Large Heaps Research Articles

Design and Fabrication of Safe Mask and Hand Gloves Disposal Machine

The origin of the novel human coronavirus (SARS-CoV-2) and its potential for harm increased face mask and medical waste in the environment, thereby necessitating the urgent prevention and control of the pandemic. The article estimates the face mask and medical waste generation in Asia during the pandemic to convince the waste management and scientific communities to find ways to address the negative impact that the waste disposal has on the environment. Standardization, procedures, guidelines and strict implementation of medical waste management related to COVID-19, community habitats and public areas should be carefully considered to reduce pandemic risks in hospitals, as proper medical waste disposal effectively controls infection sources. Improper disposal of the face mask can lead to various problems which include large heaps of mask all over, bacteria causing infection, unhygienic environment etc. The used mask that have not been disposed of properly sometimes block the drainage system. Incineration is a better technique to dispose of such waste but burning of used mask releases harmful gases that effects health and environment. To incinerate mask, electrical or physical fire – based incinerators can be used. Toilet facilities in India are very poor as they lack bins for the disposal of mask [1]. This system is one of the best way to dispose waste burn mask using electrical fire based burner without allowing smoke generate in the process to escape into the atmosphere. This steps must be taken to solve the problems that improper disposal of mask causes to the environment and to the public health

Ecological performances of exotic and native woody species on coal mine spoil in Indian dry tropical region

Coal extraction by opencast mining involves the dumping of overburden or mine spoil as large heaps. These large heaps of overburdened materials can act as a serious threat to ecological integrity and, therefore, overall societal well-being. Plantations are often employed to establish revegetation and management of mine spoil, thus mitigating the effects of mining on the environment. However, the performance of plant species can be highly variable due to environmental and species-specific effects. Therefore, the present paper's primary objective is to compare exotic (Acacia auriculiformis, Cassia siamea, Casuarina equisetifolia and Grevillea pteridifolia) and native (Albizia lebbeck, Albizia procera, Dendrocalamus strictus and Tectona grandis) species' performance on the coal mine spoils. Previous studies on the Singrauli coalfields allowed us to compare the growth performance, standing biomass, and net primary production (NPP) of four exotic and four native species plantations. Our results showed that native species have significantly higher survival, stem diameter, biomass, and NPP than exotic woody plantations. Thus, exotic species might not be useful in mine spoil rehabilitation than the native species. Overall, this study suggests that native species are useful for mine spoil rehabilitation despite the faster growth of exotic species.

Distribution of Antimony and Gold in Old Tailings and Heaps at the Milešov Locality (Příbram District)

Antimony ores were extracted and processed near the village of Milešov (Příbram district) for about twenty years in the second halfof the 19th century. Large heaps and a small sludge pond were left behind after this period. In 1988, this locality was inspected andsampled in order to gather information about residual resources of gold and antimony. The original archive data from this surveywere now studied again and interpreted using modern statistical and geostatistical methods. The interpolations methods chosenfor this purpose were inverse distance weighting (IDW), simple kriging and geostatistical sequential Gaussian simulation (SGS).These procedures allowed for a much more accurate determination of the spatial distribution of the elements or substances studied.The results showed significantly higher volumes and a more accurate localization of the studied elements in both bodies (heap andtailings). This procedure can be considered as the basis of a new methodology for the assessment of similar objects.

Systems biology of acidophile biofilms for efficient metal extraction

Society’s demand for metals is ever increasing while stocks of high-grade minerals are being depleted. Biomining, for example of chalcopyrite for copper recovery, is a more sustainable biotechnological process that exploits the capacity of acidophilic microbes to catalyze solid metal sulfide dissolution to soluble metal sulfates. A key early stage in biomining is cell attachment and biofilm formation on the mineral surface that results in elevated mineral oxidation rates. Industrial biomining of chalcopyrite is typically carried out in large scale heaps that suffer from the downsides of slow and poor metal recoveries. In an effort to mitigate these drawbacks, this study investigated planktonic and biofilm cells of acidophilic (optimal growth pH < 3) biomining bacteria. RNA and proteins were extracted, and high throughput “omics” performed from a total of 80 biomining experiments. In addition, micrographs of biofilm formation on the chalcopyrite mineral surface over time were generated from eight separate experiments. The dataset generated in this project will be of great use to microbiologists, biotechnologists, and industrial researchers.

The effects of simulated stacking phenomena on the percolation leaching of crushed ore, Part 2: Stratification

Unstratified and artificially stratified samples of oxide-copper ore were percolated with water followed by acid leaching in a custom-made laboratory apparatus. During two consecutive experiments run over collectively 335 days, stratification actually increased the width over which solution distributed throughout the ore, opposed to the expectation that it would be detrimental to solution distribution. However this did not manifest in a measurable or reproducible difference in rate or extent of copper extraction or of gangue acid consumption.The increase in effective dripper spacing was the only variable studied which clearly exhibited an influence over rate and extent of extraction. This is already qualitatively known and utilised in the scale-up from columns to cribs and to large heaps. However the present study provides a quantified case study where the 153 mm diameter columns used in Part 1 yielded a dual-porosity diffusion time (Γ) of around 5 days and extractable (κxκw) fraction of about 100 percent. In contrast, the wide boxes used for Part 2, representing 900 mm dripper spacing, yielded Γ > 10 days and κxκw = 60(±12)%. In contrast, little difference was noted between the leaching of stratified versus un-stratified ore.The poor predictability observed for the gangue acid consumption (GAC) rate constant needs to be borne in mind if predictive modelling is attempted. Since GAC competes with the copper leaching reaction for acid, it also exhibits an important influence over the rate of oxide-copper extraction.

Practice and Determinants of Solid Waste Collection: The Case of Private Collectors in Five Ethiopian Cities

Forty private companies involved in solid waste collection (SWC) in five Ethiopian cities were studied to identify key factors affecting their service performance. Investments, operational management capability and regulation are the factors investigated. The major determinants of SWC according to a regression analysis are number and carrying capacity of vehicles, distance from disposal sites and (unobserved) city characteristics. Route planning and a more flexible contract substantially increase collection. Investments in SWC depend on access to capital by the private companies. Different experiences of regulation (scope of contract) on SWC have been noticed. Service contract arrangements are impediments in Mekelle. While, service zoning allows competition in Addis Ababa, Hawasa and Bahir Dar. Rectifying the challenging nature of the contracts for private sector involvement (PSI) in SWC is vital so that the cities with large heaps of solid waste left uncollected become clean. The study findings suggest that for a number of reasons the Ethiopian government needs to entrust private companies with opportunities for more meaningful and sustainable involvement in SWC. We recommend that the contract shall also have conditions concerning sustainability.

Using X-Ray Fluorescence to Examine Ancient Extractive Metallurgy Practices: A Case Study from Iron Age Khirbat al-Jariya, Jordan

The first industrial revolution to appear in the southern Levant (Israel, Jordan, Palestine, Lebanon, southern Syria and the Sinai Peninsula) occurred during Iron Age (ca. 1200-500 BCE) when large scale copper smelting occurred. The hub of this technological development occurred in the Faynan region of Southern Jordan, which is home to the largest copper ore deposits in the southern Levant. Throughout history, these abundant ores were exploited by local populations with copper production reaching an industrial scale in the 10th and 9th centuries BCE. The evidence for this massive production remains visible on the surface throughout Faynan at ancient smelting sites populated with large heaps of industrial copper slag. Khirbat al-Jariya (KAJ), one such copper smelting center, was the focus of renewed excavations by the Edom Lowlands Regional Archaeology Project in the summer of 2014. In order to investigate the history of metal production at KAJ, a test probe was excavated into one of the site’s slag mounds. The 1×1 meter sounding was excavated to bedrock to provide a complete representation of copper smelting activities during the site’s history. To supplement excavations, our team collected geo-referenced slag samples from stratigraphically controlled contexts within the probe and from several other slag mounds around the site at KAJ. These samples were subsequently the focus of post-season X-Ray Fluorescence (XRF) analysis to provide insight beyond the visible record. By combining the XRF results with the chronological framework provided by archaeological excavation, it is possible to examine diachronic changes in the elemental compositions of the slag samples. In turn, the elemental contents of the slag can be used as a proxy for evaluating the extractive metallurgy practices of the ancient metalworkers. Thus, this paper presents the results of the XRF analyses and the possible conclusions to be drawn concerning ancient copper smelting at Khirbat al-Jariya.

Using archaeological shell middens as a proxy for past local coastal upwelling in northern Chile

Abstract Shell middens, large heaps of refuse materials that are often interspersed with burials, hearths and other cultural features, provide important data regarding the lifestyles of past coastal and maritime dwellers. Despite the abundance of organic materials, radiocarbon ages from shell middens can be a challenge to interpret because marine shells are depleted in radiocarbon with respect to their contemporaneous atmosphere, known as the “reservoir effect” (R). This issue is particularly problematic in regions like the coastal Atacama Desert where the upwelling of subsurface radiocarbon-depleted waters creates a shell “local” reservoir effect (ΔR) with a time-variable intrinsic uncertainty. Here we review and discuss how the dating of diverse materials from these deposits, including the shells themselves, can reveal large shifts between the terrestrial (atmospheric) and marine carbon cycles. Furthermore, a chronology of such shifts can be used as a proxy of upwelling intensity and to help establish the duration of strong versus weak local upwelling episodes. To test and evaluate these ideas, we present a chronology of R and ΔR variations from a 2-m shell midden sequence from Caleta Vitor in northern Chile that spans the middle Holocene, which remains underrepresented by regional ΔR values. The ∼2000 y sequence of Caleta Vitor, located onshore from a major upwelling center, displays dramatic shifts in radiocarbon reservoir effects which we hypothesize are linked to strong changes in the intensity of local upwelling. Further replication of such archaeomalacological records will be key for not only solving methodological problems regarding the dating of coastal sites but can provide further insights into the evolving terrestrial and marine carbon cycles and how these relate to past climate change.

A partial read barrier for efficient support of live object-oriented programming

Live programming, originally introduced by Smalltalk and Lisp, and now gaining popularity in contemporary systems such as Swift, requires on-the-fly support for object schema migration, such that the layout of objects may be changed while the program is at one and the same time being run and developed. In Smalltalk schema migration is supported by two primitives, one that answers a collection of all instances of a class, and one that exchanges the identities of pairs of objects, called the become primitive. Existing instances are collected, copies using the new schema created, state copied from old to new, and the two exchanged with become, effecting the schema migration. Historically the implementation of become has either required an extra level of indirection between an object's address and its body, slowing down slot access, or has required a sweep of all objects, a very slow operation on large heaps. Spur, a new object representation and memory manager for Smalltalk-like languages, has neither of these deficiencies. It uses direct pointers but still provides a fast become operation in large heaps, thanks to forwarding objects that when read conceptually answer another object and a partial read barrier that avoids the cost of explicitly checking for forwarding objects on the vast majority of object accesses.

Concurrent compaction using a field pinning protocol

Compaction of memory in long running systems has always been important. The latency of compaction increases in today’s systems with high memory demands and large heaps. To deal with this problem, we present a lock-free protocol allowing for copying concurrent with the application running, which reduces the latencies of compaction radically. It provides theoretical progress guarantees for copying and application threads without making it practically infeasible, with performance overheads of 15% on average. The algorithm paves the way for a future lock-free Garbage Collector.

ABDF Integratable Machine Learning Algorithms-MapReduce Implementation

Abstract As the amount of data generated on a day to day basis is on the uphill the urgency for efficient frameworks to handle, store and process the same is also increasing. Frameworks like Hadoop have proven its strength to churn huge volume of data to bring out the hidden patterns supporting decision making. Project that is being assigned to us is to develop Mapreduce based Machine Learning Algorithms to run on Hadoop clusters. Algorithms will be assigned on a case to case basis. Algorithms so developed will be integrated with Amrita BigData Framework (ABDF). Among those algorithms an application area or an end to end comparison will be done against different processing modes like linear implementation. Key matrix such as execution speed, usage of resources, accuracy, etc will be measured as applicable to the algorithm. Amrita Bigdata Framework (ABDF) is essentially an all integrated framework for effortless BigData analytics. ABDF is feature rich analytics framework, providing user community with an easy to use GUI for analyzing large data heaps. ABDF is capable of switching its processing modes between, Hadoop, Spark streaming/in-memory, Storm in-memory and Linear execution. Implementing Machine Learning algorithm in a distributed environment is trickier than its sequential implementation. While writing a mapreduce job we need to identify what part of the algorithm can be parallelized and how to parallelize.

En stendyngegrav ved Kvorning - Fund, kontekst og betydning

En stendyngegrav ved Kvorning - Fund, kontekst og betydning

Research on the relationship between grain composition and repose angle of coal gangue in Dongkuang mine, Heshan city, Guangxi, China

Heshan, a city in Southwest China, has been built over an old coal mining area. Due to low level of reclamation, coal gangue had been stacked in large heaps and caused geological environmental problems. To facilitate designing management project of coal gangue, we made an investigation of the largest coal gangue heap in Dongkuang Mine of Heshan. Firstly, the grain composition of coal gangue was estimated through the sieving method, then the representative grading curve was drawn through the statistics method of coarse grain content, and lastly the relationship between the repose angle and grain grading was studied by piling up coal gangue with different mix proportion. The result indicates that there is a wider range of grain size in the upper part of coal gangue heap, and the representative grain grading is well graded and easy to be compacted as filling materials. Besides, the wavy relationship curve of repose angle and coarse grain content shows that the content of 70% is the inflection point of ascent stage and 85% the inflection point of descent stage of the repose angle. What’s more, the repose angle corresponding to the representative grading of coal gangue is approximately 38.4° and this has guiding significance for management project of coal gangue.

Hydrogen Sulfide Gas Emissions during Disturbance and Removal of Stored Spent Mushroom Compost

Spent mushroom compost (SMC) is a by-product of the mushroom industry that is used as an agricultural fertilizer. In Europe, SMC storage and use are governed by EU Nitrates Directive 91/676/EEC to protect waterways against pollution by nitrates. A health and safety risk was identified during the removal of stored SMC for land application, as the stored SMC released high levels of toxic H2S gas into the atmosphere when disturbed. In this study, emissions of H2S were monitored at two outdoor and two indoor locations where stored SMC was being removed for land application. A repeating peak-trough pattern of H2S emissions was detected at all sites, with peaks corresponding to periods of active disturbance of SMC. The highest H2S concentrations (10 s average) detected at the SMC face were, respectively, 680 and 2083 ppm at outdoor sites 1 and 2, and 687 and 89 ppm at indoor sites 3 and 4. Higher concentrations of H2S were released from older SMC compared to newer material. Indoor-stored SMC had lower moisture content (53% to 65%) compared to outdoor-stored material (66% to 72%), while the temperature of indoor-stored SMC was higher (33 degrees C to 51 degrees C) compared to outdoor-stored material (24 degrees C to 36 degreees C). The current short-term exposure limit (STEL) of 10 ppm was exceeded at all sites except site 4, which was smaller than the other sites, indicating a significant health and safety risk associated with working in the vicinity of stored SMC when it is being actively disturbed. Results suggest that SMC stored under cover in small heaps (600 m3) emits less H2S during disturbance and removal compared to SMC stored outdoors in large heaps (> 1500 m3). This should be taken into consideration in the design, construction, and management of SMC storage facilities. Health and safety protocols should be in place at SMC storage facilities to cover the risks of exposure to toxic H2S gas during disturbance of stored SMC.

Characteristics of large three-dimensional heaps of particles produced by ballistic deposition from extended sources

This paper reports a detailed numerical investigation of the geometrical and structural properties of three-dimensional heaps of particles. Our goal is the characterization of very large heaps produced by ballistic deposition from extended circular dropping areas. First, we provide an in-depth study of the formation of monodisperse heaps of particles. We find very large heaps to contain three new geometrical characteristics: they may display two external angles of repose, one internal angle of repose, and four distinct packing fraction (density) regions. Such features are found to be directly connected with the size of the dropping zone. We derive a differential equation describing the boundary of an unexpected triangular packing fraction zone formed under the dropping area. We investigate the impact that noise during the deposition has on the final heap structure. In addition, we perform two complementary experiments designed to test the robustness of the novel features found. The first experiment considers changes due to polydispersity. The second checks what happens when letting the extended dropping zone to become a point-like source of particles, the more common type of source.

Nonuniformities in the Angle of Repose and Packing Fraction of Large Heaps of Particles

We report a numerical investigation of the structural properties of very large three-dimensional heaps of particles produced by ballistic deposition from extended circular dropping areas. Very large heaps are found to contain three new geometrical characteristics not observed before: they may have two external angles of repose, an internal angle of repose, and four distinct packing fraction (density) regions. Such characteristics are shown to be directly correlated with the size of the dropping zone. In addition, we also describe how noise during the deposition affects the final heap structure.

Agricultural by-products provide critical habitat components for cold-climate populations of an oviparous snake (Natrix natrix)

Populations of snakes and other reptiles are declining worldwide. Habitat loss and degradation is thought to be a significant factor in these declines, so to improve management strategies it is important to increase our understanding of reptilian habitat requirements. Modern agriculture is abandoning the tradition of gathering compost and manure in large heaps. Consequently these unusually warm environments are disappearing from the landscape. This may imperil populations of grass snakes (Natrix natrix) that rely on these anthropogenic heat sources to incubate their eggs. We conducted a relocation experiment to examine if eggs can develop successfully in other more natural environments that grass snakes potentially could utilize in the absence of manure heaps and compost piles. We found that hatching success was high (71 %) when we placed eggs in manure heaps and non-existent (0 %) when we placed them in potential ‘natural’ nests. Placement in compost piles resulted in intermediate (43 %) hatching success. Eggs in manure heaps hatched earlier than eggs in compost piles and thermal data from the nests showed that temperatures were higher and more stable in manure heaps than in compost piles and potential ‘natural’ nests. Jointly these results suggest that manure heaps generally provide a better nesting habitat than compost piles, attributable to thermal differences between the environments. Our findings facilitate improvement of current management strategies and have implications for conservation of oviparous reptiles in general.

Potential for reuse of tungsten mining waste-rock in technical-artistic value added products

Mining and quarrying activities in Europe generate approximately 55% of total industrial wastes, according to a recent Eurostat report. Most of these wastes are directly dumped on land or deposited in landfill sites. The first solution may lead to negative environmental impacts on land (removal of vegetation, deforestation, land slope changes and increased risk of erosion), water (pollutant transport through surface runoff, soil infiltration and contamination of water resources), may lead to the contamination of agricultural goods and may impose risks on human health. In Portugal, about 20% of industrial waste produced originates from mines and quarries, particularly from Panasqueira mining, one of the largest tungsten mines in the world. Currently, Panasqueira mining generates almost 100 tonnes of waste-rock, per day. Such waste-rock have accumulated over a number of years into very large heaps and it is desirable to seek new economic solutions that can contribute towards their reuse. In this context, this work discusses the potential for reuse of waste-rock piles of Panasqueira tungsten mine, which may be a case statement to be followed. The proposed solution described in this paper consists in developing innovative polymer-based composite materials, obtained from non-contaminated waste-rock tailings. Such materials must have suitable properties for technical-artistic value added applications, such as conservation, restoration and/or rehabilitation of historic monuments, sculptures, decorative and architectural intervention, or simply as materials for building revetments.

The Compressor

The widely used Mark-and-Sweep garbage collector has a drawback in that it does not move objects during collection. As a result, large long-running realistic applications, such as Web application servers, frequently face the fragmentation problem. To eliminate fragmentation, a heap compaction is run periodically. However, compaction typically imposes very long undesirable pauses in the application. While efficient concurrent collectors are ubiquitous in production runtime systems (such as JVMs), an efficient non-intrusive compactor is still missing.In this paper we present the Compressor, a novel compaction algorithm that is concurrent, parallel, and incremental. The Compressor compacts the entire heap to a single condensed area, while preserving the objects' order, but reduces pause times significantly, thereby allowing acceptable runs on large heaps. Furthermore, the Compressor is the first compactor that requires only a single heap pass. As such, it is the most efficient compactors known today, even when run in a parallel Stop-the-World manner (i.e., when the program threads are halted). Thus, to the best of our knowledge, the Compressor is the most efficient compactor known today. The Compressor was implemented on a Jikes Research RVM and we provide measurements demonstrating its qualities.

Mineralogical controls on storage of As, Cu, Pb and Zn at the abandoned Mathiatis massive sulphide mine, Cyprus

AbstractThe Mathiatis massive sulphide deposit in Cyprus was a low-grade (0.3% Cu), three million ton ore body of pyrite and minor chalcopyrite occurring within basaltic lavas of the Troodos ophiolite. Cessation of mining in 1987 left a deep open pit surrounded by large heaps of spoil, which are undergoing oxidation and leaching. The aim of this study was to determine the mineralogical controls on the storage and potential remobilization of As, Cu, Pb and Zn within, and from, mine spoil heaps. Most of the spoil samples collected, and related materials (stream sediment, reaction zone between a boulder of massive pyrite and calcareous chert, salt crusts on stream beds), are enriched in As (27—220 ppm), Cu (110—400 ppm), Pb (10—140 ppm) and Zn (290—12,000 ppm) relative to both the basalt and calcareous chert (As 4—10 ppm, Cu 20—76 ppm, Pb 3—6 ppm, Zn 39—200 ppm).Arsenic, Cu, Pb and Zn in the spoil and related materials are associated with Fe(-Al-S)-O, Fe(-Al-Mg)-S-O, Al(-Mg-Fe)-S-O and Mg(-Al-Fe)-S-O phases (the brackets represent minor components of less than 20 wt.% within the phases). Chemical extraction work using CaCl2 suggests that Cu, Zn and to some extent, As, are potentially more soluble than Pb. This is corroborated by the very high total concentrations of Cu and Zn in both the secondary salt crusts and the reaction zone material, high CaCl2-extractable As, Cu and Zn in the salt crusts, and aqueous data for the Mathiatis mine area collected for a European Union LIFE report. This may have implications for ecosystem health and water quality in the Mathiatis area and areas of similar mineralogy and climate world wide.