scholarly journals Robust Optimization of Alginate-Carbopol 940 Bead Formulations

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
J. M. López-Cacho ◽  
Pedro L. González-R ◽  
B. Talero ◽  
A. M. Rabasco ◽  
M. L. González-Rodríguez
Keyword(s):  
Robust Optimization ◽  
Signal To Noise Ratio ◽  
High Variability ◽  
Point Of View ◽  
Orthogonal Array Design ◽  
Complex Activity ◽  
Drug Release Profile ◽  
Independent Variables ◽  
Taguchi Orthogonal Array ◽  
Carbopol 940

Formulation process is a very complex activity which sometimes implicates taking decisions about parameters or variables to obtain the best results in a high variability or uncertainty context. Therefore, robust optimization tools can be very useful for obtaining high quality formulations. This paper proposes the optimization of different responses through the robust Taguchi method. Each response was evaluated like a noise variable, allowing the application of Taguchi techniques to obtain a response under the point of view of the signal to noise ratio. AL18Taguchi orthogonal array design was employed to investigate the effect of eight independent variables involved in the formulation of alginate-Carbopol beads. Responses evaluated were related to drug release profile from beads (t50%and AUC), swelling performance, encapsulation efficiency, shape and size parameters. Confirmation tests to verify the prediction model were carried out and the obtained results were very similar to those predicted in every profile. Results reveal that the robust optimization is a very useful approach that allows greater precision and accuracy to the desired value.

Effect of autumn feeding on dynamics of rectal congestion with excrement in carpathian breed honey bees

2020 ◽  
pp. 26-28
Author(s):  
Olesya V Strelbitskaya ◽  
◽  
Vladimir I. Kravchenko ◽  
Keyword(s):  
Point Of View ◽  
Theory And Practice ◽  
Complex Activity ◽  
Important Indicator ◽  
Apple Cider ◽  
Sugar Syrup ◽  
Main Indicator ◽  
Biological Laws ◽  
Honey Solution ◽  
Bee Colonies

Basic biological laws that govern the life of the bee family, as well as considering it as a whole organism, are necessary instruments for implementing effective methods of beekeeping and increasing the productivity of the industry. The study of the exterior features of bees must be carried out from different points of view for the concept of the complex activity of the bee family and in order to recommend methods for improving the preparation of bees for winter. Study of the mass of working bees and their rectum began to be used as the main indicator that affects the nature of the preparation of bee individuals for wintering. From the point of view of both theory and practice, filling the rectum with excrement in the autumn period will be an important indicator of an effective wintering in terms of preserving and further developing bee colonies. Effect of two kinds of liquid top feeding acidified with apple cider vinegar on the rectum congestion with excrement in working bees in the autumn, and the safety of bee colonies after winter was discussed in the article. The results of the indicators of the mass of working bees and intestinal mass when feeding two types of top dressing in the form of sugar syrup and honey solution with the addition of apple cider vinegar for the purpose of acidification are presented. The dynamics of rectal congestion in this group of bees is less compared to the group of bees receiving food in the form of sugar syrup. After wintering, during the spring audit, it was found that the safety of bees fed the autumn top dressing in the form of a honey solution with the addition of apple cider vinegar was 95% compared to bee families that received sugar syrup, the safety was 80.5%, with the detection of liquid excrement on the walls of hives and honeycombs

Kinematic interpretation in the prestack depth‐migrated domain

Geophysics ◽  
1997 ◽  
Vol 62 (4) ◽  
pp. 1226-1237 ◽  
Author(s):  
Irina Apostoiu‐Marin ◽  
Andreas Ehinger
Keyword(s):  
Signal To Noise Ratio ◽  
Velocity Model ◽  
Point Of View ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Velocity Models ◽  
Time Domain Data ◽  
And Migration ◽  
Point To Point ◽  
Homogeneous Media

Prestack depth migration can be used in the velocity model estimation process if one succeeds in interpreting depth events obtained with erroneous velocity models. The interpretational difficulty arises from the fact that migration with erroneous velocity does not yield the geologically correct reflector geometries and that individual migrated images suffer from poor signal‐to‐noise ratio. Moreover, migrated events may be of considerable complexity and thus hard to identify. In this paper, we examine the influence of wrong velocity models on the output of prestack depth migration in the case of straight reflector and point diffractor data in homogeneous media. To avoid obscuring migration results by artifacts (“smiles”), we use a geometrical technique for modeling and migration yielding a point‐to‐point map from time‐domain data to depth‐domain data. We discover that strong deformation of migrated events may occur even in situations of simple structures and small velocity errors. From a kinematical point of view, we compare the results of common‐shot and common‐offset migration. and we find that common‐offset migration with erroneous velocity models yields less severe image distortion than common‐shot migration. However, for any kind of migration, it is important to use the entire cube of migrated data to consistently interpret in the prestack depth‐migrated domain.

STOCHASTIC RESONANCE IN CHUA’S CIRCUIT DRIVEN BY AMPLITUDE OR FREQUENCY MODULATED SIGNALS

1994 ◽  
Vol 04 (02) ◽  
pp. 441-446 ◽  
Author(s):  
V.S. ANISHCHENKO ◽  
M.A. SAFONOVA ◽  
L.O. CHUA
Keyword(s):  
Numerical Simulation ◽  
Stochastic Resonance ◽  
Signal To Noise Ratio ◽  
Point Of View ◽  
Chua’S Circuit ◽  
Signal Distortion ◽  
Signal To Noise ◽  
Chua's Circuit ◽  
Noise Ratio ◽  
Modulated Signals

Using numerical simulation, we establish the possibility of realizing the stochastic resonance (SR) phenomenon in Chua’s circuit when it is excited by either an amplitude-modulated or a frequency-modulated signal. It is shown that the application of a frequency-modulated signal to a Chua’s circuit operating in a regime of dynamical intermittency is preferable over an amplitude-modulated signal from the point of view of minimizing the signal distortion and maximizing the signal-to-noise ratio (SNR).

scholarly journals Alterações dimensionais em pastas de óxido de zinco/eugenol: um novo método para sua mensuração

2021 ◽  
pp. 39-55
Author(s):  
Léo Werner Süffert ◽  
Ennio Pessôa
Keyword(s):  
Standard Deviation ◽  
Personal Information ◽  
High Variability ◽  
Point Of View ◽  
New Method ◽  
Extensive Review ◽  
Review Of The Literature ◽  
Dimensional Changes ◽  
Impression Materials ◽  
Clinical Point

After an extensive review of the literature, regarding zinc.oxide/eugenol impression pastes, we selected 20 of the most representatives as our references. Trough personal information of several of the investigators it was discovered that dimensional changes of theese materials is one of the most difficult properties to be measured. A new method was developed to measure dimensional changes ot 4 (four) of the most widely used zinc.oxide/eugenol impression materials in Brazil. The results, presented through several graphs and tables showed that dimensional changes varied from 0,003%, values which may probably be considered negligible from a clinical point of view. We noticed, however, high values for standard deviation and variance which indicate the high variability within the experiments. Those values were not found when we used the same method with mercaptan and silicone impression materials, in which the measurement of dimensional changes was highly reproducible. One hypothesis (which we intend to investigate in a later research) is that, during storage, a sedimentation could occur, of the components of greater density! Consequently ther might result a change in composition, independent of the method used to establishe the proportion of the two pastes, be it by wheight or measurement of lenght, which could be the cause of variability of the composition of each mixture!

scholarly journals NOISE STABILITY OF SIGNAL RECEPTION ALGORITHMS WITH MULTIPULSE PULSE-POSITION MODULATION

2018 ◽  
Vol 42 (1) ◽  
pp. 167-174 ◽  
Author(s):  
V. I. Parfenov ◽  
D. Y. Golovanov
Keyword(s):  
Communication Systems ◽  
Pulse Sequence ◽  
Signal To Noise Ratio ◽  
Point Of View ◽  
Estimation Accuracy ◽  
Pulse Position Modulation ◽  
Signal To Noise ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Noise Ratio

An algorithm for estimating time positions and amplitudes of a periodic pulse sequence from a small number of samples was proposed. The number of these samples was determined only by the number of pulses. The performance of this algorithm was considered on the assumption that the spectrum of the original signal is limited with an ideal low-pass filter or the Nyquist filter, and conditions for the conversion from one filter to the other were determined. The efficiency of the proposed algorithm was investigated through analyzing in which way the dispersion of estimates of time positions and amplitudes depends on the signal-to-noise ratio and on the number of pulses in the sequence. It was shown that, from this point of view, the efficiency of the algorithm decreases with increasing number of sequence pulses. Besides, the efficiency of the proposed algorithm decreases with decreasing signal-to-noise ratio.It was found that, unlike the classical maximum likelihood algorithm, the proposed algorithm does not require a search for the maximum of a multivariable function, meanwhile characteristics of the estimates are practically the same for both these methods. Also, it was shown that the estimation accuracy of the proposed algorithm can be increased by an insignificant increase in the number of signal samples.The results obtained may be used in the practical design of laser communication systems, in which the multipulse pulse-position modulation is used for message transmission. 

scholarly journals Collecting Microplastics in Gardens: Case Study (i) of Soil

2021 ◽  
Vol 9 ◽  
Author(s):  
Zahra Sobhani ◽  
Yunlong Luo ◽  
Christopher T. Gibson ◽  
Youhong Tang ◽  
Ravi Naidu ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Point Of View ◽  
Signal To Noise ◽  
Statistical Point ◽  
Image Mapping ◽  
Noise Ratio ◽  
In The Beginning ◽  
Raman Image ◽  
Selection Of

As an emerging contaminant, microplastic is receiving increasing attention. However, the contamination source is not fully known, and new sources are still being identified. Herewith, we report that microplastics can be found in our gardens, either due to the wrongdoing of leaving plastic bubble wraps to be mixed with mulches or due to the use of plastic landscape fabrics in the mulch bed. In the beginning, they were of large sizes, such as > 5 mm. However, after 7 years in the garden, owing to natural degradation, weathering, or abrasion, microplastics are released. We categorize the plastic fragments into different groups, 5 mm–0.75 mm, 0.75 mm–100 μm, and 100–0.8 μm, using filters such as kitchenware, meaning we can collect microplastics in our gardens by ourselves. We then characterized the plastics using Raman image mapping and a logic-based algorithm to increase the signal-to-noise ratio and the image certainty. This is because the signal-to-noise ratio from a single Raman spectrum, or even from an individual peak, is significantly less than that from a spectrum matrix of Raman mapping (such as 1 vs. 50 × 50) that contains 2,500 spectra, from the statistical point of view. From the 10 g soil we sampled, we could detect the microplastics, including large (5 mm–100 μm) fragments and small (<100 μm) ones, suggesting the degradation fate of plastics in the gardens. Overall, these results warn us that we must be careful when we do gardening, including selection of plastic items for gardens.

scholarly journals HUNGARIAN AND SLOVAK ISSUES IN THE TEXTS OF LAJOS HAAN IN THE BACKGROUND OF CULTURAL AND LITERARY SCIENCE

2020 ◽  
Vol 14 (4) ◽  
pp. 659-674
Author(s):  
Patrik Šenkár
Keyword(s):  
Cultural Context ◽  
Point Of View ◽  
Integrative Model ◽  
Cultural Identification ◽  
Peaceful Coexistence ◽  
Complex Activity ◽  
Cultural Center ◽  
Historical Basis ◽  
Characteristic Features ◽  
The City

Slovaks living abroad form an integral part of the Slovak national cultural context. They create values that need to be preserved, enhanced and point out their versatility and use for contemporary forms of cultural identification. Slovaks in Hungary, who have been living in the vicinity of Békéscsaba for more than three hundred years, are also an important component of the Slovak minority of Hungarian Lowland. From this “Slovak Palestine”, as Ján Kollár named it, in the 18th and 19th century a historical-religious-cultural center of Slovaks (and also Hungarians) was created, which can still be rightfully proud of its heritage. Being a part of it, as a kind of pioneer, even as a historical basis, is also the personality of Lajos Haan (1818-1891), who performed his versatile activity in the chronotope of “Hungarian and Slovak” Békéscsaba. In this spirit, the article interprets his letters, his diary, “Pamätnosti” (Memoirs) and “Dejiny” (History), while presenting material and immaterial sources, monuments, inspirations that have been, are and will certainly be useful in artistic, cultural and literary “communication”. It is based on the attributes of cultural and literary science, which is thus an integrative model of literature research: a set of approaches that focus on cultural topics, theories and methods. The region of Békéscsaba ( pars pro toto: contemporary Hungary) is its focus. In selected texts of his material writings, Lajos Haan reflects his closer understanding of cooperation with the environment, from a broader point of view the intra- and interculturality of Hungarians and Slovaks: their coexistence, cooperation and diverse creative efforts. It points out the importance of Haanʼs personal contacts within the contemporary social environment, which is also specified in his personal letters. Memoirs are a testimony of an intellectual from the second half of the 19 century; to today's reader they will reveal the “strange, interesting, Hungarian” atmosphere of the time - in the background of social, political, historical, cultural and literary attributes. The description of the characteristic features of the city is a symbol of the peaceful coexistence of nations and nationalities in the Lowlands. In fact, the article presents the complex activity of an unusual personality: a Hungarian historian and a Slovak priest in one person, Lajos Haan, whose texts are interesting and current for today.

scholarly journals Ranitidine Loaded Biopolymer Floats: Designing, Characterization, and Evaluation

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Abdul Karim ◽  
Muhammad Ashraf Shaheen ◽  
Tahir Mehmood ◽  
Abdul Rauf Raza ◽  
Musadiq Aziz ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Lag Time ◽  
Zero Order ◽  
Release Profile ◽  
Drug Release Profile ◽  
Independent Variables ◽  
Zero Order Kinetics ◽  
Model Drug ◽  
Predicted Values

The float formulation is a strategy to improve the bioavailability of drugs by gastroretentive drug delivery system (GRDDS). A drug delivery model based on swellable and reswellable low density biopolymers has been designed to evaluate its drug release profile using ranitidine (RNT) as a model drug and formulations have been prepared utilizing 32factorial designs. The drug release (DR) data has been subjected to various kinetic models to investigate the DR mechanism. A reduction in rate has been observed by expanding the amounts of PSG and LSG parts, while an expansion has been noted by increasing the concentration of tragacanth (TG) and citric acid (CA) with an increment in floating time. The stearic acid (SA) has been used to decrease the lag time because a decrease in density of system was observed. The kinetic analysis showed that the optimized formulation (S4F3) followed zero-order kinetics and power law was found to be best fitted due to its minimum lag time and maximum floating ability. The resemblance of observed and predicted values indicated the validity of derived equations for evaluating the effect of independent variables while kinetic study demonstrated that the applied models are feasible for evaluating and developing float for RNT.

The Human Controller as an Adaptive, Low Pass Filter

1967 ◽  
Vol 9 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Gordon H. Robinson
Keyword(s):  
Signal To Noise Ratio ◽  
Noise Signal ◽  
Manual Control ◽  
Future Research ◽  
Research Needs ◽  
Descriptive Model ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Independent Variables ◽  
Low Pass

Data is presented on the ability of a human controller to track a signal contaminated with noise. Signal frequencies and signal-to-noise ratio are the independent variables. An optimal, adaptive filter is presented for comparison. A descriptive model is derived based on known human characteristics in manual control. Future research needs are discussed.

scholarly journals A Critical Review of the Support for Variability as an Operant Dimension

2020 ◽  
Vol 43 (3) ◽  
pp. 579-603 ◽  
Author(s):  
Siv Kristin Nergaard ◽  
Per Holth
Keyword(s):  
Animal Behavior ◽  
Critical Review ◽  
Dynamic Interaction ◽  
High Variability ◽  
Behavioral Variability ◽  
Independent Variables ◽  
Abundant Evidence ◽  
Alternative Hypotheses ◽  
Direct Reinforcement ◽  
Underlying Mechanisms

AbstractThere is abundant evidence that behavioral variability is more predominant when reinforcement is contingent on it than when it is not, and the interpretation of direct reinforcement of variability suggested by Page and Neuringer, Journal of Experimental Psychology: Animal Behavior Processes, 11(3), 429–452 (1985) has been widely accepted. Even so, trying to identify the underlying mechanisms in the emergence of stochastic-like variability in a variability contingency is intricate. There are several challenges to characterizing variability as directly reinforced, most notably because reinforcement traditionally has been found to produce repetitive responding, but also because directly reinforced variability does not always relate to independent variables the same way as more commonly studied repetitive responding does. The challenging findings in variability experiments are discussed, along with alternative hypotheses on how variability contingencies may engender the high variability that they undeniably do. We suggest that the typical increase in behavioral variability that is often demonstrated when reinforcement is contingent on it may be better explained in terms of a dynamic interaction of reinforcement and extinction working on several specific responses rather than as directly reinforced.

Sign in / Sign up

Export Citation Format

Share Document