Top PDF Decadal changes in extreme daily precipitation in Greece

Decadal changes in extreme daily precipitation in Greece

Decadal changes in extreme daily precipitation in Greece

Large changes in the wintertime atmospheric circulation have had a profound effect on regional distributions of sur- face temperature and precipitation. Anomalies in precipita- tion, including dry wintertime conditions over southern Eu- rope and the Mediterranean and wetter-than-normal condi- tions over northern Europe and Scandinavia since 1980, are linked to the behaviour of North Atlantic Oscillation Index (NAOI) (Hurrell and van Loon, 1997). Besides, according to the results of Krichak and Alpert (2005), the precipita- tion decline over the Mediterranean region during the last decades of the past century can be explained by the positive trend in the East Atlantic Western Russia pattern, which was induced by the positive trend of the North Atlantic Oscilla- tion. Regarding Greece, Feidas et al. (2007) found out that the observed downward trend in winter and annual precipita- tion in Greece is linked mainly to a rising trend in the hemi- spheric circulation modes of the NAOI, which are connected with the Mediterranean Oscillation Index. Moreover, low- frequency fluctuations in the circulation over the Atlantic have been closely linked to the coherent large-scale precip- itation anomalies that have persisted, particularly in winter, over Turkey since the early 1960s (Turkes and Erlat, 2003).
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Trend analysis of extreme precipitation in the Northwestern Highlands of Ethiopia with a case study of Debre Markos

Trend analysis of extreme precipitation in the Northwestern Highlands of Ethiopia with a case study of Debre Markos

Abstract. Understanding extreme precipitation is very im- portant for Ethiopia, which is heavily dependent on low- productivity rainfed agriculture but lacks structural and non- structural water regulating and storage mechanisms. There has been an increasing concern about whether there is an increasing trend in extreme precipitation as the climate changes. Existing analysis of this region has been descrip- tive, without taking advantage of the advances in extreme value modeling. After reviewing the statistical methodology on extremes, this paper presents an analysis based on the generalized extreme value modeling with daily time series of precipitation records at Debre Markos in the Northwest- ern Highlands of Ethiopia. We found no strong evidence to reject the null hypothesis that there is no increasing trend in extreme precipitation at this location.
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A geostatistical exploratory analysis of precipitation extremes in southern Portugal

A geostatistical exploratory analysis of precipitation extremes in southern Portugal

In Mediterranean climate regions, prolonged periods of unusually dry conditions re- duce the availability of water resources and affect vegetation cover; while other areas can be affected by an increase in the number of heavy precipitation events, with an increase in the flood risk. Issues such as drought and erosive rainfall have been raising concern about the risks of land degradation and desertification. The main objective of this paper is to provide an insight of the geographic distribution of extreme precip- itation events in the Southern region of continental Portugal, as a basis for a future study of the relationships between extreme rainfall patterns, both spatial and tem- poral, and desertification processes. The data used in this study are a set of 105 station records with daily precipitation observations for the period 1940–1999. This 60-year period was chosen to optimize data availability across the region, taking into consideration the quality control analysis performed. Among the numerous indices of extreme precipitation described in the literature, we selected three of them for an exploratory analysis: one index representing dry conditions, another one represent- ing extremely heavy precipitation events and another index representing flood events. For each of these three indices, yearly trends and decadal space-time patterns are investigated. The results show no significant trends in the regional extreme indices. The geostatistical study concluded that the spatial patterns are more continuous in the last decade than the other ones before. The preliminary results of this study agree with other similar studies of the same region reported in the literature.
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Precipitation dominates fire occurrence in Greece (1900–2010):  its dual role in fuel build-up and dryness

Precipitation dominates fire occurrence in Greece (1900–2010): its dual role in fuel build-up and dryness

Additionally, there is a clear outperformance of precipitation-related variables compared to temperature- related weather ones. This outperformance reveals that, at least in Greece, extreme fires are controlled by precipitation rather than air temperature. This is contrary to the findings in other regions, where air temperature was among the most important fire drivers and conditionally outperformed precipitation variables (Turetsky et al., 2004; Vázquez and Moreno, 1993). However, similar to our results, maximum air temperature outperformed mean air temperature in correlating with area burned (Vázquez and Moreno, 1993). In Portugal, monthly means (mean and maximum) of the daily maximum air temperatures together with the mean fire weather index managed to summarize a fairly large part of the variation in annual area burned, while total precipitation did not enter the regression model (Carvalho et al., 2008). In Greece, it has been shown that precipitation is well correlated with area burned (Dimitrakopoulos et al., 2011b) and that air temperature has a low direct influence on extreme fire risk (Good et al., 2008). Yet Dimitrakopoulos et al. (2011a) showed that during the period 1990–2003, the vast majority of large wildfires occur during heat
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Assessment of local dynamics in extreme precipitation frequency using direct sequential cosimulation

Assessment of local dynamics in extreme precipitation frequency using direct sequential cosimulation

A common approach to understand and assess the rainfall patterns over a region is based on the analysis of changes in climate indices, which are estimated from the empirical distribution of the daily observations [10], [11], [12]. The R30mm index was chosen to characterize the frequency of heavy precipitation events in the South of Portugal for the 1940–1999 period. Annual scenarios of this climate index were produced for that period using direct sequential cosimulation with elevation. Those scenarios were then used to produce an additional set of maps of indicators summarizing the scenarios’ underlying local dynamics.
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Extreme precipitation events in the Czech Republic in the context of climate change

Extreme precipitation events in the Czech Republic in the context of climate change

Abstract. As an introduction, short survey of two analyses of long-term fluctuations of annual precipitation totals in the Czech Republic is presented. The main focus of this paper is to contribute to investigation of precipitation trends in the Czech Republic by another point of view. For every pixel of 1 km 2 size, annual maxima of daily precipitation were obtained for time period of 112 years (1895–2006). Based on these time series, we were trying to answer question if there are some changes of area size/distribution of annual maximum of daily precipitation totals. Courses and trends are analyzed for some parameters of area distribution of an- nual maximum of daily precipitation totals in the area of the Czech Republic. No significant climate changes of tested precipitation characteristics were found.
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TEMPERATURE AND PRECIPITATION CHANGES IN TÂRGU-MURES (ROMANIA) FROM PERIOD 1951-2010

TEMPERATURE AND PRECIPITATION CHANGES IN TÂRGU-MURES (ROMANIA) FROM PERIOD 1951-2010

ABSTRACT. – Temperature and precipitation changes in Târgu Mures (Romania) from period 1951-2010. The analysis was made based upon meteorological data collected at Târgu Mures meteorological station (Romania, Mures county, lat. 46°32’N, lon. 24°32’E, elevation 308 m), between 1951 and 2010. Several climatic parameters were studied (for instance, annual and monthly mean temperature, maximum precipitation in 24 hours, number of summer days, etc). Detected inhomogeneities are not related to instrumental causes or geographical relocation. Positive and statistical significant trends (Mann-Kendall test) are indicated for: mean annual temperatures, mean temperatures of warm months, average of the maximum and minimum temperatures (annual and warm months data), number of days with mean temperature between 20.1-25.0 °C , number of days with precipitation ≥0 mm, and for all parameters of precipitation of September. The sequential version of Mann-Kendall test show a beginning of a trend in 1956 in the case of mean temperature (at same, the two and three parts regression denote this year like a moment of change), years 1965 and 1992 in the case of annual amount of precipitation. CUSUM charts indicate occurs of changes points at 1988, 2005, 2009 (mean temperature) respectively at 1989, 2004 (precipitation), and at 1968, 1992 (daily temperature range). Tendencies of overlapped time series reveal a more important increase at the end of period (mainly for mean temperature). The analysis with RClimDex show for 5 extreme climate indices a significant trend: positive for summer days, warm nights, warm spell duration indicator and negative for cold nights and cold days.
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Evaluation of space-time dynamics in extreme precipitation frequency using geostatistical cosimulation with elevation

Evaluation of space-time dynamics in extreme precipitation frequency using geostatistical cosimulation with elevation

Abstract: This study evaluates local dynamics in extreme precipitation frequency from 1940 to 1999 in the South of Portugal. The analysis is based on a climate index defined by the annual count of days with precipitation above the 30 mm threshold (R30mm). The space-time scenarios of this index, and their uncertainty evaluation, were produced through direct sequential cosimulation (coDSS) with elevation. The methodology incorporates space-time models that follow the premises that elevation and precipitation extremes may interact differently both in time and space. The results indicate that the relationship between elevation and the R30mm index has decreased through time over the study region, especially in the southeast area. Furthermore, the spatial patterns of the extreme precipitation index have become more homogenous during the last decades of the twentieth century. The more frequent heavy rainfall events occur in the mountainous areas of the South, which are desertification prone areas at risk of water erosion and floods. As expected, the space-time scenarios have greater spatial variability at regions less densely sampled. However, the uncertainty in mountainous regions is noticeably small given that elevation was used as secondary exhaustive information. The coDSS proved to be a valuable tool to deepen the knowledge on the local dynamics of the extreme precipitation frequency.
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Linking meteorological fire danger and burnt area in Brazil under present and future climate conditions

Linking meteorological fire danger and burnt area in Brazil under present and future climate conditions

Nevertheless, as mentioned before, fire is not only constrained and influenced by meteorological parameters. In fact, fire’s behaviour has a strong linkage to human activity with anthropogenic factors explaining e.g. most of the variance in fire size [Hantson et al., 2015]. In South America, human fac- tors might even outweigh climatic drivers [Aldersley et al., 2011]. Activities such as logging increase flammability of the forest, by reducing forest leaf canopy coverage by 14-50%, allowing sunlight to pen- etrate the forest floor and drying the organic debris left by the activity, and thus increasing vulnerability to future fires [Brando et al., 2014]. As such, given the importance of human activity, it is essential to communicate fire vernacular in a consistent and coherent way. Hardy [2005] discusses the importance of having a clear and concise terminology, and resorts to several studies to define various terms in the fire vernacular. As opposed to “fire risk” that addresses values or damages, “fire danger” refers only to the probability of fire ignition, with both anthropogenic and natural causes. The term “hazard” must only be used to express the state of the fuel complex and is independent of weather or the environment in which the fuel is found. “Severity” is not a concise term, as it concerns the characterization of the effects of fire on wildland systems not the fire itself. Also, expressions such as “catastrophic” are not used in the fire community, as it derives from expressions of social, cultural and economic value. On the other hand, Williams [1977] defines “fire spread” as a meaningful concept only under situations in which both burning and non-burning combustibles are identified, as it can occur only if there is some type of communication between the burning region and the non-burning fuel. This dissertation focuses on the predisposition of vegetation to be burnt and as such, following Hardy [2005], the term “fire danger” will be used to refer to probability of fire ignition as constrained by vegetation and climate.
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Assessment Of NPK In Human Male And Female Urine For Its Fertilising Potential In Agriculture

Assessment Of NPK In Human Male And Female Urine For Its Fertilising Potential In Agriculture

ABSTRACT: The study evaluated concentrations of Nitrogen, Phosphorus and Potassium in male and female urine stored over six months and its potential as a fertilizing agent in agriculture. Urinals were constructed to allow for easy collection of male and fe male urine and then stored in transparent bottles for six months in a greenhouse. Monthly triplicate analysis of male a nd female urine was done for nitrogen, phosphorus, potassium, temperature, pH and colour change. Bray P1 and Flame photometry methods were used in the determination of phosphorus and potassium contents and Kjedahl digestion and non-digestion (direct) methods for nitrogen content. Temperature, pH and colour were determined using mercury thermometer, temperature/pH meter and a colour chart. Results showed that nitrogen in female urine was significantly (p<0.05) higher than that in male urine after 2 to 5 months of storage. However, there were no significant differences (p>0.05) with respect to the direct method. Contrastingly, phosphorus in male urine was significantly (p<0.05) higher than th at in female urine after 2 to 3 months of storage but there were no significant differences in potassium content for all male and female urine samples. Generally, NPK yields in both urine sources peaked four months after storage . There was a moderate positive correlation between the direct female urine Nitrogen, and storage time. The phosphorus levels also correlated positively with storage time and temperature but weakly negative with pH. Generally, urine nitrogen strongly correlated positively with potassium but moderately with temperature and pH. Colour of matured urine (after six months storage) was yellow for females and brown for males. NPK contents in both male (30.4(3.4*)-1-43.7) and female (34.4(6.5*)-1-62.8) urine were comparable to those of chemical fertilizers, such as 21% N ammonia. However, the nitrogen content of digested female urine was significantly higher than that of male urine. Phosphorus concentration was higher in male urine tha n in female urine during the 2nd and 3rd months of storage. Ecosan urinals (a designed urinal that seeks to separately collect urine to optimize its usefulness) should be designed to separately collect urine for specific NPK requirements for crop production. Results of this study suggest that concentration of NPK in human urine is comparable to commercial chemical fertilizers. Hum an urine in agriculture should progressively be promoted by governments and other agencies.
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Meteorological driving mechanisms and human impacts of the February 1979: extreme hydro-geomorphological event in Western Iberia

Meteorological driving mechanisms and human impacts of the February 1979: extreme hydro-geomorphological event in Western Iberia

Abstract: The large number of floods and landslides that occurred on 5–16 February 1979 in Portugal was a major hydro-geomorphologic extreme event according to the DISASTER database in terms of number of displaced people. The February 1979 event is the top ranked episode in terms of the total number of evacuated people (4244), displaced people (14,322) and also on the number of days of event duration (12 days) for the period 1865–2015. In this event, 62 damaging floods and five damaging landslides causing eight fatalities were recorded in Portugal. This event was driven by an unusually intense atmospheric forcing mechanism acting at different time scales. Despite the intense magnitude and the widespread impact on the population, this event has not been studied in detail. In this study, we show that the precipitation period of February 1979 had produced several multi-day accumulated precipitation events over the Portuguese continental territory, ranking among the top 10 events observed between 1950–2008. Additionally, most of the precipitation from this event occured in days in which atmospheric circulation was dominated by “wet” circulation weather types (CWTs), namely, cyclonic (C), west (W) or southwest (SW) types.
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Copula based multisite model for daily precipitation simulation

Copula based multisite model for daily precipitation simulation

Turning to the detail of jointly modelling occurrences and amounts of rainfall at more than one site, Herr and Krzyszto- fowicz (2005) developed a normal quantile based procedure for modelling pairs of rain gauge records, in particular they separately modelled the dry and wet probabilities and the marginal and joint wet distributions. In this paper, we use that approach as a point of departure to model many sites through the use of multivariate copulas which implicitly cap- ture the pair-wise joint wet and dry processes as well as the mixed wet and dry possibilities. The approach goes be- yond the combination of Markov chains for occurrences and the separate generation of correlated amounts for the wet sites used previously by most authors quoted above. These are typified by Srikanthan and Pegram (2009), who used a two-tiered model: a multi-site bivariate Markov chain to model the wet-dry occurrences and a multivariate Gamma AR(1) process to model the jointly wet events. Although that model satisfactorily mimics and reproduces the histor- ical daily, monthly and annual statistics, there is no feature built in to that approach to mimic the congregation of high values, other than cross-correlation.
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PRECIPITATION INDICES TRENDS AND CORRELATIONS AT A RAINGAUGE STATION IN PORTUGAL

PRECIPITATION INDICES TRENDS AND CORRELATIONS AT A RAINGAUGE STATION IN PORTUGAL

To identify significant linear trends at monthly, seasonal and annual time scales, several pre- cipitation indices were evaluated by Norrant and Douguédroit (89-106) for 63 stations in the Mediterranean, and a few significant monthly trends were identified, diminishing primarily during the winter months and especially in March in the Atlantic region. At the same time, it was observed a significant decrease in winter rainfall on the Iberian Peninsula during the second half of the 20th century (Bustins, Vide and Lorenzo 171-76).

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Rev. bras. meteorol.  vol.27 número4

Rev. bras. meteorol. vol.27 número4

The precipitation based climate indices did not show statistically signiicant trends (Table 2). However, the 5-day accumulated rainfall (Rx5day) and the number of very heavy rainy days (R50mm) present weak positive trends, in agreement with the contemporary idea that severe weather events are becoming more frequent. When correlated with the SST related indices in the Paciic and Atlantic Oceans, positive, though weak, correlations are obtained between Nino 1+2 and Nino 3 SST anomalies and the heavy and very heavy rainfall event precipitations (Table 3). This is an interesting result for the forecasters of the region. The Northeast and the Southern Regions of Brazil are known to have strong affects of the El Nino phenomenon, Northeast having negative and South Brazil having positive inluences. The meteorologists have few clues about the inluence of ENSO phenomenon over the transition region situated in between the two regions. The results shown here may provide some useful information. The Tropical North Atlantic Index (TNAI) also shows a positive inluence on the number wet days (CWD) and the 5-day accumulated rainfall (Rx5day) at Rio Claro. Niño 3.4, Niño 4 and TNAI SST anomalies have a negative effect on the consecutive dry
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Factors Affecting The Adoption Of Mhealth In Maternal Health Care In Nakuru Provincial General Hospital

Factors Affecting The Adoption Of Mhealth In Maternal Health Care In Nakuru Provincial General Hospital

ages 55-64 (7%). Adoption of mHealth is higher in developing economies than in developed economies. A study conducted by McKinsey & Company [22] on global healthcare revealed that, mobile healthcare solutions were being deployed more rapidly in emerging markets than in developed economies with 59% of emerging-market patients using at least one mHealth application or service, compared with 35% in the developed world. Among those who do not, emerging-market residents were more interested in starting. The study further revealed that these trends would imply that the larger developed economies could end up spending nearly 15 percent of their GDP on healthcare within the next two decades. McKinsey [22] conducted a market survey of 3,000 people in the US, China, Germany, South Africa, India, and Brazil. Participants were asked about their willingness to adopt and pay for mHealth services, specifically SMS medication reminders; remote medical advice, phone-prompted drug delivery, and health watch (remote monitoring of factors such as blood pressure and pulse). The survey revealed that a sizeable proportion of consumers were willing to pay USD 15 to 58 a month for a remote monitoring solution (in the survey the health watch), with interest in both emerging and developed markets. If the results are extrapolated to organization for economic co-operation and development (OECD) and BRIC countries (considering the different populations), we can estimate an untapped consumer-led market potential of up to USD 30 to 35 billion. The world of apps is set to transform healthcare in the coming years. It is estimated that some 30 percent of smartphone users are likely to use wellness apps by 2015, while the smartphone and tablet are becoming the most popular technological development for doctors since the invention of the stethoscope (Boston Consulting Group [BCG], 2012). The drivers of mHealth in each country are thus different. For Indian respondents, the three biggest attractions are cost reduction (cited by 58%), convenience of access (55%)and ability to obtain otherwise unavailable information (40%). Convenience is the biggest consideration of British patients (49%), but this is followed by a desire to take greater control of their own health (43%). Cost reduction (25%) is far down the list [23].
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RBRH  vol.22

RBRH vol.22

We considered the implementation of a detention reservoir (on-line) along the main drainage network, more speciically in the area of inluence on the looding point. There are different methods to estimate the detention volume, many of these are known as simpliied. Experience has revealed that the methods based on the use of hydrodynamic models (SWMM, HECRAS, etc.) compensate the additional effort at the dimensioning stage for allowing lower costs and the veriication of hydraulic dimensioning failures in the project, which would be impossible to visualize using more simpliied methodologies (NEVES et al., 2005).
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European and national legislative frame of hygiene and safety of foods

European and national legislative frame of hygiene and safety of foods

Educational )nstitute  TE)  of Athens, Greece . MD,  PhD,  Assistant  Professor  in  Nursing,  Technological  Educational  )nstitute  TE)   of . Athens, Greece .[r]

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HYDROLOGICAL RESPONSES OF A WATERSHED TO VEGETATION CHANGES IN A TROPICAL SEMIARID REGION

HYDROLOGICAL RESPONSES OF A WATERSHED TO VEGETATION CHANGES IN A TROPICAL SEMIARID REGION

ABSTRACT - The objective of this work was to assess the effect of vegetation on the runoff coefficients of a Caatinga dry tropical forest before and after thinning. Thus, an experiment was conducted with evaluations in three hydrological years (2008, 2011 and 2013) in Iguatu, State of Ceará, Brazil. In 2008, the vegetation consisted of a 30-year regenerating Caatinga forest. The vegetation was subjected to thinning in 2009, 2011 and 2013, removing trees with less than 10-cm diameter at breast height. Hydrological responses were evaluated as a function of daily precipitation water depths, based on cumulative frequency distribution, by dividing precipitation events into three classes (CP) (CP≤30, 30<CP≤50 and CP>50 mm). Significant differences between runoff coefficients before and after vegetation thinning were assessed through the Student's t-test (p<0.01). Before thinning (2008), CP≤30 mm showed the highest runoff coefficient, differing statistically (p<0.01) from the other years. The results of precipitation events of great magnitude (CP>50 mm) indicate that the runoff is greatly dependent on rainfall characteristics and soil moisture conditions. The greater development of herbaceous vegetation due to thinning reduced the surface runoff.
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Top-down regulation, climate and multi-decadal changes in coastal zoobenthos communities in two Baltic Sea areas.

Top-down regulation, climate and multi-decadal changes in coastal zoobenthos communities in two Baltic Sea areas.

The structure of many marine ecosystems has changed substantially during recent decades, as a result of overexploitation, climate change and eutrophication. Despite of the apparent ecological and economical importance of coastal areas and communities, this aspect has received relatively little attention in coastal systems. Here we assess the temporal development of zoobenthos communities in two areas on the Swedish Baltic Sea coast during 30 years, and relate their development to changes in climate, eutrophication and top-down regulation from fish. Both communities show substantial structural changes, with a decrease in marine polychaetes and species sensitive to increased water temperatures. Concurrently, opportunistic species tolerant to environmental perturbation have increased in abundance. Species composition show a similar temporal development in both communities and significant changes in species composition occurred in both data sets in the late 1980s and early 1990s. The change in species composition was associated with large scale changes in climate (salinity and water temperature) and to the structure of the local fish community, whereas we found no effects of nutrient loading or ambient nutrient concentrations. Our results suggest that these coastal zoobenthos communities have gone through substantial structural changes over the last 30 years, resulting in communities of different species composition with potentially different ecological functions. We hence suggest that the temporal development of coastal zoobenthos communities should be assessed in light of prevailing climatic conditions considering the potential for top-down effects exerted by local fish communities.
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Determination Of Longevity Of Teeth In Buckets Of Loading Equipment In Coal Mines - A Case Study

Determination Of Longevity Of Teeth In Buckets Of Loading Equipment In Coal Mines - A Case Study

device was studied. The study took into account the effects of machine scale, wear surface structure of the rolls, grinding pressures and rolls speed, gap settings, feed size distribution and moisture content for a range of ores. The authors proposed a prevailing wear mechanism and a methodology for minimising wear of the grinding rolls, specific to the high pressure grinding device only. An example of a direct method, Bond (1964) and Buchi (1995) developed testing apparatus that determine rock abrasiveness in a low abrasion/medium impact mode of wear where rock abrasiveness is measured as the amount of material lost by a standard steel paddle which rotates on a shaft in a sample of loose rock particles of a certain specified size range. As can be seen from the above examples, the indirect methods of rock abrasivity assessment have the advantage of using data which is either readily available or relatively straightforward to obtain. However, they do not take into account process variables for specific modes of wear. Hence, they are normally not used in isolation, but rather in combination with direct methods, or holistic approaches, to supplement or confirm other more relevant direct measures. However, there is no universally accepted one standard test to determine the rock abrasivity although a large number of different tests are in use. All the studies about rock abrasiveness are concentrated on the amount of quartz, grain size and cementation degree of quartz, the geometry of the abrasive mineral and mechanical strength of rock.
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