Cut Area Research Articles

Tree species composition and height structure of undergrowth in fresh hornbeam-oak-pine forest on relatively rich soils of the Ukrainian Roztochia

The fresh hornbeam-oak-pine forest on relatively rich soils of the Ukrainian Roztochia is characterized by a good natural regeneration of tree species, both under the forest canopy after the first irregular shelterwood cutting, and on two clear cut areas. After the first irregular shelterwood cutting, the total amount of self-seeding and undergrowth changes from unsatisfactory (10.480 pieces/ha) at the beginning of the 2020 vegetation season to good (41.528 pieces/ha) at the end of the 2020 growing season. A year later, its number has not changed and 42.693 individuals/ha were counted. However, the share of pedunculate oak in the total number of undergrowth here is only 1.7%. Natural regeneration of all tree species under the forest canopy is characterized by an uneven distribution in the area. Hornbeam has the highest incidence rate - 75.6%. Species such as Scots pine, hanging birch and goat willow have a frequency of 30.8 to 39.7%. Other tree species are much less common, including pedunculate oak (abundance from 1.3% to 12.8%). On clear cut areas the total amount of self-seeding and undergrowth varies from 175.6-275.3 units/ha at the beginning of the vegetation period of 2020 to 299.4 thousand pieces/ha at the end of that vegetation period, and a year later, in autumn 2021 it reached 461.2 thousand pieces/ha. Hornbeam also had the highest abundance rate - 97.3-98.1%, followed by pedunculate oak (43.5-77.3%), birch (42.6-52.7%) and pine (29.6-34.0%). Other tree species, such as lime, willow, sycamore, beech, elm, aspen, and others, had a frequency of 0.7 to 20%. In general, in all the studied areas, the composition of self-seeding and undergrowth was dominated by a small fraction up to 20 cm in height. To ensure the advantage of pedunculate oak in the naturally formed young stands in all areas it is necessary to carry out silvicultural treatments such as cleaning or precommercial thinning.

Understory vegetation response to alternative silvicultural systems in coastal British Columbia montane forests

This study is one of several investigating the biological effects of silvicultural systems at the Montane Alternative Silvicultural Systems (MASS) project located on Vancouver Island in British Columbia (BC). We compared understory vegetation cover and diversity under four silvicultural systems (clearcutting, patch cutting, dispersed retention, and shelterwood) to an adjacent old-growth forest. Long-term plots were measured pre-harvest and at intervals up to 26 years post-harvest. We also compared vegetation response to fertilization and vegetation control treatments. All harvesting resulted in a short-term reduction in understory cover from logging debris and ground disturbance. Recovery from disturbance varied by species, life-form and system. Understory tree species returned to pre-harvest cover after 15 years and significantly exceeded initial cover after 26 years. Shrubs returned to pre-harvest cover after 5–10 years and continued to increase in most systems. Herb cover was low in the pre-harvest forest but increased rapidly in years three through 10 due to herbaceous colonizers; this was least pronounced in the shelterwood. Herbs have declined rapidly since year fifteen. Forest floor bryophytes were reduced to less than 5% cover in all systems except the shelterwood and they remain at one-third or less of their pre-harvest cover. The shelterwood retained more stand structure and plant species from the original old-growth forest than other systems immediately after logging, except for the retained patches. All the harvesting treatments increased species richness and diversity compared to the pre-harvest forest. The increase in total species and abundance was highest for year 15 when early-seral colonizers were still present, and many pre-harvest species had returned. By year 26, richness and diversity began to decrease as early-seral species were lost. For overall species diversity of vascular plants and forest floor bryophytes, silvicultural system did not have an effect after 26 years. All the late-seral herbs that occur at MASS were present after harvesting but several were locally eliminated or had reduced abundance in cut areas. We found no significant edge effects into retention patches, which had comparable species richness and diversity to the pre-harvest old growth—suggesting that aggregated retention can be effective for maintaining late-seral species. Silvicultural system had more significant long-term effects on shrubs and bryophytes than early vegetation control.

The density and distribution of Pacific Oyster (Crassostrea gigas) in Krueng Cut, Aceh Besar

Crassostrea gigas is a Pacific oyster that has the largest size among the other oysters. This oyster is most often found because of its ability to adapt to a variety of environments. Krueng Cut is an estuary area that gets a lot of nutrient input from sea water because it is directly adjacent to the ocean. This condition makes this area has a high abundance of oysters with high fishing and antropogenic activities as well. The purpose of this study was to determine the density and distribution of the oyster population from 3 representative stations along the estuary area of Krueng Cut. The method used in this study is random sampling using a quadratic transect. The results show that the highest density is indicated by station 3 with 55.67 ind/m2 and the lowest density is indicated by station 1 is 40.33 ind/m2. These results indicate that the activities of residents, the entry of contaminants from antropogenic affect the density of oysters. The distribution of oysters from the three stations showed similarities, namely they tended to grouping. The aquatic environment at the three research stations still supports the growth of oysters. This study confirms that there has been a decline in the population, which is characterized by a decrease in the number of catches and a smaller size of oysters.

Measurement of Soil Tillage Using UAV High-Resolution 3D Data

Remote sensing methodologies could contribute to a more sustainable agriculture, such as monitoring soil preparation for cultivation, which should be done properly, according to the topographic characteristics and the crop’s nature. The objectives of this work are to (1) demonstrate the potential of unmanned aerial vehicle (UAV) technology in the acquisition of 3D data before and after soil tillage, for the quantification of mobilised soil volume; (2) propose a methodology that enables the co-registration of multi-temporal DTMs that were obtained from UAV surveys; and (3) show the relevance of quality control and positional accuracy assessment in processing and results. An unchanged-area-matching method based on multiple linear regression analysis was implemented to reduce the deviation between the Digital Terrain Models (DTMs) to calculate a more reliable mobilised soil volume. The production of DTMs followed the usual photogrammetric-based Structure from Motion (SfM) workflow; the extraction of fill and cut areas was made through raster spatial modelling and statistical tools to support the analysis. Results highlight that the quality of the differential DTM should be ensured for a reliable estimation of areas and mobilised soil volume. This study is a contribution to the use of multi-temporal DTMs produced from different UAV surveys. Furthermore, it demonstrates the potential of UAV data in the understanding of soil variability within precision agriculture.

Groundwater–surface water interactions in a river estuary and the importance of geomorphology: Insights from hydraulic, thermal and geophysical observations

AbstractThis study presents the groundwater flow and salinity dynamics along a river estuary, the Werribee River in Victoria, Australia, at local and regional scales. Along a single reach, salinity across a transverse section of the channel (~80 m long) with a point bar was monitored using time‐lapse electrical resistivity (ER) through a tidal cycle. Groundwater fluxes were concurrently estimated by monitoring groundwater levels and temperature profiles. Regional porewater salinity distribution was mapped using 6‐km long longitudinal ER surveys during summer and winter. The time‐lapse ER across the channel revealed a static electrically resistive zone on the side of the channel with a pronounced cut bank. Upward groundwater flux and steep vertical temperature gradients with colder temperatures deeper within the sediment suggested a stable zone of fresh groundwater discharge along this cut bank area. Generally, less resistive zones were observed at the shallow portion of the inner meander bank and at the channel center. Subsurface temperatures close to surface water values, vertical head gradients indicating both upward and downward groundwater flux, and higher porewater salinity closer to that of estuary water suggest strong hyporheic circulation in these zones. The longitudinal surveys revealed higher ER values along deep and sinuous segments and low ER values in shallow and straighter reaches in both summer and winter; these patterns are consistent with the local channel‐scale observations. This study highlights the interacting effects of channel morphology, broad groundwater–surface water interaction, and hyporheic exchange on porewater salinity dynamics underneath and adjacent to a river estuary.

Control of meadowsweet Filipendula ulmaria through a change of management from grazing to mowing at an English floodplain meadow.

Floodplain meadow grassland is a diverse habitat which has become increasingly rare throughout Europe. Meadowsweet Filipendula ulmaria, is a characteristic species of its plant community, however it can become overly dominant in the sward resulting in detrimental effects on the community as a whole. High abundance can reduce both the diversity of the sward, by shading out low growing species, and the quality of the hay crop. An eight-year management trial (2011-2019) was undertaken at Fancott Woods and Meadows SSSI by the BCN Wildlife Trust and the Floodplain Meadows Partnership, to test whether it was possible to reduce the dominance of meadowsweet through an annual hay cut with aftermath grazing instead of grazing management only, across three blocks of experimental treatments. A secondary aim of the trial was to investigate whether a change in management could also increase the plant-species diversity. Three plots were cut in June and then aftermath grazed, compared to three control plots that were only grazed from July onwards. The study found that cover of meadowsweet decreased from 55% to 6% under the annual cut and aftermath grazing treatment compared to a decrease from 58% to 35% in the control (grazed only) areas. This was accompanied by an increase in plant-species diversity in the cut areas compared to control plots. The study concluded that annual cutting can be used to control coarse and dominant meadowsweet effectively, and that cutting followed by aftermath grazing in a floodplain meadow delivers greater botanical diversity compared to grazing alone.

The self-healing of Bacillus subtilis biofilms.

Self-healing is an intrinsic ability that exists widely in every multicellular biological organism. Our recent experiments have shown that bacterial biofilms also have the ability to self-heal after man-make cuts, but the mechanism of biofilm self-healing have not been studied. We find that the healing process of cuts on the biofilm depends on cut geometries like its location or direction, the biofilm itself like the biofilm age, the growing substrate properties like its hardness, and also the environments such as the competitive growth of multiple biofilms. What is more, the healing rate along the cut is heterogeneous, and the maximum healing rate can reach 260μm/h, which is three times the undestroyed biofilm expansion rate. The cut does not change the rounded shape growth of biofilms. Further study of phenotypic evolution shows that the cut delays bacterial differentiation; motile cells perceive the cut and move to the cut area, while the cut only heals when there are enough matrix-producing cells in the cut area. Our work suggests new ideas for developing self-healing materials.

Medicinal Plants Galega officinalis L. and Yacon Leaves as Potential Sources of Antidiabetic Drugs.

Hypoglycemic and antioxidant properties of extracts of medicinal plants Galega officinalis L. (aboveground part) and yacon (Smallanthus sonchifolius Poepp. & Endl.) (leaves) as potential sources of biologically active substances with antidiabetic action have been studied. The pronounced hypoglycemic effect of Galega officinalis extract, devoid of alkaloids, at a dose of 600 mg/kg in experimental diabetes mellitus (DM) has been proven. The established effect is evidenced by a decrease in the concentration of glucose and glycosylated hemoglobin in the blood, increase glucose tolerance of cells, increase C-peptide and insulin content in the plasma of rats’ blood. The effective hypoglycemic effect of the extract in the studied pathology was confirmed by histological examination of the pancreas. The cytoprotective effect of the studied extract on pancreatic cells at a dose of 1200 mg/kg was experimentally confirmed. In the standard cut area, an increase was found in the number of Langerhans islets, their average area, diameter, volume, and a number of β-cells relative to these indicators in animals with diabetes. Comparative screening of the antioxidant properties of 30, 50, 70, and 96% water–ethanol extracts of yacon indicates the highest potential of 50% water-ethanol extract to block free radicals in in vitro model experiments. The non-alkaloid fraction of Galega officinalis extract showed moderate antioxidant activity and was inferior to yacon extract in its ability to neutralize reactive oxygen species (ROS) and bind metal ions of variable valence. The level of antioxidant potential of the studied extracts is due to differences in the quantitative content of compounds of phenolic nature in their compositions. The obtained data on the biological effects of Galega officinalis extract on the structural and functional state of β-cells of the pancreas and antioxidant properties of Galega officinalis and yacon extracts substantiate the prospects of using these plants to create antidiabetic medicines and functional foods based on them.

Klasifikasi Ketertarikan Belajar Anak PAUD Melalui Video Ekspresi Wajah Dan Gestur Menggunakan Convolutional Neural Network

Abstract—The Covid-19 pandemic has transformed the offline education system into online. Therefore, in order to maximize the learning process, teachers were forced to adapt by having presentations that attract student's attention, including kindergarten teachers. This is a major problem considering the attention rate of children at early age is very diverse combined with their limited communication skill. Thus, there is a need to identify and classify student's learning interest through facial expressions and gestures during the online session. Through this research, student's learning interest were classified into several classes, validated by the teacher. There are three classes: Interested, Moderately Interested, and Not Interested. Trials to get the classification of student's learning interest by teacher validation, carried out by training and testing the cut area of the center of the face (eyes, mouth, face) to get facial expression recognition, supported by the gesture area as gesture recognition. This research has scenarios of four cut areas and two cut areas that were applied to the interest class that utilizes the weight of transfer learning architectures such as VGG16, ResNet50, and Xception. The results of the learning interest classification test obtained a minimum validation percentage of 70%. The result obtained through scenarios of three learning interest classes four cut areas using VGG16 was 75%, while for two cut areas using ResNet50 was 71%. These results proved that the methods of this research can be used to determine the duration and theme of online kindergarten classes.

Using satellite data to assess management frequency and rate of regeneration on heather moorlands in England as a resilience indicator

Peatland resilience, defined here as the rate of recovery from perturbation, is crucial to our understanding of the impacts of climate change and land management on these unique ecosystems. Many peatland areas in the UK are managed as grouse moors using small burns (or increasingly, heather cutting) to encourage heather growth and limit fuel load. These small burns or cuts are distinct disturbance events which provide a useful means of assessing resilience. Until now, it has been difficult to monitor the area affected by management each season due to the remoteness and size of moorland sites. Newer satellite sensors such as those on Sentinel-2 are now collecting data at a spatial resolution that is fine enough to detect individual burns or cut areas, and at a temporal resolution which can be used to monitor occurrence and recovery each year. This study considered four areas of moorland; the North Pennines, Yorkshire Dales, North York Moors, and the Peak District. For each of these areas Sentinel-2 optical data was used to detect management areas using the dNBR (differenced Normalized Burn Ratio), and to monitor vegetation recovery using the NDVI (Normalised Difference Vegetation Index). Significant differences were found between the four selected sites in management repeat interval, with the North York Moors having the shortest repeat interval of 20 years on average (compared to 40–66 years across the other three study sites). Recovery times were found to be affected by burn size and severity, weather during the summer months, and altitude. This suggests that the interactions between peatland management and climate change may affect the future resilience of these areas, with hot, dry summers causing longer management recovery times.

Landscape Variables Influence over Active Restoration Strategies of Nothofagus Forests Degraded by Invasive Castor canadensis in Tierra del Fuego

North American beavers (Castor canadensis) are responsible for the major changes in the Tierra del Fuego Archipelago, altering riparian forests for the long-term. Passive restoration of the areas affected was ineffective in the medium-term (up to 20 years), being necessary active strategies. Plantations in abandoned ponds were made with Nothofagus pumilio and N. antarctica tree species across Tierra del Fuego island (Argentina). In the first experiment, we analysed the influence of biotic and abiotic factors in three micro-habitats in the impacted areas: front and tail of ponds, and cut not-flooded forest areas. Five-years-old N. pumilio seedlings had 39% survival in front, 21% in tails, and 46% in cut areas at year-3 of the restoration experiments, being negatively influenced by plant cover and soil moisture. Lower growth was recorded during year-1 (0.7–0.9 cm yr−1), but increased on time (1.9 cm yr−1 front, 1.6 cm yr−1 tail, 4.3 cm yr−1 cut areas). A second experiment explores the alternative to substitute the tree species to face the harder conditions of the impact and climate change. For this, we conducted a new plantation at four locations across the main bioclimatic zones, where 10–40 cm N. antarctica plants attained 17% survival in meadows (front and tail) and 30% in cut areas, being higher with larger than smaller plants (25% vs. 18%), and where they are mainly influenced by rainfall (4% in sites <400 mm yr−1 and 41% in >400 mm yr−1). The main damage was detected in the above-ground biomass due to dryness, but root survival allowed the emergence of new shoots in the following growing season. It is necessary to monitor different Nothofagus species across natural environments in the landscape to determine the feasibility and effectiveness of different strategies in restoration plans, considering the selection of climate-resilient tree species.

Global and regional impacts of land cover changes on isoprene emissions derived from spaceborne data and the MEGAN model

Abstract. Among the biogenic volatile organic compounds (BVOCs) emitted by plant foliage, isoprene is by far the most important in terms of both global emission and atmospheric impact. It is highly reactive in the air, and its degradation favours the generation of ozone (in the presence of NOx) and secondary organic aerosols. A critical aspect of BVOC emission modelling is the representation of land use and land cover (LULC). The current emission inventories are usually based on land cover maps that are either modelled and dynamic or satellite-based and static. In this study, we use the state-of-the-art Model of Emissions of Gases and Aerosols from Nature (MEGAN) model coupled with the canopy model MOHYCAN (Model for Hydrocarbon emissions by the CANopy) to generate and evaluate emission inventories relying on satellite-based LULC maps at annual time steps. To this purpose, we first intercompare the distribution and evolution (2001–2016) of tree coverage from three global satellite-based datasets, MODerate resolution Imaging Spectroradiometer (MODIS), ESA Climate Change Initiative Land Cover (ESA CCI-LC), and the Global Forest Watch (GFW), and from national inventories. Substantial differences are found between the datasets; e.g. the global areal coverage of trees ranges from 30 to 50×106 km2, with trends spanning from −0.26 to +0.03 % yr−1 between 2001 and 2016. At the national level, the increasing trends in forest cover reported by some national inventories (in particular for the US) are contradicted by all remotely sensed datasets. To a great extent, these discrepancies stem from the plurality of definitions of forest used. According to some local censuses, clear cut areas and seedling or young trees are classified as forest, while satellite-based mappings of trees rely on a minimum height. Three inventories of isoprene emissions are generated, differing only in their LULC datasets used as input: (i) the static distribution of the stand-alone version of MEGAN, (ii) the time-dependent MODIS land cover dataset, and (iii) the MODIS dataset modified to match the tree cover distribution from the GFW database. The mean annual isoprene emissions (350–520 Tg yr−1) span a wide range due to differences in tree distributions, especially in isoprene-rich regions. The impact of LULC changes is a mitigating effect ranging from 0.04 to 0.33 % yr−1 on the positive trends (0.94 % yr−1) mainly driven by temperature and solar radiation. This study highlights the uncertainty in spatial distributions of and temporal variability in isoprene associated with remotely sensed LULC datasets. The interannual variability in the emissions is evaluated against spaceborne observations of formaldehyde (HCHO), a major isoprene oxidation product, through simulations using the global chemistry transport model (CTM) IMAGESv2. A high correlation (R > 0.8) is found between the observed and simulated interannual variability in HCHO columns in most forested regions. The implementation of LULC change has little impact on this correlation due to the dominance of meteorology as a driver of short-term interannual variability. Nevertheless, the simulation accounting for the large tree cover declines of the GFW database over several regions, notably Indonesia and Mato Grosso in Brazil, provides the best agreement with the HCHO column trends observed by the Ozone Monitoring Instrument (OMI). Overall, our study indicates that the continuous tree cover fields at fine resolution provided by the GFW database are our preferred choice for constraining LULC (in combination with discrete LULC maps such as those of MODIS) in biogenic isoprene emission models.

Estimation of Surface Canopy Water in Pacific Northwest Forests by Fusing Radar, Lidar, and Meteorological Data

Surface Canopy Water (SCW) is the intercepted rain water that resides within the tree canopy and plays a significant role in the hydrological cycle. Challenges arise in measuring SCW in remote areas using traditional ground-based techniques. Remote sensing in the radio spectrum has the potential to overcome the challenges where traditional modelling approaches face difficulties. In this study, we aim at estimating the SCW by fusing information extracted from the radar imagery acquired with the Sentinel-1 constellation, aerial laser scanning, and meteorological data. To describe the change of radar backscatter with moisture, we focused on six forest stands in the H.J. Andrews experimental forest in central Oregon, as well as four clear cut areas and one golf course, over the summers of 2015–2017. We found significant relationships when we executed the analysis on radar images in which individual tree crowns were delineated from lidar, as opposed to SCW estimated from individual pixel backscatter. Significant differences occur in the mean backscatter between radar images taken during rain vs. dry periods (no rain for >1 h), but these effects only last for roughly 30 min after the end of a rain event. We developed a predictive model for SCW using the radar images acquired at dawn, and proved the capability of space-based radar systems to provide information for estimation of the canopy moisture under conditions of fresh rainfall during the dry season.

The Efficiency of Large Hole Boring (MSP) Method in the Reduction of Blast-Induced Vibration

Drill and blast is the most cost-effective excavation method for underground construction, however, vibration and noise, induced by blasting, have been consistently reported as problems. Cut blasting has been widely employed to reduce the blast-induced problems during underground excavation. We propose that the large hole boring method using the state-of-the-art MSP (Multi-setting smart-investigation of the ground and pre-large hole boring) machine (“MSP method”) can efficiently improve vibration reduction. The MSP machine will be used to create 382 mm diameter empty holes at the tunnel cut area for this purpose. This study assessed the efficiency of the MSP method in reducing blast-induced vibration in five blasting patterns using a cylinder-cut, which is a traditional cut blasting method. The controlled blasting patterns using the MSP method demonstrated up to 72% reduction in blast-induced vibration, compared to the base case, Pattern B, where only cylinder-cut and smooth blasting method were applied. Therefore, the MSP method proves to be a promising alternative for blasting in sensitive urban areas where non-vibration excavation techniques were initially considered. Geological characteristics of 50 m beyond the excavation face can be acquired through the proposed real-time boring data monitoring system together with a borehole alignment tracking and ground exploration system. The obtained geological information will be a great help in preparing alternative designs, and scheduling of construction equipment and labour during the tunnel construction.

Новые представления о связеобразовании волокон в многослойном композиционном материале

The article presents the results of new views of fiber bonding in a multilayer composite material. New views of fiber bonding based on the obtaining a cross-section by ion beam cut cutting with further quantitative assessment of the main factors, namely the combined effect of hydrogen bonds of mechanical coupling forces and Van-Der-Waals forces, nature of fibrous, mutual arrangement of fibrous, uniformity of fibro distribution, presence of impurities. The combination of effects of the above forces is determined by the length of fibro contacts and uniformity of distribution of contact lines in the cross section of the multilayer fibrous material. In study, area of cut and uniformity of distribution of area of cut fibrous are determined, chalk distribution is estimated at different technologies of preparation of fibrous material. According to the obtained data, mechanical and surface indices of fibrous material are analyzed.

Polydatin Beneficial Effects in Zebrafish Larvae Undergoing Multiple Stress Types.

Polydatin is a polyphenol, whose beneficial properties, including anti-inflammatory and antioxidant activity, have been largely demonstrated. At the same time, copper has an important role in the correct organism homeostasis and alteration of its concentration can induce oxidative stress. In this study, the efficacy of polydatin to counteract the stress induced by CuSO4 exposure or by caudal fin amputation was investigated in zebrafish larvae. The study revealed that polydatin can reduced the stress induced by a 2 h exposure to 10 µM CuSO4 by lowering the levels of il1b and cxcl8b.1 and reducing neutrophils migration in the head and along the lateral line. Similarly, polydatin administration reduced the number of neutrophils in the area of fin cut. In addition, polydatin upregulates the expression of sod1 mRNA and CAT activity, both involved in the antioxidant response. Most of the results obtained in this study support the working hypothesis that polydatin administration can modulate stress response and its action is more effective in mitigating the effects rather than in preventing chemical damages.

Design of a Kirigami Structure with a Large Uniform Deformation Region.

We designed a kirigami structure with a particular shape at both ends to provide a large uniform deformation region when stretched. When a kirigami structure is stretched, non-deformation regions, where the regions’ cuts do not open, and non-uniform deformation regions, where the regions’ cuts are not uniformly deformed, are produced. The extent of the non-deformation and non-uniform deformation regions increases in proportion to the number of cut cycles in the width direction nw this reduces the percentage of the uniform deformation region. We propose a method that increases the uniform deformation region in a kirigami structure by deforming the shape of the ends from a rectangle to a trapezoid when stretched. The proposed kirigami structure has separation lines at both ends that separate cuts in the width direction, and the position of contacts at both ends are moved to the center. The proposed kirigami structure has a large uniform deformation region, even when nw is large, as evidenced by calculating the area of open cuts under stretching. The product of our study realizes a stretchable electro device with a large area, which maintains the position of evenly mounted functional elements when stretched.

Approbation of the tectonophysical model of fracture estimation at the deposits of the inner zone of the Precarpathian Foredeep

A promising method for assessing the fracturing of reservoir rocks is the analysis of their stress-strain state by mathematical modeling of tectonophysical processes in the sandy-silty flysch strata. Previous studies were aimed at substantiating the main approaches to tectonophysical modeling of sandy-silty strata in order to assess the fracturing of oil and gas promising deposits. However, the developed model of the symmetric anticline cannot be used in the conditions of the Intristic zone of the Pre-Carpathian Foredeep due to the complex forms of layers. The model was improved and tested at such well-known deposits of the Inner Zone of the Pre-Carpathian Foredeep as Starosambir and Pivdenno-Hvizdetsk. A corresponding model for an asymmetric anticline with different layer thickness of the reservoir rock of the Yamna formation of the Paleocene of the Starosambir deposit has been constructed. The simulation results showed, that the zone of increased fracturing is located within the crest of the anticline. This statement is proved by field studies of the core. Increased fracturing within the cut area was not detected. The upper layer of sandstone of the menilite formation of the South Hvizdetsk deposit almost completely belongs to the fractured, pore-fractured type of reservoir. The question arose as to whether it was possible to explain such an abnormally large area of increased fracturing by the developed model. To solve the problem, the boundary conditions for reproducing the real deformation of the sandstone formation were improved. According to the results, the area of increased fracturing almost completely covers the layer. Thus, the results of approbation of the tectonophysical model within deposits of the Inner Zone of the Pre-Carpathian Foredeep indicate that with the help of the developed model it is possible to research complex structures on tectonic fracturing.

Truck routing cut and fill problem in roadworks using integer programming

Planejar as atividades de distribuição de materiais em obras de terraplenagem pode representar um ganho na obra como um todo. Uma das formas de fazer isso é minimizar a distância total percorrida pelos veículos, por exemplo caminhões na movimentação de terra entre as zonas de corte e aterro. Há muitos estudos e trabalhos que focam a otimização da distribuição de materiais entre zonas de corte e aterro, porém poucos aplicaram em projetos reais com a consideração de múltiplos equipamentos, além de não terem feito uma análise baseada na distância entre estacas. Este artigo tem como objetivo desenvolver um modelo de Programação Inteira que minimize a distância percorrida pelos caminhões basculantes em atividades de distribuição de materiais na terraplenagem. O modelo elaborado com princípios da Programação Linear Inteira foi baseado no problema de roteamento, cujo objetivo é minimizar o caminho percorrido. O modelo foi aplicado em dois estudo de casos cujos resultados destacam ganhos significativos, em termos de flexibilidade do processo de planejamento. Engenheiros, planejadores e analistas têm uma importante ferramenta computacional que facilitará a tomada de decisão.

Influence of void ratio on “Blast Pull” for different confinement factors of development headings in underground metalliferous mines

Development headings such as adits, ramps, haulages, cross-cuts, ore drives and exploratory drives are the important structures of any underground metalliferous mines. Drilling and blasting is the most preferred excavation method used to create such drivages for extracting mineral deposits, since the progress rate of drivages impacts the overall productivity of mines. There are many controllable blast design parameters and uncontrollable geological-geotechnical parameters influencing the blast pull (i.e. advancement factor). This paper investigates the influence of void ratio (i.e. the ratio between total area of empty holes and cut area of a first shot hole) on blast pull for development faces having different confinement factors. The confinement factor is defined as the ratio of drill hole length and cross-sectional area of development headings. For this study, field investigations were performed in four lead–zinc mines. Thereafter, experimental blasts were conducted in haulage drives on the footwall side, ore drives and exploratory drives on the hanging wall side, for different confinement factors ranging from 0.10 to 0.37. Several parallel hole cut designs were experimented upon, with the void ratios varying from 19.80% to 75%. Results revealed that the void ratio plays an important role in the advancement factor of development headings. Furthermore, with an increasing confinement factor, the void ratio should be kept high for achieving maximum blast pull. Statistical analysis was carried out to establish trends between the void ratio and the confinement factor of development faces using accuracy indicators of MAPE, MAD and MSD. Eventually, a relationship was established for the effective parallel hole cut designs to achieve more than 90% advancement factor.