Stone Manufacturing Research Articles

砥石을 통해 본 한반도 동남부지역의 開始期 철기 제작기술

In relation to the beginning of ancient iron production in the southeastern part of the Korean Peninsula, the issue of wrought iron production has been a major issue, with research focused on furnace wall and tuyre fragments, iron materials, and slag found in association within dwellings. However, whetstones, which functioned as a processing tool throughout humankind’s long history, have yet to be fully examined in relation to wrought iron production. Therefore, this paper presents the results of analysis undertaken on the use traces of the ground whetstones excavated from archaeological sites. It was found that the whet-stones can be largely divided into those with the abrasive section located partially or along the entire surface of the stone. In the areas where the iron tools were used from the initial stage, it was identified that the stone manufacturing technology of the local communities was utilized and evidence of the working of iron products could be observed on the sur-face of the whetstones. In addition, the fact that iron objects have have been unearthed in contexts in which iron production by-products have not been identified shows that the use of whetstones was not limited to iron smithing. In addition, in relation to the initial period of iron use ob-served mainly in the Geumho River basin, the characteristics and distribution of iron pro-duction sites from the same period are not uniform, indicating that the nature of iron use and production in the initial period in the southeastern region was not uniform. The development of the initial iron production technology for the southeastern part of the Korean Peninsula was examined by identifying different aspects in the southeastern part of Kyushu, Western Japan, where the situation of reusing iron fragments was con-firmed over a long period of time and over a wide area.

Models of Grinding Stone Manufacture, Use, and Discard from Tigrai, Ethiopia: Opportunities for Cultural Comparisons and Implications for Usewear Analysis

ABSTRACT Grinding stones are a worldwide technology, instrumental in processing food as far back as the African Middle Stone Age. Research interest in grinding stones, and the usewear on their surfaces, has grown in the last few decades. Models of grinding stone manufacture, use, and discard provide a reference for cross-cultural comparisons of practices and guide methodologies in planning usewear analysis based on kinetics. In Ethiopia, traditional knowledge of grinding stones is still accessible, and grinding stones remain in use. The models developed through interviews with, and observations of, local practitioners show processes and behaviors but also decisions made at various stages. Particular behaviors and decisions have impacts on tool wear.

OPTIMIZING FINE AGGREGATE AND CEMENT REPLACEMENT WITH STONE DUST: IMPACT ON CONCRETE COMPRESSIVE STRENGTH

The utilization of stone dust in concrete presents a promising avenue for reducing environmental impact through decreased dependence on traditional fine aggregate and cement components, primarily focusing on the properties of fresh and hardened concrete. This study delves into the direct integration of stone dust sourced from stone companies, particularly as random samples collected during the sawing phase of stone manufacturing. Through meticulous analysis, the replacement of stone dust is thoroughly examined to assess its influence on the fresh and hardened characteristics of concrete, aiming to optimize the mix for superior performance. Experimental investigations reveal that quarry dust can effectively substitute for fine aggregate and cement, albeit with the caveat that a comprehensive chemical analysis of the stone dust is imperative prior to integration to ensure compatibility with the concrete mix. Moreover, the study quantifies the compressive strength of concrete across varying percentages of stone dust, evaluating its impact on the concrete class. By analyzing replacement percentages ranging from 5% to 12.5% for fine aggregate and optimal cement replacement, the research explores mix design preparation, fresh property assessments, and hardened concrete sample evaluations, with a particular focus on compressive strength comparisons against reference concrete formulations.

OPTIMIZING FINE AGGREGATE AND CEMENT REPLACEMENT WITH STONE DUST: IMPACT ON CONCRETE COMPRESSIVE STRENGTH

The utilization of stone dust in concrete presents a promising avenue for reducing environmental impact through decreased dependence on traditional fine aggregate and cement components, primarily focusing on the properties of fresh and hardened concrete. This study delves into the direct integration of stone dust sourced from stone companies, particularly as random samples collected during the sawing phase of stone manufacturing. Through meticulous analysis, the replacement of stone dust is thoroughly examined to assess its influence on the fresh and hardened characteristics of concrete, aiming to optimize the mix for superior performance. Experimental investigations reveal that quarry dust can effectively substitute for fine aggregate and cement, albeit with the caveat that a comprehensive chemical analysis of the stone dust is imperative prior to integration to ensure compatibility with the concrete mix. Moreover, the study quantifies the compressive strength of concrete across varying percentages of stone dust, evaluating its impact on the concrete class. By analyzing replacement percentages ranging from 5% to 12.5% for fine aggregate and optimal cement replacement, the research explores mix design preparation, fresh property assessments, and hardened concrete sample evaluations, with a particular focus on compressive strength comparisons against reference concrete formulations.

Dose-response relationship between lung function and chest imaging response to silica exposures in artificial stone manufacturing workers

BackgroundOccupational exposure to artificial stone, a popular material used for countertops, can cause accelerated silicosis, but the precise relationship between silica dose and disease development is unclear.ObjectivesThis study evaluated the impact of silica exposure on lung function and chest imaging in artificial stone manufacturing workers.MethodsQuestionnaire and spirometry assessments were administered to workers in two plants. A high-exposure subset underwent further evaluation, including chest CT and DLco. Weighting factors, assigned as proxies for silica exposure, were based on work tasks. Individual cumulative exposures were estimated using area concentration measurements and time spent in specific areas. Exposure-response associations were analyzed using linear and logistic regression models.ResultsAmong 65 participants, the mean cumulative silica exposure was 3.61 mg/m3-year (range 0.0001 to 44.4). Each 1 mg/m3-year increase was associated with a 0.46% reduction in FVC, a 0.45% reduction in FEV1, and increased lung function abnormality risk (aOR = 1.27, 95% CI = 1.03–1.56). Weighting factors correlated with cumulative exposures (Spearman correlation = 0.59, p < 0.0001), and weighted tenure was associated with lung function abnormalities (aOR = 1.04, 95% CI = 1.01–1.09). Of 37 high-exposure workers, 19 underwent chest CT, with 12 (63%) showing abnormal opacities. Combining respiratory symptoms, lung function, and chest X-ray achieved 91.7% sensitivity and 75% specificity for predicting chest CT abnormalities.ConclusionLung function and chest CT abnormalities occur commonly in artificial stone workers. For high-exposure individuals, abnormalities on health screening could prompt further chest CT examination to facilitate early silicosis detection.

Curtailing the Environmental Impact of Waste Plastics through Re-use for Sustainable Paving Stone Manufacture in Kinshasa City

In Kinshasa, attacks on the environment and human well-being continue to increase with the accumulation of thermoplastic waste (LDPE, HDPE and PET) mainly produced. Collected in unsanitary landfills, this waste pollutes the environment with all the consequences on health. This study makes it possible to reduce the socio-environmental impacts of thermoplastic waste by reusing them for the manufacture of paving stones for the sanitation of Kinshasa. Specifically, it initiates the collection of thermoplastic waste, recycling techniques for the production of paving stones and raising awareness among Citizens and Decision-Makers of the importance of their management. Thus, a survey questionnaire was administered to a sample of 1276 households. The proportions of materials used to obtain the resistant paving stones are: 60% fine sand, 35% LDPE and HDPE and 5% PET. Melted at 200°C, the thermoplastics are mixed with sand until a homogeneous paste is obtained to be poured into moulds prearranged on a metal table. The consolidated pavers are removed from the mould after 45 minutes using a hammer. The results obtained show that 4% of households manage their waste better and that 96% contribute to plastic pollution. 87.1% of households denounce the harmful effects of thermoplastics on the environment and point out the clogging of gutters (28.4%), the pollution of space (25%) and the pollution of rivers (16.5%). Twenty-two pavers with an average weight of 1953.33 ± 6.22 gr are manufactured. The weight loss of the materials is 14.2% (7.1 kg). The compressive strength of the pavers is 32.74 ± 0.94 N/mm². In short, reducing the socio-environmental impacts of thermoplastic waste in Kinshasa is complex and requires a multidimensional approach with the efforts of all stakeholders.

Design and implementation of a digital twin for a stone-cutting machine: a case study

The use of digital twins in the development and management of stone-cutting devices presents real challenges in the field of industrial stone manufacturing. Digital twins help manufacturers achieve increased precision, efficiency, and cost-effectiveness, ultimately transforming the landscape of stone manufacturing operations. Such digital twins enable real-time monitoring, predictive maintenance, and virtual simulations. This paper explores two options for connecting a physical stone-cutting machine in a company to its digital twin. The first option involves using Industrial Internet of Things (IIoT) devices and a Message Queuing Telemetry Transport (MQTT) broker to enable real-time data exchange. This approach provides agile and efficient communication between the physical machine and its digital twin. The second option employs conventional automation devices and a VPN connection to ensure data security during transmission. The two options were evaluated by considering criteria such as communication speed, security, scalability, ease of implementation, cost, complexity, and technical requirements. The results of the comparative analysis provide valuable insights for the implementation of the digital twin of the stone-cutting machine, allowing the selection of the most suitable option based on these considerations.

Effect of artificial interior stone sludge on physicomechanical properties of mortars

Artificial interior stone is a decorative building material, which mostly consists of quartz. Sludge is generated during the stone manufacturing process, and the amount of sludge is increasing due to the high demand; however, most of the generated sludge is disposed of in landfills. In the present study, the effects of the sludge addition on the physicomechanical properties of mortars were investigated via flowability, penetration resistance, mercury intrusion, and compressive strength tests. The independent variable was the replacement ratio of the sludge to the fine aggregate. The test results showed that the addition of the sludge reduced the flowability, and initial and final setting times, while the percentage of the pores involved in the hydrates increased. The compressive strength of mortars with the sludge was improved compared to that of the mortars without the sludge. Quantum chemistry simulations were conducted to understand the strength enhancement mechanism of the specimens, and a straightforward machine learning-based model equation was proposed by applying the experimental variables and measurement results.

A comparative life cycle energy and green house emissions of natural and artificial stone-manufacturing phase

The natural stone industry in many countries plays an essential role in its cultural heritage, history and economy. However, the stone industry consumes large amounts of energy in the production phase. The total energy in the natural stone production is a collective summation of energy levels consumed in each phase of production, starting from stone quarries or from mixture preparation to finally produce natural or artificial stone as an end product. The study aims at evaluating the total embodied energy of the stone industry in Palestine to further conduct a comparative Life Cycle Assessment (LCA) for both energy levels consumed in the manufacturing of natural and artificial stone. Personal interviews, observations, and stone quarry sites and workshops visits were used to collect data in Hebron – south of the West Bank. The results have shown a more sustainable production of artificial stone over natural stone in terms of energy consumption; and the (GHG) emissions accordingly as the amounts of energy for natural and artificial stone manufacturing were 120 MJ/m2 and 70.71 MJ/m2 respectively. As a conclusion, the study proves that natural stone (limestone) manufacturing produces more (GHG) emissions than the locally made artificial stone manufacturing in the study context under the studied circumstances. The environmental impact can be decreased through locating the workshops near the quarries and the sourcing points of raw materials. In addition, this can be obtained by depending on electrical vehicles and using green energy sources.

A Future with Engineering Stone Made from Silica-Rich Iron Ore Tailings from Vale

Among the many initiatives being developed to recover and reuse mineral waste at Vale mining sites, the new business solution presented here uses silica-rich tailings as a substitute for primary silica to produce engineering stone products like kitchens countertop, bathroom vanities and floor tiles in a booming, multi-billion dollar industry. Engineering stone is an alternative to natural stone like granite. It is manufactured from approximately 93% primary silica, 7% resin, colour pigments and selected aesthetic additives, with the recipes varying depending on desired colour and aesthetic properties. Using primary (typically white) silica allows engineering stone manufactures to produce products with a wide colour range, so when used, residual (darker) iron ore in tailings can somewhat decrease colour control. Through innovative technological advances combined with a skilled and highly motivated workforce, Vale has been able to systematically improve separation efficiency of its concentration/beneficiation processes (primarily aimed at maximizing the recovery of iron ore). Fortuitous laws governing mass balances have ensured that increased recovery of iron ore in one stream has meant an associated increase in silica content of the other stream (tailings), in some strategic process streams as high as 90-96% SiO2. Such a systematic increase in the silica content (becoming whiter) has meant an increase in the colour control Vale silica-rich tailings can deliver the industry. Since 2014 Vale has been working closely with leaders in the engineering stone manufacturing industry to develop recipes. This collaboration is delivering engineering stone that not only meet EN 14617 industry standards for resistance to stain, strength and impact but also have colour ranges able to satisfy market needs.

Multivariate Nonconformity Analysis for Paving Stone Manufacturing Process Improvement

Abstract The article presents the result of multidimensional analysis of ‘Behaton’ type paving stones’ nonconformities for improving the production process by improving the quality of the final product. Statistical tools, including SPC tools and quality tools, both basic and new, were used to analyse nonconformities in the spatial-temporal system, i.e. according to the type of nonconformity and according to the examined months. The purpose of using the data analysis tools was to thoroughly analyse the cases of nonconformities of the tested product, obtain information on the structure of these nonconformities in the various terms, and information on the stability and predictability of the numerical structure of nonconformity over time. Potential causes influencing a large percentage of paving stone defects were identified, factors and variables influencing the most frequently occurring nonconformities were determined, and improvement actions were proposed. As a result of the multidimensional and multifaceted analyses of paving stone nonconformities, it was shown that in the structure of nonconformity there were cases that were unusual in terms of the number of occurrences, and the lack of stability in the number of nonconformities in terms of the examined months was proven. Three critical nonconformities of the tested product were identified: side surface defects, vertical edge defects, and scratches and cracks. It was determined that the most important factor causing a large percentage of nonconformity was the time of shaking and vibrating the concrete, which was significantly related to the technical condition of the machines, and the most important reason for a large percentage of paving stone nonconformity was the lack of efficient maintenance. Machine, method, and man turned out to be the most important categories of problem factors and specific remedial actions were proposed. A multidimensional look at the structure of paving stone nonconformity as well as the factor and causes causing them has brought a lot of valuable information for the management staff of the analysed company, thanks to which it is possible to improve the production process and improve the quality of the final product.

ДОСЛІДЖЕННЯ ДОЦІЛЬНОСТІ ЗАСТОСУВАННЯ СКЛОПЛАСТИКОВИХ ТА БАЗАЛЬТОПЛАСТИКОВИХ СТЕРЖНІВ ДЛЯ АРМУВАННЯ ВИРОБІВ З КАМЕНЮ

Purpose. The purpose of this work is to study the feasibility of using different types of composite materials for natural stone products reinforcement by comparing their strength characteristics. Methodology. Recommendations for the preparation of samples for strength research have been implemented and described. Recommendations for the preparation, adjustment and commissioning of fixed assets and materials used in the study are given. The constituent elements of the experiment aimed at determining the strength characteristics of the samples are developed and described. Based on the results of the obtained data, the values of the basic strength parameters during the destruction of the samples under the action of bending loads have been calculated. Results. The study of the technology of stone products reinforcement allows solving a number of problems related to improving the quality and competitiveness of stone manufacturing. A holistic and scientifically sound study of reinforcement technology allows an array of empirical data and developing the optimal order of its use. Scientific novelty. Systematization and review of existing methods of natural stone products reinforcement are performed and methods of their optimization with the help of modern composite materials are offered. The expediency of using fiberglass and basalt-plastic composite materials for the purpose of reinforcing stone products has been empirically investigated. The expediency of using fiberglass and basalt-plastic composite materials for natural stone products reinforcement by comparing the obtained values of strength characteristics has been substantiated. Practical significance. The practical significance of the obtained results lies in the possibility of their application in order to simplify, modernize and improve the technology of stone products reinforcement for its widespread introduction as one of the basic technologies in the conditions of stone processing enterprises. However, the research results confirm the fact of the expediency of using composite reinforcement (especially basalt-plastic) to improve the strength properties of stone products.

Development of technology and equipment for the manufacture of road stone in the USSR (pre-war period)

The paper covers the road stone manufacturing history and the development of related quality requirements in the pre-war USSR. The chronological framework of the study is limited between 1922 (USSR foundation year) and 1941 (the beginning of the Great Patriotic War). Publications on scientific research in mining and road construction released in the indicated period are used as the data source. The specified period is divided into two parts by the year of 1928, marking the beginning of industrialization in the country. The interval between 1922 and 1928 is viewed as the recovery period for the industry after the Civil War and the interval between 1928 and 1941 as the active development period. The crushing theory started to develop in the USSR during this time, founded by Professor Henryk Czeczott, founder and first director of the Mekhanobr Institute (1920&ndash;1922). The increasing crushed stone output led to the mechanization of related manufacturing processes. This, in turn, boosted the development of the Soviet mining technology: as early as in the 1930s, the USSR was already organizing the manufacture of domestic crushers to replace the initially used foreign-made crushing equipment. The improved crushed stone technology and equipment required standards to assess the quality of the stone materials manufactured. The necessary laboratory tests were being discussed; the requirements for the stone materials used as road stone were formulated. These changes were mainly driven by the increased demand for high-grade crushed stone and higher production volumes due to the industrialization in the country and the development of the road network and road transportations.

Застіноченське та буданівське родовища пісковику – потенційні геотуристичні об’єкти Тернопільської області

The article provides information on existing quarries for sandstone mining as promising geotourism locations within the Ternopil region (Western Ukraine). The study area is famous for its ancient mining of natural stone from Terebovlya sandstones. The object of research is located within the Eastern European platform on the territory of Zastinoche and Budanіv deposits. Since princely times, stone has been mined here for the construction of fortresses and defensive structures. Sediments of the Neogene and Devonian ages take part in the geological structure of the Zastinoche deposit. The mineral is represented by Devonian sandstone with an average thickness of 12 m, broken by horizontal and vertical cracks into boulders. Macroscopically, sandstone is represented by red-brown, brownish-red, greyish-red, reddish-grey, brownish-grey, pink-grey, greenish-grey and light grey variations. The Budaniv deposit is composed of Quaternary, Neogene, Cretaceous and Devonian rocks. The minerals here are the sandstones of the Ivanovo formation (Devonian), the sandstone stratum consists of two horizons. The average thickness of sandstones of the first horizon (red, thick-tiled) is 14.4 m, in the thickness of sandstones there are layers of argillites and siltstones. Sandstones of the second horizon are more thinly tiled, characterized by a thickness of 2.6 to 4.3 m. With depth, sandstones have a pink and pink-red colour. Both gray and pink variations of sandstones are fine-grained, quartz, feldspar-quartz, mica.. Cement is iron-clay; the clay part of it is sericite-silicon. Mining of sandstones at both deposits is carried out manually with the help of crowbars and wedges to the full depth. All processes for the extraction and manufacture of side and rubble stone are performed manually. Terebovlya sandstone is environmentally friendly, so it is used for the construction of facades as a natural heat insulator. Sandstone is frost-resistant and acid-resistant. It is widely used in modern architectural design and restoration of historical monuments in Europe; it is made of almost everything for facades. Among the architectural structures built of Terebovlya sandstone – a nine-arch railway bridge-viaduct near the village. Plebanivka, Terebovlya and Budaniv castles, Pidhoryany monastery of St. Basil the Great, a large number of churches and cathedrals. Geological and geotourism survey of Zastinoche and Budanіv sandstone quarries in the Ternopil region gives grounds to consider these locations as potential geotouristic objects.

Life-cycle-Assessment of Cast Stone Manufacturing: A Case Study

This research paper aims to perform a “cradle-to-gate” carbon dioxide emissions Life Cycle Assessment (LCA) on cast stone products, i.e. to quantify their accumulated CO2 emissions from the extraction of raw materials to a complete finished product. The collected data is mapped using Energy Value Stream Mapping (EVSM) and Sankey diagrams. Areas of carbon footprint reduction are identified, and transportation, packaging and mold-making recommendations are made. The study was undertaken at a manufacturing facility located in the UK and based on three types of materials.

Men at work: Grinding stone production by the experts and others in northern Ethiopia

It is necessary to access the oral forms of local histories often held in traditional African communities to help us understand the African past and avoid framing interpretations solely in terms of Western epistemologies. Ethnoarchaeological fieldwork was carried out in villages in the Gulo Makeda region of northeastern Tigrai, northern Ethiopia, where access to mechanical mills has only been available in the last few decades. Individuals in this area still have knowledge and memory of manufacturing, using and discarding grinding stones. Interviews were held with male advisors who shared their knowledge and expertise about the entire process of manufacturing grinding stones. To move beyond understanding just the technical aspects of grinding stone manufacturing (what and how), the theory and methods associated with the chaîne opératoire and design theory were incorporated into the research to allow discovery of intricate socio-economic interrelationships (how and why) that exist through grinding manufacture within this culture. Manufacturing offers opportunities for socialization, cooperation and community engagement.&#x0D; Through ethnoarchaeology it became clear that the manufacturing of grinding stones in northeastern Tigrai is a complex process requiring design decisions, skills, knowledge, and social interaction that builds interpersonal relationships. By arranging two separate manufacturing sessions, one with experts and one with non-experts, comparisons were made of technological and social differences between experts and non-experts. The individuals who are experts in manufacturing grinding stones made higher quality grinding stones than the non-experts. The experts are also afforded a special respect by others, as they are the creators of the technology “necessary for life” in a culture traditionally dependent on cereal flours for sustenance. Potentially this respect for experts could be true for the past as well. Since the grinding stone artifacts from Mezber are large stones, likely meant to produce significant amounts of flour, they would have been important to daily life. Those who manufactured these tools important for subsistence would likely have been considered important individuals in the community.

Manufacture of road stone and respective quality requirements in the pre-revolutionary Russia

The paper studies the establishment and development history for road stone quality requirements and covers its manufacture in the pre-revolutionary Russia. It is shown that industrial-scale production of road stone was first initiated in Russia as late as at the end of the 19 century. Due to the development of road construction technologies, it became requisite to assess the quality of rocks used to produce crushed stone. The first speculative conclusions on the effect of moisture, mechanical and temperature loads on the quality of crushed stone were made in the middle of the 19 century; however, at the time, there was no uniformity in how to establish the material quality. Crushed stone quality indicators (strength, abrasion, grain shape, and some others) were formulated at the beginning of the 20 century, when mechanized crushed stone manufacturing methods were being first introduced in Russia. In the same period, methods were developed for establishing certain crushed stone quality indicators in laboratory conditions. The underlying principles for these methods, in fact, correspond to the current methods of testing physical and mechanical properties of rocks. The difference lies in the equipment design, experimental conditions, and quantitative assessments of the indicators studied. In general, the late 19 – early 20 centuries may be referred to as the period when the scientific approach was first applied to crushed stone quality studies in Russia and the foundations for its standardization were laid.

Hominin dental remains from the Pliocene localities at Lomekwi, Kenya (1982–2009)

Increasing evidence for both taxonomic diversity and early stone manufacture during the Pliocene highlights the importance of the hominin fossil record from this epoch in eastern Africa. Here, we describe dental remains from Lomekwi (West Turkana, Kenya), which date from between 3.2 and 3.5 Ma. The sample was collected between 1982 and 2009 and includes five gnathic specimens and a total of 67 teeth (mostly isolated permanent postcanine teeth). Standard linear dimensions indicate that, although the Lomekwi teeth are relatively small, there is broad overlap in size with contemporary Australopithecus afarensis and Australopithecus deyiremeda specimens at most tooth positions. However, some dental characters differentiate this sample from these species, including a relatively large P4 and M3 compared with the M1, a high incidence of well-developed protostylids, and specific accessory molar cuspules. Owing to a lack of well-preserved tooth crowns (and the complete absence of mandibular teeth) in the holotype and paratype of Kenyanthropus platyops, and limited comparable gnathic morphology in the new specimens, it cannot be determined whether these Lomekwi specimens should be attributed to this species. Attribution of these specimens is further complicated by a lack of certainty about position along the tooth row of many of the molar specimens. More comprehensive shape analyses of the external and internal morphology of these specimens, and additional fossil finds, would facilitate the taxonomic attribution of specimens in this taxonomically diverse period of human evolution.

Making Paving Stones from Copper Mine Tailings as Aggregates.

Copper mining, the central axis of Chile’s economic development, produces a large number of tailings, which become a potential environmental risk. This study aims to evaluate the mechanical properties resulting from the making of Portland cement mixtures with tailings as aggregates so that they can be eventually used in paving stones for building inactive tailings dams. Tailings coming from two dams at a concentration plant located in Taltal (Chile) were used. Currently, Dam 1 is inactive, while Dam 2 is active. The tailings samples obtained from both dams were granulometrically characterized by sieving. In addition, pH, humidity, Eh, and mineralogical assays (sulfides, oxides, sulfates, carbonates, phosphates, and silicates) were measured. The fines content of the tailings from Dams 1 and 2 with a sieve size of N°200 ASTM were 76.2% and 29.6%, respectively. Therefore, owing to their high percentage of fines, they cannot be as used as concrete aggregates. Aggregates must contain a maximum percentage of fines so that mortars and concrete can meet Chilean standards. In this paper, to comply with a 7% and 15% fines content lower than 0.075 mm, tailings materials were mixed with conventional aggregates containing very little fines. In addition, a reference mixture was made with only tailings aggregates with and without a superplasticizer additive. To measure the mixtures of cement, aggregates, and tailings, bending and compression strength assays were made of the specimens after a 28-day curing, according to the Chilean standard. The results of the study show that the addition of only part of the tailings to the mixture increases bending strength by 26% and compression strength by 180% compared with the reference mortar, with a fines content lower than 0.075 mm in the 7% mixture, thus allowing paving stone manufacture with tailings materials. In addition, it was possible to increase the workability of the reference mixture by using superplasticizers as additives.

Short communication: Effects of mesh leggings on fly pressure and fly avoidance behaviors of pastured dairy cows

Ectoparasitic stable flies (Stomoxys calcitrans [L.]), horn flies (Haematobia irritans [L.]), and face flies (Musca autumnalis De Geer) negatively affect dry matter intake, milk production, and health of pastured dairy cows. These flies cause fly avoidance behaviors and are a major welfare concern for dairy producers. The objective of this study was to evaluate the effects of mesh Shoofly Leggins (Stone Manufacturing & Supply, Kansas City, MO) on fly avoidance behaviors and numbers of flies attacking pastured dairy cows. In a crossover design, lactating dairy cows (n = 80) were randomly assigned to groups with and without leggings (Shoofly Leggins worn on all legs). All cows were managed in one group. Cows were observed for 2-wk periods, and then treatments were reversed in the next 2-wk interval. Counts of stable flies, horn flies, and face flies on all cows were recorded twice daily (once in morning per cow: 0930 to 1230 h; and once in the afternoon per cow: 1330 to 1630 h), 3 times per wk on Tuesday, Wednesday, and Thursday of each week during the study period. The total number of flies per cow was greater on cows with leggings than cows without leggings. The number of horn flies per cow was greater on cows in with leggings (26.4 flies/side) compared with cows without leggings (24.1 flies/side). Stable fly numbers were similar for cows with and without leggings (12.8 flies/leg). A random subset of 20 focal cows per group was observed during 5-min intervals to record frequencies of 4 behaviors: leg stomps, head tosses, skin twitches, and tail swishes. Counts of head tosses (2.6 vs. 3.1), skin twitches (20.9 vs. 19.6), and tail swishes (21.3 vs. 19.3) were similar for cows without leggings versus cows with leggings, respectively. However, foot stomps were 39% lower for cows with leggings compared with cows without leggings, and leg stomps were 26% higher in the afternoon than in the morning (2.9 vs. 2.4, respectively). A positive correlation was observed between stable and horn flies and all insect avoidance behaviors. Numbers of stable flies were 1.5 times greater in the afternoon than in the morning. The results of this study indicated that flies were associated with cow fly avoidance behaviors regardless of the use of leggings, but leggings effectively reduced foot stomps by 39%, so their use may provide some relief from stable fly injury to pastured dairy cows.