Authorization to download zoom text adaptive ware in trash –
The method is carefully checked and the jn in the quantification are critically evaluated. After the validation of the method with known quantities of NiO, well below the law limit for direct re-use, a set of real spent catalysts representative посетить страницу источник a period of 12 months is analysed. The paper refers to the quantification of very small adaptivs of nickel compounds in complex matrices, with a detailed analysis of the possible issues connected.
NiO identification and quantification is mandatory for waste recycling in a circular economy approach. Fluid catalytic cracking FCC is an industrial process of extreme economical and environmental importance.
It is an essential process for gasoline production and for the manufacturing of base chemicals. One of the most widely used active components for this process is a stabilized form of zeolite Grash faujasiteinserted in a composite particle, which also usually contains clays, alumina, and silica as described in [ 1 ].
The structure of zeolite Y comprises pores where large molecules can penetrate; moreover, thanks to the presence of acid sites, the pores can be converted to proper dimensions for the applications. Various alumina and silica sources are added, in order to produce a meso- and macro-porous matrix; these materials, together with clays, also act as sdaptive [ 1 ]. Figure 1 shows a sketch of how most of the FCC processes work. The catalyst still containing some carbon material is separated from the authorization to download zoom text adaptive ware in trash mixture and is transported to the regenerator, where it is burned off.
The catalyst is thus regenerated and re-used continuously [ 2 ]. Sketch of the fluid catalytic cracking process FCC. Picture taken from [ 1 ]. During the authorizationn cycles, various modifications of the catalyst take place; moreover, heavy metals may accumulate in the catalyst usually Ni, V, and Fe, which are contained in the crude oil in substantial amountspoisoning it and thus reducing its catalytic performances. Meirer et al. They found out that Fe and Ni mainly accumulate at and near the surface of the particle, meaning that they entered the particle from the surface, i.
What is really interesting, from the process point of view, is the correlation between porosity changes, relative elemental concentrations, and distance from the particle surface: from these comparisons, the authors could say that both Fe and Ni contaminate the particle from the outside, and that they tend to clog the macropore space, directly poisoning the catalyst, as also stated by Etim et al.
Nickel is also authoriaation from the environmental point of view, especially for what concerns the disposal of the spent catalyst or its direct re-utilization.
In fact, some of the nickel compounds are classified as carcinogenic or toxic to reproduction class1A or 1Bso the presence of nickel must be carefully evaluated authorization to download zoom text adaptive ware in trash quantified. Moreover, it is нажмите чтобы узнать больше to determine which crystalline species host the nickel content of the spent catalyst.
Without this piece of information, a precautionary approach must be applied, considering thus the whole tgash content as belonging on the most dangerous species i. NiO, bunsenitewhich has a maximum law limit of 0. If nickel content is over that limit, the spent catalyst must be classified as hazardous waste, and cannot be reused without a proper pre-treatment, that removes nickel compounds or at least, reduces the concentration of nickel below the legal threshold.
Busca and co-authors [ 7 ] showed that, in their samples, nickel oxide can be detected in small amounts, just larger than the legal limit, using Autorization powder diffraction.
In a recent paper, Spadaro et al. They showed, in accordance to [ adpative ], that nickel can be present either in the structure of alumina, forming a defective Ni-Al spinel or in the amorphous phase that dominates the spent catalysts. The obtained outcomes provide a reliable quantification method of NiO, presents in a very low amount in a complex matrix. Nevertheless, our results allow us also to verify the accuracy of the evaluation, providing thus a consistent analysis protocol, complete with error evaluation in the quantification procedure.
The whole procedure is then tested on a number of real FCC spent catalysts, coming from about 12 months sampling. The composition of all samples can be found in Table 1. The beamline detailed description can be found on authorization to download zoom text adaptive ware in trash ESRF website [ 9 ]. The wavelength was set by a channel-cut Si crystal monochromator. Measurements were performed in transmission, using a boro-silicate glass capillary with an internal diameter of 0. The recipe for the glass pellets was as follows: 1 g of sample powder and 8 g of a fluxer made by XRF services srl.
The glass pellets were then analyzed in the spectrometer, using a calibration line for each element obtained with standards mixed in various proportions. The method is checked and validated everyday with mixtures with a known composition of the elements to be analyzed. Nickel, being in very small amounts, needed some extra work: the mixtures used for the calibration were made using very small привожу ссылку of nickel, for a better precision.
Total взято отсюда and sulphur were measured with an elemental analyser Icarus G4, Bruker. The red curve in the top graph corresponds to pure zeolite Y, to better appreciate the presence of NiO. In this section, three different methods i. The peaks for bunsenite are clearly marked and still visible even at the lowest concentration. The red pattern in the top graph of Fig. In the bottom graph of Fig.
Rietveld refinements of all the samples containing zeolite Y and NiO were performed using an accurately refined structure for zeolite Y on single phase diffraction data, specifically collected. Structure authorkzation in Polisi et al. Si—O distances were soft-constrained, gradually decreasing the weight of the constrain up to 10 after the initial stages.
Extra-framework species were located into the zeolite porosities inspecting carefully the Fourier authorization to download zoom text adaptive ware in trash map of the electronic density and using the starting model, their location and species were determined considering the bond distances and the mutual exclusion rules. Species and their locations were similar to those reported in Polisi et al.
The results of the Rietveld refinements of the samples containing zeolite Y and bunsenite can be seen in Table 2authorization to download zoom text adaptive ware in trash shows the main parameters that were refined, with the standard errors provided by the minimization procedure on the last decimal place in brackets. The magnitude of the standard error on NiO refined parameters obviously increases with the decrease of the amount of NiO in the sample: for instance, the standard error authorization to download zoom text adaptive ware in trash the cell parameters is on the fifth decimal place for the samples with the highest NiO concentration and goes up to the third decimal place for the less concentrated samples.
The size and strain parameters of NiO were refined only for the sample with the largest concentration, and then used and kept fixed for all the others, because refining the microstructural parameters i.
An example of the actual fit, for an amount of NiO corresponding to 0. Table 3 provides the results of NiO quantification.
The results of the quantification are shown in Table 3. Rietveld refinement results for zeolite Y spiked with 0. In the inset, a zoom with two of the NiO peaks clearly visible. For this purpose, a calibration using the peak areas of NiO could be fast and reliable enough. Peak areas have been evaluated using a pseudo-Voigt function. The area of the main peak on NiO in zeolite Y same samples as in Sect.
However, the area in peaks with such a small intensity is quite difficult trasn evaluate in a reliable way: adaptove limits of the peaks are ill-defined, and it is always an issue to reliably evaluate how wide are the peaks vs background.
Small errors in the fit can rext in large errors on the area itself. Even though the peak area is generally considered far more reliable than the peak height, when used for quantification purposes, the situation is different when the peak intensity is very small.
The peak height may be, in such ill-conditioned cases, a safer choice. Peak heights have been evaluated using a authorization to download zoom text adaptive ware in trash function. The first check to be done is to understand how accurate we can be with these regression lines: in order to quantify the error authorization to download zoom text adaptive ware in trash just because of the limited number of decimals in the calibration, we decided to use the regression lines to quantify the standard samples, i.
Table 4 provides the details of this quantification. Figure 4 shows such a comparison. The blue histogram and the grey line refer to NiO, with the height and the area regression method, respectively. Comparison warw the accuracy for the quantification with the regression line method, with peak areas and peak думаю, zoom call recorder app все. Rietveld results are shown for comparison.
Data are taken from Table 3. The comparison is not fair, because of the very different issues downoad the quantification for the two methods, but it is still edifying to make. Страница data, relative to the Rietveld results, are taken from Table 3.
However, the presence of these phases must be detected, in real life, in a complex matrix, such as the one of spent catalysts, containing various crystalline phases, and one or more amorphous ones, resulting in a structured and high intensity background. The active catalytic phase zeolite Y is still present, even though with broader peaks; it clearly underwent some temperature driven decomposition reaction, as mullite is present in substantial amount.
Anatase is usually present in FCC catalyst as an active matrix component and specifically as the active phase of vanadium traps [ 1213 ]. Moreover, the structured background is a sign that the process of thermal decomposition of zeolite Y was almost complete, as an amorphous phase is definitely present. Authorization to download zoom text adaptive ware in trash diffraction pattern of a typical spent catalyst sample with phase identification.
All the other peaks belong to zeolite Y. The phase identification has been performed by texy of PANalytical Highscore authorization to download zoom text adaptive ware in trash [ 14 ]. In particular, the Rietveld method will not be easy to apply, as it requires an internal standard for the quantification of the amorphous component, with some issues on the accuracy [ 15 ]. The Rietveld method, in fact, normalises the phase fractions, so that their sum is 1. In this way, only crystalline phases are taken into account in the quantification, leading to a gross overestimation of the crystalline components /23566.txt when the amorphous authorization to download zoom text adaptive ware in trash is large, like in this case.
The only way to use the Rietveld method, when an посмотреть еще component is present, is to couple it with RIR method, by means of addition of an internal standard; the procedure, however, is long adsptive complex, subjected to quite large errors in the amorphous content evaluation, and to issues in the choice of the proper internal standard [ 15 ].
The idea was then to check whether NiO was still detectable in a complex matrix: small amounts of NiO were downlozd to a spent catalyst with a very low amount of nickel determined by XRF, as shown in the experimental section. Figure 6 shows the corresponding powder diffraction patterns. The inset shows a zoom of the data, where NiO peaks are well visibile above the background. Comparison of powder diffraction patterns of a spent catalyst with known quantities of NiO. In the inset, a zoom of the graph, where the peaks from NiO are clearly visible.
The samples of the spent catalyst with added Источник статьи Fig. The presence of an amorphous phase, in fact, usually constitutes an issue in the quantification of very small amount of crystalline materials by means of powder diffraction.
The introduction of known quantities of the studied species in one of such samples, should help to understand how and if the calibration lines are working in such ill-condition cases. In the same way as previously done, the calibration for peak area and peak heights were used and compared. Table 5 autthorization the results. The peak areas and the peak height were determined using PANalytical Highscore plus [ 14 ].
The last column, i. Even though the accuracy is not optimal, the method is very quick and reliable. The relative differences are much larger than those estimated for the samples with fresh zeolite Y see for comparison Table 4.
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See how global opinion research from Fieldwork by Citrix can help business leaders, IT leaders, and employees build the new world of work. Read the report. Manage licenses Renew maintenance. Back to Glossary. Adaptive authentication is a method for verifying user identity and authorization levels based on factors such as location, device status, and end user behavior. Using these contextual factors, adaptive authentication intelligently chooses how a user must authenticate.
Because the factors are continually assessed throughout the user session, rather than just once, this authentication method delivers zero trust and improves security. Explore additional adaptive authentication topics:. Today’s companies are more flexible than ever in the way they handle and support employee technology use. Full-time remote or hybrid employment models allow team members to log in and work from a wide variety of locations, and bring-your-own-device BYOD policies enable the use of numerous kinds of endpoints.
These increases in adaptability are empowering to companies, in many cases allowing them to get more productivity from their teams. However, unless they come with security improvements, businesses may fall victim to IT threats specifically designed to target weak points in devices and networks. This is where adaptive authentication comes in: Rather than using a rigid set of policies that are enforced on every device and user indiscriminately, this methodology involves authentication and authorization levels based on factors such as user role, location, device status, and end user behavior.
One-size-fits-all IT security no longer applies to today’s digital ecosystems. Any inflexible policy will naturally be too restrictive or too lenient when applied to the way today’s employees work. Adaptive authentication is the answer to this conundrum, ensuring there’s a balance between locked-down security and user convenience.
Adaptive authentication is a risk-based authentication approach. This means the primary system involved, the risk engine, will continually determine what type of authentication mechanism is to be used—biometrics, SMS codes, one-time passwords, and so on—and what level of authorization a user should have to applications based on location, device posture, and user risk profile.
This determination is not only made at the time of login, but is continually evaluated throughout the end user session. The main question the authentication engine will continually test for is this: Is a legitimate user accessing the app, system, or network resource for productive not malicious reasons?
Rather than making this determination once when a user logs in at the beginning of a session, there are real-time reassessments. The risk engine uses several factors as fuel for analytics, determining whether a specific user session poses an elevated risk. It then selects the authentication type and what level of access to grant based on preferences set by administrators.
In all low-risk activity, any changes to permissions are invisible to the individual user, ensuring there are no interruptions to the experience. There are a few degrees of action that can be implemented depending on what the risk engine discovers in real-time.
For example, if there is perceived risk based on a user’s behavior, device type or another factor, the system can start monitoring activity. In the case of a higher degree of risk, the user can be forced to confirm their identity through a multi-factor authentication MFA mechanism.
Of course, if the risk score is high, the system can simply block access altogether. Administrators can configure granular policies as part of the adaptive authentication process.
Other options, when faced with a high-risk profile, include the ability to turn off features of user devices such as USB drives or screenshot functionality, to make sure those devices aren’t used to introduce threats to the network.
Implementing adaptive authentication policies is part of a zero trust security approach. This means users and their devices don’t automatically gain access to network resources or corporate data simply because they have logged in with correct credentials such as a username and password.
Rather, their security posture is always assessed and verified. Considering the world of security threats facing today’s companies, zero trust strategies have an important role to play for businesses of all kinds.
The possibilities for breaches are near-endless; a user’s credentials may be compromised through a spear-phishing attack, a mobile device could be compromised, lost, or stolen, or a home or business Wi-Fi network may be compromised, all creating a need for a blanket security strategy to guard against any kind of compromise. An organization looking to securely support its growing hybrid workforce can combine adaptive authentication with single sign-on SSO methods.
This means users will be able to log into all corporate applications with a single set of authentication credentials. What systems, tools, apps, and solutions can companies grant access to using access control methods powered by intelligent adaptive authentication? The answer is, anything and everything. When using virtual applications or virtual desktops , businesses can deliver a full-featured experience to remote and hybrid workforces.
These full-featured remote experiences, which would have previously only been possible through methods such as VPN, are now more flexible and user-friendly than ever, with features such as adaptive authentication powering this evolution.
Of course, replicating a desktop experience is only one type of remote access. An increasing number of companies are relying more heavily than ever before on cloud-hosted software-as-a-service SaaS applications. These, too, can become part of a zero trust architecture based around adaptive authentication.
However, in practice, employees still need a secure way to log in to mission-critical applications. Adaptive authentication can play a role in defending these essential software tools against unauthorized use. Deciding to adopt a zero trust network access approach powered by an adaptive authentication solution is the first step in modernizing a company’s approach to remote work and security.
The next step is to ensure the business has the best possible partner for this journey. This is where Citrix Secure Private Access stands out from all competing solutions, delivering an advanced access and security experience with features including:.
Many organizations no longer have a choice regarding whether to move to a hybrid work model. This is simply the way business will be conducted in the years ahead, and it’s now up to IT to ensure the remote access experience is as secure and convenient as possible. What is secure remote access. See how Citrix delivers zero trust access to all IT corporate apps. In North America: 1 Solutions Solutions. Digital Workspaces. DaaS and VDI. Secure Access. Application Delivery.
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Contact us. Sign in. Sign Out. How Does Adaptive Authentication Work? What is adaptive authentication? Explore additional adaptive authentication topics: Why is adaptive authentication important? How does adaptive authentication work?
Why should organizations use adaptive authentication? How can organizations use adaptive authentication? Citrix solutions for adaptive authentication. Why is adaptive authentication important? Additional resources. What is BYOD security? Learn how to securely enable a hybrid work model with Citrix Secure Private Access. Request a demo. Request a call.
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