Theoretical and experimental investigation of an absorption refrigeration and pre-desalination system for marine engine exhaust gas heat recovery

Absorption-refrigeration-cycle-based exhaust gas heat recovery technology is effective in improving the thermal efficiency and fuel economy of marine diesel engines. However, the absorption refrigeration system is inflexible in the start–stop operation, and this cannot fulfil the fluctuating demand of refrigeration. This paper presents both the theoretical and experimental investigations of an absorption refrigeration and freezing pre-desalination-based marine engine exhaust gas heat recovery system. The energy storage subcycle is introduced to overcome the energy underutilisation and balance the excessive refrigerating output of the absorption refrigeration cycle. Seawater is utilised as the phase-change material and it is pre-desalinated in the energy storage subcycle. A mathematical model of the system is established and experimental investigation is conducted. Furthermore, the theoretical and experimental performances are compared, and an economic analysis of seawater desalination is performed to evaluate its economy. The results show that the total refrigeration output of the system ranges from 6.1 kW to 9.9 kW, and the system COP (Coefficient of Performance) can reach 16% under the experimental operating conditions. Additionally, the salinity of pre-desalinated seawater can be reduced to below 10 ppt. Moreover, the cost of RO (Reverse Osmosis) seawater desalination can be reduced by 26% through the pre-desalination process of seawater

Study of hot processing map of AISI 1035 steel under high temperature

In this study, AISI 1035 steel was selected as the research object, and a single-pass thermal compression simulation experiment was carried out. Based on the true stress-strain curve obtained from the experiment, the dynamic DMM thermal processing map theory was used to draw the material under different thermal deformation conditions. and the rheological instability map based on the Prasad instability criterion, and the thermal processing map is used to predict the suitable processing interval and rheological instability interval for the thermal deformation process of the material under different process conditions. So as to provide theoretical support for the optimization of the material processing technology

Tris(piperazinediium) phosphatododeca­molybo(V,VI)phosphate

The title compound, (C4H12N2)3[PMo12O40] or (H2pip)3[PMo12O40] (pip is piperazine), was prepared under hydro­thermal conditions. The asymmetric unit contains one-sixth of a mixed-valent Mo(V,VI) pseudo-Keggin-type [PMo12O40]6− anion and half a piperazinediium cation, (H2pip)2+. The discrete Keggin-type [PMo12O40]6- anion has site symmetry and the three (H2pip)2+ cations each have site symmetry at the centres of the mol­ecules. The central P atom is on special position , which is a roto-inversion position and generates the disorder of the PO4 tetra­hedron. Furthermore, six doubly bridging oxide groups are also disordered with an occupancy factor of 0.5 for each O atom. The anions and cations are linked by an extensive network of inter­molecular N—H⋯O and C—H⋯O hydrogen bonds

Q345C weld deformation analysis of butt joints

Q345C steel is welded under two different pre-welding heating methods of traditional flame heating and ceramic sheet heating. The finite element analysis of the butt joint weldment by ABAQUS software is used to summarize the law of welding deformation and compare the welding quality under different pre-welding heating methods according to the residual stress and deformation trend of the welding joint weld. The results show that the main stress after welding is concentrated in the weld seam and the surrounding area. The residual stress after welding after the heating and welding of the ceramic sheet is significantly less than the residual stress after the traditional flame heating welding, and the welding after the heating of the ceramic sheet can obtain better welding quality

Assessment of genetic diversity and relationships among Osmanthus fragrans cultivars using AFLP markers

This study was conducted to reveal genetic diversity among 100 Osmanthus fragrans cultivars using amplified fragment length polymorphism (AFLP) markers. Eight AFLP primer combinations produced a total of 443 polymorphic fragments with an average of 64 per primer combination. The percentage of polymorphic bands (86.81%), the resolving power (Rp) (32.71) and the PIC values (0.331) showed the efficiency of used primer combinations. The revealed AFLP makers were effective in distinguishing all the cultivars considered. Cluster analysis were performed to assess patterns of diversity among cultivars and showed the abundant genetic diversity. The overall distribution pattern of molecular variation suggested that 93.33% of the total genetic variance was within the identified groups and 6.67% of the genetic variation was among the identified groups. Our results showed that AFLP markers are useful for Osmanthus fragrans germplasm discrimination as well as for investigation of genetic diversity and variation. The information will facilitate germplasm identi\ufb01cation, conservation and new cultivar developmen

Q345C steel welding process simulation analysis

In order to meet the requirements for the quality of steel structure welding projects in severe cold areas, reasonable and effective technical research and welding scheme improvement are carried out for welding in low temperature environments. Based on ABAQUS software to simulate different welding conditions, mainly for welding after traditional flame heating and ceramic sheet heating in low temperature environment, the corresponding temperature field is obtained. Compared with the actual welding results, it is concluded that the weldment welded after heating with ceramic sheet is of better quality, fully verify the accuracy of welding simulation, optimize process design, shorten the time required for practical inspection accumulation

Q345C weld deformation analysis of butt joints

Q345C steel is welded under two different pre-welding heating methods of traditional flame heating and ceramic sheet heating. The finite element analysis of the butt joint weldment by ABAQUS software is used to summarize the law of welding deformation and compare the welding quality under different pre-welding heating methods according to the residual stress and deformation trend of the welding joint weld. The results show that the main stress after welding is concentrated in the weld seam and the surrounding area. The residual stress after welding after the heating and welding of the ceramic sheet is significantly less than the residual stress after the traditional flame heating welding, and the welding after the heating of the ceramic sheet can obtain better welding quality

Q345C steel welding process simulation analysis

In order to meet the requirements for the quality of steel structure welding projects in severe cold areas, reasonable and effective technical research and welding scheme improvement are carried out for welding in low temperature environments. Based on ABAQUS software to simulate different welding conditions, mainly for welding after traditional flame heating and ceramic sheet heating in low temperature environment, the corresponding temperature field is obtained. Compared with the actual welding results, it is concluded that the weldment welded after heating with ceramic sheet is of better quality, fully verify the accuracy of welding simulation, optimize process design, shorten the time required for practical inspection accumulation