Characteristics and Energy Efficiency of the Industrial Concentrators with Thermocompression

An analysis of the thermal characteristics of the industrial thermocompression heat pump systems is presented in this paper By using thermocompression, waste heat is thermotransformed to a higher temperature level to be convenient for its usage in thermal processes. The thermocompression heat pumps can be optimally applied in various industrial plants （production of fruit, grape and tomato concentrates, in beer, sugar and dairy industries, in chemical and pharmaceutical industries etc.）. The range of optimal application of the turbo compressor, screw compressor and ejector thermocompression is estimated. The complex thermal and flow phenomena in the processes of thermocompression, evaporation and condensation are discussed. The theoretical and experimental results of the investigations on the experimental grape vacuum concentrator and on the industrial NaOH concentrator are presented. A significant increment of the energy efficiency can be achieved by optimal application of the thermocompression in the thermal concentrating processes. A significant feature and great advantage of the concentrating technology with thermocompression are a possibility for realization of the low temperature concentrating processes, which is very important for the quality of many concentrating products with high energy efficiency technology.

Effect of Recycling Cycles on the Mechanical and Damping Properties of Flax Fibre Reinforced Elium Composite:Experimental and Numerical Studies

This manuscript deals with the effects of recycling on the static and dynamic properties of flax fibers reinforced thermoplastic composites.The corresponding thermoplastic used in this work is Elium resin.It’s the first liquid thermoplastic resin that allows the production of recycled composite parts with promising mechanical behavior.It appeared on the resin market in 2014.But until now,no studies were available concerning how it can be recycled and reused.For this study,a thermocompression recycling process was investigated and applied to Elium resin.Flax fiber-reinforced Elium composites were produced using a resin infusion process and were subjected to different thermomechanical recycling operations.For each material,five recycling operations were carried out on the raw material.A total of 10 different materials were investigated and tested by means of tensile and free vibration tests to evaluate the effect of recycling on their behavior.In addition,a finite element model of the dynamic problem was developed to evaluate the loss factor and natural frequencies regarding different cases.The results obtained show that the failure tensile properties of Elium resin as well as flax fiber reinforced composites decrease during recycling operations.Conversely,recycling induces a rise in the elastic modulus.Moreover,improvement in the dynamic stiffness was observed with recycling operations.But repeated recycling appeared to have negligible effects on the loss factor of the recycled materials.The results obtained from the experiment and the numerical analyses were in close agreement.

Multi-hierarchical flexible composites towards superior fire safety and electromagnetic interference shielding

Vast amounts of electromagnetic waves are generated in modern society,which severely endanger human health and cause instrument disturbance.Furthermore,practical application of electromagnetic shielding polymer-based materials aspires to flame retardancy.Herein,cellulose acetate butyrate modified ammonium polyphosphate(CAPP)and phosphoramide flame retardant decorated short carbon fiber(MSCF)were synthesized separately and then simultaneously blended into thermoplastic polyurethane(TPU)to prepare a series of flame retardant TPU composites.Then,the multi-hierarchical flexible TPU/CAPP/MSCF composites were fabricated via our self-developed air-assisted thermocompression method.The results revealed that the TPU/CAPP/MSCF showed improved thermal stability.Moreover,the TPU/10CA/2.5F incorporated with 10.0 wt.%CAPP and 2.5 wt.%MSCF respectively exhibited 77.8%and 58.6%reduction in peak of heat release rate(PHRR)and total heat release(THR),compared to those of pure TPU.In addition,the TPU/10CA/2.5F passed the UL-94 V-0 rating test and achieved a higher limit oxygen index(LOI)(27.3%)than pure TPU(21.7%).In the case of electromagnetic interference shielding effectiveness(EMI SE),the TPU/10CA/10.0F-SW with 10 wt.%CAPP and 10 wt.%MSCF dispersed in the surface layer and Ti_(3)C_(2)Tx MXene intercalated in the interlayer exhibited EMI SE of 43.8 dB in X band and 32.0 dB in K band.Summarily,synergistic effect between CAPP and MSCF together with scattered and multiply adsorbed effect of MSCF,MXene and CAPP was responsible for fire safety and EMI shielding property improvements.This work provides a fascinating strategy for fabricating multi-hierarchical flexible TPU composites with outstanding flame retardant and EMI shielding performances.

High-performance flexible nanocomposites with superior fire safety and ultra-efficient electromagnetic interference shielding

High-performance multifunctional polymeric materials integrated with high fire safety,excel-lent mechanical performances and electromagnetic interference(EMI)shielding properties have great prospects in practical applications.However,designing highly fire-safe and mechanically ro-bust EMI shielding nanocomposites remains a great challenge.Herein,hierarchical thermoplastic polyurethane/cyclophosphazene functionalized titanium carbide/carbon fiber fabric(TPU/CP-Ti_(3)C_(2)T_(x)/CF)nanocomposites with high fire safety and mechanical strength and toughness were prepared through the methods of melt blending,layer-by-layer stacking and thermocompression.The TPU/CP-Ti_(3)C_(2)T_(x)showed improved thermal stability.Moreover,the peak of heat release rate and total heat release of the hi-erarchical TPU sample containing 4.0 wt.%CP-Ti_(3)C_(2)T_(x)were respectively reduced by 64.4%and 31.8%relative to those of pure TPU,which were far higher than those of other TPU-based nanocomposites.The averaged EMI shielding effectiveness value of the hierarchical TPU/CP-Ti_(3)C_(2)T_(x)-2.0/CF nanocomposite reached 30.0 dB,which could satisfy the requirement for commercial applications.Furthermore,the ten-sile strength of TPU/CP-Ti_(3)C_(2)T_(x)-2.0/CF achieved 43.2 MPa,and the ductility and toughness increased by 28.4%and 84.3%respectively compared to those of TPU/CF.Interfacial hydrogen bonding in combination with catalytic carbonization of CP-Ti_(3)C_(2)T_(x)nanosheets and continuous conductive network of CF were re-sponsible for the superior fire safety,excellent EMI shielding and outstanding mechanical performances.This work offers a promising strategy to prepare multifunctional TPU-based nanocomposites,which have the potential for large-scale application in the fields of electronics,electrical equipment and 5 G facilities.