Application Of Logistics Simulations For Scaling Up A Semiconductor Pilot Line: A Case Study

Our study presents a comprehensive approach to upscaling pilot lines in the semiconductor industry, combining logistics simulation with discrete event simulation (DES) to achieve operational excellence. Based on both existing literature and partner company requirements, our five-step methodology facilitated the transition of a pilot line to medium-volume series production within a brownfield factory environment. We validated the effectiveness of DES in production planning and control (PPC) and demonstrated its application in a real-world planning task encompassing multiple facets of production system planning and optimization. Given the expected increase in brownfield factory planning within the semiconductor industry, our structured methodology provides a valuable pathway to enhance operational efficiency and competitiveness in that context. This case study underscores the vital role of DES in optimizing production systems, enabling informed decision-making and significant cost savings

Exponential algorithmic speedup by quantum walk

We construct an oracular (i.e., black box) problem that can be solved exponentially faster on a quantum computer than on a classical computer. The quantum algorithm is based on a continuous time quantum walk, and thus employs a different technique from previous quantum algorithms based on quantum Fourier transforms. We show how to implement the quantum walk efficiently in our oracular setting. We then show how this quantum walk can be used to solve our problem by rapidly traversing a graph. Finally, we prove that no classical algorithm can solve this problem with high probability in subexponential time.Comment: 24 pages, 7 figures; minor corrections and clarification

The QAOA gets stuck starting from a good classical string

The Quantum Approximate Optimization Algorithm (QAOA) is designed to maximize a cost function over bit strings. While the initial state is traditionally a superposition over all strings, it is natural to try expediting the QAOA: first use a classical algorithm to produce some good string, and then run the ordinary QAOA starting in the computational basis state associated with that string. Here we report numerical experiments that this method of initializing the QAOA fails dramatically, exhibiting little to no improvement of the cost function. We investigate criteria for the rare instances in which there is any improvement at all, and we provide a statistical argument for the more typical case of no improvement. The statistical argument holds for any string that locally mimics the thermal ensemble at the appropriate temperature. Our numerical experiments indicate this property holds for typical good strings. We emphasize that our negative results only apply to our simple incarnation of the warm-start QAOA and may not apply to other approaches in the literature. We hope that our theoretical analysis will inform future algorithm design.Comment: 26 pages, 1 figure, 6 table

A conserved circadian function for the Neurofibromatosis 1 gene

Summary: Loss of the Neurofibromatosis 1 (Nf1) protein, neurofibromin, in Drosophila disrupts circadian rhythms of locomotor activity without impairing central clock function, suggesting effects downstream of the clock. However, the relevant cellular mechanisms are not known. Leveraging the discovery of output circuits for locomotor rhythms, we dissected cellular actions of neurofibromin in recently identified substrates. Herein, we show that neurofibromin affects the levels and cycling of calcium in multiple circadian peptidergic neurons. A prominent site of action is the pars intercerebralis (PI), the fly equivalent of the hypothalamus, with cell-autonomous effects of Nf1 in PI cells that secrete DH44. Nf1 interacts genetically with peptide signaling to affect circadian behavior. We extended these studies to mammals to demonstrate that mouse astrocytes exhibit a 24-hr rhythm of calcium levels, which is also attenuated by lack of neurofibromin. These findings establish a conserved role for neurofibromin in intracellular signaling rhythms within the nervous system. : Bai et al. show that the gene mutated in the disease Neurofibromatosis 1 is required for maintaining levels or cycling of calcium in circadian neurons in Drosophila and in mammalian cells. These effects likely account for effects of Nf1 on circadian behavior in Drosophila and may be relevant in explaining sleep phenotypes in patients. Keywords: circadian rhythms, neurofibromatosis 1, Drosophila, peptide signaling, cycling of calcium, mouse astrocyte

Water and small organic molecules as probes for geometric confinement in well- ordered mesoporous carbon material

Mesoporous carbon materials were synthesized employing polymers and silica gels as structure directing templates. The basic physico-chemical properties of the synthetic mesoporous materials were characterized by 1H and 13C MAS solid-state NMR, X-ray diffraction, transmission electron microscopy (TEM) and nitrogen adsorption measurements. The confinement effects on small guest molecules such as water, benzene and pyridine and their interactions with the pore surface were probed by a combination of variable temperature 1H-MAS NMR and quantum chemical calculations of the magnetic shielding effect of the surface on the solvent molecules. The interactions of the guest molecules depend strongly on the carbonization temperature and the pathway of the synthesis. All the guest-molecules, water, benzene and pyridine, exhibited high-field shifts by the interaction with the surface of carbon materials. The geometric confinement imposed by the surface causes a strong depression of the melting point of the surface phase of water and benzene. The theoretical calculation of 1H NICS maps shows that the observed proton chemical shifts towards high-field values can be explained as the result of electronic ring currents localized in aromatic groups on the surface. The dependence on the distance between the proton and the aromatic surface can be exploited to estimate the average diameter of the confinement structures

How Can We Design Instruction to Support Student Reasoning about Physicists\u27 Ethical Responsibilities in Society?

STEM professionals make decisions that impact society in a wide variety of ways. Making thoughtful decisions often requires them to consider a complex set of real-world implications that can impact multiple stakeholders, and there may not be a single best solution to be discovered. These decisions can also be political in nature. In contrast, science is often portrayed as being purely objective and apolitical. Physics instruction often reinforces this portrayal by focusing exclusively on physics content knowledge and skills. Some physics programs have been expanding to include technical skills that are relevant in the workforce, and this expansion likely benefits students in their careers. But undergraduate physics programs, and STEM courses generally, rarely prepare students to grapple with the types of complex, ethical decision-making that they will encounter in STEM