Diatomite Modified With Alkyl Ketene Dimer For Hydrophobicity of Cellulosic Paper

Multi-functionalization of papermaking chemicals is one of its main developing strategies. Fillers and internal sizing agents are often mutually restricted in practice. Therefore, it is feasible to prepare a new papermaking chemical by combining its functions. A process of diatomite modified with Alkyl ketene dimer (AKD) was developed in this study. The modified diatomite (AD) can concurrently play the role of mineral filler and sizing agent in the papermaking process. With the equal dosage of AKD, the AD had better sizing and retention performance than the commercial AKD emulsion in the case of cationic polyacrylamide (CPAM) and the CPAM/ bentonite retention system. The sizing mechanism of the AD can be interpreted as numerous hydrophobic sites and micro-surface structure of the paper sheet caused by the AD. Since the ester linkages were not detected in FT-IR spectra of the paper sheet filled by the AD, the chemical reaction may not be indispensable for its sizing performance. What’s more, an interesting “sticky” hydrophobicity phenomenon was observed when filling with AD. The approach in this study to prepare the “sticky” hydrophobic paper sheet can find its applications in some non-traditional application fields of cellulosic paper.

Sea-ice derived meltwater stratification slows the biological carbon pump: results from continuous observations

The ocean moderates the world’s climate through absorption of heat and carbon, but how much carbon the ocean will continue to absorb remains unknown. The North Atlantic Ocean west (Baffin Bay/Labrador Sea) and east (Fram Strait/Greenland Sea) of Greenland features the most intense absorption of anthropogenic carbon globally; the biological carbon pump (BCP) contributes substantially. As Arctic sea-ice melts, the BCP changes, impacting global climate and other critical ocean attributes (e.g. biodiversity). Full understanding requires year-round observations across a range of ice conditions. Here we present such observations: autonomously collected Eulerian continuous 24-month time-series in Fram Strait. We show that, compared to ice-unaffected conditions, sea-ice derived meltwater stratification slows the BCP by 4 months, a shift from an export to a retention system, with measurable impacts on benthic communities. This has implications for ecosystem dynamics in the future warmer Arctic where the seasonal ice zone is expected to expand.

Intelligent Employee Retention System for Attrition Rate Analysis and Churn Prediction

The paper aims to examine the factors that influence employee attrition rate using the employee records dataset from kaggle.com. It also aims to establish the predictive power of Deep Learning for employee churn prediction over ensemble machine learning techniques like Random Forest and Gradient Boosting on real-time employee data from a mid-sized Fast-Moving Consumer Goods (FMCG) company. The results are further validated through a regression model and also by a multi-criteria Fuzzy Analytical Hierarchy Process (AHP) model which takes into account the relative variable importance and computes weights. The empirical results of the machine learning models indicate that Deep Neural Networks (91.2% accuracy) are a better predictor of churn than Random Forest and Gradient Boosting Algorithm (82.3% and 85.2% respectively). These findings provide useful insights for human resource (HR) managers in an organizational workplace context. The model when recalibrated by the human resource team of organizations helps in better incentivization and employee retention.

Development of a bio-retention system for urban storm water management

Urban stormwater that flows through all the manmade structures contains high levels of BOD TSS, orthophosphate, surfactants etc. It raises concerns of water quality in the receiving natural water courses. Bio-retention is one of the prominent methods of stormwater management for the removal of contaminants from stormwater. In this esxperimental study, a column containing mulch, blast furnace slag, sand, silt etc. was used to assess the removal of suspended solids and nutrients (nitrate and phosphate) from stormwater. The tests were conducted with a flow through period of 3, 7 and 15 days. Removal efficiency of 80% total suspended solids for 15 day, 60% nitrate for 7 days and 70% phosphorous for 3 and 7 days was observed through the column. pH variation was found to be insignificant in the range of 6-7.5.

Intelligent Employee Retention System for Attrition Rate Analysis and Churn Prediction

The paper aims to examine the factors that influence employee attrition rate using the employee records dataset from kaggle.com. It also aims to establish the predictive power of Deep Learning for employee churn prediction over ensemble machine learning techniques like Random Forest and Gradient Boosting on real-time employee data from a mid-sized Fast-Moving Consumer Goods (FMCG) company. The results are further validated through a regression model and also by a multi-criteria Fuzzy Analytical Hierarchy Process (AHP) model which takes into account the relative variable importance and computes weights. The empirical results of the machine learning models indicate that Deep Neural Networks (91.2% accuracy) are a better predictor of churn than Random Forest and Gradient Boosting Algorithm (82.3% and 85.2% respectively). These findings provide useful insights for human resource (HR) managers in an organizational workplace context. The model when recalibrated by the human resource team of organizations helps in better incentivization and employee retention.

Stress distribution in prosthetic abutments: a finite element analysis comparison of conical and UCLA abutments

The effect of prosthetic abutment type on single-screwed prostheses in posterior mandibular molar rehabilitations is not yet known. Thus, the aim of this study was to evaluate the distribution of stresses in the crowns, prosthetic components, implant and bone in implant-supported restorations with or without a prosthetic abutment, maintaining an equal total height of the implant-crown set. Virtual 3-dimensional (3D) finite element models were constructed, the models were designed to represent a posterior single crown rehabilitation with a screwed retention system and external hexagon implants placed in the lower first molar region. Two rehabilitation methods were designed to simulate a monolithic zirconia crown screwed onto a conical abutment, which was screwed onto an external hexagon implant (M1); and a monolithic zirconia crown screwed directly onto the external hexagon implant using an UCLA abutment (M2). An axial load of 200 N was simulated and applied axially in the occlusal region of the restoration divided into 5 points. The quantitative and qualitative description of the maximum principal stress for crowns, von Mises stress for screws, conical abutment and implant; and minimal principal stress for cortical and medullary bone were evaluated. M1 presented similar stress distribution for crowns, cortical and medullary bone compared to M2. Conversely, the stress values were considerably higher for crowns screw and implants in the M2 group. In conclusion, single implant-supported rehabilitations of mandibular first molars using external hexagon implants presented better stress distribution on the crown screw and implants for the M1 group compared to M2.

Evaluation of mulberry branch waste as raw material for nanocellulose synthesis: effects of the synthesis method on product properties

The mechanical pulp of mulberry branches was evaluated as a raw material for the production of cellulose II and its subsequent conversion to nanocellulose via high-pressure homogenization, 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidation, and sulfuric acid hydrolysis. The morphology, chemical structure, crystallinity, and thermal stability of the nanocellulose samples prepared by each method were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, atomic force microscopy, and thermogravimetric analysis. The results showed that nanocellulose prepared by high-pressure homogenization exhibited higher aspect ratio (>100), and the weight loss peak in the DTG chart was 361 °C, with the best thermal stability, whereas that prepared by sulfuric acid hydrolysis featured shorter fiber length (96±31 nm) and a higher crystallinity (78.2 %).The TEMPO oxidized nanocellulose (TOCN) had smaller width (5.5±1.6 nm) and high carboxyl content (1.5 mmol/g). In addition, we have further studied the application of TOCN in the wet end of papermaking, replacing the colloidal SiO2 in CPAM/ colloidal SiO2/APAM retention system with the same amount (3600 ppm) of TOCN. The study found that the strength of the paper obtained by adding TOCN instead of the traditional wet end additives is similar, and the water drainage and retention properties of the pulp are improved.

ACADEMIC RETENTION, RESEARCH CAPACITY, AND SUSTAINABLE DEVELOPMENT IN AFRICAN UNIVERSITIES

There is a shift of interest towards the current pace of development in Africa especially with regard to science and technology. The rate at which advancements are being recorded in this and other sectors has not been encouraging, as evident from official records. Scholars and researchers in various disciplines have correlated development to education and identified close associations between the level of performance of any citizenry or manpower, and the quality of its education. Accordingly, the quality of life and experience on the African continent has, to an appreciable extent, been characterised as the output variable and the quality of education including that of the teachers, as the input variable. The antecedent variable, too, which in this context is the totality of experience that informs educational directions in Africa, is arguably a product of the input variable. Consequently, the tertiary educational level especially the university system, unlike both the primary and the secondary, may be more strongly associated with the quality of performance. This may be explained through the dominant thinking that the tertiary system is primarily concerned with the production of manpower for various sectors. While there is evidence of research into this question, there is insufficient evidence of research into the interplay of the academic retention system and research capacity development orientation in African universities. This paper is an attempt to investigate that hitherto underrepresented dimension. The study employs a combination of the historical method and analytic philosophy. Its significance lies in its potential to expose, with evidence, the association between the dominant academic retention system and research capacity development orientation in African universities, as well as the implication of such an association for sustainable development in Africa. The study ultimately offers an ameliorative proposal for revitalizing an outcome-oriented research capacity development system in African universities.