Doped polypyrrole for MAPLE deposition: Synthesis and characterization

The contribution deals with synthesis and characterization of conductive polypyrrole (PPY), which should be suitable for depositions of thin layers by Matrix Assisted Pulsed Laser Evaporation (MAPLE) method. The samples of doped PPY containing various organic dopants – (i) p-toluenesulfonic acid, (ii) dodecyl-benzenesulfonic acid, (iii) dioctyl-sulfosuccinic acid and (iv) camphorsulfonic acid – were synthesized by polymerization of pyrrole in acidic or neutral solution. Solubility of synthesized PPY and settlement time of PPY particles in water and dimethylsulfoxide – parameters critical for MAPLE method – were investigated. The composition of prepared PPY was verified by FTIR spectroscopy. Conductivity of the polymer in solid state was determined to be in range from σ = 2.6 × 10^?6 S cm^?1 to σ = 6.0 × 10^?2 S cm^?1. The optimal material for MAPLE deposition is PPY containing organic dopants (ii)–(iv), dissolved in DMSO matrix (solubility from 4.1% to 6.5% by weight and settlement time 140–240 h).     

Polymer anion selective membranes for electrolytic splitting of water. Part I: stability of ion-exchange groups and impact of the polymer binder

In this study, the chemical stability of three types of the anion-exchange functional groups in an alkaline environment was tested. The following groups were selected for the test: trimethylbenzylammonium, methyl pyridinium, and tributhylbenzylphosphonium. A KOH solution with various concentrations and temperatures was used as the environment. The trimethylbenzylammonium group showed the highest stability of the materials tested under conditions relevant to water electrolysis. In the next step, four types of polymeric binders, including ethylene-co-methacrylic acid, linear polyethylene, linear polyethylene blended with poly(ethylene-co-vinylalcohol), and low-density polyethylene, were selected to determine their impact on the resulting electrochemical properties of a heterogeneous membrane. This study reveals the morphology of the membrane, ion-exchange capacity, ionic conductivity, and performance in alkaline water electrolysis conducted on a laboratory scale. The material showing the most promising properties was selected for further optimization and testing.     

Combined design and load shifting for distributed energy system

Renewable distributed energy generation (DEG) system plays an important role in future power developments and is one of the options to reduce energy consumption. It is envisaged that energy efficiency of DEG systems can be improved via load shifting (LS). This study proposed a heuristic-based numerical approach to perform LS analysis on renewable stand-alone DEG systems. The technique is an extension from a method known as the Electric System Cascade Analysis (ESCA). The new technique, which focuses on efficient electricity utilisation is able to determine the optimal: (i) load profiles, (ii) capacity of power generator, (iii) capacity and power of energy storage (ES) and (iv) charging/discharging schedule of ES. The stage-wise technique allows user to compare and determine the optimal design in a flexible way while having a better understanding of the selection of options. The application of ESCA-LS on a case study revealed that after incorporation of direct LS (load manipulation) in addition to LS by ES (supply manipulation), the power generators and ES capacity can be further reduced. While reduction of 3.1 % for solar-PV installation area and 3.9 % for biomass power generator is recorded, ES power-related capacity and energy-related capacity managed a higher reduction of up to 19.0 and 13.2 % for the main case study     

Swelling and photoelastic behaviour of ionized hydrogels of poly(acrylic acid)

Summary The photoelastic and swelling behaviour of poly(acrylic acid) gels swollen in 1 M NaCl aqueous solution was studied as a function of crosslinking degree (1–5 wt.% ethylene glycol dimethacrylate) and degree of ionization _g = 0 – 1. The degree of swelling passes through a minimum at _g – 0.15 regardless of the degree of crosslinking, probably due to the formation of hydrogen bonds between ionized and nonionized carboxyl groups. In the same neutralization region, the equilibrium modulus reaches a maximum; on the other hand, the modulus related to the dry state is independent of for all crosslinker concentrations. Thus the mechanical behaviour of poly(acrylic acid) gels is in accord with the Gaussian theory and no contribution of permanent physical interactions to the modulus is observed. The optical behaviour is more complex — the sign of the stress-optical coefficient C _e changes three times with increasing due to the orientation of the side groups. The analysis of the optical data shows that the C _e value is controlled by the degree of swelling and by the ionization.     

Influence of fatty acids content in non-edible oil for biodiesel properties

Physical and chemical properties of biodiesel are influenced by the structural features of fatty acid, such as with saturated, monounsaturated and polyunsaturated fatty acids. In this study, seven non-edible oils have been selected, which include waste cooking oil derived palm olein, Calophyllum inophyllum, jatropha oil, castor oil, rubber seed oil, kapok seed oil and karanja oil. The critical parameters, e.g. cetane number (CN), iodine value (IV) and oxidation stability (OS) of biodiesel were correlated with the degree of unsaturated (DU) fatty acid, whereas the cold filter plugging point (CFPP) was correlated with the long chain saturated factor (LCSF). To meet the minimum EU requirement of EN 14214 of the critical parameter, the DU value of the CN was ≤133.5, IV ≤123.2 and OS ≤98.9. The LCSF values satisfied the Spanish regional standard—RD 61/2006 in summer (0 °C) at ≤8.4 and winter (?10 °C) at ≤0.1 of the CFPP. Based on the composition of the saturated, monounsaturated and polyunsaturated fatty acids, a triangular chart for the biodiesel property prediction was developed. This can then be used as a reference for non-edible oils.     

Optimal heat exchanger network synthesis with operability and safety considerations

Research on the optimal design of heat exchanger networks (HENs) has primarily revolved around trading off technical design requirements for aspects of economy, such as capital cost of heat exchangers and utilities. As a result, considerations for safety, operability, and flexibility have received much less attention. This study presents a Pinch Analysis-based methodology that considers the inherent safety and operability aspects of an optimal HEN design. The procedure begins with data extraction, followed by utility targeting that gives due consideration to how each process stream impacts the inherent safety of the HEN. This is made possible via the use of a hot and cold Stream Temperature versus Enthalpy Plot (STEP) that prioritises the inherent safety index (ISI) on top of the heat capacity flow rate (CPs) during simultaneous targeting and design of the HEN. The Pinch temperatures and minimum utilities were determined using STEP. At the same time, the hot and cold stream pairs with higher ISIs and those with lower ISIs were matched together so that safety considerations could be emphasised and precautions taken with a particular heat exchanger. The disturbance propagation path through the HEN and the affected streams were also analysed. Network modification was performed using the downstream path concept in order to reduce disturbance propagation downstream of the HEN. The ?T _min violations and energy penalties from network changes were assessed. Flexibility and structural controllability of each network option were compared. The highest percentage of change in every stream of the network indicates that network is the most flexible, while the index of structural controllability closest to 1 demonstrates that the network is most controllable. Application of this method within an illustrative case study showed that network 3 was the most flexible as it yielded the highest percentage of change at 22 %. It was also the most controllable as it had a controllability index closest to 1.0, i.e. at 0.917.     

Zum mechanismus des elektropolierens von metallen

This book deals with the study of the electrode processes that occur on iron and nickel during their electro-polishing in alcoholic sulphic acid solution.     

Investigation of the compressible flow through the tip-section turbine blade cascade with supersonic inlet

The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade.