Preparation of SAPO-34 catalyst and presentation of a kinetic model for methanol to olefin process (MTO)

Conversion of methanol to light olefins (MTO) using acidic SAPO-34 molecular-sieve as the reaction catalyst was studied in a differential fixed bed reactor within the temperature range of 375-425 °C and under 4 bar pressure. The importance of MTO process is due to the increasing demand for light olefins in recent years. SAPO-34 was synthesized by hydrothermal method, applying morpholine as the template. The latter compound was then changed into protonated form by ion exchange method with ammonium chloride at 80 °C. A simple stoichiometric scheme has been presented for MTO. In addition a mechanism for this process based on Langmuir-Hinshelwood formulation has been put forward and the kinetic parameters have been evaluated as functions of temperature.     

Power grid analysis and verification considering temperature variations

Process variations significantly impact leakage power, a pivotal parameter in designing a power grid. Because of the strong relationship between temperature and leakage power, the variations also impose statistical behavior on the operating temperature. In addition, the metal resistivity of a power grid increases with temperature. Therefore, ignoring the interdependency between leakage and temperature can introduce large errors in the power grid design. In this paper, a power grid analysis is proposed considering a statistical thermal profile across the grid. In addition, an efficient verification method is provided that ensures the robustness of the power grid in the presence of variations. A reliable estimation of the statistical thermal profile at the architecture level makes it possible to address any voltage violation early in the design process.     

Particle Size Modification of Thermally Stable Secondary Explosives for IM Applications

As well as improving the survivability of weapons and platforms, insensitive munitions (IM) reduce both casualty rates and mission losses. Their use also leads to improved safety during storage and transportation. For a munition to fulfil IM criteria, each of its energetic sub‐sections must be IM compliant. The initiator and explosive train are the most critical of these sub‐systems as their safety and reliability are of paramount importance if the weapon is to be suitable for service use, yet they are generally the most difficult part of a weapon to protect from inadvertent initiation. As part of an ongoing study into initiation methods suitable for use in IM systems, an investigation into the behaviour of energetic materials when impacted by laser‐driven flyers was performed. Laser‐based detonators exhibit increased safety characteristics over conventional initiation methods as they can be based on insensitive secondary explosives rather than sensitive primary explosives. Also, they are less susceptible to accidental initiation due to an external hazard threat. Single pulses from a high‐powered Q‐switched Nd:YAG laser were used to launch flyers from substrate‐backed aluminium films to velocities up to 6 km s⁻¹ across a short stand‐off to impact explosive targets. Several novel energetic materials have been selected for investigation as potential candidates for inclusion within flyer‐based initiation systems and explosive train applications. The materials are of interest due to their increased thermal stability and power output over conventional explosives currently in service. Attempts were made to increase the flyer responsiveness of the materials by tuning their particle size using ultrasound. The effect of particle size on the initiation threshold energy was investigated for three materials.     

A System for Synchronized Pulsed Perfusion of the Coronary Arteries During Cardiopulmonary Bypass

A system for providing near-physiologic flow patterns in the coronary arteries during cardiac surgery is described. Results in 40 dogs demonstrate the effectiveness of the method.     

Abdominal aortic resection in thoracic dissection

Dissection nearly always begins in the thorax, but it commonly extends into the abdominal aorta, which may become the focal point of the disease. We report five patients who illustrate the surgical management of this disease variant. Clinical manifestations included retroperitoneal rupture, expanding false aneurysm, and lower aortic occlusion. All patients had an aortic bifurcation graft, with reentry of the false lumen at the renal level. Two patients also had thoracic-aortic resection or plasty or both. Although one patient had thoracic aortic rupture at the five-year interval, these abdominal aortic resections provided effective palliation in all. This successful experience in managing complex dissections shows that when aortic dissection extends into the abdomen, resection of the distal aorta with a reentry procedure may be appropriate therapy.     

Cooperative advertising in a capacitated manufacturer–retailer supply chain: a game‐theoretic approach

To achieve a more realistic understanding of how the supply chain's components interact, it is helpful to consider the operational limitations of the underlying supply chain while analyzing cooperative advertising. This paper studies cooperative advertising in a manufacturer–retailer supply chain under the practical operational assumption that the manufacturer's production capacity is limited. The retailer advertises locally, and the manufacturer advertises in national media and supports part of the retailer's promotional costs. Equilibria are determined under two different scenarios. In the first scenario, both retailer and manufacturer move simultaneously, while in the second scenario, they move sequentially, with the manufacturer being the leader. The sales function is a bivariate version of the diminishing returns response function. When the production capacity is unlimited, several important properties can be proven, which cannot be shown analytically for the existing sales functions. Considering the production‐capacity constraint leads to new managerial insights into cooperative advertising. For example, only if the production capacity is large enough, both manufacturer and retailer are better off under the second scenario than the first scenario. In other words, the sequential move is not necessarily Pareto‐improving when the production capacity is limited. It is also observed that, under the first scenario, there are multiple equilibria whenever the production capacity is not too high. Under the second scenario, the manufacturer supports the retailer only when the retailer's margin is relatively small compared to the manufacturer's margin and production capacity.     

Red-emitting CaSc2O4:Eu3+ phosphor for NUV-based warm white LEDs: structural elucidation and Hirshfeld surface analysis

We have prepared Eu³⁺ activated phosphor from the host CaSc₂O₄ (CSO) via high-temperature facial solid-state route and characterized by various spectral techniques. Surface morphology and composition was determined via scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDAX). The crystal structure refinements show the Pnam 62 space group with two active centres for Eu³⁺ in the prepared CSO:Eu³⁺ phosphor. Additionally, first time the detailed investigation of intermolecular interactions through Hirshfeld surface (HSs) analysis for the inorganic phosphor has been reported, the analysis indicates that the Sc/Eu O and Ca O contacts in the CSO:Eu³⁺crystal account for more than 60% and 26% of the total HSs area. The synthesized phosphor shows an intense red emission at 618 nm (Ex 394 nm) with a CIE coordinates of (0.633, 0.358) and measured internal quantum efficiency (IQE) was found to be 84%. Further, correlated colour temperature was estimated to be about 6049 K including colour purity of 93.04% for Eu = 0.10 and the thermal stability were established by their temperature dependent study (400 K = 92%). Therefore, the phosphor of CSO:Eu³⁺ exhibits a potential application for UV-based warm white LEDs and in the determination of intermolecular interactions through HSs surface analysis studies.