Advanced technique for measuring relative length changes under control of temperature and helium-gas pressure

We report the realization of an advanced technique for measuring relative length changes $\Delta L/L$ of mm-sized samples under control of temperature ($T$) and helium-gas pressure ($P$). The system, which is an extension of the apparatus described in Manna et al., Rev. Sci. Instrum. 83, 085111 (2012), consists of two $^4$He-bath cryostats each of which houses a pressure cell and a capacitive dilatometer. The interconnection of the pressure cells, the temperature of which can be controlled individually, opens up various modes of operation to perform measurements of $\Delta L/L$ under variation of temperature and pressure. Special features of this apparatus include the possibilities (1) to increase the pressure to values much in excess of the external pressure reservoir, (2) to substantially improve the pressure stability during temperature sweeps, (3) to enable continuous pressure sweeps both with decreasing and increasing pressure, and (4) to simultaneously measure the dielectric constant of the pressure-transmitting medium helium, $\varepsilon_{\mathrm{r}}^{\mathrm{He}}(T,P)$, along the same $T$-$P$ trajectory as used for taking the $\Delta L(T,P)/L$ data. The performance of the setup is demonstrated by measurements of relative length changes $(\Delta L/L)_T$ at $T=180\,\mathrm{K}$ of single crystalline NaCl upon continuously varying the pressure in the range $6\,\mathrm{MPa}\leq P \leq 40\,\mathrm{MPa}$.Comment: 11 pages, 11 figure

Situation Awareness Monitor And Liquidity Assessment For Enterprise Resilience Management

Currently, companies are becoming increasingly vulnerable towards unforeseen disruptive events. One example of such an event is the COVID-19 pandemic, in which many companies are facing existential difficulties. The sudden loss of suppliers and customers as well as frequent changes in regulations at short notice present companies with considerable challenges. Potential uncertainties and complexity complicate the planning and the implementation of measures. A fast and effective overview and the benefit of measures is usually missing. Situation awareness monitors have long provided orientation for first responders and rescue operators within the field of crisis management and can be just as relevant for companies. Identifying, gathering, interpreting and visualizing external information from the corporate environment in relation to relevant disruptions remains an unsolved problem. In addition to the decision to implement effective measures before, during and after a crisis, an approach for the simulation of the disruptive impact and the effect of resilience measures on the company’s performance as well as liquidity is required. In this paper, a Situation Awareness Monitor (SAM) for resilience management is presented to address the aforementioned issues. First, the model-based IT architecture for the monitor is depicted. The enterprise model is coupled with an approach to assess critical processes of small and medium enterprises. Statistical models are applied to draw up the balance between single components, like input, output, supplier, storage and production. The result shows a continuous performance-based liquidity assessment to evaluate the resilience against disruptive events. Finally, single enhancement measures in alignment to the resilience phases – prepare, prevent, protect, respond and recover – can be analyzed