981 resultados para pit crater
Resumo:
In the mining optimisation literature, most researchers focused on two strategic-level and tactical-level open-pit mine optimisation problems, which are respectively termed ultimate pit limit (UPIT) or constrained pit limit (CPIT). However, many researchers indicate that the substantial numbers of variables and constraints in real-world instances (e.g., with 50-1000 thousand blocks) make the CPIT’s mixed integer programming (MIP) model intractable for use. Thus, it becomes a considerable challenge to solve the large scale CPIT instances without relying on exact MIP optimiser as well as the complicated MIP relaxation/decomposition methods. To take this challenge, two new graph-based algorithms based on network flow graph and conjunctive graph theory are developed by taking advantage of problem properties. The performance of our proposed algorithms is validated by testing recent large scale benchmark UPIT and CPIT instances’ datasets of MineLib in 2013. In comparison to best known results from MineLib, it is shown that the proposed algorithms outperform other CPIT solution approaches existing in the literature. The proposed graph-based algorithms leads to a more competent mine scheduling optimisation expert system because the third-party MIP optimiser is no longer indispensable and random neighbourhood search is not necessary.
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Determining the genetic bases of adaptations and their roles in speciation is a prominent issue in evolutionary biology. Cichlid fish species flocks are a prime example of recent rapid radiations, often associated with adaptive phenotypic divergence from a common ancestor within a short period of time. In several radiations of freshwater fishes, divergence in ecomorphological traits - including body shape, colour, lips and jaws - is thought to underlie their ecological differentiation, specialization and, ultimately, speciation. The Midas cichlid species complex (Amphilophus spp.) of Nicaragua provides one of the few known examples of sympatric speciation where species have rapidly evolved different but parallel morphologies in young crater lakes. This study identified significant QTL for body shape using SNPs generated via ddRAD sequencing and geometric morphometric analyses of a cross between two ecologically and morphologically divergent, sympatric cichlid species endemic to crater Lake Apoyo: an elongated limnetic species (Amphilophus zaliosus) and a high-bodied benthic species (Amphilophus astorquii). A total of 453 genome-wide informative SNPs were identified in 240 F-2 hybrids. These markers were used to construct a genetic map in which 25 linkage groups were resolved. Seventy-two segregating SNPs were linked to 11 QTL. By annotating the two most highly supported QTL-linked genomic regions, genes that might contribute to divergence in body shape along the benthic-limnetic axis in Midas cichlid sympatric adaptive radiations were identified. These results suggest that few genomic regions of large effect contribute to early stage divergence in Midas cichlids.
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This paper proposes a new multi-resource multi-stage mine production timetabling problem for optimising the open-pit drilling, blasting and excavating operations under equipment capacity constraints. The flow process is analysed based on the real-life data from an Australian iron ore mine site. The objective of the model is to maximise the throughput and minimise the total idle times of equipment at each stage. The following comprehensive mining attributes and constraints are considered: types of equipment; operating capacities of equipment; ready times of equipment; speeds of equipment; block-sequence-dependent movement times; equipment-assignment-dependent operational times; etc. The model also provides the availability and usage of equipment units at multiple operational stages such as drilling, blasting and excavating stages. The problem is formulated by mixed integer programming and solved by ILOG-CPLEX optimiser. The proposed model is validated with extensive computational experiments to improve mine production efficiency at the operational level.
Resumo:
This article contributes an original integrated model of an open-pit coal mine for supporting energy-efficient decisions. Mixed integer linear programming is used to formulate a general integrated model of the operational energy consumption of four common open-pit coal mining subsystems: excavation and haulage, stockpiles, processing plants and belt conveyors. Mines are represented as connected instances of the four subsystems, in a flow sheet manner, which are then fitted to data provided by the mine operators. Solving the integrated model ensures the subsystems’ operations are synchronised and whole-of-mine energy efficiency is encouraged. An investigation on a case study of an open-pit coal mine is conducted to validate the proposed methodology. Opportunities are presented for using the model to aid energy-efficient decision-making at various levels of a mine, and future work to improve the approach is described.
Resumo:
The aim of this study was to evaluate the feasibility of pit and fissure sealants and the effectiveness of the two sealant methods applied in every-day practice in public dental health care in Finland. Two sealant methods were evaluated according to their effectiveness in preventing dentin caries and sealant retention. Application time with these sealant methods was compared. The survival rate of sealed first and second molars was followed for nine and 13 year periods, respectively. Caries risk evaluation and observed increased caries risk were the basis for considering sealant application. A questionnaire, sent to all public dental health centers in Finland, monitored the attitudes of the dental profession towards sealant application and explored the current policies used as well as changes noted in the sealant application protocol. DMFT (Decayed, Missing or Filled Teeth) index values collected from the health centers were evaluated. The difference in caries rate between two methods investigated was highly significant. When compared to the glass ionomer sealant method (GIC), the effectiveness of the resin-based method (RB) in preventing dentin caries was 74% and the rate difference 3%. The relative risk for RB-sealed surfaces vs. GIC-sealed surfaces of having detectable dentin caries was 0.3 (95% CI 0.12, 0.57). The retention rate of sealants was higher with RB than GIC (P<0.001). Application of RB sealant material was less time-consuming than application of GIC sealant. Occlusal dentin caries lesions were found in 4% and proximal caries in less than 2% of sealed teeth. The majority of respondents reported application of sealants on a systematic basis along with caries-risk evaluation. Those health centers sealing over suspected or detected enamel caries had lower average DMFT index values (1.0) when compared to DMFT values (1.2) of health centers applying sealants by alternative criteria. It is concluded that the RB sealant method is more effective than the GIC sealant method in preventing dentin caries. Sealant maintenance may increase the costs of a sealant program. Occlusal caries management may be improved if the applied sealant policies are changed towards an interceptive approach i.e. applying the sealants over detected or suspected enamel caries lesions instead of sealing sound teeth in a preventive manner.
Resumo:
Maan törmäyskraaterien ikäjakauman mahdollinen ajallinen jaksollisuus on herättänyt laajaa keskustelua sen jälkeen, kun ilmiö ensimmäistä kertaa raportoitiin joukossa arvostettuja tieteellisiä artikkeleita vuonna 1984. Vaikka nykytiedon valossa on kyseenalaista perustuuko havaittu jaksollisuus todelliseen fysikaaliseen ilmiöön, on kuitenkin mahdollista, että jaksollisuus on todella olemassa ja se voitaisiin havaita laajemmalla ja tarkemmalla törmäyskraateriaineistolla. Tutkimuksessa luotiin simuloidut kraaterien ajalliset tiheys- ja kertymäfunktiot tapauksille, jossa kraaterit syntyvät joko täysin jaksollisella tai satunnaisella prosessilla. Näiden kahden ääritapauksen lisäksi luotiin jakaumat myös kahdelle niiden yhdistelmälle. Nämä mallit mahdollistavat myös erilaisten kraaterien iänmäärityksen epätarkkuuksien huomioonottamisen. Näistä jakaumista luotiin eri pituisia simuloituja kraaterien ikien aikasarjoja. Lopulta simuloiduista aikasarjoista pyrittiin Rayleigh'n menetelmän avulla etsimään jakaumassa ollutta jaksollisuutta. Tutkimuksemme perusteella ajallisen jaksollisuuden havaitseminen kraateriaikasarjoista on lähes mahdotonta mikäli vain yksi kolmasosa kraatereista on jaksollisen ilmiön aiheuttamia, vaikka nykyistä kraateriaineistoa laajempi ja tarkempi aineisto olisi tulevaisuudessa saatavilla. Mikäli kaksi kolmasosaa meteoriittitörmäyksistä on jaksollisia, sen havaitseminen on mahdollista, mutta vaatii huomattavasti tämän hetkistä kattavamman kraateriaineiston. Tutkimuksen perusteella on syytä epäillä, että havaittu kraaterien ajallinen jaksollisuus ei ole todellinen ilmiö.
Resumo:
Mud crabs (Scylla spp.) are intensively caught throughout South-East Asia and support a very substantial commercial, recreational fishing and aquaculture industry. Identification of individual animals is important to improve understanding and management of this species. However, tagging of crustaceans is difficult as they frequently molt and internal tags can pose a hazard to consumers. In this pilot study we tested a new method combining passive integrated transponder tags and t-bar tags externally. 45 giant mud crabs (Scylla serrata) were captured from the wild and kept in tanks for a maximum of 10 months. We inserted tags into the abdomen of 35 giant mud crabs and tested a modified method where the combined t-bar/PIT-tag was inserted into the muscle tissue of the rear leg between the dorsal carapace plate and the top of the abdominal flap. Tagged crabs with the modified method showed 85% tag retention for molting crabs. We tested the same method in the field where 852 individuals were tagged with combined t-bar/PIT-tags of which 82 were recaptured showing 100% tag retention but without any evidence of molting having occurred. The tested method of combined t-bar/PIT-tags in giant mud crabs can further improve monitoring for wild and aquaculture populations and can be deployed widely with low cost.
Resumo:
Mud crabs (Scylla spp.) are intensively caught throughout South-East Asia and support a very substantial commercial, recreational fishing and aquaculture industry. Identification of individual animals is important to improve understanding and management of this species. However, tagging of crustaceans is difficult as they frequently molt and internal tags can pose a hazard to consumers. In this pilot study we tested a new method combining passive integrated transponder tags and t-bar tags externally. 45 giant mud crabs (Scylla serrata) were captured from the wild and kept in tanks for a maximum of 10 months. We inserted tags into the abdomen of 35 giant mud crabs and tested a modified method where the combined t-bar/PIT-tag was inserted into the muscle tissue of the rear leg between the dorsal carapace plate and the top of the abdominal flap. Tagged crabs with the modified method showed 85% tag retention for molting crabs. We tested the same method in the field where 852 individuals were tagged with combined t-bar/PIT-tags of which 82 were recaptured showing 100% tag retention but without any evidence of molting having occurred. The tested method of combined t-bar/PIT-tags in giant mud crabs can further improve monitoring for wild and aquaculture populations and can be deployed widely with low cost.
Resumo:
This study presents a comprehensive mathematical formulation model for a short-term open-pit mine block sequencing problem, which considers nearly all relevant technical aspects in open-pit mining. The proposed model aims to obtain the optimum extraction sequences of the original-size (smallest) blocks over short time intervals and in the presence of real-life constraints, including precedence relationship, machine capacity, grade requirements, processing demands and stockpile management. A hybrid branch-and-bound and simulated annealing algorithm is developed to solve the problem. Computational experiments show that the proposed methodology is a promising way to provide quantitative recommendations for mine planning and scheduling engineers.
Resumo:
Tässä tutkielmassa tutkitaan Saarnaajan kirjan ja Sirakin kirjan mieskuvaa. Tutkimuksessa nämä kirjat ajoitetaan 200-luvulle eKr. Ptolemaiosten valtakunnan aikaan ja etsitään vastausta siihen, millaiseen miehuuteen Juudean eliittiin kuuluneet viisaudenopettajat Saarnaaja ja Ben Sira opastivat virkauralle pyrkiviä niin ikään eliittiin lukeutuneita oppilaitaan. Metodina on tutkia lukijalähtöisesti tekstin sisältöä ja etsiä siinä piileviä ideologioita, tässä tapauksessa siis miehenä olemiseen liittyviä oletuksia, joista nämä tekstit eivät puhu suorasanaisesti vaan joita on tulkittava rivien välistä. Tavoitteeseen pääsemiseksi Saarnaajan kirjan ja Sirakin kirjan tekstiä peilataan antiikin ajan mieskäsitystä ja toisaalta Vanhan testamentin maskuliinista ihannetta vasten. Samalla pyritään myös vertailemaan Saarnaajan kirjan ja Sirakin kirjan yhtäläisyyksiä ja eroja. Lähteinä ovat Saarnaajan kirjan masoreettinen teksti sekä pääasiassa Sirakin kirjan hepreankieliset ja niiden puuttuessa kreikankieliset käsikirjoitukset. Tutkimuksessa todetaan, että antiikin ajan juutalaisen yhteisön suurin miehelle asettama odotus oli se, että miehen oli aina, kaikkialla ja kaikissa tilanteissa hallittava itsensä. Tämä tarkoitti sekä oman käytöksenä että omien tunteittensa hallitsemista mutta myös elämän olosuhteiden ja siihen liittyvien ihmisten hallitsemista. Elämän oli siis oltava järjestyksessä ollakseen kunniallista. Eliittiin kuuluva juutalaismies saattoi myös epäonnistua eikä silloin täyttänytkään miehelle asetettua mittaa. Yhteisön kunnioituksen menettänyt mies oli pahassa tilanteessa. Juuri tilanteessa, missä häpeä astuu miehen elämään, käy parhaiten selväksi Saarnaajan ja Ben Siran ajattelun perimmäinen ero. Ben Sira perustelee miesihannettaan kunnian ja häpeän käsitteillä. Saarnaajalle kunnian ja häpeän käsitteillä ei ole merkitystä. Todellinen ongelma on Saarnaajan mielestä kuolema. On parempi elää vaikka häpeässä kuin olla kuollut, ja vaikka viisaus tuokin miehelle menestystä, sen olennaisin tehtävä on pitää mies hengissä ja elossa vaikka elämä ei niin kovin kunniakasta olisikaan. Lisäksi tutkimuksessa päädytään toteamaan, että mieheen kohdistui paljon vaatimuksia mutta hänellä oli myös voimavaroja, jotka tukivat hänen suoritustaan. Toinen näistä tukevista elementeistä oli miespuolinen ystävä ja uskottu. Saarnaajasta ja Ben Sirasta muistetaan usein heidän hyvin negatiiviset toteamuksensa naisen pahuudesta. Silti kummankin teksteistä juuri nainen paljastuu yhdeksi miehen voimavaroista.
Resumo:
This thesis investigates factors that impact the energy efficiency of a mining operation. An innovative mathematical framework and solution approach are developed to model, solve and analyse an open-pit coal mine. A case study in South East Queensland is investigated to validate the approach and explore the opportunities for using it to aid long, medium and short term decision makers.
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The present study focuses on the drug market in Helsinki in the early 2000s, mainly on the dealing in and use of amphetamines, cannabis and the pharmaceutical Subutex. The drug market is usually analysed into upper, middle and lower level markets. These levels are very different in terms of their operating practices, although there may be some mingling. The present study is mainly concerned with drug dealers and users in the lower and middle level markets. Operations also differ depending on whether the dealing involves just one drug or several. Dealing in and using Subutex is a very different business from dealing and using home grown cannabis, for instance: both the customers and the dealers are mostly quite different. The study material was mostly collected through ethnographical field work, including observations and interviews. Interviews with officials and minutes of pre-trial investigations concerning aggravated drug crimes are also included. The study discusses the roles of dealers on the various levels of the drug market in Helsinki and traces activities at various levels. Ethnographical methods are employed to observe day-to-day drug dealing and use and leisure pursuits in private homes and in public premises. The study takes note of the risks inherent in drug dealing and estimates what kind of drug dealers can last the longest on the market without the authorities intervening. At the same time, the study discusses how small groups on the middle and lower levels of the drug market avoid control measures undertaken by the authorities and how the authorities address these groups. Moreover, the study discusses what the drug market is like in prison from the perspective of a drug dealer sent to prison, what their everyday lives are like after release, and how much money dealers on various levels of the drug market make. The study demonstrates that drug dealing in Helsinki, whether we consider the very top or the very bottom of the pyramid, is a far from rational pursuit. The undertakings are not very systematic; they are more a reaction to intoxicant addiction( s) and other problems caused by other dealers, the dealers own actions and the actions of the police. The everyday lives of drug dealers are often chaos only alleviated by drug use in the company of buyers or alone. If a drug dealer uses drugs himself/herself, things become even more complicated and a vicious circle develops. At the same time, everyday life is certainly exciting, and a drug dealer often has a highly eventful if brief life. Drug dealing is a very masculine pursuit, and there is a sort of macho code governing it, although this does not nearly always work as it should. This macho code, typically for illegal activities, involves the threat of violence as a control measure. Hence the untranslatable slang expression Kill the cows : the Finnish word for calf has the slang meaning snitch or police informant . No more cows, no more calves. But informing on others to the authorities is a fact of life in the drug-dealing world. Contributing factors to being reported to the authorities are the dealer s own mistakes and the actions of other dealers and the police. A determined drug dealer will not be deterred from drug dealing by a prison sentence. However, following time in prison only few dealers manage to gain an income from drug dealing commensurate with its risks.
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The focus of this discourse analytical study was to review the meanings which prison education and its participants are given in the formal educational policy and to find out whether these meanings are agreed by the prison students. The intrestes of this thesis were to examine what kind of social and individual promises are related to the prison education and what kind of subject positions are possible to the prison students. The thesis was also interested in the meanings of education in different contexts. The aim of this study was to examine prison education especially for women. This thesis was based on Michel Foucault s ideas of power and the view of this study was directly critical. The prison education was seen as normalizing governance which tends to prepare its subjects to the normal. In this process of differentiating the normal and the abnormal the subjects of prison education are reconstructed as the others . The three research questions of this thesis were: how and what kind of prison education is reconstructed firstly in the strategy of prison education and secondly in the interviews. Thirdly it was questioned how and what kind of meanings gender receive in the discourse of prison education. The main data was consisted by the Finnish Criminal Sanctions Agency s document The Strategy of the Prison education for years 2008 2012 and the three interviews of women who participated to prison education. The interviews were made for this thesis in Autumn 2010. Two other Finnish Criminal Sanctions Agency s documents Prisoners in education (2007) and Visible women (2008) - the report of the working group on female prisoners were also used as subtext materials. The methods of critical and realistic discourse analysis and rhetorical analysis were applied in the analysis. The results of the thesis support the outlook of prison education as a form of normalizing governance which reconstruct the others position for the prison students. Prison education was seen supportive for personal life control and for integrating to the society. The participants of prison education repeated the official discourses in their accounts which is a signal of internalized governance. The interviewees also used different types of anti-discourses when forming implications of prison education.
Resumo:
Yksinäisyyden merkitys hyvinvointia uhkaavana tekijänä on viimeaikoina noussut esiin yhä enenevissä määrin. Yksinäiset korkeakouluopiskelijat ovat erityisen haavoittuvassa elämäntilanteessa, sillä nuoren aikuisen elämään liittyvät erityiset kehitykselliset haasteet. Tärkeää on, että opiskelijat saavat tukea tilanteeseensa, jotta yksinäisyyden kauaskantoisilta vaikutuksilta vältyttäisiin. Vertaistuki voi monen kohdalla olla tärkeää, ja Internet mahdollistaa matalan kynnyksen paikan avun hakemiseen. Tutkielmassani perehdyn Nyyti ry:n ylläpitämään, korkeakouluopiskelijoille tarkoitettuun Yksinäisyys-nettiryhmään, ja siinä esiintyvään vertaistukeen. Erityisen tutkimusasetelmastani tekee vertaistuen tarkastelu sen kaksijakoisuuden kautta: millaisia avunsaajana olemisen ja avunantajana toimimisen tapoja kirjoituksista on löydettävissä, ja miten ne suhteutuvat toisiinsa. Näin voidaan ymmärtää paremmin keskustelijoiden tarpeita ja odotuksia, ja sitä, miten ryhmä pystyy niihin vastaamaan. Aineistoa on tutkittu sisällönanalyysin menetelmin. Näyttäisi siltä, että ryhmään kohdistetaan enemmän odotuksia ja tarpeita kuin mihin se pystyy vastaamaan. Avunsaajana olemisen luokkia oli yhteensä 15, jotka kuvasivat viittä eri ulottuvuutta. Ulottuvuudet olivat kokemuksellisuus, kontrolliodotus, vaikeusaste, suhde tietoon ja odotuksellisuus. Avunantajana toimimisen kohdalla luokkia muodostui kahdeksan, jotka kuvasivat neljää ulottuvuutta. Näitä olivat empatia, eteenpäin suuntaavuus, opastus ja kyseenalaistus. Avunsaajana oleminen hallitsi nettiryhmän keskusteluja, ja sitä kuvastavat tekstit olivat paitsi määrällisesti pidempiä, myös sisällöllisesti rikkaampia. Suhteutettaessa avunsaajan ja avunantajan tapoja toisiinsa havaitaan, että ryhmässä osoitettu tuki pystyy hyvin vastaamaan moniin odotuksiin, mutta toisaalta jokin tuenmuoto saattaa olla päinvastainenkin joidenkin luokkien tarpeille. Voikin olla, että vertaistuesta on keskustelijoille hyötyä tiettyyn tasoon asti, mutta suuri määrä erilaisia tarpeita ja odotuksia tekee mahdottomaksi niihin kaikkiin vastaamisen. Hyvä jatkotutkimuksen aihe olisi haastatteluin selvittää kirjoittajien omia näkemyksiä siitä, mistä kokevat ryhmään kirjoittaessaan hyötyvänsä. Tutkielman keskeisimpiä lähteitä ovat olleet: Weiss, R.S. (1973). Loneliness: the experience of emotional and social isolation, Kraut, R. ym (1998). Internet paradox. A social technology that reduces social involvement and psychological well-being?, Jung, J. (1987) Toward a social psychology of social support., Dennis, C-L. (2003). Peer support within a health care context: a concept analysis.