Претрага

Упит dcterms_subject_txt:Utilization and Storage

2351 items

  • Differently shaped nanocrystalline (Fe, Y)3O4 and its adsorption efficiency toward inorganic arsenic species

    Biljana P Dojčinović, Boštjan Jančar, Lotfi Bessais, Aleksandar Kremenović, Nataša P Jović-Jovičić, Predrag T Banković, Dalibor M Stanković, Miloš Ognjanović, Bratislav V Antić (2019)
    Herein we report effects of partial substitution of Fe3+ by Y3+ in magnetite (Fe3O4) on morphology and inorganic arsenic species adsorption efficiency of the Fe3−xYxO4 nanoparticles formed. The series of Fe3−xYxO4 (x=0.00, 0.042 and 0.084, labeled as Y00, Y05 and Y10, respectively) was synthesized using co-precipitation followed by microwave-hydrothermal treatment (MW) at 200°C. With increase of yttrium content(xvalue), both the morphological inhomogeneity of the samples and the fraction of spinel nanorods as compared to spinel pseudospherical particles increased. By ...
    microstructure, microwave-hydrothermal synthesis, adsorption, magnetic nanoparticles, arsenic

  • Strategic Environmental Assessment in the Application of Preventive Protection for Wind Farm Noise—Case Study: Maestrale Ring Wind Farm

    Boško D. Josimović, Aleksandar Cvjetić, Božidar Manić (2021)
    Determining the spatial position of wind turbines is the initial and most important phase in the development of a wind farm project. In this sensitive phase, all potential problems that may arise in the later stages of project development should be prevented by means of spatial and urban planning instruments. This makes it possible to achieve maximum use of the potential of wind in a particular space and, thus, fulfil the technical and economic requirements of the project while ...
    Energija,energetski inženjering i elektroenergetska tehnologija,obnovljivi izvori energije, održivost i životna sredina,električni i elektronski inženjering,kontrola i optimizacija,inženjering
    ... administrative zone with apartments, zones along highways and roads 65 55 6 Industrial, storage and service areas and transport terminals without residential buildings At the border of this zone, the noise must not exceed the limit value in the zone with which it borders Energies 2021, 14 ...
    ... , hospital zones and convalescent homes, cultural and historical sites, large parks 50 40 2 Tourist areas, camps and school zones 50 45 3 Residential areas 55 45 4 Business/residential and commercial/residential areas and children’s playgrounds 60 50 5 Town/city center, business, adm ...
    ... possible negative effects on human health, which Pedersen and Waye [30] classify into three groups: subjective effect (discomfort, disturbance and dissatisfaction); interference with certain daily activities (speech, sleep and learning); and physiological effect (anxiety, tinnitus, or in the worst ...

  • Utilizing sewage wastewater heat in district heating systems in Serbia: effects on sustainability

    Marija Živković, Dejan Ivezić (2021)
    Transformation of the heating sector is recognized as being essential for ensuring reliable and afordable energy services provided with reduced consumption of energy sources and diminished impact on the environment and less import dependency. The possibility of utilizing energy sources that otherwise would be wasted needs to be considered and treated as a big advantage of district heating systems. Despite many advantages, sewage wastewater heat is still a mostly unused resource at the global level and a totally unused ...
    рекуперација топлоте из отпадних вода, систем даљинског грејања, топлотне пумпе, енергетске уштеде, емисија угљендиоксида, енергетска безбедност, Србија
    ... consideration the distance between heat sources and areas with DH. Analysis of economic feasibility of wastewater heat utilization showed the strong influence of the distance between WWTP and DH systems (Santin et al. 2020). Ðurđevic et al. (2019) analyzed and determined the potential for utilizing wastewater ...
    ... , processing/refining, storage, transport and combustion of the fuels. Since there are no national values for the primary carbon dioxide coefficients, default values were applied (Ecoheat4cities, 2016). Determination of technical potential of treated sewage wastewater and availability of heat energy ...
    ... index, the share of renewables) and environmental impact (carbon dioxide emission coefficient). Values of the selected indicators are determined for the current state of district heating systems and for the possible future state that could be achieved after full utilization of sewage wastewater potential ...

  • Centar za hidrogeologiju karsta - 15 godina nauke i struke

    urednici Saša Milanović, Ljiljana Vasić, Zoran Stevanović, Branislav Petrović (2023)
    Centar za hidrogeologiju karsta
    ... the conference “KARST 2022: Importance, State of the Art, and Prospective of Utilization and Protection of Resources in Karst Multidisciplinary conference “KARST 2022: Importance, State of the Art, and Prospective of Utilization and Protection of Resources in Karst” The multdisciplinary conference ...
    ... assessment and the implementation of the Framework Directive on waters resources of the Furopean Union in Serbia, Montenegro and Bosnia and Herzegovina. Dr. Veljko Marinović actively participates in teaching at BS (Methods of Hydrogeological Research, Groundwater Utilization in Water Supply) and MS «·&studies ...
    ... (Herzegovina, Montenegro) and for the first-time successful results were achieved in such porous media as karst. Technical applications for the control and regulation of karst aquifer through the construction of galleries, batteries of wells, and groundwater rTeservoirs (storage) represented an important ...

  • Sustainable Modularity Approach to Facilities Development Based on Geothermal Energy Potential

    Nataša Čuković-Ignjatović, Ana Vranješ, Dušan Ignjatović, Dejan Milenić, Olivera Krunić (2021)
    The study presented in this paper assessed the multidisciplinary approach of geothermal potential in the area of the most southeastern part of the Pannonian basin, focused on resources utilization. This study aims to present a method for the cascade use of geothermal energy as a source of thermal energy for space heating and cooling and as a resource for balneological purposes. Two particular sites were selected—one in a natural environment; the other within a small settlement. Geothermal resources come ...
    геотермална енергија, Панонски басен, геотермална каскада, енергетска ефикасност, бањски центри, балнеологија, биоклиматска архитектура, стратегије пасивног дизајнирања, модуларни објекти
    ... support the overall design goals. Placement and orientation: Placement of all open-air features and enclosed spaces was done in a way that provided optimal daylight, solar exposure and shading. North- facing sections were used for technical rooms like storage and sanitary spaces. Circulation corridors connecting ...
    ... Geothermal sources and utilization practice in six countries along the southern part of the Pannonian basin. Environ. Earth Sci. 2020, 79, 1–12. [CrossRef] 20. Nádor, A. (Ed.) Cascades and Calories: Geothermal Energy in the Pannonian Basin for the 21st Century and Beyond; Faculty of Mining and Geology, Belgrade ...
    ... for both sites, Ljuba and Banatsko Veliko Selo. Geothermal investigations and monitoring last for 12 months. 3. Results and Discussion The concept of a multidisciplinary approach to geothermal energy utilization has been justified by building modular wellness facilities. The calculated thermal power ...

  • Long-term planning methodology for improving wood biomass utilization

    Vladimir Vukašinović, Dušan Gordić, Marija Živković, Davor Koncalović, Dubravka Živković (2019)
    The insufficiently developed forest management system is often followed by undeveloped forest resources supply chain and insufficient institutional support. These cause inefficient usage of fuel-wood as well as huge amounts of unused forest residues. In order to achieve optimal and long-term sustainable utilisation of biomass, an original methodology based on the interaction of mathematical optimization and backcasting approach has been developed. Mathematical optimization is used for both generation and consideration of techno-economic parameters of the forest biomass supply chain. ...
    Long-term planning methodology, Forest biomass, MINLP, Backcasting

  • Отпад из процеса сагоревања угља као сировина за добијање елемената ретких земаља

    Бојан Земљак (2024)
    Због великог броја индустрија у којима се користе ови ресурси, глобална економија се у великој мери ослања на елементе ретких земаља. Елементи ретких земаља су есенцијална сировина — материјал за развој савремених технологија, али у односу на њихову огромну потражњу, њихово вађење је ограничено и повезано је са значајним утицајима на животну средину. Због њихове ограничене доступности, проблема који се јављају при процесима експлоатације, све више и више земаља почиње да тражи повољније могућности вађења елемената [REE] из секундарних ...
    Елементи ретких земаља, резерве, употреба, представници и методе опоравка елемената ретких земаља
    ... materials with high-efficiency energy storage and conversion for batteries and fuel cells. Coordination Chemistry Reviews, 253(23-24), p.2805-2813. [62] Malczewska-Toth, B., 2012. Titanium, zirconium, and hafnium. Paffty's Toxicology. 6th ed. New York: John Wiley and Sons Ltd, p.427-74. [63] Balaram ...
    ... Fuel, 87(6), p.857-869. [166] Panda, L. and Dash, S., 2020. Characterization and utilization of coal fly ash: a review. Emerging Materials Research, 9(3), p.921-934. [167] Wang, Z., Dai, S., Zou, J., French, D. and Graham, I.T., 2019. Rare earth elements and yttrium in coal ash from the Luzhou power ...
    ... Technologies: Beneficiation, Utilization, Transport Phenomena and Prospective. p. 431-471. Cham: Springer International Publishing. [175] Mukaba, J.L., Eze, C.P., Pereao, O. and Petrik, L.F., 2021. Rare carths” recovery from · phosphogypsum: an overview on direct and indirect | leaching techniques ...

  • Утечњени природни гас (УПГ) – технологија производње и регасификације

    Јована Милетић (2024)
    У овом раду истраживање је обухватило сагледавање карактеристика утечњеног природног гаса као извора енергије и његове улоге у савременој расподели потрошње енергије на глобалном и европском нивоу. Проучени су елементи тржишта утечњеног природног гаса, сектори коришћења, транс-портне руте и количине испорука. Сагледан је пут природног гаса од лежишта до корисника преко утечњавања и транспорта у резервоарима, са посебним акцентом на технологијама производње и регасификације. Објашњено је пречишћавање сировог природног гаса ради уласка у процес утечњавања, процеси утешњавања и настојања ...
    утечњени природни гас, технологија производње и рега- сификације, транспорт, директно коришћење УПГ-а, могућност коришћења УПГ-а у Србији
    ... _detail.php?id—3 pristupljeno 1.9.2024. 24. GMS Consult (2021). P/nat is an LNG Storage Tank? Mhat is it used Jor? GMS INTERNEER Co., Ltd. Thailand, Bangkok. https://www.gmsthailand.com/blog/what- is-Ing-storage-tank/ pristupljeno 1.9.2024. 25. International Gas Union (IGU), (2024). 2024 W/orld ...
    ... Facilifafing a wide-scale use of LNG as fuel and cargo for inland shipping. Pro Danube company. https://www.prodanube.eu/images/LNG_MP_INFO_Brochure.pdf pristupljeno 10.9.2024. Marine Portal for Amateurs and Professionals. Preparafion of loading and unloading operations for LNG/LPG carriers. ...
    ... Pitblado, R. (2010). LNG Properties and Overview of Hazards. _NG Risk Based Safety: Modeling and Consequence A4nalysis, pp. 1-19. DO!IT:10.1002/0780470590232.ch1 Zand, M. (2024). Unveiling the Potential of Marine LNG: Exploring the Impact of FSRU, SRU, and RU Technologies. Energy Department Ministry ...

  • Low-temperature phase transition and magnetic properties of K3YbSi2O7

    Predrag Dabić, Volker Kahlenberg, Biljana Krüger, Marko Rodić, Sabina Kovač, Jovan Blanuša, Zvonko Jagličić, Ljiljana Karanović, Václav Petříček, Aleksandar Kremenović (2021)
    alkalni silikati elemenata retkih zemalja, fazni prelazi, magnetne karakteristike, razdvajanje kristalnog polja, silikati lantanica
    ... Petřı́ček and Aleksandar Kremenović Acta Cryst. (2021). B77, 584–593 IUCr Journals CRYSTALLOGRAPHY JOURNALS ONLINE Author(s) of this article may load this reprint on their own web site or institutional repository provided that this cover page is retained. Republication of this article or its storage in ...
    ... crystal structures of �-K3YbSi2O7 and �0- K3YbSi2O7, the phase transition and the observed twinning are presented in Sections 3.1 and 3.2. The most relevant information about data collections and refinements is compiled in Table 2. Selected bond lengths, bond angles and research papers 586 P. Dabić ...
    ... crystal structures of 6-K3;YbSi,0, and ’- K;YbSi,O,, the phase transition and the observed twinning are presented in Sections 3.1 and 3.2. The most relevant information about data collections and refinements is compiled in Table 2. Selected bond lengths, bond angles and Experiments were carried out with ...

  • Hypogene speleogenesis related to porphyry magmatic intrusions and its influence on subsequent karst evolution in the Peruvian high Andes

    Alexander Klimchouk, David Evans, Sasa Milanovic, Cristian Bittencourt, Mauro Sanchez, F. Carlos Aguirre (2022)
    Earth-Surface Processes

  • Uticaj raspadanja na stabilnost kosina u mekoj stenskoj masi

    Anđela Despotov (2024)
    U radu je opisano ponašanje mekih stenskih masa koje su izložene porecesu raspadanja tokom određenog vremenskog perioda. Meke stenske predstavljaju kritične vrste stenskih masa pošto izazivaju različite probleme tokom izvođenja građevinskih radova. Meke stene mogu biti sedimentne stene, raspadnute metamorfne i magmatske stene. Odlikuju se niskim vrednostima čvrstoće, visokom deformabilnošću, visokom plastičnošću, podložne su dezintegraciji i fizičko-hemijskom raspadanju, odnosno ubrzanom dejstvu površinskog raspadanja usled atmosferskih uticaja.Za klasifikaciju mekih stenskih masa koriste se modifikovane verzije već postojećih klasifikacionih sistema. Jedan ...
    meke stenske mase, dezintegracija, klasifikacioni sistemi, Slake durability test
    ... Colloquium. Schubert & Kluckner (eds.) OGG 5. Barla, G., (1990), Stress, Strength and Deformability Assessment for the Design of Large Storage Caverns in a Weak Jointed Chalk. Third Cycle of Conferences on Rock Mechanics and Engineering - MIR90 - Le Tocce Tenere -Weak Rocks (pp.22-1 to 22-21). Politecnico ...
    ... Institution of Mining and Metallurgy 527 p, London 19. ISO 14689:2017 Geotechnical investigation and testing - Identification, description and classification of rock 20. Sandeen, J., (2023), Mechanical Weathirng, CK-12 Foundation 21. Kanji, M., (2014), Journal of Rock Mechanics and Geotechnical Engineering ...
    ... , Pineda, J.A., (2006) Weathering and degradation of shales: experimental observations and models of degradation. VI South American Rock Mechanics Conference. Cartagena de Indias, Colombia 3. ASTM. (2008) Standard Test Method for Slake Durability of Shales and Similar Weak Rocks. ASTM designation ...

  • Geomagnetna bura kategorije G5 u maju 2024. godine

    Magdalena Marčeva (2024)
    Zemlja poseduje magnetno polje, koje je generisano u njenom spoljašnjem jezgru. Magnetno polje Zemlje je konstantno izloženo dejstvu sunčevog magnetnog polja i zračenja koje se sa Sunca emituje. Naelektrisane čestice koje pristižu sa Sunca stupaju u interakciju sa magnetosferom, što dovodi do različitih geomagnetnih poremećaja.Geomagnetna aktivnost direktno je proporcionalna intenzitetu sunčevog zračenja koje dolazi do Zemlje. Pod uticajem sunčevog korpuskularnog zračenja dolazi do pojave geomagnetnih bura koje su praćene porastom intenziteta magnetnog polja.Količina i jačina dolaznog sunčevog zračenja zavisi ...
    magnetosfera, sunčevo zračenje, geomagnetna bura, indeksi geomagnetne aktivnosti, polarna svetlost
    ... spiralni oblik Parkerove spirale upoređen je sa balerininom suknjom (slika 5.1.3). Slika 5.1.3. Parkerova spirala (https://www.esa.int/var/esa/storage/images/esa_multimedia/images/2019/03/parker_spiral/ 9277782-1-eng-GB/Parker_spiral_pillars.jpg ) 17 5.2. Karakteristike bura od 10. do 13. maja ...
    ... & Huang, C., 2017. A comprehensive study of geomagnetic storm effects on ionospheric total electron content and its relationship with solar wind parameters. Journal of Space Weather and Space Climate, 7, A33. URL:https://www.SWSC- journal.org/articles/swsc/full_html/2017/01/swsc170014/swsc170014 ...
    ... слободном приступу. - Претрага репозиторијума доступна је на www.dr.rgf.bg.ac.rs The Digital repository of The University of Belgrade Faculty of Mining and Geology archives faculty publications available in open access, as well as the employees' publications. - The Repository is available at: www.dr.rgf ...

  • Surface functional groups and degree of carbonization of selected chars from different processes and feedstock

    Marija Ilić, Franz-Hubert Haegel, Aleksandar Lolić, Zoran Nedić, Tomislav Tosti, Ivana Sredović Ignjatović, Andreas Linden, Nicolai D. Jablonowski, Heinrich Hartmann (2022)
    The knowledge ofthe structural and chemical properties of biochars is decisive for their application as technical products. For this reason, methods for the characterization of biochars that are generally applicable and allow quality control are highly desired. Several methods that have shown potential in other studies were used to investigate two activated carbons and seven biochars from different processes and feedstock. The chars were chosen to cover a wide range of chemical composition and structural properties as a hardness ...
    Biougalj, različiti procesi dobijanja, različite sirovine, površinski aktivne grupe, x-ray, FT-IR,XPS
    ... activated carbon production: Multiple applications in environmental protection and energy storage. PLOS ONE | hitps://doi.org/10.1371/journal.pone.0277365 November 17, 2022 33/38 PLOS ONE Surface functional groups and degree of carbonization of selected chars 19. 20. 21. 22. 23. 24. ...
    ... intercept is 0.067 and represents the mean influence of the initial composition of the biomass and the changes due thermal degradation. Decarboxylation and decarbonylation result in lower O/C and higher H/C, dehydrogenation in lower H/C and demethanization in lower H/C and higher O/C. Evolution ...
    ... a broad double peak for amorphous carbon between 5 and 29". In addition, HW500f shows sharp intense peaks of quartz and small peaks for Whewellite (Ca(C>Ox)·H»O) at 24.38* and 14.86* (3.650 and 2.987 A) [53] and calcite. The presence of Si and Ca is consistent with the chemical composition (Table ...

  • Hidrogeohemija prirodnih radioaktivnih elemenata u podzemnim vodama Srbije

    Marina D. Ćuk (2018-02-23)
    Osnovni cilj doktorske disertacije predstavljao je definisanje prirodnih koncentracija (engl. background values) U, Th, i K u podzemnim vodama, i definisanje hidrogeohemijskih uslova koji utiču na distribuciju navedenih elemenata u podzemnim vodama...
    prirodni radioaktivni elementi, podzemna voda, geohemijske sredine, hidrogeohemijski uslovi, neparametarska statistička analiza, logistički model, hidrohemijsko modeliranje
    ... (ICP-MS) and the Associated Dose Contribution. International Journal of Environmental Sciences 4(1): 7 – 13. 117. Nikić Z, Kovačević J, Papić P. 2008. Uranium minerals of Bukulja mountain controls on storage reservoir water. In: Merkel B, Hasche-Berger A (eds.). Uranium, Mining and Hydrogeology ...
    ... concentration of SO4 in the solution and geochemical environment within the Oligocene-Miocene magmatic belt and the southern margin of the Pannonian Basin), and potassium (pH and TDS values, and Na-HCO3 groundwater types). Keywords: natural radioactive elements, groundwater, different ...
    ... (U, Th, and K) in the groundwater, and to establish hydrogeochemical conditions affecting the distribution of these elements in groundwater. The methodology of the research was carried out with contemporary field and laboratory methods (ICP - MS HR) during the process of collecting and analyzing ...

  • Процена емисије гасова са ефектом стаклене баште као последице енергетске активности

    Горана Остојић (2024)
    Рад се бави анализом и проценом емисија гасова са ефектом стаклене баште, са посебним акцентом на емисије које настају као последица енергетских активности. Ефекат стаклене баште представља природни процес који је неопходан за одржавање живота на Земљи, али антропогене активности, попут индустријске производње и сагоревања фосилних горива, значајно повећавају концентрацију ових гасова у атмосфери, што доводи до климатских промена. Рад истражује узроке, последице и могућности за смањење емисија гасова, као и развој стратегија за ублажавање негативних ефеката на животну ...
    емисија гасова, ефекат стаклене баште, енергетске активности, климатске промене, мобилно сагоревање, стационарно сагоревање
    ... charcoal, bagasse, saw dust, cotton stalks and carbonizing of biofuels as well as fuel used for coal mining, oil and gas extraction and the processing and upgrading of natural gas. This category also icludes emissions from - processmng for CO,; capture and storage. Combuston emissioms from pipeline transport ...
    ... ISIC Group 271 and Class 2731 ISIC Group 272 and Class 2732 ISIC Division 24. ISIC Divisioms 21 and 22 ISIC Divisioms 15 and 16 Includes products such as glass, ceramic, cement, etc., ISIC Division 26 ISIC Divisions 34 and 35 Includes fabncated metal products, machinery and equipment oother ...
    ... offs and landings. Comprises civil commercial use of airplanes, including: scheduled and charter traffic for passengers and freight, atr taxiing, and general aviation. The mtemational/domestic split should be determined on the basis of departure and landing locations for cach flight stage and not ...

  • Споменица 1991. – 2015. година: 135 година геологије и 70 година рударства на Универзитету у Београду

    главни и одговорни уредник Душан Поломчић (2016)
    Рударско-геолошки факултет
    ... research and Integrated utilization. The min. Pribram Symp. Int. Section Geoethica, Pribram, The CZech Rep., G 30, p. 1–7, Pribram. MILOVANOVIĆ D., TOMANEC R., SEKE L., 2005: Sustainable development indica- tors and mineral economy of Serbia and Montenegto. 20 th World Mining Con- gress and EXPO, Teheran ...
    ... JOVIĆ M., 2011: Economic And Technical Aspects Of Transformer Operation. Energy Sources, Part B: Economics, Planning and Policy. ALEKSANDROVIĆ S., JOVIĆ M., 2011: Analysis of Belt Weigher Accuracy Limiting Factors. International Journal of Coal Preparation and Utilization. Уџбеници, скрипте, ...
    ... 14J KNEŽEVIĆ D, LILIĆ N, NIŠIĆ D, STANIĆ M, KUZMANOVIĆ V., 2015: Using previously polluted sites for waste storage, Prahovo phosphogypsum storage case study. 5th Inter. Symp. Mining and environmental protection, Vrdnik, pp. 356–365. NIŠIĆ D., KNEŽEVIĆ D., PANTELIĆ U., TOMAŠEVIĆ A., 2015: Klasifikacija ...

  • Upravljanje proizvodnjom nafte – novi alat na bazi fazi logike

    Мирослав Црногорац, Душан Даниловић, Лола Томић (2020)
    ... water available to satisfy demand exist; 2) Economic Water Scarcity: where the lack of infrastructure development that controls storage, distribution and access exist; and Preduzetništvo, inženjerstvo i menadžment PIM9 ...
    ... aims of this study are to determine the effect of ascorbic and citric acid on the nutritional characteristics of frozen plum fruits, taking into account the period of storage of frozen fruits in freezing chambers at -18 ° C, the 71 karakasoval@yahoo ...
    ... characteristics of frozen plum fruits, as well as to give a recommendation for the treatment of fruits and which is a more suitable plum variety for the freezing process. After three months of storage of frozen fruits at a temperature of -18 ° C, was performed an analysis of the obtained results. Compared ...

  • Multiple-Criteria Decision-Making in Mine Development Planning

    Sanja Bajić (2023)
    The Borska Reka ore deposit is an experimental location where developed methodologies have been applied. It is the largest ore body within the Bor mining complex, which has been the subject of numerous studies and analyses for more than three decades. The paper focuses on the application of FAHP and the VIKOR method to address ranking of alternatives and select the optimal mining method by means of fuzzy multicriteria optimization.

  • Природни потенцијал минералних вода Србије - Natural potential of mineral waters in Serbia

    Оливера Крунић (2021)
    минералне воде

  • Rezultati ispitivanja parametara čvrstoće i dinamičkih svojstava mermera i mogućnost njihove korelacije

    Jelena Majstorović-Necković, Vladimir Čebašek, Veljko Rupar (2023)
    Ispitivanja stena kao radne sredine, odnosno materijala sa kojim se gradi, na kome se gradi i u kome se gradi, svojom složenošću zahteva njeno svestrano izučavanje po velikom broju parametara. Zadatak Mehanike stena je da što bolje upozna ponašanje stenske mase i njenu otpornost na dejstvo pritiska, zatezanja i smicanja, kao i dinamičkih svojstava. Poznavanje navedenih parametara i njihova korelacija omogućavaju pouzdaniji izbor parametara za projektovanje danas sve zahtevnijih uslova kako podzemne, tako i površinske eksploatacije. U ovom radu ...
    mermer, jednoosna čvrstoća na pritisak, čvrstoća na istezanje, brzina longitudinalnih elastičnih talasa, korelacija