Thermodynamic and heat transfer analysis of heat recovery from engine test cell by Organic Rankine Cycle

During manufacture of engines, evaluation of engine performance is essential. This is accomplished in test cells. During the test, a significant portion of heat energy released by the fuel is wasted. In this study, in order to recover these heat losses, Organic Rankine Cycle (ORC) is recommended. The study has been conducted assuming the diesel oil to be composed of a single hydrocarbon such as C₁₂H₂₆. The composition of exhaust gases (products of combustion) have been computed (and not determined experimentally) from the stoichiometric equation representing the combustion reaction. The test cell heat losses are recovered in three separate heat exchangers (preheater, evaporator and superheater). These heat exchangers are separately designed, and the whole system is analyzed from energy and exergy viewpoints. Finally, a parametric study is performed to investigate the effect of different variables on the system performance characteristics such as the ORC net power, heat exchangers effectiveness, the first law efficiency, exergy destruction and heat transfer surfaces. The results of the study show that by utilizing ORC, heat recovery equivalent to 8.85 % of the engine power is possible. The evaporator has the highest exergy destruction rate, while the pump has the lowest among the system components. Heat transfer surfaces are calculated to be 173.6, 58.7, and 11.87 m² for the preheater, evaporator and superheater, respectively.     

High‐Throughput Measurement of Binding Kinetics by mRNA Display and Next‐Generation Sequencing

There is great demand for high‐throughput methods to characterize ligand affinity. By combining mRNA display with next‐generation sequencing, we determined the kinetic on‐ and off‐rates for over twenty thousand ligands without the need for synthesis or purification of individual members. Our results are reproducible and as accurate as those obtained with other methods of affinity measurement.     

Tempered Fractional Stable Motion

Tempered fractional stable motion adds an exponential tempering to the power-law kernel in a linear fractional stable motion, or a shift to the power-law filter in a harmonizable fractional stable motion. Increments from a stationary time series that can exhibit semi-long-range dependence. This paper develops the basic theory of tempered fractional stable processes, including dependence structure, sample path behavior, local times, and local nondeterminism.     

Borate,lithium borate,and borophosphate powders by sol–gel precipitation

Borate, lithium borate and borophosphate powders were synthesized by the sol–gel method. Triethyl borate, lithium methoxide, and orthophosphoric acid were used as precursors for B₂O_3, Li₂O, and P₂O₅, respectively. Powders were characterized by FTIR, DTA, XRD and SEM techniques. Powders from the Li₂O–B₂O₃ system exhibited glassy features while borate and borophosphate powders contained mainly crystalline B₂O₃ according to XRD analysis. However, a 500 °C heat treatment transformed these crystalline powders into glass powders. Conversely, heat treatment of Li₂O–B₂O₃ powders transformed their structure from glassy to crystalline (Li₂B₄O₇). Chemical durability studies conducted in water at 60 °C showed that minor additions of P₂O₅ into borate and lithium borate powders improved their chemical durability significantly. Furthermore, Li₂O and P₂O₅ acted synergistically on the chemical durability when added simultaneously to borate compositions.     

Synthesis of mixed-donor amido/amino/siloxo ligands from symmetrical diamidosilylether ligands via a retro-Brook rearrangement and their chromium(II) complexes

The dilithio salts of two chelating diamidosilylether ligands undergo a retro-Brook rearrangement from oxygen to the amido-nitrogen, thereby directly yielding a new mixed-donor amido/amino/siloxo ligand. When reacted with chromium(II), siloxo-bridged dimers and a very strong eta(2)-(N,C(ipso)) arylamido interaction are featured.     

Direct Ink Writing of Polymer Composite Electrolytes with Enhanced Thermal Conductivities

Proper distribution of thermally conductive nanomaterials in polymer batteries offers new opportunities to mitigate performance degradations associated with local hot spots and safety concerns in batteries. Herein, a direct ink writing (DIW) method is utilized to fabricate polyethylene oxide (PEO) composite polymers electrolytes (CPE) embedded with silane-treated hexagonal boron nitride (S-hBN) platelets and free of any volatile organic solvents. It is observed that the S-hBN platelets are well aligned in the printed CPE during the DIW process. The in-plane thermal conductivity of the printed CPE with the aligned S-hBN platelets is 1.031 W ⁻¹ K⁻¹, which is about 1.7 times that of the pristine CPE with the randomly dispersed S-hBN platelets (0.612 W ⁻¹ K⁻¹). Thermal imaging shows that the peak temperature (°C) of the printed electrolytes is 24.2% lower than that of the CPE without S-hBN, and 10.6% lower than that of the CPE with the randomly dispersed S-hBN, indicating a superior thermal transport property. Lithium-ion half-cells made with the printed CPE and LiFePO₄ cathode displayed high specific discharge capacity of 146.0 mAh g⁻¹ and stable Coulombic efficiency of 91% for 100 cycles at room temperature. This work facilitates the development of printable thermally-conductive polymers for safer battery operations.     

Economics of “design for test” to remain competitive in the 90s

This article emphasizes the criticality of maximizing value adders and minimizing the costs of design for test (DFT) in order to remain competitive in ASIC manufacturing in the 90s.