Search results for "racking"

Mentalizing eye contact with a face on a video : Gaze direction does not influence autonomic arousal

2018

Recent research has revealed enhanced autonomic and subjective responses to eye contact only when perceiving another live person. However, these enhanced responses to eye contact are abolished if the viewer believes that the other person is not able to look back at the viewer. We purported to investigate whether this "genuine" eye contact effect can be reproduced with pre-recorded videos of stimulus persons. Autonomic responses, gaze behavior, and subjective self-assessments were measured while participants viewed pre-recorded video persons with direct or averted gaze, imagined that the video person was real, and mentalized that the person could see them or not. Pre-recorded videos did not …

The elephant in the living room: Centenarians' autobiographies, co-authorship and narratives of extreme longevity.

2020

Centenarians, but not octogenarians, up-regulate the expression of microRNAs

2012

Centenarians exhibit extreme longevity and a remarkable compression of morbidity. They have a unique capacity to maintain homeostatic mechanisms. Since small non-coding RNAs (including microRNAs) are implicated in the regulation of gene expression, we hypothesised that longevity of centenarians may reflect alterations in small non-coding RNA expression. We report the first comparison of microRNAs expression profiles in mononuclear cells from centenarians, octogenarians and young individuals resident near Valencia, Spain. Principal Component Analysis of the expression of 15,644 mature microRNAs and, 2,334 snoRNAs and scaRNAs in centenarians revealed a significant overlap with profiles in you…

Serum BPIFB4 levels classify health status in long-living individuals

2015

Background People that reach extreme ages (Long-Living Individuals, LLIs) are object of intense investigation for increase/decrease of genetic variant frequencies, genetic methylation levels, protein abundance in serum and tissues. The aim of these studies is the discovery of the mechanisms behind LLIs extreme longevity and the identification of markers of well-being. We have recently associated a BPIFB4 haplotype (LAV) with exceptional longevity under a homozygous genetic model, and identified that CD34+ of LLIs subjects express higher BPIFB4 transcript as compared to CD34+ of control population. It would be of interest to correlate serum BPIFB4 protein levels with exceptional longevity an…

Selective Introduction of Acid Sites in Different Confined Positions in ZSM-5 and Its Catalytic Implications

2018

Controlling the location of acid sites in zeolites can have a great effect on catalysis. In this work we face the objective of directing the location of Al into the 10R channels of ZSM-5 by taking advantage of the structural preference of B to occupy certain positions at the channel intersections, as suggested by theoretical calculations. The synthesis of B-Al-ZSM-5 zeolites with variable Si/Al and Si/B ratios, followed by B removal in a postsynthesis treatment, produces ZSM-5 samples enriched in Al occupying positions at 10R channels. The location of the acid sites is determined on the basis of the product distribution of 1-hexene cracking as a test reaction. The higher selectivity to prop…

Comparison of the activity, selectivity and decay properties of lay and hyultrastable zeolites during the cracking of alkanes

1984

Abstract The cracking of n-heptane on LaY ultrastable zeolite has been studied in a continuous glass flow reactor, at atmospheric pressure, up to 470°C. The initial selectivity to cracking, isomerization and disproportionation, kinetic rate constants, activation energies and decay parameters have been calculated and compared with those obtained using a HY ultrastable zeolite as a catalyst. It has been found that the HY ultrastable zeolite is about 7 times more active for cracking, and about 10 times more active for isomerization and disproportionation than the LaY ultrastable zeolite. The protolytic to β-cracking ratio is higher for the HY ultrastable zeolite. The deactivation takes place b…

Catalytic cracking of alkanes on MCM-22 zeolite. Comparison with ZSM-5 and beta zeolite and its possibility as an FCC cracking additive

1995

Abstract N-heptane cracking has been carried out on MCM-22, and its kinetic and decay behaviour is compared with that of ZSM-5 and Beta zeolites. In the case of MCM-22 cracking occurs in the 10-member ring channel system, as well as in the large cavities formed by 12-member rings. Product selectivities show that MCM-22, while presenting features which indicate structural similarities with ZSM-5, it also presents characteristics corresponding to pores or cavities larger than ZSM-5. The selectivities to the individual products together with C1 + C2/iC4, C3/C4, C5/C2, iC4/total C4, and alkane/alkene ratios indicate that MCM-22 has good properties to be used as an FCC octane booster additive sp…

Formation of products responsible for motor and research octane of gasolines produced by cracking The implication of framework Si/Al ratio and operat…

1989

Abstract An alkane in the range of gasoline fraction ( n -heptane) has been used as a reactant to study the influence of zeolite Y catalyst and process variables (i.e., framework Si Al ratio and procedure of dealumination, time on stream, and contact time) on the formation of products responsible for motor and research octane of gasoline during cracking, namely branched, aromatics, and olefins. It is found that the branched isomers in the C 5 and C 6 fractions appear as primary products and are partly produced by disproportionation, since the ratio of iso to normal compounds is above equilibrium. The ratio of branched to linear products strongly decreases when the number of carbon atoms of …

Catalytic cracking of n-alkane naphtha: The impact of olefin addition and active sites differentiation

2015

An extended dual kinetic model allows to fit the n-heptane cracking results working in a wide range of reaction conditions. The duality of the model is provided by the contribution of monomolecular and bimolecular cracking mechanisms. It takes into account the role played by the olefins formed on the global cracking or added within the feed. Furthermore by means of this model and the kinetic parameters obtained when cracking n-heptane on ZSM-5, it has been observed that, while some characterization techniques show a homogeneous zeolite surface from the point of view of the active sites, rigorous kinetic experiments point to the possibility that the reactant sees a heterogeneous surface with…

Cracking of n-heptane on a hzsm-5 zeolite. The influence of acidity and pore structure

1985

Abstract The crackino of n-heptane on a HZSM-5 zeolite has been studied in a continuous qlass flow reactor, at atmospheric pressure, up to 470°C. The initial selectivities to the different reaction products, kinetic rate constants, activation energies and decay parameters have been calculated and compared with those obtained using a large pore zeolite (HYUS). A different product distribution is obtained with the two zeolites. In that way, and considering initial selectivities, different C 6 /C 1 , C 5 /C 2 , C 4 /C3, i-C 4 /n-C 4 , ethylene/ethane, propylene/propane ratios have been found on the two zeolite catalysts. The results have been quantitatively explained by considerinq a direct cr…