scholarly journals EXPLORATION OF INTERCALATED KAOLINITE CLAY FOR THE UPTAKE OF BASIC DYE BY ADSORPTION − EQUILIBRIUM, KINETICS AND THERMODYNAMIC STUDIES

2021 ◽  
Vol 46 (1) ◽  
Author(s):  
C. E. Chigbundu ◽  
K. O. Adebowale

Dyes are complex and sensitive organic chemicals which exposes microbial populations, aquatic lives and other living organisms to its toxic effects if their presence in water bodies or industrial effluents are not properly handled. This work therefore, comparatively studied the adsorption efficiencies of natural raw kaolinite (NRK) clay adsorbent and dimethyl sulphoxide (DMSO) faciley intercalated kaolinite clay (DIK) adsorbent for batch adsorption of Basis Red 2 (BR2) dye. The impact of varying the contact time, temperature and other operating variables on adsorption was also considered. The two adsorbents were characterized using SEM images, FTIR and XRD patterns. Linear and non-linear regression analysis of different isotherm and kinetic models were used to describe the appropriate fits to the experimental data. Error analysis equations were also used to measure the goodness-of-fit. Langmuir isotherm model best described the adsorption as being monolayer on homogenous surfaces while Kinetic studies showed that Elovich model provides the best fit to experimental data. The adsorption capacities of NRK and DIK adsorbents for the uptake of BR2 were 16.30 mg/g and 32.81 mg/g, respectively (linear regression) and 19.30 mg/g and 30.81 mg/g, respectively (non-linear regression). The thermodynamic parameter, ∆G showed that BR2 dye adsorption onto the adsorbents were spontaneous. DIK adsorbent was twice efficient compared with NRK for the uptake of BR2 dye.

Author(s):  
MILTON CANO-CHAUCA ◽  
AFONSO M. RAMOS ◽  
PAULO C. STRINGHETA ◽  
JOSÉ ANTONIO MARQUES ◽  
POLLYANNA IBRAHIM SILVA

Curvas de secagem de banana passa foram determinadas, utilizando-se três temperaturas do ar de secagem. Os resultados indicaram que para reduzir o teor de umidade do produto até 23,5% foram necessários tempos de secagem de 51, 36 e 30 horas paras as temperaturas de 50, 60 e 70ºC, respectivamente. O modelo exponencial U/Uo = exp(-kt) foi ajustado para os dados experimentais mediante análise de regressão não-linear, encontrandose alto coeficiente de regressão linear. Determinou-se a atividade de água do produto ao longo do processo de secagem para as três temperaturas testadas. Estudou-se a correlação entre a atividade de água e o teor de umidade do produto, determinando-se as isotermas de dessorção da banana passa a 25ºC. Observou-se que a atividade de água diminuiu em função do tempo de secagem e do teor de umidade para as três temperaturas de secagem. Os dados experimentais foram ajustados mediante regressão não-linear ao modelo polinomial e a seguinte equação foi obtida: U = -1844,93 + 7293,53Aa – 9515,52Aa2 + 4157,196Aa3. O ajuste mostrou-se satisfatório (R2 > 0,90). DRYING CURVES AND WATER ACTIVITY EVALUATION OF THE BANANA-PASSES Abstract Banana drying curves were determined by utilizing three drying air temperatures. The results indicated that to reduce the moisture content of the product until 23.5% it were necessary drying times of 51, 36 and 30 hours for temperatures of 50, 60 and 70ºC, respectively. The exponential model U/Uo = exp(-kt) was adjusted for the experimental data by means of non linear regression analysis, and a high coefficient of linear regression was found. The water activity of the product was determined throughout the drying process for the three tested temperatures. The correlation between the water activity and moisture content of the product was studied, and the sorption isotherms were determined at 25º C. It was observed that the water activity decreased in function to the drying time and moisture content for the three drying temperatures. The experimental data were adjusted by means of non linear regression to the polynomial model and the following equation was obtained: U = - 1844.93 + 7293.53A a – 9515.52 Aa 2 + 4157.196A a 3. The final adjust was satisfactory (R2 > 0.90).


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 454.1-454
Author(s):  
N. Schlesinger ◽  
A. Yeo ◽  
P. Lipsky

Background:Hyperuricemia is associated with non-alcoholic fatty liver disease (NAFLD)1,2, but the relationship to fibrosis remains uncertain3. Moreover, it is not known whether lowering serum urate will affect the course of NAFLD. The availability of data from two randomized trials of pegloticase, a pegylated recombinant mammalian uricase, that profoundly decreases serum urate afforded the opportunity to test the hypothesis that lowering urate might improve NAFLD.Objectives:To determine whether treatment of chronic refractory gout patients with pegloticase was associated with improvement in NAFLD determined by Fibrosis 4 index (Fib4).Methods:Databases from patients with chronic refractory gout who participated in two randomized 6 month clinical trials (RCTs) of pegloticase were analyzed4. Sub-sets who had persistent urate lowering to levels <1 mg/dL in response to biweekly pegloticase (Responders, n=36) were compared to those who received placebo (n=43). Since liver biopsy information was not available on these subjects, we relied on Fib4, a validated non-invasive estimate of liver fibrosis in a variety of liver diseases5,6calculated from measurements of AST, ALT, platelet count and age (Age x AST/platelets x √ALT). A Fib4 value of 1.3 is an indication that further evaluation of liver disease is warranted.Results:At baseline, the mean Fib4 values were 1.40 ± 0.86 in pegloticase responders and 1.04 ± 0.53 in subjects receiving placebo. As shown in figure 1, subjects receiving placebo exhibited a change of 0.26 ± 0.41 in the Fib4 score over the six months of the RCTs compared with 0.13 ± 0.62 in the pegloticase responders (p=0.048; by linear regression). When only the subjects with a Fib4 value > 1.3 were considered, a significant difference in the change in the Fib4 values over the 6 months of the trial between pegloticase responders and those receiving placebo was also observed (-0.15 ± 0.67 vs 0.37 ± 0.42, p=0.004, by linear regression). The correlations between serum urate area under the curve (AUC) over the 6 months of the trial and the change in Fib4 value was rs=0.33, p=0.0.0004 (Spearman rank-order correlation coefficient). Finally, multiple linear regression analysis indicated serum urate AUC (as a surrogate measure for group) is the main contributor to the change in Fib4 (p=0.018 by linear regression).Conclusion:The data are consistent with the conclusion that persistent lowering of serum urate had a significant impact on Fib4 levels, implying a possible effect on the course of NAFLD. The results support a more complete analysis involving biopsy examination of the impact of urate on liver inflammation and fibrosis.References:[1]Yang C et al. PlosOne2017; 12:e0177249[2]Jaruvongvanich V et al. Eur J Gastroenterol Hepatol 2017; 29:1031[3]Jaruvongvanich V et al. Eur J Gastroenterol Hepatol 2017; 29:694[4]Sundy JS, et al. JAMA. 2011; 306 (7):711-20[5]Sterling RK et al. Hepatol 2006; 43:1317[6]Shah AG et al. Clin Gastroenterol Hepatol 2009;7:1104Disclosure of Interests: :Naomi Schlesinger Grant/research support from: Pfizer, Amgen, Consultant of: Novartis, Horizon Therapeutics, Selecta Biosciences, Olatec, IFM Therapeutics, Mallinckrodt Pharmaceuticals, Anthony Yeo Employee of: Horizon Therapeutics, Peter Lipsky Consultant of: Horizon Therapeutics


Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 299
Author(s):  
Jaime Pinilla ◽  
Miguel Negrín

The interrupted time series analysis is a quasi-experimental design used to evaluate the effectiveness of an intervention. Segmented linear regression models have been the most used models to carry out this analysis. However, they assume a linear trend that may not be appropriate in many situations. In this paper, we show how generalized additive models (GAMs), a non-parametric regression-based method, can be useful to accommodate nonlinear trends. An analysis with simulated data is carried out to assess the performance of both models. Data were simulated from linear and non-linear (quadratic and cubic) functions. The results of this analysis show how GAMs improve on segmented linear regression models when the trend is non-linear, but they also show a good performance when the trend is linear. A real-life application where the impact of the 2012 Spanish cost-sharing reforms on pharmaceutical prescription is also analyzed. Seasonality and an indicator variable for the stockpiling effect are included as explanatory variables. The segmented linear regression model shows good fit of the data. However, the GAM concludes that the hypothesis of linear trend is rejected. The estimated level shift is similar for both models but the cumulative absolute effect on the number of prescriptions is lower in GAM.


2000 ◽  
Vol 14 (5-6) ◽  
pp. 667-692 ◽  
Author(s):  
E. V. Bystritskaya ◽  
A. L. Pomerantsev ◽  
O. Ye. Rodionova

2016 ◽  
Vol 5 (3) ◽  
Author(s):  
Basri Basri

The objective of the study was to evaluate the impact of stores existence toward sales turnover of stalls in Mataram city. Associative research design was adopted as the study guide. Purposive sampling techniques were used in which 100 copies of the research instrument were administered to stalls owner in Mataram city, out of which 100 copies of questionnaire were filled and returned. Test of validity and reliability, classical assumption test, and multiple linear regression analysis was used to analyse the data generated from respondents. The findings revealed that stores existence variable consisted of services, product diversification, price, and comfortable of consumer have significant influence on sales turnover of stalls at 0,05 level (2-tailed). The result of the research shows the variables negatively affecting sales turnover of stalls. Furthermore, price ranks the first follow by comfortable, product diversification, and services. This research will help the owner of stalls to understand and recognize the ranking of variables affecting sales turnover of stalls in Mataram city. Keywords:   Stores Existence, Stall, and Sales Turnover.


2022 ◽  
Vol 18 (1) ◽  
pp. 80-100
Author(s):  
Rahayu Mardikaningsih ◽  
Samsul Arifin

Human assets as one of the elements of manufacturing are the riding pressure of each organisation. They have a main function in understanding the organisation's goals. Companies ought to constantly inspire them to offer the excellent paintings effects in order that organisation sports aren't hampered consistent with their workload and responsibilities. Good paintings effects are primarily based totally at the lifestyles of a cause for fulfillment and there are numerous variables that have effect on this. This studies targets to research and decide the impact of labor supervision, paintings revel in, and paintings cappotential on fulfillment motivation. This quantitative studies takes the populace targeted on personnel who paintings withinside the manufacturing phase of a multinational organisation in Sidoarjo. Respondents on this observe have been a hundred and twenty respondents. The analytical device used, particularly SPSS model 25 program. The sampling method on this observe the usage of purposive sampling method. The analytical device used is more than one linear regression analysis. The effects confirmed that each one hypotheses have been demonstrated correct. Work supervision has a massive effective impact on fulfillment motivation. Work revel in and paintings cappotential even have a massive have effect on fulfillment motivation. The 3 of them offer a massive impact concurrently on fulfillment motivation. Keywords: job supervision, work experience, work ability, achievement motivation.


2021 ◽  
Author(s):  
Eva Trisnawati Chumairoh ◽  
Trianggoro Wiradinata

This purpose of this study was to determine the effect of leadership, motivation and discipline on employee performance. The independent variables were leadership (X1), motivation (X1) and discipline (X3). The dependent variable was employee performance (Y). This was explanatory research with a quantitative approach. The study was conducted at PT Surabaya Marine with employees. Data analysis was carried out through multiple linear regression analysis with the F test and t test. Employee performance was strongly influenced by leadership, motivation and discipline. Keywords: leadership, motivation, discipline, employee performance


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