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Cationisation of cellulose fibres has been studied extensively as an alternative to permit salt free reactive dyeing, however chemical balances of the cationisation reaction often are not taken into account. The chemical consumption of cationisation processes described in the literature is substantial and often over-compensates savings in salt in a conventional reactive dyeing. Besides very high consumption of chemicals the high level of cationisation generates problems of uneven dyeings and shade variations. In a new approach low concentrations of 3-chloro-2-hydroxypropyl-N,N,N-trimethylammonium chloride (CHPTAC) were applied in a pad batch cationisation process for cotton fabric to achieve a low level cationisation. The cationic group content of the processed fibres ranged from 5 to 79 mmol kg−1. Exhaust dyeing experiments with Reactive Blue 19 demonstrated that a salt free reactive dyeing is possible with low cationic group content 14 mmol kg−1. The optimised low-level cationisation reduces the overall chemical consumption of the reactive dyeing, and thus represents a cleaner alternative to present reactive dyeing operations which are based on addition of high amounts of salt.

In this paper, D-optimal chemical balance weighing designs with three objects are considered. The error terms are assumed to form a first-order autoregressive process, which implies that the covariance matrix of the vector of errors depends on the known parameter ρ . It is shown that the designs constructed by Katulska and Smaga (Metrika 76:393–407, 2013 ) are still D-optimal weighing designs with three objects under a wider interval of possible values for parameter ρ than that considered in that paper. Those designs are also proved to be highly D-efficient designs, when D-optimal design is not known.

In this paper we consider issues related to the determination of chemical balance weighing designs satisfying the criterion of D-optimality. This problem is considered under the assumption that the measurements are equally positively correlated and they have the same variances. We answer the question of how to add four runs to a regular D-optimal chemical balance weighing design in order to obtain a highly D-efficient design. The problem formulated in this way leads to an extension of results contained in a previous paper in

In this paper we consider issues related to the determination of chemical balance weighing designs satisfying the criterion of D-optimality. This problem is considered under the assumption that the measurements are equally positively correlated and they have the same variances. We answer the question of how to add four runs to a regular D-optimal chemical balance weighing design in order to obtain a highly D-efficient design. The problem formulated in this way leads to an extension of results contained in a previous paper in

The first four years of the CALIPSO lidar measurements have revealed the existence of an aerosol layer at the tropopause level associated with the Asian monsoon season in June, July and August. This Asian Tropopause Aerosol Layer (ATAL) extends geographically from Eastern Mediterranean (down to North Africa) to Western China (down to Thailand), and vertically from 13 to 18 km. The Scattering Ratio inferred from CALIPSO shows values between 1.10. 1.15 on average with associated depolarization ratio of less than 5%. The Gaussian distribution of the points indicates that the mean value is statistically driven by an enhancement of the background aerosol level and not by episodic events such as a volcanic eruption or cloud contamination. Further satellite observations of aerosols and gases as well as field campaigns are urgently needed to characterize this layer, which is likely to be a significant source of non-volcanic aerosols for the global upper troposphere with a potential impact on its radiative and chemical balance

Aerosol particles play a critical role in the tropical tropopause layer (TTL) through cloud formation and heterogeneous chemistry, influencing the radiative and chemical balance of the stratosphere. However, aerosol measurements in the TTL are sparse, resulting in poor knowledge of aerosol abundance and distribution in this important region. Here, we present in situ aircraft measurements over the western tropical Pacific, revealing a persistent and altitude‐dependent enhancement of aerosol mass in the TTL compared to the convectively influenced troposphere below. Notably, our data demonstrate a striking positive correlation between aerosol mass and ozone. Model simulations suggest that organic materials constitute a substantial fraction of the total aerosol mass within the TTL. We further derived an empirical parameterization of TTL aerosol mass as a function of ozone based on their linear relationship. This framework holds potential for estimating the TTL aerosol abundance but requires further validation and refinement through future measurements. Plain Language Summary We investigated tiny particles called aerosols in a specific atmospheric layer called the tropical tropopause layer (TTL). These particles are crucial because they affect cloud formation and chemical processes in the atmosphere, influencing how energy is distributed. Unfortunately, there hasn't been much research on aerosols in the TTL, leading to gaps in our understanding of their abundance and distribution in this important region. To fill this knowledge gap, we conducted measurements using aircraft over the western tropical Pacific. Our findings revealed that aerosol mass in the TTL is consistently higher compared to the lower troposphere, which is influenced by upward air movement. What's interesting is that we observed a clear connection between the amount of aerosol and ozone. Our model simulations indicated that a significant portion of the aerosol mass in the TTL is made up of organic materials. To make it easier to estimate aerosol levels and their impact on climate, we developed a way to predict TTL aerosol mass based on ozone measurements. Since ozone is relatively straightforward to measure and model, our method could provide a useful framework for understanding aerosol abundance in the TTL and its effects on the climate. Key Points Aircraft measurements reveal persistent enhancement of aerosol mass in the TTL The TTL aerosol enhancement tightly correlates with ozone. An empirical parameterization of TTL aerosol as a function of ozone is derived Modeling suggests that TTL aerosol particles are mainly composed of organics and sulfate

Based on the full-diurnal-cycle sodium (Na) lidar observations at Beijing (40.41∘ N, 116.01∘ E), we report pronounced downward extensions of the Na layer bottomside to below 75 km near mid-December 2014. Considerable Na atoms were observed even as low as ∼ 72 km, where Na atoms are short-lived. More interestingly, an unprecedented Na density of ∼ 2500 atoms cm−3 around 75 km was observed on 17 December 2014. Such high Na atoms concentration was 2 orders of magnitude larger than that normally observed at the similar altitude region. The variations of Na density on the layer bottom were found to be accompanied by warming temperature anomalies and considerable perturbations of minor chemical species (H, O, O3) in the upper mesosphere. Different from the previous reported metal layer bottom enhancements mainly contributed by photolysis after sunrise, these observational results suggest more critical contributions were made by the Na neutral chemical reactions to the Na layer bottom extensions reported here. The time–longitudinal variations of background atmospheric parameters in the upper mesosphere and stratosphere from global satellite observations and ERA reanalysis data indicated that the anomalous structures observed near the lidar site in mid-December 2014 were associated with planetary wave (PW) activities. The anomalies of temperature and O3 perturbation showed opposite phase in the altitude range of 70–75 and 35–45 km. This implied that the vertical coupling between the mesosphere and stratosphere, possibly driven by the interactions of PW activities with background atmosphere and modulation of gravity wave (GW) filtering by stratospheric wind, contributed to the perturbations of background atmosphere. Furthermore, the bottom enhancement on 17 December 2014 was also accompanied by clear wavy signatures in the main layer. The strong downwelling regions are likely due to the superposition of tide and GW, suggesting the wave-induced adiabatic vertical motion of the air parcel contributed greatly to the formation of the much stronger Na layer bottom enhancement on 17 December 2014. These results provide a clear observational evidence for the Na layer bottom response to the planetary-scale atmospheric perturbations in addition to tide and GW through affecting the chemical balance. The results of this paper also have implications for the response of the metal layer to vertical coupling between the lower atmosphere and the mesosphere.

This study presents several results concerning the determination of chemical balance weighing designs that satisfy the criterion of D-optimality. The designs are examined under the assumption that all measurements exhibit equal positive correlation and identical variances. We introduce a method for augmenting a regular D-optimal chemical balance weighing design with additional measurements in order to obtain a highly D-efficient chemical balance weighing design.

Some elements concerning the problem of determining chemical balance designs are considered. A method is presented for determining the best design in classes where no D-optimal design exists. In this case, we obtain a design that is highly D-efficient. The efficiency of such a design is presented as a function of the number of parameters and measurements, and its properties are studied. Charts showing the efficiency function for selected classes of designs are presented.

In this study, poly(lactic-co-glycolic acid) microspheres (PLGA MS)for controlled protein release by double emulsion-solvent evaporation were produced and characterized for their morphological and technological features. MS autocatalytic degradation was described by a mathematical model based on a Michaelis and Menten-like chemical balance. Here, for the first time MS degradation was correlated to the advancement of MS degradation front with respect to the degraded radius, derived from mass loss experiments. The model can satisfactorily describe the kinetics of advancement of the degradation front experimentally derived for all MS formulations, especially when produced at higher PLGA concentrations.