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In everyday life, people generally wear two layers of clothes (a knitted vest and a knitted t-shirt) during the summer. It is essential to understand which types of innerwear and outerwear maximize comfort. The primary objective of this research is to investigate the influence of layering outerwear on innerwear, as well as the air gap between two layers, on thermal comfort properties.

In this study, a total of 12 combinations were created from four vest fabrics and three T-shirt fabrics. The thermal properties (thermal conductivity, thermal resistance, thermal absorptivity, thermal diffusion and peak heat flow) were evaluated for the individual inner and outer layers. Each inner layer was layered with an outer layer to observe the effect of layering on the thermal properties. An air gap of 2 mm was introduced between the inner and outer layers to study the effect of air gap on thermal properties.

Tencel fibre exhibits higher thermal conductivity and absorptivity than cotton and polyester. Upon layering an outer layer on an inner layer, the thermal conductivity and thermal absorptivity increase to a slight extent, thermal resistance and diffusion increase drastically and the peak heat flow reduces. With an air gap between the two layers, the thermal conductivity did not improve, the difference in thermal resistance among all the combinations reduced, the thermal absorptivity of the combination textiles was lower than that of the innerwear alone, the thermal diffusion increased and the peak heat flow diminished for all the combinations.

In practice, this comprehensive thermal comfort analysis provides specific combinations of inner and outer articles of clothing that are most appropriate for enhancing comfort during the summer season.

Though there are many studies on the effect of multilayer fabrics on thermal properties, no extensive research analyses the influence of innerwear and outerwear combinations on thermal comfort properties.

Modern wireless communications need novel microwave components that can be effectively used for high data rate and low-power applications. The operating environment decides the severity of the noise coupled to the transceiver system from the ambient environment. In a deep fading environment, narrowband systems fail where the wideband systems come for rescue. Thus, the microwave components are ought to switch between the narrowband and wideband states. This paper aims to study the design of a bandpass filter to meet the requirements by appropriately switching between the dual narrowband frequencies and single ultra-wideband frequency band.

The design and implementation of a compact microwave filter with reconfigurable bandwidth characteristics are presented in this paper. The proposed filter is constructed using a hexagonal ring with shorted perturbation along one corner. The filter is capacitively coupled to the external excitation source. External stubs are connected to the corners of the hexagonal resonator to obtain dual passband characteristics centred at 2.1 and 4.5 GHz. The external stubs are configured to achieve bandwidth reconfigurable characteristics. PIN diodes are used with a suitable biasing network to obtain reconfiguration. In the reconfigured state, the proposed two-port filter offers a continuous bandwidth from 2.1 to 5.9 GHz. The roll-off rate along the band edges is improved by increasing the order of the filter.

The proposed filter operates in two states. In state 1, the filter operates with dual frequencies centred around 2 and 4.5 GHz with insertion loss less than <1 dB and return loss greater than 13 dB with a peak return loss of 21 and 31 dB at 2.1 and 2.15 GHz, respectively. In state 2, the filter operates from 2.1 to 5.9 GHz with insertion loss less than 1 dB and return loss greater than 12 dB. The filter exhibits four-pole characteristics with a peak return loss greater than 22 dB. Thus, the fractional bandwidth of the proposed filter is 17% and 16% in state 1, whereas the fractional bandwidth is 95% in state 2.

The proposed filter is the first of its kind to simultaneously offer miniaturization and bandwidth reconfiguration. The proposed second-order filter has two-pole characteristics in the narrowband state, whereas four-pole characteristics are realized in the wideband state. The growing interest in 4G and 5G wireless communications makes the proposed filter a suitable candidate for operation in the rich scattering environment.

Corrosion sensors and networks are the most effective techniques to obtain the corrosion information and recognize the corrosion status of reinforced concrete structures. However, reference electrode is the key element to provide the baseline for potential control of the corrosion monitoring sensors during corrosion measurement process. Therefore, the purpose of this paper is to provide the novel solid‐state reference electrode for the corrosion sensors.

A solid‐state Ag/AgCl reference electrode has been prepared. Furthermore, the performance of the reference electrode, such as stability, temperature response, anti‐polarization and influence of the concrete admixture, has been investigated.

The results indicate that the balance potential and the temperature coefficient of the reference electrode are 3.64±1mv (vs. SCE) at 25°C and −0.51 mv/°C±0.03 mv/°C, respectively. Furthermore, the polarization curve exhibits characteristics of three stages as the polarization current is in (−10μA/cm2,+10μA/cm2). Additionally, the reference electrode is insensitive to the concrete admixtures which include Na2SO4, NaCl, NaNO3 and NaNO2.

The research provides the key element for the corrosion monitoring sensors to integrate structural health monitoring system in future.

The term microbiologically induced corrosion (MIC) appears to be very closely related to the composition of the bio‐film which harbours the micro‐organism. Formation of an initial slimy layer on immersed metallic substrates is the rate‐controlling parameter of bio‐fouling, as uninterrupted undesirable growth of bio‐films occurs over this layer. To contain this bio‐film problem, formation of an adherent layer of toxic and inhibited corrosion product, that interacts with biofilm, could be exploited. Deals with the preliminary interactions of a few copper‐based alloys, with mildly toxic alkaloid class‐inhibitive compounds, in a simulated marine environment. It is assumed that the toxic and inhibited corrosion product and bio‐film interaction layer will interfere with the formation of the initial slimy cover on the immersed surface, responsible for bio‐fouling. It is seen that these alkaloid compounds exert a limited response on the inhibition of copper‐based alloys like monel. Brucine appears to be a more effective inhibitor for the monel surface. Pre‐oxidation of the uninhibited brass surface and also post‐oxidation of the inhibited surface appear to consolidate the corrosion product bio‐film‐inhibitor interaction layers, indicating the compatibility of these alkaloid compounds to the probable thermal strains to be encountered in engineering services. This indicates the possibility of using these compounds in heat transfer devices, like heat exchangers, where seawater is used as coolant.

Phosphonic acids are good complexing agents. However, they are not good as inhibitors except for a very few. Synergistic inhibition is offered in the presence of metal cations like Ca²⁺, Mg²⁺, Zn²⁺ and others in neutral media. The zinc ion is an ideal choice. The part of zinc ions are now replaced by polymers, azoles to prepare eco‐friendly inhibitor formulations. They are also used as corrosion inhibitors in concrete, coatings, rubber blends, acid cleaners, anti‐freeze coolants, etc. Discusses the various applications of phosphonic acids and their action mechanisms.

Besides with a large amount of Na⁺ and Cl⁻ ions in seawater, the presence of Mg⁺² and SO₄⁻² ions builds more complex corrosion mechanism. This paper aims to investigate the corrosion of embedded reinforcement in concrete with the environment of both Cl⁻ and SO₄⁻² anions associated Mg⁺² cation.

The concrete specimens were prepared by using ordinary Portland cement (OPC), and OPC blended with metakaolin (MK) for water to cementitious material ratio (w/cm) 0.48 and 0.51. The concrete mixes were contaminated with the addition of MgCl₂ alone and combined MgCl₂ and MgSO₄ in mix water. Reinforcement corrosion was evaluated by half-cell potential and corrosion current densities (I_corr) at regular intervals. Moreover, the influence of cementitious material type, salt type and w/cm ratio on electrical resistivity of concrete was also investigated. The statistical models were developed for electrical resistivity as a function of calcium to aluminium content ratio, compressive strength, w/cm ratio and age of concrete.

Although the corrosion initiation time increases in the concomitant presence of MgSO₄ and MgCl₂ as internal source compared to MgCl₂, I_corr values are higher in both OPC and MK blended concrete. However, electrical resistivity decreased with addition of MgSO₄. MK blended concrete performed better with increased resistivity, corrosion initiation time and decreased I_corr values.

This study reports statistical distributions for scattered I_corr of rebar in different concrete mixtures. Stepwise regression models were developed for resistivity by considering the interactions among different variables, which would help to estimate the resistivity through basic information.

The inhibition efficiencies of ethyl phosphonic acid (EPA) and 2‐chloroethyl phosphonic acid (2‐Cl EPA) in the presence of Zn²⁺, in controlling the corrosion of mild steel in a neutral aqueous environment containing 60ppm Cl^‐ have been evaluated by weight‐loss method and compared. It is observed that 2‐Cl EPA‐Zn²⁺ system has more inhibition efficiency than an EPA‐Zn²⁺ system. It is due to the electron withdrawing power of the Cl atom and its size. The nature of the protective film formed on the surface of the metal has been analysed by X‐ray diffraction, uv‐visible reflectance and luminescence spectra.

The formulation consisting of 50ppm polyacrylamide (PAA), 300ppm phenyl phosphonic acid (PPA) and 50ppm Zn²⁺ has 95 per cent inhibition efficiency in controlling corrosion of mild steel in a neutral aqueous environment, containing 60ppm Cl^—, a situation commonly encountered in cooling water systems. A discussion of mechanistic aspects of corrosion inhibition is based on the results obtained from a potentiostatic polarization study, UV‐visible, FTIR and luminescence spectra. The protective film is found to be luminescent and to consist of Fe²⁺‐PAA complex, Fe²⁺‐PPA complex and Zn(OH)₂.

In smart cities striving for innovation, development, and prosperity, hydrogen offers a promising path for decarbonization. However, its effective integration into the evolving energy landscape requires understanding regional intricacies and identifying areas for improvement. This chapter examines hydrogen transport from production to utilization, evaluating technologies’ pros, cons, and process equations and using Analytic Hierarchy Process (AHP) as a Multi-Criteria Decision-Making (MCDM) tool to assess these technologies based on multiple criteria. It also explores barriers and opportunities in hydrogen transport within the 21st-century energy transition, providing insights for overcoming challenges. Evaluation criteria for hydrogen transport technologies were ranked by relative importance, with energy efficiency topping the list, followed by energy density, infrastructure requirements, cost, range, and flexibility. Safety, technological maturity, scalability, and compatibility with existing infrastructure received lower weights. Hydrogen transport technologies were categorized into three performance levels: low, medium, and high. Hydrogen tube trailers ranked lowest, while chemical hydrides, hydrail, liquid organic hydrogen carriers, hydrogen pipelines, and hydrogen blending exhibited moderate performance. Compressed hydrogen gas, liquid hydrogen, ammonia carriers, and hydrogen fueling stations demonstrated the highest performance. The proposed framework is crucial for next-gen smart cities, cutting emissions, boosting growth, and speeding up development with a strong hydrogen infrastructure. This makes the region a sustainable tech leader, improving air quality and well-being. Aligned with Gulf Region goals, it is key for smart cities. Policymakers, industries, and researchers can use these insights to overcome barriers and seize hydrogen transport tech opportunities.

The influence of a cationic surfactant, N‐cetyl‐N, N, N‐trimethyl ammonium bromide (CTAB) on the inhibition efficiency (IE) of calcium gluconate (CG) – Zn²⁺ system in controlling corrosion of mild steel in a neutral aqueous environment containing 60ppm Cl^‐ has been evaluated by weight‐loss method. The formulation consisting of 200 ppm CG and 50ppm Zn²⁺ has 86 per cent IE (immersion period = three days). Addition of various concentrations of CTAB to the above system improves the IE to 99 per cent. Presence of CTAB facilitates the transport of CG and Zn²⁺ from the bulk of the solution to the metal surface. The nature of the protective film formed on the surface of mild steel has been analysed by FTIR and fluorescence spectra. The protective film is found to be fluorescent and to consist of iron‐CG complex, iron‐CTAB complex and Zn(OH)₂.