Secondary EM Research Articles

Compressible thermoplastic polyurethane/silver nanorod foams for absorption dominant electromagnetic interference shielding

Conductive polymer composites (CPCs) have attracted significant interest in the field of flexible electromagnetic protection, but the challenge of balancing high electromagnetic interference shielding effectiveness (EMI SE) and low reflection losses still exists. Herein, thermoplastic polyurethane/silver nanorod (TPU/AgNR) composite foams have been successfully prepared using both the salt template and vacuum-assisted thermal compression methods. By varying the AgNRs content and employing a layer-by-layer bonding approach, a gradient structure with optimized impedance matching is achieved. The “absorb-reflect-reabsorb” EM attenuation mechanism of the asymmetric gradient EMI shielding in the internal structure is exploited, resulting in TPU/AgNR foam (TAF) with high EMI SE and significantly reduced EM reflection. Notably, the three-layer foams exhibit an average shielding efficacy of 35.5 dB and a reflected power coefficient (R) of 0.085 in the X-band, thereby substantially mitigating secondary EM wave reflections. Furthermore, these foams demonstrate exemplary compressive resilience, with the sample maintaining excellent EMI shielding stability even after undergoing 100 compression cycles at 50 % strain. Consequently, a straightforward approach is employed to fabricate materials with high EMI SE and low reflectivity, offering the potential for use in EM shielding applications of next-generation flexible electronic devices.

Complex retrograde transarterial access and embolization of a giant internal iliac artery aneurysm after occlusion failure of Micro vascular plug (MVP) embolization and preceding EVAR in the distal ectatic Aorta and bilateral iliac artery aneurysms

The therapy of pelvic aneurysms is minimally invasive through interventional radiology using various devices and embolic agents: 
 1. By using a covered stent/prosthesis to maintain antegrade flow when a landing zone, i.e., a
 vascular segment angiographically present into which the stent can be placed to bridge the neck of the aneurysm, thereby interrupting aneurysm perfusion. 
 2. Through complete embolization of the aneurysm using embolic agents/coils. 
 3. As performed in our case, by covering the aneurysm (Img 14 A-C) with a covered stent /prosthesis, following prior embolization of the branching vessels using macroembolic agents. In cases where there is insufficient occlusion of the aneurysm with residual perfusion, secondary em- bolization becomes considerably more complex due to the occlusion of the anatomically antegrade access and the altered hemodynamics around the aneurysm causing retrograde collateralization. Through detailed analysis of CT angiography, even in static CT, retrograde circulation could be iden- tified, allowing for a minimally invasive secondary approach to the aneurysm without the need for general anesthesia and/or surgery. By completely eliminating the aneurysm, the risk of rupture in the elderly patient was minimally invasively eliminated. The treatment of this patient exemplifies the possibilities that embolization with a wide array of embolic agents and catheters offers in a hemo- dynamically very complex situation.

Construction of designable and high-temperature resistant composite foams for tunable electromagnetic shielding

Conductive polymer composite (CPC) foams have been extensively studied for electromagnetic interference (EMI) shielding due to their lower density and relatively low EM reflectivity. However, most CPC foams are difficult to structurally design to regulate performance, and also limited in high-temperature application scenarios owing to the low-temperature resistance of the matrix themselves. Herein, high-performance expanded polyetherimide (EPEI) foam beads were fabricated by subcritical foaming technology with organic solvents/CO2 as co-blowing agents, and designable EPEI/CNS (carbon nanostructures) composite foams with segregated networks and high-temperature resistance were then manufactured through CNS dip-coating and epoxy bonding. The resultant EPEI/CNS composite foams showed the shielding effectiveness (SE) of ∼11.9–39.5 dB with CNS loading of only ∼0.25–0.72 vol%, along with R coefficient of only ∼0.26–0.56. The construction of asymmetric gradient structure in the foams via orderly assembling can further reduce the EM reflection in comparison with uniform structure, thereby remitting the secondary EM pollution. Moreover, the EPEI/CNS composite foams can not only maintain the structural integrity after being treated at ∼200 °C, but also maintain relatively stable EMI SE and most of their mechanical properties, enabling their applications in high-temperature environments. This work provides a simple and effective method for constructing high-temperature resistant CPC foams for tunable EMI shielding.

Multi-hierarchically Structural Polycaprolactone Composites with Tunable Electromagnetic Gradients for Absorption-Dominated Electromagnetic Interference Shielding

Achieving absorption-dominated electromagnetic interference (EMI) shielding composites with high shielding effectiveness (SE) remains a great challenge due to their minimization of secondary EM radiation pollution, which is highly desired for next-generation electronic devices. Herein, an ingenious approach is proposed to develop asymmetric hierarchical polycaprolactone (PCL) composites composed of an impedance matching layer and a conductive layer through the combination of alternate casting and electroless plating methods, while the polarization loss caused by the difference in conductivity between the two layers would further attenuate the EM waves. The gradient distribution of the shielding fillers creates a positive conductive gradient and a negative magnetic gradient; the higher the gradient, the more it induces magnetic and dielectric losses, which results in an enhanced absorption mechanism that could overcome the restrictions of the nonadjustable reflective properties. The obtained Fe3O4@rGO/Ni/Ag/PCL composite possesses a remarkable EMI SE of 47.6 dB, while the power coefficient of reflectivity (R) could be significantly reduced to 0.27. This research provides a feasible strategy for developing absorption-dominated shielding materials with tunable EM performance that are appropriate for the next generation of electronic devices.

Rare Case of Systemic Lupus Erythematosus Presenting as Erythromelalgia

Abstract Erythromelalgia (EM) is a characteristic triad of symptoms, including erythema, burning pain, and local rise of temperature. Secondary EM is associated with numerous systemic diseases and can be an initial clue to diagnose autoimmune disease such as systemic lupus erythematosus (SLE). Here, we have reported a case of SLE with EM being a predominant presentation of SLE in the absence of any other classical clinical manifestations.

ELDER MISTREATMENT, MORTALITY, AND HOSPITAL READMISSION AMONG MEDICARE BENEFICIARIES, 2015–2018

Abstract Elder mistreatment (EM) is a growing public health and safety crisis, with long-term consequences for individuals, families, and communities. We explored whether older adults hospitalized with a primary diagnosis of EM was associated with an increased risk of mortality and unplanned hospital readmission compared to those with a secondary EM diagnosis. We further examined whether EM type and hospital setting was associated with risk of mortality and unplanned hospital readmission. Using 100% of 2015-2018 Medicare files of hospitalized Medicare Fee-for-Service beneficiaries aged 66 and over, we used Kaplan-Meier and Cox proportional hazard models to estimate mortality and unplanned readmission rates by primary versus secondary EM diagnosis, EM type, and facility type. 11,023 patients were hospitalized with an EM diagnosis. The majority were female (64.1%) and Non-Hispanic/Latinx White (74.3%). Neglect was the most common EM type. The three-year mortality rate was 56.7% and one-year readmission rate was 53.8%. Compared to other EM types, patients diagnosed with neglect had a 2.20 (95% Confidence Interval [CI]=1.88-2.56) and 3.21 (95% CI=2.32-4.43) times greater risk for mortality within and after 50-days from discharge, respectively. Patients discharged from a skilled nursing facility (SNF) were at an increased risk of mortality and unplanned readmission compared to those discharged from an acute hospital. Hospitalized patients with a primary EM diagnosis were associated with an increased risk of mortality and readmission compared to those with a secondary diagnosis. Future work should explore care patterns before and after EM diagnosis to identify potential time points for medical and social intervention.

Absorption-dominant EMI shielding polymer composite foams: Microstructure and geometry optimization

Absorption-dominant electromagnetic interference (EMI) shielding materials have garnered considerable attention to mitigate secondary EM pollution. The generation of a microcellular structure offers great promise in the development of absorption-dominant shielding materials. However, the underlying mechanisms governing the structure-EMI shielding properties relationship of microcellular shielding materials have rarely been studied. In this work, an input impedance model was applied to explore the thickness dependency of reflectivity (R) in microcellular conductive polymer composite (CPC) foams and then decouple the effect of thickness on the R-value from other structural variables, such as the void fraction (VF) and cellular morphology. As suggested by a theoretical model, PVDF/carbon nanotube (CNT)/SiC nanowire (SiCnw) composite foams having a 65% VF were fabricated. Absorption-dominant EMI shielding effectiveness was achieved by changing the foam thickness from 1.4 to 2.4 mm, with a decreased R-value from 0.63 to 0.48 and a correspondingly increased absorptivity/reflectivity (A/R) ratio from 0.53 to 1.07 (102%). Also, by increasing the VF from 0% to 85% while maintaining a constant cell size of around 10 μm, the optimal A/R ratio for each VF increased from 0.35 to 1.61. Furthermore, it was demonstrated that increased cell density in the cellular morphology with a fixed VF can create additional solid/air heterogeneous interfaces, promoting the EM wave attenuation capability via internal scattering and reflection of the incident EM waves. Consequently, this work allows for theoretically driven fabrication of absorption-dominant EMI shielding CPC foam with a tailored A/R ratio.

Evaluation, fabrication and dynamic performance regulation of green EMI-shielding materials with low reflectivity: A review

Electromagnetic interference (EMI) shielding materials have been employed to diminish environmental electromagnetic radiations by reflecting and absorbing transmitted EM wave. However, most of the researchers focus on improving the electrical conductivity of the materials, which is conducive to improving EMI shielding performance, but it will also increase the EM reflection, leading to the inevitable secondary EM pollution. Therefore, it is momentous to develop novel green EMI shielding materials with low reflectivity for environmentally friendly applications. In this review, we introduce the evaluation methods and influence factors of low-reflectivity green EMI shielding materials. Subsequently, the recently reported fabrication approaches as well as the corresponding EMI shielding performance and mechanism in regards to the low-reflectivity green EMI shields are summarized, and the ways for dynamic performance regulation of recently reported EMI shielding materials are concluded as well. Finally, the extant challenges of design and fabrication for low-reflectivity EMI shielding materials needed to be concerned are proposed, and the research tendency of low-reflectivity EMI shielding materials are prospected.

A controllable gradient structure of hydrophobic composite fabric constructed by silver nanowires and polyvinylidene fluoride microspheres for electromagnetic interference shielding with low reflection

Electromagnetic interference (EMI) shielding fabrics with high electrical conductivity generally could result in massive reflection and secondary EM radiation pollution. It is necessary to develop excellent EMI shielding fabrics with low surface reflection. A flexible EMI cotton composite with good hydrophobic performance was realized by constructing positive silver nanowires (AgNWs) gradient and negative poly(vinylidene fluoride) (PVDF) microspheres gradient via simple dip-coating method, which was automatically formed because of the gravity effect. The positive gradient structure of AgNWs ensured the good EMI shielding performance with a low surface reflection loss. The EMI shielding effectiveness (SE) values of Cotton/AgNWs/PVDF@GO composite fabrics exceeded 50 dB with power coefficient of reflectivity of only 0.39 at 10 GHz. Meanwhile, the negative PVDF microspheres gradient provided a hydrophobic surface on cotton. This work provides a novel strategy for fabricating EMI shielding fabrics with low reflection and high hydrophobic performance that suitable for application in wearable and portable electronic devices.

Anisotropic cellulose nanofibril composite sponges for electromagnetic interference shielding with low reflection loss

With the development of the electronic industry bringing convenience to people, a series of caused electromagnetic pollution problems (e.g., electromagnetic interference (EMI)) have recently also become urgent tasks. In this work, an anisotropic composite sponge consisting of cellulose nanofibrils (CNFs) and chemical co-precipitated silver nanowire (AgNW)@Fe3O4 composites was successfully prepared. Due to the introduction of anisotropic structures and the synergistic effect among CNFs, AgNWs, and Fe3O4, this composite sponge exhibited low density (16.76 mg/cm3), good saturation magnetization (4.21 emu/g) and electrical conductivity (0.02 S/cm), and anisotropic EMI shielding ability. By adjusting the proportion (1:0.3) between AgNWs and Fe3O4 and their loading (0.15 vol%) inside the sponge, the reflection loss of the sponge with the improved interface impedance mismatch was only 2.3 dB, accounting for 7.2% of the total loss. It is expected to become a promising EMI shielding material, especially for effectively alleviating the secondary reflection EM pollution.

Light-weight and flexible silicone rubber/MWCNTs/Fe3O4 nanocomposite foams for efficient electromagnetic interference shielding and microwave absorption

Light-weight and flexible methyl vinyl silicon rubber (VMQ)/multi-walled carbon nanotubes (MWCNTs)/ferriferrous oxide (Fe3O4) nanocomposite foams with efficient electromagnetic interference (EMI) shielding performance were firstly prepared by supercritical carbon dioxide (Sc-CO2) foaming process. The microwave-absorbing ability of the VMQ/MWCNTs/Fe3O4 foams has been greatly improved owing to the existence of cellular structure and magnetic Fe3O4 nanoparticles, thus significantly reducing the secondary EM wave pollution caused by reflection. These nanocomposite foams with density of ∼0.48 g−1 cm3 exhibited an EMI shielding effectiveness (SE) of 27.5 dB, and its average absorption ratio can reach up to 64% in the frequency range of 8.2–12.4 GHz. Such highly conductive (∼14.6 S/m) and specific EMI SE (∼72 dB·g−1cm3) can be obtained with filler loading of 1.78 vol%. Moreover, the flexible silicone rubber foams present excellent EMI shielding stability after repeated bending. The shielding mechanism of the composite foams was also discussed, and the results show that the main shielding mechanism of the foams was absorption with the addition of Fe3O4 nanoparticles. Furthermore, the foams exhibits excellent superparamagnetic and thermal properties, the maximum onset decomposition temperature can reach 467 °C. In view of the uncomplicated, low-cost and environmental protection preparation procedure, the light-weight, flexible, magnetic and highly conductive silicone rubber nanocomposite foams are expected to be used in lightweight and flexible electromagnetic shielding materials.

Risk Factors Associated with Development of Extramedullary Disease in Multiple Myeloma

Background Multiple myeloma (MM) is the second most common hematological malignancy characterized by plasma cell (PC) infiltration of the bone marrow. Unfortunately, better imaging techniques convey multiple reports about increased incidence of the so-called extramedullary disease of MM (EM), an aggressive, mostly resistant entity with poor prognosis for patients. EM probably develops because of ‘bone marrow escape’ of PC subclone that migrates out of the BM infiltrating soft tissues losing dependence on the BM microenvironment, either partially or completely. There are two types of EM - primary, found at the time of MM diagnosis, and secondary, found at the time of MM relapse. However, there are very few reports about EM.Aims This study aims to analyze risk factors connected to EM development.Methods Data from the Registry of Monoclonal Gammopathies (RMG) were analyzed. The RMG represents a database for collection of clinical data concerning diagnosis, treatment and follow-up of Czech MM and other monoclonal gammopathies patients. In total, data of 4985 MM patients were collected into the RMG database between 2007 and June 2017. Our analysis compared patients who developed EM at initiation of first or higher line of therapy with patients without EM during at least 5-year-long follow-up (patients who died earlier included). Logistic regression analysis was used to assess the association of baseline characteristics at MM diagnosis with EM occurrence at first line and relapse, respectively.Results In total, 4985 MM patients data were collected into the RMG database between 2007 and 2017. Patients were treated with bortezomib, lenalidomide, thalidomide, pomalidomide, ixazomib and daratumumab. Regardless of treatment, EM patients responded worse than MM patients did to any form of treatment. While primary EM patients had similar PFS as MM patients, OS was significantly worse (48.7 vs 60.6 months, resp.). Secondary EM patients did even worse, with PFS 8.7 months and OS 23.8 months only. We found 543 MM patients (10.9%) who developed EM during the entire follow-up. Out of these EM patients, we found 309 patients who were diagnosed with primary EM at initiation of first line of therapy. At initiation of 2nd line of treatment, we found 111 secondary EM patients. At 3rd, 4th and 5th, we found 61, 39 and 23 EM patients, resp. Finally, 309 patients who developed EM at initiation of 1st line and 234 patients who developed EM at initiation of further treatments were compared to 2092 patients who did not develop EM during the entire course of the disease. Overall, occurrence of EM at 1st or higher lines of treatment was associated with younger age, male sex, low ISS, D-S substage A, low B2 microglobulin, low creatinine, high hemoglobin, elevated thrombocytes, other types of M-Ig than IgG and presence of bone lesions. For EM cases found only at initiation of 1st line (primary EM), we found association with high ECOG status, low LDH, low M-protein quantity and low % of plasma cells infiltration in the bone marrow. For EM cases found at MM relapse (secondary EM), we found association with high D-S stage, high LDH, high CRP, high Ca, del13q and gain1q.Conclusion EM remains an aggressive disease with poor prognosis regardless of use of novel drugs. Surprisingly, in our group of patients, most EM disease developed early in the course of the disease - more than 60% at first relapse. We analyzed risk factors connected to development of EM and found that LDH, hemoglobin, thrombocytes and M-Ig status were associated with EM development. We suggest that in such patients, PET/CT or whole body MRI should be performed regularly to ensure early detection of EM.Grant support: AZV 17-29343A. DisclosuresMaisnar:BMS: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Hajek:Amgen: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding.

Can IT and ITES be an engine of growth for India: An empirical analysis

India emerged as one of the fastest growing economies of the world during the 1990s because of the spectacular dynamism shown by the services sector. India’s services sector has been burgeoning fast and one of the major driver’s of the growth of services sector is Information Technology (IT) and Information Technol ogy Enabled Services (ITES). It is well documented in literature that IT impacts growth by different channels. In this study we try to empirically verify the question: Can IT and ITES be an engine of growth? Using micro‐level data of 100 households of 20 IT and ITES firms along with secondary data we tried to estimate the extent of indirect employment generation at macro‐level and the share of IT and ITES in total employment and total value added. According to our study, one job for skilled professional employed in IT and ITES spins off jobs for 0.48 semi‐skilled, low skills or unskilled workers. As per our estimates, the 16 lakh workers who are expected to be directly employed in IT sector in the FY 2008 would generate secondary em ployment for 7,68,000 people which would constitute 0.16 per cent of total employment. However, the share of consumption expenditure of 16 lakh professionals would be 20 per cent of total value added. Assuming the consumption expenditure of the IT and ITES workers and total value added to be the same/constant when we tried to assess the contribution of consumption expenditure of 2.3 million workers (who are projected to be directly absorbed by IT sector by 2010, NASSCOM, 2005) to total value added it comes out to be 29 per cent of total value added. The study says that the proportion of IT‐ITES in total employment may be small but its contribution to total value added is still very high. Indeed IT and ITES can be an engine of growth in India’s economy by way of generating demand impulses in the economy as has been hypothesised and shown through the present study. Keeping in view the contributions of this sector and its huge untapped potential as evident from the present study and various other studies, there is a need for introduction and implementation of policy initiatives to address the challenges faced by this sector and to sustain the growth driven by the services sector.

Biological characterization of young and aged embryogenic cultures of Pinus pinaster (Ait.)

Pinus pinaster (Ait.) somatic embryogenesis (SE) has been developed during the last decade, and its application in tree improvement programs is underway. Nevertheless, a few more or less important problems still exist, which have an impact on the efficiency of specific SE stages. One phenomenon, which had been observed in embryogenic tissue (embryonal mass, EM) initiated from immature seed, has been the loss of the ability to produce mature somatic embryos after the tissue had been cultured for several months. In an attempt to get insight into the differences between young cultures of EM (3-mo-old since the first subculture) of P. pinaster that produced mature somatic embryos and the same lines of significantly increased age (18-mo-old, aged EM) that stopped producing mature somatic embryos, we analyzed in both types of materials the levels of endogenous hormones, polyamines, the global DNA methylation, and associated methylation patterns. In addition, we included in the analysis secondary EM induced from mature somatic embryos. The analysis showed that the two tested genotypes displayed inconsistent hormonal and polyamine profiles in EM cultures of a similar phenotype and that it might be difficult to attribute one specific profile to a specific culture phenotype among genotypes. Experiments were also undertaken to determine if the global DNA methylation and/or the resulting methylation pattern could be manipulated by treatment of the cultures with a hypomethylating drug 5-azacytidine (5-azaC). An aged EM was exposed to different concentrations and durations of 5-azaC, and its response in culture was established by fresh mass increases and somatic embryo maturation potential. All of the analyses are new in maritime pine, and thus, they provide the first data on the biochemistry of EM in this species related to embryogenic potential.

Induction of mixed erythroid-megakaryocyte colonies and bipotential blast cell colonies by recombinant human erythropoietin in serum-free culture

The effects of recombinant human erythropoietin (rEp) on murine hematopoietic progenitors were studied using a serum-free culture. A high concentration of rEp stimulated the formation of mixed erythroid- megakaryocyte colonies (EM colonies) and blast cell colonies, as well as erythroid colonies, erythroid bursts, and megakaryocyte colonies from normal mouse bone marrow cells. Direct effects of rEp on EM colony, megakaryocyte colony, and erythroid burst formation were confirmed by depletion of accessory cells such as T cells, B cells, and macrophages from crude bone marrow cells, and inhibition of the colonies by the addition of rabbit anti-rEp antibody to the culture in a dose-dependent fashion. Replating experiments were performed to confirm the differentiating ability of blast cell colonies grown in the presence of rEp. Most of the blast cell colonies yielded not only secondary erythroid colonies but also megakaryocyte colonies in the presence of 2 IU/mL rEp. Some of the blast cell colonies produced secondary EM colonies in the presence of 16 IU/ml rEp of 2 IU/mL rEp plus interleukin-3, although no granulocyte-macrophage colonies were found in the secondary culture. These results suggest that Ep acts not only as a late-acting factor that is specific for erythroid progenitors, but also as a bipotential EM-stimulating factor for murine hematopoietic cells.

Induction of Mixed Erythroid-Megakaryocyte Colonies and Bipotential Blast Cell Colonies by Recombinant Human Erythropoietin in Serum-Free Culture

The effects of recombinant human erythropoietin (rEp) on murine hematopoietic progenitors were studied using a serum-free culture. A high concentration of rEp stimulated the formation of mixed erythroid-megakaryocyte colonies (EM colonies) and blast cell colonies, as well as erythroid colonies, erythroid bursts, and megakaryocyte colonies from normal mouse bone marrow cells. Direct effects of rEp on EM colony, megakaryocyte colony, and erythroid burst formation were confirmed by depletion of accessory cells such as T cells, B cells, and macrophages from crude bone marrow cells, and inhibition of the colonies by the addition of rabbit anti-rEp antibody to the culture in a dose-dependent fashion. Replating experiments were performed to confirm the differentiating ability of blast cell colonies grown in the presence of rEp. Most of the blast cell colonies yielded not only secondary erythroid colonies but also megakaryocyte colonies in the presence of 2 IU/mL rEp. Some of the blast cell colonies produced secondary EM colonies in the presence of 16 IU/ml rEp of 2 IU/mL rEp plus interleukin-3, although no granulocyte-macrophage colonies were found in the secondary culture. These results suggest that Ep acts not only as a late-acting factor that is specific for erythroid progenitors, but also as a bipotential EM-stimulating factor for murine hematopoietic cells.

An Investigation of the Goodenough-Harris Drawing Test and the (Coopersmith) Self-Esteem Inventory

Two groups of educable mentally retarded (EMR) primary and secondary pupils were compared on measures of self-esteem and intelligence (IQ) to determine whether scores on a self-drawing test and those on a self-perception test were related. The results of the Pearson product-moment correlations revealed for the secondary EM R subjects a significant relationship between scores on the Goodenough-Harris Drawing Test (DT) and those on the Self-Esteem Inventory (SEI).

The CSIRO Electromagnetic Scale Modelling Facility

Scale model studies may be used to determine the structure of secondary EM fields for geometries where the mathematical approach is unreasonably difficult or requires independent verification. To encompass the wide range of EM techniques used by industry and to enable realistic traverses to be simulated, a model facility of considerable physical size must be employed. Such a facility is now operational at the CSIRO Division of Mineral Physics. At a typical scale factor of 300:1 the model can simulate surface or airborne traverses over 1 km in length and borehole logs beyond 600 m in depth. The model facility features accurate positioning of the scale sensors in three axes, computer-based traverse control and data acquisition. Target and host can be accurately simulated with a wide variety of materials. Up to four distinct conductivities can be currently used at reasonable scale factors. This is achieved with the assistance of synthetic conducting material whose conductivity can be controlled over a range to fill the gap between electrolytes and graphite. The physical size of the facility is such that reasonable scale factors and operating frequencies enable field situations to be modelled with common electrolytes and the synthetic material.