho-structural unit, which is mostly formed by Jurassic limestone and dolostone formations. In this study, we focus exclusively on its northern segment, conventionally known as “the Haouz subunit”. First, a rockfall inventory was conducted. Then, two datasets were prepared: one covering exclusively the source area and the other representing the entirety of the mass movements (source + propagation area). Two algorithms were then used to build rockfall susceptibility models (RSMs). The first one (Logistic Regression: LR) yielded the most unreliable results, where the RSM derived from the source area dataset significantly outperformed the one based on the entirety of the rockfall affected area, despite the lack of significant visual differences between both models. However, the RSMs produced using Artificial Neural Networks (ANNs) were more or less similar in terms of accuracy, despite the source area model being more conservative. This result is unexpected given the fact that previous studies proved the robustness of the LR algorithm and the sensitivity of ANN models. However, we believe that the non-linear correlation between the spatial distribution of the rockfall propagation area and that of the conditioning factors used to compute the models explains why modeling rockfalls in particular differs from other types of landslides.CNRST within the framework of the research project PPR2/205/6

Mapping of Elastic Properties of Twisting Metamaterials onto Micropolar Continuum using Static Calculations

Recent developments in the engineering of metamaterials have brought forth a myriad of mesmerizing mechanical properties that do not exist in ordinary solids. Among these, twisting metamaterials, acoustical chirality, or Willis coupling are sample-size dependent. The purpose of this work is, first, to examine the mechanical performance of a new twisting cubic metamaterial. Then, we perform a comparative investigation of its twisting behavior using the finite element method on microstructure elements computation, an analytical model, and we compare them to Eringen micropolar continuum. Notably, the results of the three models are in good qualitative and quantitative agreements. Finally, a systematic comparison of dispersion relations was made for the continuum and for the microstructures with different sizes in unit cells as final proof of perfect mapping.Comment: 9 pages, 5 figure

5-Nitro-1-(prop-2-yn-1-yl)-2,3-dihydro-1H-1,3-benzodiazol-2-one

In the two independent mol­ecules of the title compound, C10H7N3O3, the nitro substitutent is twisted slightly with respect to the benzodiazol fused-ring system [dihedral angles = 4.9 (3) and 8.5 (1)°]. The two independent mol­ecules are disposed about a pseudo inversion center and are held together by N—H⋯O hydrogen bonds. The supramolecular dimer is essentially planar [dihedral angle between the fused rings = 2.0 (1)°]. Adjacent dimers are linked by acetyl­ene–nitro C—H⋯O inter­actions, generating a ribbon motif along (110)