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This paper reports the results of development work conducted on nitrogen‐based atmospheres in order to improve the firing of copper thick film systems through continuous furnaces. The proposed solution is particularly suitable for industrial production conditions since it allows variations of the material quantity processed per unit time, resulting not only in an improvement in quality but also in productivity. Such improvements have been achieved by using a new gas distribution system which provides both zone control and regulation of oxygen additions in the nitrogen furnace atmosphere. An efficient set‐up of this system has become possible thanks to precise control of the oxygen profile in relation to the temperature cycle, taking into account various inks' characterisation, and owing to an extensive study of the effects of oxygen additions on copper thick film properties. The solution was tested in a muffle‐lined belt furnace with several commercial dielectric and copper inks, and for increasing oxygen additions into the furnace preheat zone. Different sample patterns were designed to test both monolayer and multilayer systems. The test programme includes measurements of resistivity, bondability, solderability, dielectric breakdown voltage and adhesion of copper films on alumina and on dielectric layers before and after ageing. Ink characterisation by thermogravimetry and by several gas analyses has confirmed that the organic vehicle removal mechanism under nitrogen atmospheres doped with oxygen is a burnout. Indeed, significant oxygen consumption occurs within the temperature range of the removal, as a function of the amount of ink processed. Oxygen additions in the furnace burnout zone greatly improve both the dielectric breakdown voltage and the adhesion of copper on alumina and on dielectric (especially after ageing), while sheet resistivity, wire bondability and soft solderability are not altered below a defined O2 level. It is therefore possible to determine an optimum oxygen addition range for which the thick films fired under such conditions will have the best characteristics. This optimum oxygen window is achieved thanks to a new regulation system which operates whenever variations occur in the quantity of paste processed.

A new proprietary nitrogen‐based atmosphere control system (Alix 1) has been developed by L'Air Liquide, allowing control and regulation of the oxygen partial pressure in the burnout zone of a copper thick‐film firing furnace. The results of a collaboration programme whose objective was to test this system in industrial production conditions at Power Compact are presented. Use of this new system enables improvement of the adhesion results reached by this company in their copper thick‐film hybrid production and ensures a constant level of performance.

THE partial pressure of the oxygen content in the atmosphere decreases directly with the atmospheric pressure, i.e., with the altitude, the proportion of oxygen in the atmosphere (about 20·9 per cent) remaining practically constant in the substratosphere.

This case is based on a project carried out in a tertiary care hospital of the Northeastern region of India for a period of eight months and is written by Dr Ankit Singh, Dr Meenal Kulkarni and Mr Avinash Poojari. The case was developed with the help of the hospital’s management team, disguised on request as Mr Raghugopal Ramalinga (Chief Hospital Administrator), Mr Suresh Kumar (Chief Engineer), Ms Linney Krubah (Chief Nursing Superintendent), Dr Premanand Ale (Chief Medical Superintendent) and Mr Srikrishna Shukla (Chief Finance Officer).

This case is about Trident Hospital, which faces issues pertaining to oxygen supply. Oxygen supply at Trident Hospitals is through three options as highlighted in the case, but due to the lack of preventive maintenance and no risk assessment done for the crucial medical oxygen, interruptions and additional work for the staff became a common phenomenon. The existing situation can lead to patient harm or death and can attract medico-negligence suit against the hospital, threatening the overall existence of the hospital. The hospital administrator is currently viewing the problem from only the cost perspective, which is a high-risk and a short-term approach.

Students pursuing full time/part time/diploma programme in health-care management, hospital administration/hospital operations; and undergraduate and post-graduate level students.

This study aims to explore magnetohydrodynamic (MHD) thermo-bioconvection of oxytactic microorganisms in multi-physical directions addressing thermal gradient, lid motion, porous substance and magnetic field collectively using a typical differentially heated two-sided lid-driven cavity. The consequences of a range of pertinent parameters on the flow structure, temperature, oxygen isoconcentration and microorganisms’ isoconcentration are examined and explained in great detail.

Two-dimensional governing equations in a two-sided lid-driven porous cavity heated differentially and packed with oxytactic microorganisms under the influence of the magnetic field are solved numerically using the finite volume method-based computational fluid dynamics code. The evolved flow physics is analyzed assuming a steady laminar incompressible Newtonian flow within the validity of the Boussinesq approximation. The transport of oxytactic microorganisms is formulated by augmenting the continuum model.

The mechanisms involved with MHD-mixed thermo-bioconvection could have potential benefits for industrial exploitation. The distributions of fluid flow, temperature, oxygen and motile microorganisms are markedly modified with the change of convection regime. Both speed and direction of the translating walls significantly influence the concentration of the motile microorganisms. The concentration of oxygen and motile microorganisms is found to be higher at the upper portion of the cavity. The overall patterns of the fluid flow, temperature and the oxygen and microorganism distributions are markedly affected by the increase of magnetic field strength.

The concept of the present study could be extended to other areas of bioconvection in the presence of gravity, light or chemical attraction.

The findings of the present study could be used to multi-physical applications like biomicrosystems, pollutant dispersion in aquifers, chemical catalytic converters, geothermal energy usage, petroleum oil reservoirs, enhanced oil recovery, fuel cells, thermal energy storage and others.

The MHD-mixed thermo-bioconvection of oxytactic microorganisms is investigated under different parametric conditions. The effect of pertinent parameters on the heat and mass transfers are examined using the Nusselt number and Sherwood number.

The purpose of this study is to address magnetohydrodynamic (MHD) bioconvection caused by the swimming of oxytactic microorganisms in a linearly heated square cavity filled with porous media and Cu–water nanofluid. The effects of different multiphysical aspects are demonstrated using local distributions as well as global quantities for fluid flow, temperature, oxygen concentration and microorganisms population.

The coupled transport equations are converted into the nondimensional partial differential equations, which are solved numerically using a finite volume-based computing code. The flow of Cu–water nanofluid through the pores of porous media is formulated following the Brinkman–Forchheimer–Darcy model. The swimming of oxytactic microorganisms is handled following a continuum model.

The analysis of transport phenomena of bioconvection is performed in a linearly heated porous enclosure containing Cu–water nanofluid and oxytactic microorganisms under the influence of magnetic fields. The application of such a system could have potential impacts in diverse fields of engineering and science. The results show that the flow and temperature distribution along with the isoconcentrations of oxygen and microorganisms is markedly affected by the involved governing parameters.

Similar study of bioconvection could be extended further considering thermal radiation, chemical attraction, gravity and light.

The outcomes of this investigation could be used in diverse fields of multiphysical applications, such as in food industries, chemical processing equipment, fuel cell technology and enhanced oil recovery.

The insight of the linear heating profile reveals a special attribute of simultaneous heating and cooling zones along the heated side. With such an interesting feature, the MHD bioconvection of oxytactic microorganisms in nanofluid-filled porous substance is not reported so far.

The purpose of this paper is to investigate the bioconvection flow in a porous square cavity saturated with both oxytactic microorganism and nanofluids.

The impacts of the effective parameters such as Rayleigh number, bioconvection number, Peclet number and thermophoretic force, Brownan motion and Lewis number reduces the flow strength in the cavity on the flow strength, oxygen density distribution, motile isoconcentrations and heat transfer performance are investigated using a finite volume approach.

The results obtained showed that the average Nusselt number is increased with Peclet number, Lewis number, Brownian motion and thermophoretic force. Also, the average Sherwood number increased with Brownian motion and Peclet number and decreased with thermophoretic force. It is concluded that the flow strength is pronounced with Rayleigh number, bioconvection number, Peclet number and thermophoretic force. Brownan motion and Lewis number reduce the flow strength in the cavity.

There is no published study in the literature about sensitivity analysis of Brownian motion and thermophoresis force effects on the bioconvection heat transfer in a square cavity filled by both nanofluid and oxytactic microorganisms.

This paper aims to investigate the effect of introducing nano-ceria (CeO₂) particles to the epoxy coatings on mild steel in natural seawater.

The epoxy–ceria nanoparticles were coated with mild steel using a wire-wound draw-down bar method. The effects of ceria nanoparticles on the corrosion resistance of epoxy-coated samples were analyzed using scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS).

Localized measurements such as oxygen consumption and iron dissolution were observed using SECM in natural seawater in the epoxy-coated sample. The increase in film resistance (R_f) and charge transfer resistance (R_ct) values by the addition of nano-ceria particles in the epoxy coating was measured from EIS measurements after wet and dry cyclic corrosion test. Scanning electron microscope (SEM)/energy dispersive X-ray spectroscope (EDX) analysis showed that complex oxides of nano-ceria were enriched in corrosion products at a scratched area of the coated mild steel after corrosion testing. Focused ion beam-transmission electron microscope (FIB-TEM) analysis confirmed the presence of the nanoscale oxide layers of ceria in the rust of the steel.

The tip current at −0.70 V for the epoxy–CeO₂-coated sample decreased rapidly because of cathodic reduction of the dissolved oxygen. The increase in film resistance (R_f) and charge transfer resistance (R_ct) values by the addition of nano-ceria particles in the epoxy coating were measured from EIS measurements after wet and dry cyclic corrosion test.

The presence of complex oxide layers of nano-ceria layers protects the coated steel from rusting.

The use of this nano-ceria for corrosion protection is environment-friendly.

The results of this study indicated the significant effect of nano-ceria particles on the protective performance and corrosion resistance of the epoxy coating on mild steel. The dissolution of Fe²⁺ was lower in the epoxy–ceria nanoparticle-coated mild steel than that of the epoxy-coated mild steel resulting in a lower anodic current of steel. The increase in film resistance and the charge transfer resistance showed that the nano-ceria particles and the formation of complex oxides provide better barrier protection to the coating metal surfaces.

Recently, the constrained surface projection stereolithography (SL) technology is gaining wider attention and has been widely used in the 3D printing industry. In constrained surface projection SL systems, the separation of a newly cured layer from the constrained surface is a historical technical barrier. It greatly limits printable size, process reliability and print speed. Moreover, over-large separation force leads to adhesion failures in manufacturing processes, causing broken constrained surface and part defects. Against this background, this paper investigates the formation of separation forces and various factors that affect the separation process in constrained surface projection SL systems.

A bottom-up projection SL testbed, integrated with an in-situ separation force measurement unit, is developed for experimental study. Separation forces under various manufacturing process settings and constrained surface conditions are measured in situ. Additionally, physical models are constructed by considering the liquid resin filling process. Experiments are conducted to investigate influences of manufacturing process settings, constrained surface condition and print geometry on separation forces.

Separation forces increase linearly with the separation speed. The deformation and the oxygen inhibition layer near the constrained surface greatly reduce separation forces. The printing area, area/perimeter ratio and the degree of porousness of print geometries have a combined effect on determining separation forces.

This paper studied factors that influence separation force in constrained surface SL processes. Constrained surface conditions including oxygen inhibition layer thickness, deformation and oxygen permeation capability were investigated, and their influences on separation forces were revealed. Moreover, geometric factors of printing layers that are significant on determining separation forces have been identified and quantified. This study on separation forces provides a solid base for future work on adaptive control of constrained surface projection SL processes.

Food—national dietary standards—is a sensitive index of socio‐economic conditions generally; there are others, reflecting different aspects, but none more sensitive. A country that eats well has healthy, robust people; the housewife who cooks hearty, nourishing meals has a lusty, virile family. It is not surprising, therefore, that all governments of the world have a food policy, ranking high in its priorities and are usually prepared to sacrifice other national policies to preserve it. Before the last war, when food was much less of an instrument of government policy than now—there were not the shortages or the price vagaries—in France, any government, whatever its colour, which could not keep down the price of food so that the poor man ate his fill, never survived long; it was—to make use of the call sign of those untidy, shambling columns from our streets which seem to monopolize the television news screens—“out!” Lovers of the Old France would say that the country had been without stable government since 1870, but the explanation for the many changes in power in France in those pre‐war days could be expressed in one word—food!