Condensation and evaporation local heat transfer characteristics of the refrigerant mixture of R1123 and R32 inside a plate heat exchanger

In the present study, condensation and evaporation local heat transfer coefficients of the refrigerant mixture of R1123 and R32 inside a brazed plate heat exchanger were investigated by using a test section which is combined with two grooved stainless steel plates. In the test section, wall temperature distribution was measured. The test section consists of eight plates; two of them were processed herringbone for refrigerant flow channel other two flat plates are set for cooling plate for refrigerant, and another consist on cooling water flow channel. In order to measure local heat transfer and temperature distribution, five thermocouples were set on flow direction for each wall temperature measurement of the refrigerant side and heat source water side. Local heat transfer coefficient were calculated from local wall temperature of refrigerant side, saturation temperature and local heat flux obtained by temperature gradient between heat transfer surface of refrigerant side and heat source side

The Molecular Basis of CRL4DDB2/CSA Ubiquitin Ligase Architecture, Targeting, and Activation

The DDB1-CUL4-RBX1 (CRL4) ubiquitin ligase family regulates a diverse set of cellular pathways through dedicated substrate receptors (DCAFs). The DCAFDDB2 detects UV-induced pyrimidine dimers in the genome and facilitates nucleotide excision repair. We provide the molecular basis for DDB2 receptormediated cyclobutane pyrimidine dimer recognition in chromatin. The structures of the fully assembled DDB1-DDB2-CUL4A/B-RBX1 (CRL4DDB2) ligases reveal that the mobility of the ligase arm creates a defined ubiquitination zone around the damage, which precludes direct ligase activation by DNA lesions. Instead, the COP9 signalosome (CSN) mediates the CRL4DDB2 inhibition in a CSN5 independent, nonenzymatic, fashion. In turn, CSN inhibition is relieved upon DNA damage binding to the DDB2 module within CSN-CRL4DDB2. The Cockayne syndrome A DCAF complex crystal structure shows that CRL4DCAF(WD40) ligases share common architectural features. Our data support a general mechanism of ligase activation, which is induced by CSN displacement from CRL4DCAF on substrate binding to the DCAF