Optimization of Atmospheric Distillation Unit of Warri Refinery Using Artificial Neural Network and Exergy Rate Profiles

In this paper, the operation of atmospheric distillation unit (ADU) of  Warri refinery was optimized using Artificial Neural Network (ANN) method of optimization and exergy rate profiles (ERP). Optimization of ADU exergy efficiency using nine operating variables and ANN method of optimization improved exergy efficiency from 33% to 53%. The vapour and liquid exergy rate profiles in the distillation column were used to reveal points of inefficiency within the column and as a retrofit tool to suggest possible column modification alternatives for energy efficient operations. The exergy rate profiles in the column were found to be crossing each other. Optimization of the ADU when the crossing of the exergy rate profiles in the column was removed further improved ADU exergy efficiency from 53% to 60%. Artificial neural network was shown to be a powerful and suitable optimization method for solving constrained optimization problems such as in atmospheric distillation unit with several operating variables with constraints. Exergy rate profiles depict the driving forces between the liquid and the vapour states in a column and were shown to be a suitable tool for further improvement of ADU exergy efficiency

A window into the Cambrian basement and early Carboniferous sedimentation of the Hathern Shelf: the British Geological Survey borehole at Ticknall, South Derbyshire, UK

The Ticknall Borehole was drilled in 1995 to a depth of 209 m in order to investigate the succession on the Hathern Shelf, a fault-bounded structural province that lies on the southern margin of the Widmerpool Half-graben, part of a major early Carboniferous rift system. The borehole demonstrated a ‘basement’ of Upper Cambrian cleaved mudrocks, correlated with the Stockingford Shale Group. Unconformably overlying this is a basal Carboniferous unit, the Calke Abbey Sandstone Formation, of probable Visean (?Holkerian) age, comprising 82.34 m of fluvial sandstones and conglomerates, with interbedded red-grey palaeosols exhibiting highly distinctive ‘pseudogley’ fabrics indicative of emergent episodes. The unit may have been deposited in a localized, possibly fault-controlled basin and was in part sourced from the Precambrian volcanic terrain of Charnwood Forest. As rifting and subsidence proceeded, the encroachment of nearshore/peritidal environments is indicated at the top of the formation by interbedded calcilutites that have yielded marine faunas. Fully marine conditions were established during deposition of the overlying Peak Limestone Group, comprising the early Asbian Cloud Hill Dolostone Formation succeeded by the Ticknall Limestone Formation, of Brigantian age. Comparisons between the Ticknall Borehole and Peak Limestone strata exposed in quarries farther east, around Breedon, show major changes in water depths over a distance of only 4.5 km. Such variations can be reconciled with seismostratigraphical studies in the adjacent Widmerpool Half-graben, which show that sedimentation on the Hathern Shelf was in part controlled by movements along nearby rift-bounding faults

Sales and Operations Planning (S&OP): A Group Effectiveness Approach

Sales and Operations planning (S&OP) is an approach meant to help firms achieve demand and supply balance, yet experts agree that it has fallen short on delivering anticipated benefits. Carried out by cross-functional teams, S&OP entails getting people from different thought worlds, especially sales, aligned around common goals. Despite ample practitioner guidance, there is a dearth of scholarly research indicating pathways to success. Using a group effectiveness theoretical framework, this study identifies both internal team factors and contextual influencers that are predictors of S&OP effectiveness. Perspectives were captured from S&OP team members across a wide cross-section of industries representing sales and operations functions using a survey-based approach. Results indicate that internal team factors of social cohesion and decision making autonomy are key drivers of collaboration. Similarly, information quality, procedural quality, and team-based rewards/incentives serve as contextual influencers of collaboration. In turn, collaboration serves as a central mediator, partially linking antecedents to S&OP effectiveness and also serving as a direct influencer of success. Moreover, having joint rewards and incentives, which is often not the case among S&OP teams, is the greatest overall driver of S&OP effectiveness. Overall, these findings provide empirically-based guidance for managers seeking to determine which factors are most important for S&OP team success. Additionally, grounding S&OP in principles of group effectiveness theory will also aid future academic study in efforts to help firms achieve greater demand and supply balance

Relationship between climatic variability and water footprint of sugarcane at Dangote Sugar company Numan, Nigeria

This study investigated the relationship between climatic  variability and water footprint of sugarcane at Dangote SugarCompany (formerly Savannah Sugar Company) Numan, Nigeria. The objective of the study was to assess the level of the effect of climatic elements- rainfall, temperature, relative humidity,  sunshine and wind speed, on sugarcane production. Three sets of data were required for the study, including climatic, soil and crop parameters. Soil and crop data were unavailable. However, CROPWAT model package of Food and Agricultural Organization contains these data for all ecological zones, study area inclusive. Thirty three years’ climatic data of the area were inputted into themodel and in conjunction with the built-in soil and crop data used to model the relationship between climatic variability and water footprint of sugarcane. Furthermore, correlation and path analyses were later used to investigate the relationship between those  elements using SPSS 22 and SPSS AMOS 21 statistical packages. Results reveal that there is an evidence of climate variability in the area. Blue water footprint (WFblue) value calculated as  172/m2/ton was found to be higher than Green water footprint (WFgreen) of 102m2/ton as well as global average of 57m2/ton, whereas the WFgreen (102m2/ton) was lower than the global average (139m2/ton). This is an indication that sugarcane production is most dependent on WFblue (irrigation). Generally, rainfall, temperature and relative humidity were found to be positively correlated with water footprint whereas sunshine and wind speed were negatively correlated. Overall, climatic factors contribute about 17%, with rainfall being most influential, to water footprint of sugarcane in the area. Despite little contribution of climatic factors to water footprint of sugarcane in the area, it is recommended that the company should institute a comprehensive water consumption scheme for the two water sources (rainfall and dam) to deal with the opposing impacts of climate variability, no matter how meager it may be.Keywords: Sugarcane, Climate variability, CROPWAT, Water footprint, Dangote

Melting of hexagonal skyrmion states in chiral magnets

Skyrmions are spiral structures observed in thin films of certain magnetic materials (Uchida et al 2006 Science 311 359–61). Of the phases allowed by the crystalline symmetries of these materials (Yi et al 2009 Phys. Rev. B 80 054416), only the hexagonally packed phases (SCh) have been observed. Here the melting of the SCh phase is investigated using Monte Carlo simulations. In addition to the usual measure of skyrmion density, chiral charge, a morphological measure is considered. In doing so it is shown that the low-temperature reduction in chiral charge is associated with a change in skyrmion profiles rather than skyrmion destruction. At higher temperatures, the loss of six-fold symmetry is associated with the appearance of elongated skyrmions that disrupt the hexagonal packing

Determinants of Remittance: Panel Evidence From Selected Countries In Africa

The African continent has over 30 million people in the Diaspora and sends over 50 billion US Dollars to theirfamilies and communities back home ahead of FDI and ODA. It is on this premise that this study carries out aninvestigation on the determinants of Remittance across 21 African countries with neat selection from all theregions. The study uses the GMM estimation in a dynamic panel to find out that Remittance receipt of theprevious year, broad money growth, taxes, inflation, lending rate and age dependency ratio are significantdeterminants of remittance, while GDP per capita and real effective exchange rate are not. However, while broadmoney growth, tax revenue, GDP per capita, and real effective exchange rate are inversely related to Remittancereceipt, lending rate, age dependency ratio and inflation are positively related.Keywords: Determinants, Remittance, Africa, Dynamic panel

The Role of Prior Sales Experience of Buyers and Duration in Buyer-Seller Relationships

This paper examines the impact that a buyer’s prior sales experience and the duration of the buyer-salesperson relationship has on the satisfaction and commitment linkages established within the literature. First, two key facets of satisfaction (social and economic) are linked to buyer’s commitment to the salesperson. Next, buyer-salesperson relationship duration is examined as an influencer between the satisfaction and commitment linkages. Following this, the study shifts its focus to examine if and how buyers with prior sales experience view the buyer-salesperson relationship different than buyers without prior sales experience. Findings of the study highlight the importance of developing our understanding of buyer-salesperson relationships with regards to multi-faceted satisfaction, buyer background, and relationship length

Development of a DNA-Liposome Complex for Gene Delivery Applications

The association structures formed by cationic liposomes and DNA(Deoxyribonucleic acid)-liposome have been effectively utilized as gene carriers in transfection assays. In this research study, cationic liposomes were prepared using a modified lipid film hydration method consisting of a lyophilization step for gene delivery applications. The obtained results demonstrated that the mean particle size had no significant change while the polydispersity (PDI) increased after lyophilization. The mean particle size slightly reduced after lyophilization (520 ± 12 nm to 464 ± 25 nm) while the PDI increased after lyophilization (0.094 ± 0.017 to 0.220 ± 0.004). In addition. The mean particle size of vesicles increases when DNA is incorporated to the liposomes (673 ± 27 nm). According to the Scanning Electron Microscopy(SEM) and transmission electron microscopy (TEM) images, the spherical shape of liposomes confirmed their successful preservation and reconstitution from the powder. It was found that liposomal formulation has enhanced transfection considerably compared to the naked DNA as negative control. Finally, liposomal formulation in this research had a better function than Lipofectamine® 2000 as a commercialized product because the cellular activity (cellular protein) was higher in the prepared lipoplex than Lipofectamine® 2000