Vapor pressure (Pvap), heat of vaporization (ΔHvap), liquid heat capacity (Cpl), and ideal gas heat capacity (Cpig) are important properties for process design and optimization. This work focuses on improving the thermodynamic consistency and accuracy of the aforementioned properties since these can drastically affect the reliability, safety, and profitability of chemical processes. They can be measured for pure organic compounds from the triple point, through the normal boiling point, and up to the critical point. Additionally, ΔHvap is proportional to the derivative of vapor pressure with respect to temperature through the Clapeyron equation, and the difference between Cpl and Cpig is proportional to the derivative of heat of vaporization with respect to temperature. In order to improve temperature-dependent correlations, all the properties were analyzed simultaneously. First, a temperature-dependent error model was developed using several versions of the Riedel and Wagner Pvap correlations. The ability of each correlation to match Cpl data was determined for 5 well-known compounds. The Riedel equation performed better than the Wagner equation when the best form was used. Second, the Riedel equation form was further modified, and the best correlation form was found for about 50 compounds over 7 families. This led to the development of a new vapor pressure prediction method using different Riedel equation forms to fit Pvap, ΔHvap, and Cpl data simultaneously. Seventy compounds were tested, and the error compared to liquid heat capacity data dropped from 10% with previous methods to 3% with this new prediction method. Additionally a differential scanning calorimeter (DSC) was purchased, and melting points (Tm), enthalpies of fusion (ΔHfus), and liquid heat capacities (Cpl) were measured for over twenty compounds. For many of these compounds, the vapor pressure data and critical constants were re-evaluated, and new vapor pressure correlations were recommended that were thermodynamically consistent with measured liquid heat capacity data. The Design Institute for Physical Properties (DIPPR) recommends best constants and temperature-dependent values for pure compounds. These improvements were added to DIPPR procedures, and over 200 compounds were re-analyzed so that the temperature-dependent correlations for Pvap, ΔHvap, Cpig, and Cpl became more internally consistent. Recommendations were made for the calculation procedures of these properties for the DIPPR database.

The purpose of this bachelor thesis is to design and optimize a powder metal gear through FEM-analyzes. The moment of inertia and weight of the gear shall be reduced at the same time as the demands on tension and bending stiffness are met. The gear that is used as reference and will be optimized is the standard gear in the FZG-rig at the department of Machine Design at KTH. The work is initiated with a literary study. After that a CAD-model of the gear and its pinion is created in Solid Edge. Then the reference gear is analyzed in the FEM-program Ansys and control calculations are made according to standards and handbooks. Thereafter different geometry and density variations are made and tested. The tests are then compared to the reference gear. By varying the density of the gear and varying the geometry of the waist of the gear several different optimization proposals could be made. By cutting material off the waist of the gear the weight can be reduced by 6 % with an increase in bending stress of 1 %. If a bigger increase in bending stress is allowed more material can be removed. If the bending stress increase is allowed to be 5 % a decrease in weight and moment of inertia of 14 % is obtained. With an increase in deformation of 5 % a decrease of 11 % in weight and moment of inertia was obtained. The different tested geometries behave relatively equal up to a 3 % decrease in weight with respect to deformation but begins to vary considerably if the weight is further decreased. Removal of material should be symmetric around every gear tooth to avoid transmission failure which also leads to increased noise. The results show that it is better to remove material under each gear tooth rather than under the root. It is also advantageous to remove material close to the flange. Further work is required to analyze and optimize the gears even more. Fatigue tests as well as different load cases should be analyzed. / Syftet med kanditatexamensarbetet är att ta fram och egenskapsoptimera ett pulvermetallurgiskt kugghjul med hjälp av FEM-analyser. Tröghetsmomentet och vikten på kugghjulet ska minimeras samtidigt som kraven på spänningar och böjstyvhet uppfylls. Det kugghjul som används som referens och ska optimeras är standardkugghjulet i FZG-riggen på institutionen för maskinkonstruktion på KTH. Arbetet inleds med att en litteraturstudie görs. Sedan tas en CAD-modell för kugghjulet och dess tillhörande drev fram i Solid Edge. Därefter analyseras referenskugghjulet i FEM-programmet Ansys och kontrollberäkningar görs enligt standarder och handböcker. Därefter konstrueras och analyseras olika geometrier och densitetsvariationer och jämförs med referenskugghjulet. Genom att variera densiteten på kugghjulet och variera geometrin på kugghjulets liv kunde flertalet optimeringsförslag tas fram. Genom att göra en utskärning i livet kan vikten minskas med 6 % utan att böjspänningen påverkas mer än 1 %. Om en större ökning i böjspänning tillåts kan ytterligare material avlägsnas. Om böjspänningsökningen tillåts vara ca 5 % kan en viktminskning och tröghetsmomentsminskning på ca 14 % åstadkommas. Vid en deformationsökning på 5 % erhölls en viktminskning och tröghetsmomentsminskning på ca 11 %. De olika geometrier som testas beter sig relativt lika upp till 3 % viktminskning med avseende på deformation och börjar därefter variera kraftigt. Borttagning av material måste ske symmetriskt kring varje kuggtand för att transmissionsfel och därmed ökat buller ska undvikas. Det visar sig att ta bort material under kuggen är bättre än att ta bort material under kuggroten. Det gynnsamt att göra geometriska förändringar närmast flänsen på kugghjulet. Vidare arbete krävs för att analysera och optimera kugghjulen ytterligare. Utmattningstester och fler lastfall bör analyseras.