Metamaterials are purposely built devices mimicking structural features of normal materials, but with unusual physical properties. Photonic crystals, for example, are periodic nanostructures consisting of material components with different refractive indices. They have lattice symmetries like solids, but the constituents of the unit cell of a photonic crystal are ‘bits’ of the different bulk materials. Similar to the structure–property relationships resulting from the behavior of electrons in solids (e.g. semiconduction), photonic crystals offer ways for manipulating the propagation of light. Now, Xiao Hu at the International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan, and colleagues have succeeded in creating a photonic metamaterial that displays a special property known as a topological photonic state.
The researchers first considered theoretically a planar construction of microstrips organized in a honeycomb-like way. Strip segments inside hexagons are put narrower than those between hexagons in one half of the device, and vice versa in the other half, because a structure with alternatingly wide and narrow strips results in a so-called photonic band gap: a range of frequencies for which electromagnetic waves cannot naturally exist in the system. The nodes of the hexagonal network are connected to capacitors; the segments linking nodes act as inductors. (A capacitor, abbreviated ‘C’ in circuit theory, is an electric component capable of storing energy in an electric field. An inductor, abbreviated ‘L’, is a component that stores energy in a magnetic field when an electric current flows through it.)
The topological LC-circuit proposed by Hu and colleagues has a peculiar property. When excited by an electromagnetic wave with a frequency in the photonic band gap, at the intersection of the two halves, waves in opposite directions are created. What is remarkable is that these two waves can be assigned a quantity known as pseudospin, with values ‘up’ and ‘down’, respectively, and they are immune to backscatter even at sharp corners and robust to defects due to the topological protection.
To demonstrate their theoretical finding experimentally, the scientists fabricated the topological LC circuit from microstrips — metallic strip lengths were about 1 cm and both halves consisted of 14 × 8 hexagons — and, by using microwave near-field techniques, measured the electric-field component perpendicular to the sample. The measurements confirmed the existence of the special topological state.
Being able to generate and manipulate electromagnetic waves with pseudospin is promising for applications like communications and high-resolution imaging. The concept presented by Hu and colleagues is not restricted to the microwave range, but also applicable to infrared light. The planar geometry of the device makes it easy to include other circuit elements, such as resonators or superconducting Josephson junctions. One difficulty, though, is to channel the pseudospin modes out of the sample.
Bilfinger and Anglo-Swiss chemicals group Ineos are expanding their cooperation. Alongside industrial services in Germany, the Mannheim-based company will in future also be providing services to Ineos in Belgium. Bilfinger is to construct scaffolding for maintenance work and turnarounds of large-scale facilities at the Zwijndrecht and Doel locations in Antwerp. The double-digit million contract comes under Bilfinger’s Engineering & Maintenance (E&M) service line and will run for a period of three years.
“Bilfinger E&M is supporting Ineos in realizing its growth ambitions in Europe. We combine our proven expertise and experience in mechanical construction with Electronic Workflow Tools such as scaffolding digital work order management to drive internal productivity while boosting efficiency and transparency for our customers.”
Duncan Hall, Chief Operating Officer of Bilfinger
Bilfinger quantifies the scaffolding BOM (Bill of Materials) and optimizes the erection mode and time needed at the customer’s plant by means of a scaffolding app for smartphones or tablets. This information is then transferred digitally to a central database where all contract data is stored. Via the portal, Ineos has a transparent, up-to-the-minute overview of the status and progress of all services. The digital customer portal links operational and administrative processes on a single platform, making communication and interfacing with the customer even more efficient.
Claude Moreau, Sites Procurement Manager at Ineos, says: “Bilfinger has many years of proven expertise in mechanical construction. At the same time, the company is harnessing innovative solutions in its drive to digitalize workflows.”
Ineos at its location in Cologne, Germany, had already commissioned Bilfinger with pipe construction services in February 2018. Among other aspects, the Bilfinger team is responsible for large parts of the water-steam cycle for the new steam generator at the industrial power plant. Bilfinger’s services notably include the engineering, assembly, erection and commissioning of critical pipework.
Bilfinger has around 1,000 employees in Belgium. Services include insulation, scaffolding, painting and coating as well as fabrication, maintenance and plant turnarounds. In the Antwerp Industrial Cluster, Bilfinger is proud to work for customers in Oil & Gas, Chemical & Petrochemical as well as Energy & Utilities, such as BASF or Belgian energy provider Engie Electrabel.
Engineering and maintenance services for petrochemical company
Bilfinger wins contract from Sabic
Bilfinger has been chosen as maintenance partner for a €60 million contract by Sabic UK Petrochemicals Limited to carry out a range of services across facilities on its Teesside site. The services will include mechanical, electrical and instrumentation engineering, as well as access, insulation, painting, and asbestos management and removal. The four-year contract has a volume of circa £50 million (€57.8 million) and comes under Bilfinger’s Engineering & Maintenance service line.
“Bilfinger has a strong track record of industrial services on such large scale assets. With our Bilfinger Maintenance Concept, we help our customers boost asset efficiency and availability while cutting maintenance costs. Sabic has chosen a reliable partner in Bilfinger with a long history of proven experience to ensure smooth production and short downtimes at one of its largest sites.”
Tom Blades, CEO of Bilfinger
Bilfinger employs 2,500 employees in the UK, with approximately 200 employees dedicated to the engineering and maintenance services for Sabic. Bilfinger’s services for process industry customers include design and build, automated control and electrical systems, installation and commissioning as well as operations and maintenance.
Sabic is a global chemical company, employing over 540 people across two sites in Teesside. Its Wilton site is located on Wilton International, one of the UK’s leading process manufacturing sites.
New Greener Solvent
Merck, a science and technology company, launched Cyrene — a sustainable dipolar aprotic solvent, produced in two steps from a renewable cellulose source. The bio-derived alternative was created in response to the need for solvents to meet stricter regulation requirements for both employee safety and environmental sustainability. The new product targets the rising demand for greener alternatives to Dimethylformamide (DMF) and N-Methyl-2-pyrrolidone (NMP).
“With a strong focus on green chemistry, Merck is dedicated to providing today’s scientists with innovative solutions to help solve environmental challenges before us. As a greener alternative, Cyrene solvent allows our customers to improve the safety of their processes and reduce the environmental impact of their research and manufacturing — without compromising performance.”
Klaus Bischoff, head of Research Solutions, Life Science at Merck
The Life Science business of Merck uses the 12 Principles of Green Chemistry that were developed and published by thought leaders Paul T. Anastas and John C. Warner in 1991 as a framework for its Green Chemistry practice.
DMF and NMP are under increasing regulatory restrictions, with both being classified by the European Union’s Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) as substances of very high concern. More recently, according to the European Union, the European Commission added NMP to the restricted substances list known as REACH Annex XVII — driving the demand for alternatives. Additionally, effective May 2020, consumer products containing more than 0.3 percent NMP will be prohibited in the European Union. Initial studies and testing have found Cyrene solvent to be a more sustainable, safer option when compared with DMF and NMP.
Cyrene solvent was developed as a result of a partnership between the University of York’s Green Chemistry Centre of Excellence (GCCE) and Circa Group. Utilizing its expertise in green chemistry, the University of York’s GCCE worked to determine potential applications for the Cyrene solvent.
“Cyrene solvent actually outperformed the solvent we currently use for manufacturing graphene — providing us with both a sustainable and more effective option to traditional solvents,” said James Clark, professor, University of York and director, Green Chemistry Centre of Excellence.
Merck also researched alternate uses of Cyrene solvent in mild and robust Sonogashira cross-couplings, a common reaction used in medicinal chemistry, with Professor Allan Watson’s group at the University of St. Andrews, United Kingdom.
“It was important for us to find a safer alternative without sacrificing quality,” said Allan Watson, reader in Homogeneous Catalysis, University of St. Andrews. “Through our research, we found that Cyrene solvent features similar physical properties to those of DMF and other dipolar aprotic solvents, while enabling medicinal chemists to execute a more sustainable chemical synthesis.”
Cyrene solvent was also substituted for DMF in amide couplings — a fundamental reaction in drug discovery. By demonstrating that safer, greener alternatives offer superior performance, Cyrene solvent was recognized as the Bio-Based Chemical Innovation of the Year at the 2017 European Bio-Based Innovation Awards.