Thermodynamic characteristics of the aliphatic polyamide crystal structures: Enhancement of nylon 66α, 610α and 77γ polymers.

Despite the polymer industry's reliance on nylon polymers, numerous questions remain about their crystal structures, modeling, and other features. This work discusses the thermodynamic properties and molecular modeling of a polyamides nylon 66α, 610α, and 77γ crystal structure systems for use in various electronics and Nano-devices that feature distinct properties such as exceptional optoelectronic properties at a low cost compared to other structures. This study looked at the crystal structure of a linear polyamide chain made up of repeating units. The influence of the thermal expansion coefficient and thermodynamic parameters on crystal structures' characteristics at different temperatures has previously been explored. The findings of this study demonstrate, on the one hand, the influence of the amorphous phase on the final thermodynamic characteristics of semi-crystalline polymers and, on the other hand, pave the way for greater improvement in the durability of these polymers by increasing their crystalline features. The values of the thermodynamic parameters for nylon 66α, 610α and 77γ such as enthalpy (ΔHExp.) were 35.08, 40.25, and 1.44 kJ/mol, entropy (ΔSExp.) 113.75, 128.84, and 15.10 J/mol-K, free energy (ΔGExp.) was -44.57, -46.62, and -6.86 kJ/mol, respectively. When the nylon data is compared, the nylon 610α exhibits a significantly higher free energy, at high temperatures, the process is spontaneous and exergonic, making it a potentially viable material for use as fibers and engineering thermoplastics.

Knowledge and Awareness of Masks and N95 Respirators Used for COVID-19 Prevention Among Chemical Engineering Students at Al-Balqa Applied University, Jordan.

Background and Objectives: On March 11, the World Health Organization stated coronavirus disease 2019 (COVID-19) was a global pandemic; the rapid and extended spread of the COVID-19 pandemic has become a significant cause of concern for face-to-face university study. This study investigated the knowledge and awareness of chemical engineering students in Al-Balqa Applied University (BAU) in Jordan about respiratory protective measures against COVID-19. Materials and Methods: A cross-sectional study was developed using a multi-stage random sampling technique conducted from April 21-28, 2020. The data were collected through an online questionnaire distributed to BAU's chemical engineering students, with 179 responders completed the survey correctly. The data were analyzed statistically using the SPSS program. The questionnaire consisted of two parts: the first measured the student's general knowledge about the COVID-19 pandemic, while the second focused on the respiratory protection methods against COVID-19; it was structured to assess the student's knowledge about the suitable types of masks and respirators used in COVID-19 prevention, their detailed mechanism of action and filtration process type, their production materials, and finally how the student's knowledge affects choosing a proper preventive method. Results: The study found moderate awareness among engineering students about COVID-19 causative agent, effective preventive masks/respirators used, and the mask's viral blockage mechanisms. A total of 89 respondents (49.7%) pointed to the correct best protective mask, i.e., N95 mask. On the other hand, 119 respondents (66.5%) believed that a surgical mask is the best protective mask. The study also showed differences in knowledge between different academic years; the knowledge about respirators, masks, and their action mechanism among senior students in the last three academic years was better than the younger students with a P-value of 0.047 for knowledge about respirator used for protection against coronavirus disease and the P-value of 0.028 for knowledge of the comparisons between the N95 and surgical mask. On the other hand, the study showed a lack of awareness of the most suitable mask types used in pandemics and the appropriate use method. Conclusions: The study found that chemical engineering students in Al-Balqa university were moderately knowledgeable regarding COVID-19 respiratory preventive methods; these results provided an overview of each student's community's knowledge level. Therefore, efforts are needed to improve public awareness through comprehensive educational campaigns to increase students' knowledge, attitude, and practice.

Analysis of the potential use of major refuse-derived fuels in Jordan as supplementary fuel.

UNLABELLED: The increasing energy demand in Jordan, compounded with the country's limited natural resources as well as its dependence on importing fuel oil from neighboring countries, makes it indispensible to search for alternative fuels. The objective of this study is to analyze the potential use of refuse-derived fuel (RDF) as a supplementary fuel in Jordan, for this purpose. Nine of the major RDFs generated in Jordan were chosen for this study: wastewater sludge, oil refinery sludge, olive oil husk, olive oil residue, chicken farm waste, sheep farm waste, used cooking oil, used oil, and waste tires. The energy content was measured for each one and the results were verified using five different empirical elemental analyses. Results of measuring and calculating the higher heating value (HHV) of the samples showed that used oil had the highest potential as an alternative fuel at 45.36 MJ/kg and the residual olive waste had the lowest heating content at 5.02 MJ/kg. Results also showed that there was a good agreement between the measured and calculated values. The calculating models showed that there was a positive correlation between the HHV and C% and negative correlation between HHV and ash%. Further research is planned to be conducted into the implementation of the concept of waste to energy in the Jordanian industrial sector. IMPLICATIONS: It has been necessary to measure the higher heating value (HHV) of different types of RDFs in Jordan to estimate their potential use as supplementary fuels. The amounts generated per year in Jordan are a crucial factor to make it feasible to use these. Used oil, used cooking oil, and waste tires could be the most promising supplementary fuels.

The role of weak hydrogen-bonds on the formation of short-lived molecular associations.

Weak molecular homo- and hetero-associations among some ethene derivatives and several common solvents are studied using (1)H NMR spectroscopy. In connection with the aromatic-solvent induced shifts which is a special case of molecular association between aromatic solvents and polar molecules a model for association was suggested that involves the interaction of the positive end of the solute dipole with the aromatic pi-electrons. This model met with certain difficulties. An alternative model for configuration of associated molecules that explains the literature results and the results obtained in this paper is presented. The model is based on interaction of protons of the acceptor molecules with the lone-pair electrons or pi-electrons of the donor molecules. The present model removes the difficulties met with the former model and extends the concept of aromatic-solvent induced shifts to include non-polar molecules besides polar ones. In all cases, the interaction of protons of acceptor molecules with lone-pair electrons of donor molecules gives rise to a deshielding effect, while interaction with aromatic pi-electrons leads to shielding.