1,720,976 research outputs found
Holistic analysis of the effect on electricity cost in South Africa’s platinum mines when varying shift schedules according to time-of-use tariffs
Get PDFIn the past the cost of electricity was not a significant concern and was not common practice for mining companies to consider peak time-of-use (TOU) tariffs for their shift schedules. It has become more prevalent, as TOU tariffs continue increasing, to consider energy saving important. A study was carried out to analyse the mining operation of a South African deep-level platinum mine in respect of integrated load management, shift changes and TOU schedules. This was achieved by thoroughly analysing energy consumers, mine operational schedules and their interconnectedness. A specific mining system was analysed as a case study and a maximum savings scenario was determined, using the methodology formulated. The maximum savings scenario schedule change resulted in a 1.3% cost reduction. System improvements had an additional potential reduction effect of 8.4%, which was primarily the result of a reduction in compressors’ power consumption. The implications of the proposed schedule adjustments necessitated a realistic scenario. The realistic scenario had an effective financial reduction of 0.7%. The realistic schedule change, however, opened the door for large system operational improvements, which could increase the reduction potential by 7.6%. The study methods described illustrate the potential implications of integrated load management and operational schedule optimisation on the power demand and cost savings in the mining industry, specifically focusing on deep-level platinum mines
Using specific energy as a metric to characterise compressor system performance
No full textMine compressed air systems are inefficient and complex to analyse. There is no clear method which can be used to characterise the total performance of the supply side system in terms of the air supplied and energy consumed. A simplified and unbiased performance measuring method was lacking from research. An important implication of this study was to develop a simplified method which uses a single metric to determine the performance of a compressed air system relative to the compressor air supply and energy consumption. This metric used minimal information and can be used as a guide to improve performance as well. A compressed air system was analysed before and after project implementation, using the simplified method. The simplified method gave a good indication of the performance change as projects were implemented on the compressed air system, with an improvement of 6% on the average total specific energy from 104 to 98 Wh/m3. The off-peak specific energy decreased from 103 to 94 Wh/m3 which illustrates a 9% improvement. This study showed the possibility to characterise the performance of complex compressed air systems using a simplified metric. It can also be utilised to verify whether supply side initiatives were effectiv
Local benchmarking in mines to locate inefficient compressed air usage
No full textCompressed air is a vital source of energy for deep mines. It is therefore alarming that leaks, wastages, and losses are the highest contributing factors to the deterioration of compressed air network efficiency. However, locating these losses in the extensive underground compressed air networks are both challenging and time-consuming. This study therefore introduces a novel method to locate inefficient compressed air usage in an underground mine. Local benchmarking using the correlation between the compressed air supply and production was thus employed to identify inefficient usage. The methodology was applied to the underground network of a platinum mine as a case study. The proposed local benchmarking methodology was able to identify levels with sizeable compressed air inefficiencies. Verification was then done by implementing wastage reduction initiatives on the entire underground network and comparing the results with the identified levels. It was thus verified that the methodology could be used to identify and prioritise local compressed air inefficiencies in an underground mine. Regression analysis was used to visualise and quantify the improved efficiency of the entire underground compressed air system. Implemented initiatives reduced compressed air consumption while an increase in productivity was observed, which highlights the importance of energy management in an underground mine. The proposed methodology provides a practical support tool that can be used by mine managers for underground compressed air networks. The methodology identifies the potential for compressed air wastage reduction and guides improvement efforts within individual mine
The mechanism by which moderate alcohol consumption influences coronary heart disease
Get PDFBackground
Moderate alcohol consumption is associated with a lower risk for coronary heart disease (CHD). A suitably integrated view of the CHD pathogenesis pathway will help to elucidate how moderate alcohol consumption could reduce CHD risk.
Methods
A comprehensive literature review was conducted focusing on the pathogenesis of CHD. Biomarker data were further systematically analysed from 294 cohort studies, comprising 1 161 560 subjects. From the above a suitably integrated CHD pathogenetic system for the purpose of this study was developed.
Results
The resulting integrated system now provides insight into the integrated higher-order interactions underlying CHD and moderate alcohol consumption. A novel ‘connection graph’ further simplifies these interactions by illustrating the relationship between moderate alcohol consumption and the relative risks (RR) attributed to various measureable CHD serological biomarkers. Thus, the possible reasons for the reduced RR for CHD with moderate alcohol consumption become clear at a glance.
Conclusions
An integrated high-level model of CHD, its pathogenesis, biomarkers, and moderate alcohol consumption provides a summary of the evidence that a causal relationship between CHD risk and moderate alcohol consumption may exist. It also shows the importance of each CHD pathway that moderate alcohol consumption influencesDr Arnold van Dyk. TEMM International (Pty) Lt
Using big data for insights into sustainable energy consumption in industrial and mining sectors
No full textHuman activities related to the production and consumption of energy are negatively impacting the environment and need to be addressed by focusing on cleaner production. With this perspective, this study investigates sustainable energy consumption in the industrial and mining sectors. Although these sectors are experiencing exponential data growth, their adoption of big data technologies is limited. Hence, big data methods were applied to design a big data system that makes novel use of microservices and containers for modularity and extensibility. A hybrid architecture incorporating characteristics from polyglot persistence, data lakes and Lambda architecture was used. MongoDB served as the primary data store. The system was implemented for an engineering services company. The implementation yielded seven case studies, which illustrate the impact of big data on decision-making at the various levels of the hierarchy within an organisation. Valuable insights were delivered to personnel at the different levels of the organisational hierarchy. By developing these insights, directed at the appropriate personnel, improved decisions were taken and suitable actions initiated to achieve sustainable energy consumption reductions. The overall impact of the case studies was an energy saving of 75 622 MWh, a reduction of 74 111 Mg of carbon-dioxide-emission, and a saving of 108 141 m3 of water. Sustained reductions in energy consumption result in cleaner production and will eventually aid in addressing the various energy challenges confronting the econom
How do high glycemic load diets influence coronary heart disease?
Get PDFBackground: Diet has a significant relationship with the risk of coronary heart disease (CHD). Traditionally the effect
of diet on CHD was measured with the biomarker for low-density lipoprotein (LDL) cholesterol. However, LDL is not
the only or even the most important biomarker for CHD risk. A suitably integrated view of the mechanism by which
diet influences the detailed CHD pathogenetic pathways is therefore needed in order to better understand CHD risk
factors and help with better holistic CHD prevention and treatment decisions.
Methods: A systematic review of the existing literature was conducted. From this an integrated CHD pathogenetic
pathway system was constructed. CHD biomarkers, which are found on these pathways, are the only measurable
data to link diet with these CHD pathways. They were thus used to simplify the link between diet and the CHD
mechanism. Data were systematically analysed from 294 cohort studies of CHD biomarkers constituting 1 187 350
patients.
Results and discussion: The resulting integrated analysis provides insight into the higher-order interactions
underlying CHD and high-glycemic load (HGL) diets. A novel “connection graph” illustrates the measurable
relationship between HGL diets and the relative risks attributed to the important CHD serological biomarkers.
The “connection graph” vividly shows that HGL diets not only influence the lipid and metabolic biomarkers,
but also the inflammation, coagulation and vascular function biomarkers in an important way.
Conclusion: A focus primarily on the low density lipoprotein cholesterol biomarker for CHD risk has led to
the traditional guidelines of CHD dietary recommendations. This has however inadvertently led to HGL diets.
The influence of HGL diets on the other CHD biomarkers is not always fully appreciated. Thus, new diets or
other interventions which address the full integrated CHD impact, as shown in this paper, are require
Results and prospects of applying an ISO 50001 based reporting system on a cement plant
No full textThe cement industry plays an important role in global development and makes up a sizable portion of global energy consumption. Increased competition places strain on the oversupplied market, creating the need to improve efficiency. Since energy costs make up 30% of production costs, reducing energy consumption increases profitability. Existing energy management methods often demand large capital investments. This study reports on an electrical energy management system for improving cement plant productivity at minimal cost. The system consists of an automated energy performance report which encompasses the Plan Do Check Act approach of ISO 50001. The system collects data from various sources to provide valuable information and graphs on these reports. Large electricity-consuming systems can then be isolated, monitored, and compared with continuously updating benchmarks to identify missed saving opportunities. The system was implemented on a South African plant where the electrical energy cost of cement reduced by 25%. Qualitative consultations confirmed that the system promotes the implementation of ISO 50001 management practices. The system makes it possible to monitor the energy performance of equipment and continuously improve operations. These results prove that cement plant profitability can be improved with minimum capital investment by using an energy management syste
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
