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The Hotelling’s Rule in practice – analysis of gold mining sector

Robert Uberman

Gospodarka Surowcami Mineralnymi - Mineral Resources Management | 2021 | vol. 37 | No 2 | 63-84 | DOI: 10.24425/gsm.2021.137568

Keywords valuation corporate finance sustainable finance Hotelling Rule mineral assets

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Abstract

The paper presented intends to fill up a gap in surveying the Hotelling Rule by taking a company based, microeconomic approach based on analyses of annual reports. Using selected data three fundamental hyphothesis are tested:
1) growth rate of margins (“net margins” including a capital charge) per unit realized by mining companies must exceed a rate equal to their cost of capital,
2) output shall follow deviations from the Hotelling growth line,
3) margins shall follow a path set by individually defined expected rate of return.
The analysis was based on 5 leading gold producers, responsible for ca 15–20% of global primary production, all of them public and listed on a stock exchange for the entire period of 2004–2019/2020. As margin shall grow at a rate compensating individual risk of a company in consideration, they shall not be homogenous. At 1st step industry WACC was adopted to calculate a normalized capital charge. The calculations revealed no support for Hotelling Rule. There is no evidence that over a period of above 15 years margins follow any path determined by a growing expotential function, following a compound rate. Subsequently it was checked whether output volume is corrected due to development of actual versus expected (resulting from the Hotelling Rule) margin values. Selected companies were near indifferent to this parameter while taking decisions in area of volumes supplied. Neither there is no evidence of relation between changes in output and margins. Finally, it was checked whether differences between expected and actual margins’ growth paths could be described by a linear function, resulting from consequent adoption of a risk rate component. Here neither any evidence was found. In conclusion no support for the Hotelling rule was identified.

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Authors and Affiliations

Robert Uberman

1

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Andrzej Frycz Modrzewski Krakow University, Kraków, Poland

Hornfels from Łażany and its impact on the functional properties of granodiorite aggregate

Bartłomiej Grzesik

Gospodarka Surowcami Mineralnymi - Mineral Resources Management | 2021 | vol. 37 | No 2 | 85-102 | DOI: 10.24425/gsm.2021.137562

Keywords granodiorite hornfels aggregate asphalt mix wearing course

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Abstract

This paper presents the results of research on the admixture of other rock fragments in the granodiorite aggregate (two types of hornfels) produced in Łażany II quarry. It discusses the impact of these components on the selected chemical and mechanical properties important for the use of the aggregate in road construction. Analysed granodiorite grit is a high-class construction material suitable for bituminous mixtures. Its quality is verified in accordance with the PN-EN 13043 standard. The admixture of hornfels in aggregate composition is a consequence of the natural occuring this rock in the Łażany II granodiorite deposit in the Strzegom-Sobótka massif. As there is not selective exploitation of the deposit an extracted raw material is not separated during processing As a result, the aggregate, composed predominantly of granodiorite, comprises variable admixture of hornfels. Tests of properties, such as water absorption, resistance to freezing, resistance to fragmentation, crushing strength, carried out on grain populations of various petrographic types separated from the general samples, exhibit that the presence of hornfels in the aggregate has a beneficial effect, particularly on the mechanical parameters of the produced aggregate. Moreover, two varieties of hornfels differ in terms of some chemical properties (affinity with bitumen, presence of sulphides). These features may affect the durability of the aggregate in the wearing course which is directly influenced by the exterior conditions typical for road pavements.

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Authors and Affiliations

Bartłomiej Grzesik

1

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Silesian University of Technology, Gliwice, Poland

Determinants of mining companies’ capital structure

Marta Sierpińska

Gospodarka Surowcami Mineralnymi - Mineral Resources Management | 2021 | vol. 37 | No 2 | 125-144 | DOI: 10.24425/gsm.2021.137561

Keywords capital structure asset structure rate of return on assets ability to service debt

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Abstract

The choice of financing sources made by coal mining companies reflects a number of macro- and microeconomic factors. The paper attempts to present only those that play the most important role in mining companies’ market activities. The structure of sources of financing mining companies’ operations is presented by computing the share of equity in liabilities and shareholders’ equity, the golden balance sheet rule showing the degree of financing of non-current assets through shareholders’ equity and the silver balance sheet rule which shows the ratio of long-term capital to non-current assets. Only a few mining companies can satisfy those two rules as they finance their economic activity through equity and short-term liabilities. Mining companies are not indebted. Their caution in incurring long- -term debt results from the implementation of high volatility of financial results, which are prone to the effects of the economic situation. The basic determinants of the choice of financing sources include the structure of assets, the rate of return on assets and companies’ ability to service debt. The high capital intensity of the mining sector is reflected in the large share of non-current assets in total assets, which in some mining companies exceeds 80% of total assets. The rates of return on assets vary widely and are influenced by fluctuations in coal prices at different phases of the market situation. They also have a significant impact on companies’ ability to service debt. Empirical research conducted by the author revealed that the structure of financing sources in Polish coal mining companies is like that of global mining corporations, as are the economic relations shaping this structure.

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Authors and Affiliations

Marta Sierpińska

1

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University of Economics and Human Sciences in Warsaw, Poland

The leaching of mercury from hard coal and extractive waste in the acidic medium

Beata Klojzy-Karczmarczyk Janusz Mazurek

Gospodarka Surowcami Mineralnymi - Mineral Resources Management | 2021 | vol. 37 | No 2 | 163-178 | DOI: 10.24425/gsm.2021.137567

Keywords leaching hard coal total content extractive waste Mercury

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Abstract

Sixteen samples were designed for analysis (hard coal, aggregate – barren rock, hard coal sludge). The total mercury content and the amount of mercury leaching were determined. The percentage of leachable form in the total content was calculated. The studies were carried out under various pH medium. The leachability under conditions close to neutral was determined in accordance with the PN EN 12457/1-4 standard. The leachability under acidic medium (pH of the solution – approx. 3) was determined in accordance with principles of the TCLP method. The mercury content was determined by means of the AAS method. For hard coal the total mercury content was 0.0384–0.1049 mg/kg. The level of leaching on mean was 2.6%. At the acidic medium the amount of leaching increases to an mean 4.1%. The extractive waste of aggregate type features a higher total mercury content in the finest fraction < 6 mm (up to 0.4564 mg/kg) and a lower content in the fraction 80–120 mm (up to 0.1006 mg/kg). The aggregate shows the percentage of the leachable form on mean from 1.4 to 2.2%. With pH decreasing to approx. 3, the amount of leaching grows up to mean values of 1.7–3.2%. Coal sludge features the total mercury content of 0.1368–0.2178 mg/kg. The percentage of mercury leachable form is approx. 1.8%. With pH decreasing the value increases to mean value of 3.0%. In general, the leachability of mercury from hard coals and extractive waste is low, and the leachability in an acidic medium grows approx. twice. Such factors as the type and origin of samples, their grain composition, and the pH conditions, have basic importance for the process. The time of waste seasoning and its weathering processes have the greatest impact on increasing the leaching of mercury from the extractive waste.

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Beata Klojzy-Karczmarczyk

1

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Janusz Mazurek

1

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Mineral and Energy Economy Research Institute of the Polish Academy of Sciences, Kraków, Poland

The impact of depositing waste from coal mining and power engineering on soils on the example of a central mining waste dump

Marek Marcisz Zdzisław Adamczyk Łukasz Gawor Katarzyna Nowińska

Gospodarka Surowcami Mineralnymi - Mineral Resources Management | 2021 | vol. 37 | No 2 | 179-192 | DOI: 10.24425/gsm.2021.137566

Keywords soil heavy metals coal mining waste dumps flying ash

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Abstract

The purpose of the study was determining of degree of contamination of soil cover as a result of disposing of different industrial wastes and comparison of the soil quality with quality of soils and the grounds described in standards in relation to the reclamation works carried out on the dump. Analysed waste dump belongs to the sparse objects of this type in the Upper Silesian Coal Basin, where both coal mining wastes as well as flying ashes occur.
During investigations there was done a collection of 9 soil samples around the dump using Egner`s cane from the depth of 30 cm. The content of heavy metals was determined (Cd, Co, Cr, Cu, Ni, Pb, Zn) using method of emission spectrometry (ICP-AES) and phase composition studies using the X-ray diffraction method (XRD ).
Obtained results enabled determination of impact of disposed wastes on the degradation of pedosphere of studied area, which represents III group of fallow lands. The contents of heavy metals in soil samples vary in wide spectrum, but do not exceed permissible content of metals and metalloids for the aforementioned soil group. The highest concentrations reaches iron (average content 0,6%), while concentrations of other elements do not exceed 0.02%. In the mineral composition of soil samples the dominant components are typical for soils in the area of post-mining dumps, i.e. quartz, feldspars, clay minerals, represented by kaolinite and illite. The presence of muscovite with a share of < 5% was also found. Minerals from the carbonate group – calcite (< 3.5%) and dolomite (< 0.3%) occur rarely. In the investigated samples there was identified presence of mullite, component typical for wastes coming from energy sector.

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Authors and Affiliations

Marek Marcisz

1

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Zdzisław Adamczyk

1

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ORCID:

Łukasz Gawor

1

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ORCID:

Katarzyna Nowińska

1

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ORCID:

Silesian University of Technology, Gliwice, Poland

Transparency in extractive industry as a driver for circular economy implementation – case of Poland

Agnieszka Nowaczek Joanna Kulczycka Ewa Dziobek Daina Kalnina

Gospodarka Surowcami Mineralnymi - Mineral Resources Management | 2021 | vol. 37 | No 2 | 145-162 | DOI: 10.24425/gsm.2021.136298

Keywords extractive industry sustainable mining data transparency environmental and social factors financial burdens

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Abstract

The Green Deal and the New Industrial Strategy for Europe recognize the access to raw materials and the security of supply from secondary and primary sources as essential for Europe’s transition to sustainability. It can be expected that with the development of the circular economy approach, the extraction of primary resources would be diminished, but it is emphasized that a circular economy may need a wider range of metals and other raw materials critical to the new environmentally friendly technology, especially in renewable energy and mobility. Therefore, the latest global initiatives and EU policies focus on ensuring resource efficiency in a holistic manner, from the extraction of raw materials to the re-use of the end products, which requires data transparency not only on material and waste flows, but also on financial and economic burdens including incentives and subsidies. In addition, for sectors with significant environmental impacts, the transparency of information on payments to central governments and local authorities can increase social acceptance and accountability and allow for further development. The paper analyzes regulations and initiatives supporting the disclosure of wider data than required in financial and corporate social responsibility reporting related to the implementation of a circular economy. As circular economy indicators take upstream resource flows into account, the transparency of environmental and economic data in the value chain is required, for example for the calculation of the environmental footprint. Moreover, transparency is important for mining companies’ stakeholders to increase social acceptance of mining activities and facilitate the transition to a circular economy.

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Authors and Affiliations

Agnieszka Nowaczek

1

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ORCID:

Joanna Kulczycka

1

e-mail:

ORCID:

Ewa Dziobek

1

e-mail:

ORCID:

Daina Kalnina

2

e-mail:

ORCID:

Mineral and Energy Economy Research Institute of the Polish Academy of Sciences, Kraków, Poland
Riga Technical University, Ryga, Latvia

Metal potential in copper smelting slags from Polkowice tailings dump – preliminary studies

Karol Zglinicki Krzysztof Szamałek Anna Czarnecka-Skwarek Katarzyna Żyłka

Gospodarka Surowcami Mineralnymi - Mineral Resources Management | 2021 | vol. 37 | No 2 | 27-48

Keywords copper melting slag circular economy secondary mineral resources

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Abstract

In Poland, the mineral sector generates 110–130 million tons of wastes annually (in the last 20 years), and metal ore mining alone was responsible for 31.2 million tons of wastes in 2017. The slags deposited at the Polkowice were investigated. This waste may be a potential source of many valuable metals (Zn, Pb, Cu, Sb, Sn, Se). The tailings dump in Polkowice contains approximately 80,000 tons of slag. The material contains primary phases formed by pyrometallurgical processes and secondary phases, which are the result of transformation of primary components. The primary phases are represented by sulfides: sphalerite [ZnS]; wurtzite [(Zn,Fe)S]; pyrite [FeS2]; sulfates: beaverite-(Zn) [Pb(Fe3+ 2Zn)(SO4)2(OH)6]; palmierite [(K,Na)2Pb(SO4)2]; oxides and hydroxides: goethite [Fe3+O(OH)]; wüestite [FeO]; hematite [Fe2O3]; magnetite [Fe2+Fe3+ 2O4]; chromian spinel [Fe2+Cr3+ 2O4]; silicates: petedunnite [Ca(Zn,Mn2+,Mg,Fe2+)Si2O6]; quartz [SiO2]; and microcline [KAlSi3O8]. Additionally, SEM -BSE observations revealed that oxidized native metals (Cu, Pb, As) and metal alloys and semi-metals appear. The slag consists mainly of SiO2 (13.70–20.60 wt%), Fe2O3 (24.90–39.62 wt%) and subordinately of CaO (2.71–6.94 wt%) and MgO (1.34–4.68 wt%). High contents are formed by Zn (9.42–17.38 wt%), Pb (5.13–13.74 wt%) and Cu (1.29–2.88 wt%). The slag contains trace elements Mo (487.4–980.1 ppm), Ni (245.3–530.7 ppm), Sn (2380.0–4441.5 ppm), Sb (2462.8–4446.0 ppm), Se (168.0–293.0 ppm). High concentrations are formed by toxic elements, such as e.g. As (13 100–22 600 ppm) and Cd (190.5–893.1 ppm). It is estimated that the tailings dump has accumulated about 80,000 t of slag, which may contain about 10,000 t of Zn, about 6,700 t of Pb, and 1,500 t of Cu.

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Authors and Affiliations

Karol Zglinicki

1

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ORCID:

Krzysztof Szamałek

2

e-mail:

ORCID:

Anna Czarnecka-Skwarek

2

e-mail:

ORCID:

Katarzyna Żyłka

2 1

Polish Geological Institute – Polish Research Institute, Warszawa, Poland
University of Warsaw, Warszawa, Poland

Fly ash – a valuable material for the circular economy

Ewa Strzałkowska

Gospodarka Surowcami Mineralnymi - Mineral Resources Management | 2021 | vol. 37 | No 2 | 49-62 | DOI: 10.24425/gsm.2021.137563

Keywords microspheres magnetic fraction glass unburned coal

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Abstract

Generation of coal-based electricity is always associated with the origination of large amount of combustion waste. The presented article is a review concerning the possibilities of innovative directions of management for one of the by-products of coal combustion: fly ash. The storage of these waste products is associated with their negative impact on the environment. This is why research has been undertaken worldwide on the implementation of the concept of a circular economy. This article includes the examination of basic physical, chemical, and mineralogical properties of the most valuable components of fly ash (microspheres, magnetic fraction, and glass). It contains the examination of methods of separating these components and indicates the prospective directions of their use, e.g. as light fillers for polymers, sorbents, catalysts, composite materials, light ceramics, lightweight concretes, thermal insulation materials, biomaterials, raw material for the synthesis of zeolites or geopolymers. The paper also presents the components of fly ash, which can be treated as an alternative source of valuable elements, including critical elements. Moreover, it points to the necessity of capturing flammable substances from combustion by-products in order to obtain raw material characterised by a high degree of purity. It has been demonstrated that this way of ash management can lead to high recycling rates and bring valuable materials back to the economy. Such actions fit perfectly into global efforts for sustainable development and the circular economy.

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Ewa Strzałkowska

1

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Silesian University of Technology, Gliwice, Poland

Olfactory responses of the parasitoid wasp, Anisopteromalus calandrae (Hymenoptera: Pteromalidae) to odors from hosts and stored grain

Masoomeh Moosavi Nooshin Zandi-Sohani Ali Rajabpour

Journal of Plant Protection Research | 2021 | vol. 61 | No 2 | 189-194 | DOI: 10.24425/jppr.2021.137024

Keywords attraction Callosobruchus maculatus parasitoid volatiles

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Abstract

The ability of parasitoids in locating hosts determines their success in suppressing the pest population. Chemical stimuli emitted from food products and hosts provoke the searching behavior of parasitoids. Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) is a generalist idiobiont ectoparasitoid of coleopteran pests in stored products. In the current study, the behavioral responses of A. calandrae females were evaluated regarding host food and different life stages of the host, Callosobruchus maculatus F. (Coleoptera: Chrysomelidae), using a Y-tube olfactometer. The parasitoid was offered uninfested chickpea kernels, damaged chickpea without larvae of C. maculatus, damaged chickpea with preferred stage (4th instar) larvae of C. maculatus, uninfested chickpea + C. maculatus adults, and eggs of C. maculatus on chickpea. In another test, the preference of A. calandrae for either damaged chickpea without larva of C. maculatus or damaged chickpea with nonpreferred stage (1st instar) larvae of C. maculatus was studied. The results showed that the females did not prefer uninfested chickpea kernels and adults of C. maculatus. However, they were attracted to damaged kernels with or without larvae, and the kernels containing eggs of C. maculatus. When the female parasitoids had a choice between damaged chickpea without larva of C. maculatus and damaged chickpea with 1st instar larva, they did not prefer one over the other. The results of this investigation can be helpful for using A. calandrae as a biological control agent in stored products.

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Authors and Affiliations

Masoomeh Moosavi

1

Nooshin Zandi-Sohani

1

Ali Rajabpour

1

Plant Protection Department, Agricultural Sciences and Natural Resources University of Khuzestan, Ahvaz, Iran

Assessment of the ancestral use of garlic ( Allium sativum) and nettle ( Urtica dioica) as botanical insecticides in the protection of mesquite ( Prosopis laevigata) seeds against bruchins

Mariana González-Macedo Nathalie Cabirol Marcelo Rojas-Oropeza

Journal of Plant Protection Research | 2021 | vol. 61 | No 2 | 170-175 | DOI: 10.24425/jppr.2021.137023

Keywords biological control leguminous seed storage weevil

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Abstract

Currently, Prosopis laevigata (mesquite) has been affected by the Bruchinae coleoptera pest, whic feeds on its seed and causes significant losses in production and grain storage. In the Hñähñu community El Alberto (Ixmiquilpan, Hidalgo, Mexico), the use of aqueous extracts from garlic and nettle as botanical insecticides against different pests in agricultural fields is a known practice. Herein, we assess the efficacy of the method known by locals in the protection of mesquite seeds. Two tests were conducted: 1) Insecticidal effect on adult bruchins, and 2) Seed preservation test from Bruchinae infestation, with a germination test in seeds exposed to the treatments. There are probable insecticidal effects on immature stages of Bruchinae since there were no mortality effects on their adults during the first test. Mortality on adults in the second test was 75.6% with garlic and 50% with nettle. Nettle extract had more efficacy in seed protection with an infestation rate of 4%, whereas 27.5% of the seeds exposed to garlic extract were infested. Seed germination rate was 2.38% with nettle extract, and 1.19% with garlic extract. The method known by local inhabitants requires modifications to increase its efficacy and possible use in Integrated Pest Management in the future.

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Authors and Affiliations

Mariana González-Macedo

1

Nathalie Cabirol

1

Marcelo Rojas-Oropeza

1

Functional Soil Microbial Ecology and Environmental Protection Group − Department of Ecology and Natural Resources, Facultad de Ciencias − Universidad Nacional Autonoma de Mexico, Mexico

Prospecting of pathogen-derived elicitors for the control of tomato bacterial spot

Camila Tonelotti Simões Valdeir Nunes Carvalho Bernardo de Almeida Halfeld-Vieira

Journal of Plant Protection Research | 2021 | vol. 61 | No 2 | 183-188 | DOI: 10.24425/jppr.2021.137029

Keywords hypersensitivity response incompatibility phytopathogenic bacteria Xanthomonas euvesicatoria pv. perforans

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Abstract

Plants can recognize molecules derived from pathogens and trigger systemic acquired resistance (SAR). In phytopathogenic bacteria, elicitors are constituent components of cellular structures, such as flagellin. We sought to select structural components of Xanthomonas spp. incompatible with tomato, aiming to control bacterial spot ( Xanthomonas perforans). Initially, cell suspensions from 11 Xanthomonas spp. isolates were infiltrated into the leaves to assess their ability to cause a hypersensitivity response (HR) and the incompatible ones had their flagellin purified. The flagellin of the isolates were first applied at different concentrations, via infiltration and spraying. The pathogen, X. perforans, was inoculated after 24 h, to assess whether there would be any harmful reaction. No harmful reaction was observed in any treatment. Then, a second experiment was conducted to assess the severity of all isolates, at a concentration of 8.35 μg · ml–1, via spraying, infiltration, and soil. The greatest reduction in Area Under the Disease Progress Curve (AUDPC) was observed in the treatment with XapRR, applied via spraying. Thus, prospecting for elicitors is the first step in developing a product for agricultural use. The flagellin elicitor of XapRR is promising and capable of producing these molecules on a large scale.

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Authors and Affiliations

Camila Tonelotti Simões

1

e-mail:

ORCID:

Valdeir Nunes Carvalho

1

e-mail:

ORCID:

Bernardo de Almeida Halfeld-Vieira

2

e-mail:

ORCID:

Faculdade de Ciências Agronômicas, Universidade Estadual Paulita “Júlio de Mesquita Filho”, Botucatu, Brazil
Fitopatologia, Embrapa Meio Ambiente, Jaguariúna, São Paulo, Brazil

Farmers’ knowledge and perception of cocoa insect pests and damage and the implications for pest management on cocoa in Ghana

Godfred Kweku Awudzi Richard Adu-Acheampong Silas Wintuma Avicor Yahaya Bukari Millicent Adomaa Yeboah Edmond Kwadwo Oti Boateng Stephen Kwame Ahadzi

Journal of Plant Protection Research | 2021 | vol. 61 | No 2 | 145-155 | DOI: 10.24425/jppr.2021.137022

Keywords cocoa farmer groups insect pest identification insecticides IPM

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Abstract

Annual losses of cocoa in Ghana to insect pests are significant. The use of integrated pest management (IPM) tools is critical for effective pest management. Previous studies on the subject have considered how farmers perceive the economic impact of insect pests on cocoa. These studies however did not investigate farmers’ ability to identify pests, associated damage symptoms and their implications for pest management. The current study, therefore, assessed farmers’ ability to correctly associate insect damage with the pest species that caused it. A total of 600 farmers were interviewed in the Eastern, Ashanti, Western, Brong Ahafo and Central Regions of Ghana with a structured open and closedended questionnaire. Most farmers (>85%) were unable to correctly identify and associate pests to their damage. The majority (>80%) of farmers also could not link the immature stages of insect pests to their adult stages. Wrong identification of the major pests (>85%) led to a wide variation in the timing of insecticide application amongst farmers. The majority of the farmers (60%) interviewed had not received training in insect pest identification. The study shows that 90% of the farmers, who had received some training, got it from the Cocoa Health and Extension Division (CHED) of the Ghana Cocoa Board (COCOBOD). Almost all respondents (98%) agreed that correct pest identification is critical for effective pest control. The importance of pest identification and monitoring as a component of IPM is discussed.

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Authors and Affiliations

Godfred Kweku Awudzi

1

Richard Adu-Acheampong

1

Silas Wintuma Avicor

1

Yahaya Bukari

2

Millicent Adomaa Yeboah

3

Edmond Kwadwo Oti Boateng

4

Stephen Kwame Ahadzi

1

Entomology, Cocoa Research Institute of Ghana (CRIG), Ghana
Plant Pathology, Cocoa Research Institute of Ghana (CRIG), Ghana
Extension, Cocoa Health and Extension Division (CHED), Ghana
Social Science and Statistics Unit (SSU), Cocoa Research Institute of Ghana (CRIG), Ghana

Assessment of some physical measures as safe and environmentally friendly alternative control agents for some common coleopteran insects in stored wheat products

Khalil A. Draz Magdy I. Mohamed Reda M. Tabikha Adnan A. Darwish Mohamed A. Abo-Bakr

Journal of Plant Protection Research | 2021 | vol. 61 | No 2 | 156-169 | DOI: 10.24425/jppr.2021.137025

Keywords microwave nanosilica Sitophilus oryzae temperature Tribolium castaneum ultraviolet irradiation

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Abstract

Presently, finding effective, simple, inexpensive, hygienic and safe pest control agents are the biggest challenges in management of stored product insects, where those features are available in most physical factors. The insecticidal efficiency of four diversified physical control agents (ultraviolet and microwave irradiations, thermal remediation and silica nanoparticles) were assayed against the most common coleopteran insect species ( Sitophilus oryzae L. and Tribolium castaneum Herbst) on stored wheat. Exposing tested insects to microwave irradiations (2450 MHz) for 25 sec gave preventive efficiency for stored material, which reached 97.68 and 99.02%, respectively. Sufficient exposure periods to kill 50% of the coleopteran adults (LT50%) were 13 and 14 sec, respectively. For effective control with UV radiations, S. oryzae should be exposed for 12 h and T. castaneum for 24 h. An exposure period of 24 h caused progeny reduction 95.24 and 89.72% and gave preventive efficiency of 94.25 and 93.37%, respectively. Values of LT50% were 56.76 and 74.04 h, respectively. Exposing infested samples of the tested species to 70oC for 10 min killed 100% of adults and caused complete cessation of egg laying. Furthermore, 65°C or 70°C caused full progeny reduction. The lowest level of stored product weight loss (1.15 and 1.35%, respectively) occurred at 70°C, where sufficient exposure temperatures to kill 50% of the coleopteran adults (LTD50%) were 60.95°C and 61.63°C, respectively. Synthetic silica nanoparticles (SSiNPs) were more toxic against the tested populations than bio-silica nanoparticles (BSiNPs) after 48–72 h. A concentration of 1.00 g kg–1 of tested silica nanoparticles caused significant reduction in adult populations, saved wheat grain vitality and gave least lost weights of flour (3.35–6.85%).

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Authors and Affiliations

Khalil A. Draz

1

Magdy I. Mohamed

2

Reda M. Tabikha

1

Adnan A. Darwish

1

Mohamed A. Abo-Bakr

1

Plant Protection Department, Faculty of Agriculture, Damanhour University, Damanhour, Egypt
Stored Product Pests Department, Plant Protection Research Institute, Agricultural Research Center, Alexandria, Egypt

Occurrence of tea plant necrotic ring blotch virus in Iran

Eisa Nazerian Hossein Bayat

Journal of Plant Protection Research | 2021 | vol. 61 | No 2 | 200-202 | DOI: 10.24425/jppr.2021.137028

Keywords Blunervirus Camellia sinensis discoloration

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Abstract

The tea plant [ Camellia sinensis (L.) O. Kuntze] is one of the most significant commercial crops in Iran. Symptomatic leaves including chlorina on the edge of the leaf, and multiple necrotic ring blotches on mature leaves from different tea gardens were observed in northern Iran. RT-PCR analysis and transmission electron microscopy observations were applied to characterize the causal agent of tea leaf discoloration. Sequence analyses of the fragments revealed that all the samples were infected with tea plant necrotic ring blotch virus (TPNRBV). To our knowledge this is the first report of TPNRBV in Iran and the second in the world.

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Authors and Affiliations

Eisa Nazerian

1

e-mail:

ORCID:

Hossein Bayat

2

Department of Technology and Production Management, Tea Research Center, Horticultural Sciences Research Institute, Lahijan, Iran
Department of Technology and Production Management Ornamental Plant Research Center, Horticultural Sciences Research Institute, Mahallat, Iran

World steam coal management

Katarzyna Stala-Szlugaj Zbigniew Grudziński

Gospodarka Surowcami Mineralnymi - Mineral Resources Management | 2021 | vol. 37 | No 2 | 5-26 | DOI: 10.24425/gsm.2021.137564

Keywords steam coal trade exports imports

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Abstract

The article analyzes trends in steam coal flows (exports and imports) linked to production and consumption volumes. The analysis carried out in the article took the years from 2000 to 2019 into consideration. Coal is the second most important energy carrier. Its share in the structure of global consumption amounts to 27% and its production has an upward trend despite its decreasing share. The overall global upward trend of steam coal flows was disrupted twice over the period 2000–2019: by the effects of the 2007–2009 global financial crisis and the ongoing uncertainty of the global economy, as well as by the significant slowdown in the economic growth of developing countries (2014–2016). The European Union has seen large decreases in coal consumption over recent years, reflecting an accelerating decarbonization policy. The main area of coal trade is the Asia-Pacific basin. The Atlantic market currently accounts for about 20% of global steam coal trade, with seaborne trade covering about 95%. The volume of world trade (exports, imports) in steam coal is approximately one billion (bn) tons per year. The analysis carried out showed the following trend: decreasing coal exports to economically developed countries (mainly concentrated in Europe) and increasing exports to economies of developing countries, concentrated in the Asian part of the world. International Energy Agency (IE A) projections show that by 2040 the global coal production will fall from 5.6bn tons of coal equivalent (3.9bn tons of oil equivalent in 2019) to 5bn tce (3.5bn toe) at an average annual rate of –1.1%. Steam coal production is expected to decline by 10% to 4bn tce (2.8bn toe). Due to the fact that China is the largest producer, user and importer of steam coal in the world, all economic and political decisions taken by its government have strongly influenced international coal trade for years. For the Asia-Pacific basin alone, the IE A’s long-term forecasts predict an increase in coal-fired power generation over 2019. Forecasts regarding the coal’s share in global demand are not optimistic for many regions of the world (Europe, Africa, the Americas), predicting a significant decline in its demand. Yet, new markets for coal are emerging, especially in Asia and the Mediterranean basin, which may contribute to maintaining at least the current level of coal trade.

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Authors and Affiliations

Katarzyna Stala-Szlugaj

1

e-mail:

ORCID:

Zbigniew Grudziński

1

e-mail:

ORCID:

Mineral and Energy Economy Research Institute of the Polish Academy of Sciences, Kraków, Poland

Life table and fertility rate of Liriomyza sativae (Blanchard) (Diptera: Agromyzidae) in tomato with silicon

Adamastor Pereira Barros Hugo Bolsoni Zago Dirceu Pratissoli Paulo Cezar Cavatte Julielson Oliveira Ataide

Journal of Plant Protection Research | 2021 | vol. 61 | No 2 | 131-138 | DOI: 10.24425/jppr.2021.137020

Keywords biology study leafminer pest management silicon tomato

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Abstract

The miner fly Liriomyza sativae (Blanchard) (Diptera: Agromyzidae) is an insect of economic importance for tomato culture. The conventional control with insecticides is complex due to the mining eating habit that provides protection to the larvae inside the leaves. Therefore, farmers can opt for biological control agents, or substances that provide protection to the plant. Thus, the objective of our research was to evaluate the use of silicon to induce resistance in tomato plants against L. sativae. The results showed that in tomato plants treated with SiO2/F and K2SiO3/F there was a reduction in the net reproduction rate (Ro), in the intrinsic rate of increase in number (rm), in the finite rate of increase (λ), in the average interval between generations (IMG), in the doubling time (TD), in the number of eggs/ female/day and the accumulated egg laying of F1 females of L. sativae. The products SiO2/F and K2SiO3/F gave the tomato a protective effect against injuries caused by L. sativae.

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Authors and Affiliations

Adamastor Pereira Barros

1

e-mail:

ORCID:

Hugo Bolsoni Zago

2

e-mail:

ORCID:

Dirceu Pratissoli

2

e-mail:

ORCID:

Paulo Cezar Cavatte

3

e-mail:

ORCID:

Julielson Oliveira Ataide

2

e-mail:

ORCID:

Entomology Department, Universidade Federal Rural do Rio de Janeiro, Rio de Janeiro, Brazil
Entomology Department, Universidade Federal do Espírito Santo, Campus Alegre, Alegre, Brazil
Biology Department, Universidade Federal do Espírito Santo, Campus Alegre, Alegre, Brazil

Confirmation of resistance Monochoria vaginalis (Burm. f.) C. Presl from West Java and Lampung Indonesia to bensulfuron-methyl herbicide

Denny Kurniadie Ryan Widianto Dedi Widayat Uum Umiyati Ceppy Nasahi

Journal of Plant Protection Research | 2021 | vol. 61 | No 2 | 139-144 | DOI: 10.24425/jppr.2021.137021

Keywords resistance ratio rice weed

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Abstract

Several national rice centers in Indonesia have used acetolactate synthase herbicide inhibitors for years, especially in several regions of Lampung and West Java provinces. This practice has led to the failure of the application of bensulfuron-methyl herbicide to control Monochoria vaginalis (Burm. f.) C. Presl. The purposes of this study were to confirm that the failure of herbicide application in several areas of the provinces of Lampung and West Java was caused by weed resistance, and to determine the level of resistance. A resistance test of M. vaginalis was performed using the whole plant pot test method and split plot design with three replications. Monochoria vaginalis which indicated resistance was sampled from several regions, namely Sapto Mulyo, Ramadewa, Sarijaya, and Kalentambo. The susceptible samples of M. vaginalis as a control were taken from Cibodas and Sumberagung. The six levels of doses of herbicide bensulfuron-methyl used were: 0, 80, 160, 320, 640 and 1,280 g ha–1. The experimental results show that M. vaginalis from Sapto Mulyo, Ramadewa, Kalentambo and Sarijaya was confirmed to have developed into weeds resistant to bensulfuron-methyl herbicide. Monochoria vaginalis from Saptomulyo, Kalentambo and Sarijaya were included in the high resistance category with a resistance ratio of more than 12, while M. vaginalis from Ramadewa was included in the moderate resistance category with a resistance ratio of 9.39.

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Authors and Affiliations

Denny Kurniadie

1

e-mail:

ORCID:

Ryan Widianto

2

Dedi Widayat

1

Uum Umiyati

1

Ceppy Nasahi

3

Department of Agronomy, Faculty of Agriculture, Universitas Padjadjaran, Bandung, Indonesia
Graduate student, Faculty of Agriculture, Universitas Padjadjaran, Bandung, Indonesia
Department of Pest and Diseases, Faculty of Agriculture, Universitas Padjadjaran, Bandung, Indonesia

Bacterial watermark disease on Salix alba caused by Brenneria salicis in Iran

Esmaeil Basavand Pejman Khodaygan Mojtaba Dehghan-Niri Saman Firouzianbandpey

Journal of Plant Protection Research | 2021 | vol. 61 | No 2 | DOI: 10.24425/jppr.2021.137027

Keywords Brenneria salicis Enterobacteriaceae white willow Multilocus sequencing analysis

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Abstract

In 2016, bacterial canker symptoms, often with dried ooze, were observed on Salix alba plants in municipal lands and parks in Kerman and Fars provinces, Iran. To determine the causative agent, samples were collected from symptomatic trees, and macerates of the affected bark tissues were plated on sucrose nutrient agar (SNA). Ten isolates were identified by phenotypic characterization, pathogenicity tests, and two of them further confirmed identity using sequence analysis of the partial of 16S rRNA and gyrB genes, and phylogenetic analysis. The isolates showed the highest identity (99–100%) with Brenneria salicis. To our knowledge, this is the first report of watermark disease on S. alba caused by B. salicis in Iran.

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Authors and Affiliations

Esmaeil Basavand

1

e-mail:

ORCID:

Pejman Khodaygan

1

Mojtaba Dehghan-Niri

2

Saman Firouzianbandpey

1

Department of Plant Pathology, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
Department of Plant Pathology, Ferdowsi University of Mashhad, Mashhad, Iran

Influence of Overflow Connecting Channel Cross-Section Design on Selected Parameters of High Pressure Die Casting

J. Majerník M. Podařil D. Gojdan

Archives of Foundry Engineering | 2021 | vo. 21 | No 2 | 75-80 | DOI: 10.24425/afe.2021.136101

Keywords HPDC Gas entrapment Product development Overflows dimensions Melt flow

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Abstract

High pressure die casting technology (HPDC) is a method enabling the production of shape-complex casts with good mechanical properties, with high repeatability of production within narrow tolerance limits. However, the casts show, to some extent, basic porosity, which may reduce their mechanical and qualitative properties. One of the main areas to focus on in order to reduce the porosity of casts is the correct design and structure of the gating and overflow system. Submitted article is devoted to the assessment of the connecting channel cross-section design for connecting the overflows to the cast on selected parameters of the casting process. Five different cross-section designs of connecting channels are considered, enabling the removal of gases and vapors from the volume during the molding. The connecting channels are designed with a constant width g = 10mm and variable height h1 = 1.50 mm, h2 = 1.25 mm, h3 = 1.00 mm, h4 = 0.75 mm and h5 = 0.6 mm. The primary monitored parameter is the gas entrapment in selected points of the cast. The following is an evaluation of the pressure conditions change in the mold cavity at the end of the filling mode and local overheating of the mold material just below the surface of the mold face. With regard to the monitored parameters, based on the performed analyzes, the most suitable design solution of the connecting channel is assessed and recommendations for the design and structure of the overflows and their connection to the cast are derived.

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Bibliography

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[14] Majernik, J. & Podaril, M. (2019). Influence of runner geometry on the gas entrapment in volume of pressure die cast. A rchives of Foundry Engineering. 19(4), 33-38. DOI: 10.24425/afe.2019.129626.
[15] Dańko, R., Dańko, J. & Stojek, J. (2015). Experiments on the Model Testing of the 2nd Phase of Die Casting Process Compared with the Results of Numerical Simulation. Archives of Foundry Engineering. 15(4), 21-24. DOI: 10.1515/afe-2015-0072.
[16] Gaspar, S. & Pasko, J. (2016). Pressing Speed, Specific Pressure and Mechanical Properties of Aluminium Cast. A rchives of Foundry Engineering. 16(2), 45-50. DOI: 10.1515/afe-2016-0024

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Authors and Affiliations

J. Majerník

1

e-mail:

ORCID:

M. Podařil

1

D. Gojdan

2

Institute of Technology and Business in České Budějovice, Czech Republic
Technical University of Košice, Faculty of Manufacturing Technologies with the Seat in Prešov, Slovak Republic

Comparison of Microstructure and Mechanical Properties of Cast Steel Carried out on Cast-on Samples and Samples Cast Separately

B.E. Kalandyk Renata E. Zapała

Archives of Foundry Engineering | 2021 | vo. 21 | No 2 | 81-88 | DOI: 10.24425/afe.2021.136102

Keywords Mechanical properties Metallography Heat treatment Cast steel

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Abstract

The results of microstructure examinations and UTS, YS, El, RA carried out on low-carbon cast steel containing 0.15% C. The tests were carried out on specimens cut out from samples cast on a large-size casting and from samples cast in separate foundry moulds. It has been shown that significant differences in grain size observed in the material of the separately cast samples and cast-on samples occur only in the as-cast. In the as-cast state, in materials from different tests, both pearlite percent content in the structure and mean true interlamellar spacing remain unchanged. On the other hand, these parameters undergo significant changes in the materials after heat treatment. The mechanical properties (after normalization) of the cast-on sample of the tested cast steel were slightly inferior to the values obtained for the sample cast in a separate foundry mould. The microscopic examinations of the fracture micro-relief carried out by SEM showed the presence of numerous, small non-metallic inclusions, composed mainly of oxide-sulphides containing Mn, S, Al, Ca and O, occurring individually and in clusters.

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Authors and Affiliations

B.E. Kalandyk

1

Renata E. Zapała

e-mail:

ORCID:

AGH University of Science and Technology, Department of Cast Alloys and Composites Engineering, Faculty of Foundry Engineering, ul. Reymonta 23, 30-059 Krakow, Poland

Investigation on the Effect of Granulometric Features on the Permeability of No-Bake Resin Bonded Sand Cores

H. Hudák G. Gyarmati L. Varga

Archives of Foundry Engineering | 2021 | vo. 21 | No 2 | 99-105 | DOI: 10.24425/afe.2021.136105

Keywords Foundry sand granulometry grain size Grain morphology Grain shape Permeability

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Abstract

Foundry sand is the main element of sand mixtures from which molds or sand cores are made. Due to the continuous development of coremaking technologies, the selection of the right type of base sand becomes more and more important. The major features of foundry sand are determined by the following factors: chemical and mineralogical composition, sand grain size, grain size distribution, sand grain shape, and surface quality. The main goal of our research was to develop a qualification method that can be used to predict the characteristics of sand cores made from different sand types. Samples made from different types of foundry sand were used during the research whose properties were examined with a new qualification system, and then its connection with the gas permeability of sand cores was analyzed. Based on the research results, a strong correlation could be established between the suggested quality indicators: CQi (Core Quality Index), CG (Coefficient of Granulometry), and permeability.

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Authors and Affiliations

H. Hudák

1

G. Gyarmati

1

L. Varga

1

Institute of Foundry, Faculty of Materials Science and Engineering, University of Miskolc, Hungary

A New Technology of TRIAD Cement-Free Castables – Practical Aspects

B. Cygan J. Dorula J. Jezierski

Archives of Foundry Engineering | 2021 | vo. 21 | No 2 | 94-98 | DOI: 10.24425/afe.2021.136104

Keywords Cement-free concrete Refractory lining Pouring ladle Pouring device Cast iron

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Abstract

The article presents the new technology of the refractory materials used for the ladles and pouring devices. The aim for solving the majority of the problems that originated from the refractory lining was to develop the group of cement-free TRIAD products by Vesuvius company. The cement-free setting system in the TRIAD products eliminates calcium oxide (CaO) that occurs in low and extra low cement concretes resulting in its higher strength at higher temperatures. The features of the new cement-free castables were described. One of the most unique features of this technology is the porous material structure. Small venting microchannels are formed during the concrete setting process. These micro-channels allow for removing water vapor from the lining without affecting its refractory properties. On the other hand, the diameter of pores is so low that it disallows the penetration of slag and metal into the lining, extends its operating life at the same time facilitates cleaning and removing build-ups. The procedure of the preparation of these materials, as well as the method of building of the lining, were presented. An example of the practical use of these materials in the ductile cast iron foundry was presented, showing the advantages of the new refractory materials over the traditional ones.

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Bibliography

[1] Drevin, J. (2014). Triad – a new range of user-friendly, high-strength refractory concretes. Przegląd Odlewnictwa. 9-10, 390-393. (in Polish).
[2] Rybak, M. (2011). Influence of alumina cement hydration conditions on concrete properties. Piece Przemysłowe & Kotły. 1, 21-25. (in Polish).
[3] Drevin J. (2011). Triad – Triad high-performance castable linings. Foundry Practice. 253(6) 16-20.
[4] Cygan B., Dorula J., Jezierski J. (2018). TRIAD - modern technology of non-cement concrete in cast iron foundry. In Congress Proceedings of the 73rd World Foundry Congress "Creative Foundry", 23rd–27th September 2018 (pp. 561-562). Krakow, Poland: Polish Foundrymen's Association.

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Authors and Affiliations

B. Cygan

1 2

J. Dorula

3

J. Jezierski

1

e-mail:

ORCID:

Silesian University of Technology, Department of Foundry Engineering, 7 Towarowa, 44-100 Gliwice, Poland
Teksid Iron Poland Sp. z o.o., 49 Ciężarowa, 43-430 Skoczów, Poland
Vesuvius Poland Sp. z o.o. , Foundry Division - Biuro Handlowe, Portowa Business Center, 8 Portowa, 44-100 Gliwice, Poland

Heat Treatment of AlSi7Mg0.3 Aluminium Alloys with Increased Zirconium and Titanium Content

E. Kantoríková M. Kuriš R. Pastirčák

Archives of Foundry Engineering | 2021 | vo. 21 | No 2 | 89-93 | DOI: 10.24425/afe.2021.136103

Keywords Heat treatment Aluminum Alloys Zirconium Titan Mechanical properties

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Abstract

The paper compares changes in the structure and mechanical properties due to the synergistic effect of alloying elements Zr and Ti. It is assumed that by increasing the content of Zr and Ti in the aluminium alloy, better mechanical properties will be achieved. Paper focuses on description of the differences between the samples casted into the shell mold and the metal mold. Main difference between mentioned molds is a different heat transfer coefficient during pouring, solidification and cooling of the metal in the mold. The main goal was to analyse the influence of Zr and Ti elements and compare the mechanical properties after the heat treatment. Curing and precipitation aging were used during the experiment. The effect of the elements on AlSi7Mg0.3 alloy created differences between the excluded Zr phases after heat treatment. Evaluation of the microstructure pointed to the decomposition of large predominantly needle Zr phases into smaller, more stable formations.

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[1] Bolibruchová, D., Tillová, E. (2005). Al-Si foundry alloys. Žilina.
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E. Kantoríková

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M. Kuriš

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R. Pastirčák

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Department of Technological Engineering, University of Žilina in Žilina, Univerzitná 8215/1, 010 26 Žilina, Slovakia

Age of volcanism on Keller Peninsula and assessment of age‑constrained volcanic activity on King George Island, West Antarctica. Appendix 1. The U-Pb isotope data for volcanic rocks from the Keller Peninsula, King George Island

Jerzy Nawrocki Magdalena Pańczyk Krystian Wójcik Agata Kozłowska-Roman

Polish Polar Research | 2021 | vol. 42 | No 2

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Jerzy Nawrocki

Magdalena Pańczyk

Krystian Wójcik

Agata Kozłowska-Roman

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