2022 - Repozytorium publikacji - Politechnika Gdańska

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Conductive printable electrodes tuned by boron-doped nanodiamond foil additives for nitroexplosive detection
- Anna Dettlaff
- Michał Rycewicz
- Mateusz Ficek
- Aleksandra Wieloszyńska
- Mateusz Szala
- Jacek Ryl
- Robert Bogdanowicz
2022 Pełny tekst MICROCHIMICA ACTA
An efficient additive manufacturing-based composite material fabrication for electrochemical applications is reported. The composite is composed of commercially available graphene-doped polylactide acid (G-PLA) 3D printouts and surface- functionalized with nanocrystalline boron-doped diamond foil (NDF) additives. The NDFs were synthesized on a tantalum substrate and transferred to the 3D-printout surface at 200 °C. No other electrode activation treatment was necessary. Different configurations of low- and heavy-boron doping NDFs were evaluated. The electrode kinetics was analyzed using electro- chemical procedures: cyclic voltammetry and electrochemical impedance spectroscopy. The quasi-reversible electrochemical process was reported in each studied case. The studies allowed confirmation of the CV peak-to-peak separation of 63 mV and remarkably high heterogeneous electron transfer rate constant reaching 6.1 × 10 −2 cm s −1 for 10 k ppm [B]/[C] thin NDF fitted topside at the G-PLA electrode. Differential pulse voltammetry was used for effective 2,4,6-trinitrotoluene (TNT) detection at the studied electrodes with a 87 ppb limit of detection, and wide linearity range between peak current density and the analyte concentration (0.064 to 64 ppm of TNT). The reported electrode kinetic differences originate primarily from the boron-dopant concentration in the diamond and the various contents of the non-diamond carbon phase.
Consequences of russia’s military invasion of Ukraine for Polish-Ukrainian trade relations
- Oleksandr Melnychenko
- Tetiana Osadcha
- Anatoliy Kovalyov
- Valerii Matskul
2022 Pełny tekst Journal of International Studies
An accurate forecast of interstate trade volume allows for short-term and long-term planning, particularly deciding on state budget revenues, foreign exchange earnings, border arrangement, other infrastructure, migration and social policies. Hostilities are destructive so the russian military aggression against Ukraine in 2022 needs to be assessed in terms of its effects on key economic aspects of Polish-Ukrainian relations, as Poland has been the main economic, trade and social partner of Ukraine in recent years. This article analyses the trade dynamics between the two countries since 2005. It was found that since 2015 the main trends of this dynamics have changed. Monthly data from 2015 to 2021 were used for modelling and forecasting. Relevant SARIMA and Holt-Winters exponential smoothing models were built. These models forecast the volume of trade for the fourth quarter of 2021 and the first quarter of 2022. The relative errors of forecasting (compared to actual data) for October, November and December 2021 were as follows: according to the SARIMA model – 0.8%, 3.6% and 2.3%, respectively; for the Holt-Winters model – 1.9%, 3.6% and 0.7%, respectively. Given the expectations and consequences of russia’s military aggression against Ukraine, the average projected trade turnover between Ukraine and Poland was reduced by 20% per month for the first quarter of 2022. In comparison with the available actual (preliminary) data for January 2022, such a pessimistic forecast gave the following relative forecasting errors: according to the SARIMA model – 3.8%; according to the Holt-Winters model – approx. 1%
Consequences of suboptimal design of Building Integrated Photovoltaic Installation – a case study for Gdansk, Poland
- Małgorzata Rudnicka
- Ewa Klugmann-Radziemska
2022 Pełny tekst Przegląd Elektrotechniczny
The carried out analysis concerns 2 kWp building integrated photovoltaic installation (BIPV) at the Chemistry Faculty of Gdansk University of Technology. It was proven that the generated energy data for every month diverge significantly from the expected vales. It is corelated with suboptimal orientation of the installation itself, as well as with the tilt angle varying from optimal.
Consideration of the safety of bungee jumping in relation to mechanical properties of the instalation based on a jump accident in Gdynia
- Agnieszka Tomaszewska
- Paweł Kłosowski
2022 Pełny tekst Engineering Transactions
This paper considers a bungee jumping accident that took place in July 2019 in Gdynia, Poland. The authors conducted an investigation to determine the cause of the bungee rope failure. It was based on mechanical tests concerning the strength of the rope as well as the calculation of the force induced in the rope during the jump. Based on the theoretical and experimental results, the rope safety factor was estimated. It appeared to be three-fold lower than it is recommended in Polish regulations concerning ropes dedicated to lifting people for industrial and public purposes. However, no law regulations strictly concerning bungee installation makes it easy for accidents to occur.
Constant-Factor Approximation Algorithm for Binary Search in Trees with Monotonic Query Times
- Dariusz Dereniowski
- Izajasz Wrosz
2022
We consider a generalization of binary search in linear orders to the domain of weighted trees. The goal is to design an adaptive search strategy whose aim is to locate an unknown target vertex of a given tree. Each query to a vertex v incurs a non-negative cost ω(v) (that can be interpreted as the duration of the query) and returns a feedback that either v is the target or the edge incident to v is given that is on the path towards the target. The goal of the algorithm is to find a strategy that minimizes the worst-case total cost. We propose a constant-factor approximation algorithm for trees with a monotonic cost function. Such function is defined as follows: there exists a vertex r such that for any two vertices u,v on any path connecting r with a leaf it holds that if u is closer to r than v, then ω(u) ≥ ω(v). The best known approximation algorithm for general weight functions has the ratio of O{√{log n}} [Dereniowski et al. ICALP 2017] and it remains as a challenging open question whether constant-factor approximation is achievable in such case. This gives our first motivation towards considering monotonic cost functions and the second one lies in the potential applications.
Constrained multi-objective optimization of compact microwave circuits by design triangulation and pareto front interpolation
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
2022 EUROPEAN JOURNAL OF OPERATIONAL RESEARCH
Development of microwave components is an inherently multi-objective task. This is especially pertinent to the design closure stage, i.e., final adjustment of geometry and/or material parameters carried out to improve the electrical performance of the system. The design goals are often conflicting so that the improvement of one normally leads to a degradation of others. Compact microwave passives constitute a representative case: reduction of the circuit footprint area is detrimental to electrical figures of merit (e.g., the operating bandwidth). Identification of the best available trade-off designs requires multi-objective optimization (MO). This is a computationally expensive task, especially when executed at the level of full-wave electromagnetic (EM) simulation. The computational complexity issue can be mitigated through the employment of surrogate modeling methods, yet their application is limited by a typically high nonlinearity of system responses, and the curse of dimensionality. In this paper, a novel technique for fast MO of compact microwave components is proposed, which allows for sequential rendition of the trade-off designs using triangulation of the already available Pareto front as well as rapid refinement algorithms. Our methodology is purely deterministic; in particular, it does not rely on population-based nature-inspired procedures. The three major benefits are low computational cost, possibility of handling explicit design constraints, and a capability of producing a visually uniform representation of the Pareto front. The algorithm is demonstrated using a compact branch-line coupler and a three-section impedance matching transformer. In both cases, considerable savings are obtained over the benchmark, here, the state-of-the-art surrogate-assisted MO technique.
Constructive Controllability for Incompressible Vector Fields
- Sergey Kryzhevich
- Eugene Stepanov
2022
We give a constructive proof of a global controllability result for an autonomous system of ODEs guided by bounded locally Lipschitz and divergence free (i.e. incompressible) vector field, when the phase space is the whole Euclidean space and the vector field satisfies so-called vanishing mean drift condition. For the case when the ODE is defined over some smooth compact connected Riemannian manifold, we significantly strengthen the assertion of the known controllability theorem in absence of nonholonomic constraints by proving that one can find a control steering the state vector from one given point to another by using the observations of only the state vector, i.e., in other words, by changing slightly the vector field, and such a change can be made small not only in uniform, but also in Lipschitz (i.e. C^1) topology.
Contemporary Architectural Design in the Context of Historic Remains: The Case of the Old City of Gdańsk
- Antoni Taraszkiewicz
- Karol Grębowski
- Karolina Taraszkiewicz
- Jarosław Przewłócki
2022 Pełny tekst Heritage and Society
This article presents several examples of modern developments designed to preserve and coexist with fragments of historic brick buildings. These building projects each faced a similar task; to save and display the historical urban fabric, but they differed significantly in how they chose to achieve that goal. Not all of the projects presented in this study meet the requirements of the Venice Charter equally well. In this field, the solution often means choosing the “lesser evil”. Each of the projects presents a unique example of interdisciplinary research used to solve complex construction problems. Numerical analysis using the finite element method (including the damage model based on plastic degradation adopted for brick walls)was carried out for one of the projects.
Context of Digitalized Employment for Older Adults with Autism Spectrum Disorder in the New Normal
- Elias Mpofu
- Michał Tomczak
- Nathan Hutson
- Lucy Gafford
- Ronfang Zhan
2022
Employers are actively considering how to normalize remote work technology across different industries. The residual risk of coronavirus disease-19 (COVID-19) will necessarily lower the bar for allowing some workers to stay remote on a more permanent basis. This is based on the realization that many essential jobs can be teleworked while retaining or enhancing productivity. The decisions employers make regarding future work arrangements are based upon assumptions and evidence collected over the course of the pandemic, which are framed in a neurotypical context. This chapter examines the potential benefits and risks of mainstreaming telecommuting or remote working for older adults with autism spectrum disorder (ASD). In doing so, this chapter considers different work and job redesign tools, which might be necessary to enable successful remote working including assistive technology and low-cost solutions based on publicly available software. Moreover, we consider technology-based solutions aimed at improving the long-term work well-being of older adults with ASD. Finally, we examine career stage and transition considerations with older adults with ASD in the context of the new normal.
Continuum models for pantographic blocks with second gradient energies which are incomplete
- Maximilian Stiltz
- Francesco dell'Isola
- Ivan Giorgio
- Victor Eremeev
- Georg Ganzmuller
- Stefan Hiermaier
2022 Pełny tekst MECHANICS RESEARCH COMMUNICATIONS
We postulate a deformation energy for describing the mechanical behavior of so called pantographic blocks, that is bodies constituted by stacking of layers of pantographic sheets. We remark that the pantographic effect is limited in the plane of pantographic sheets and therefore only the second derivatives of transverse displacements along the pantographic fibers appear in the chosen deformation energy. We use this novel energy to predict the behavior of pantographic blocks when subjected to : (i) compression and traction test, (ii) torsion, (iii) shear and (iv) bending. A linearization of the energy shows one floppy mode in addition to the rigid body motions, assuming perfect pivots, similar to pantographic sheets.
Contribution of dynamic vehicle loads to pavement failure
- Dawid Ryś
2022
Pavement surfaces are not ideally even, which causes dynamic loads of vehicle axles. Distribution of dynamic loads of a given axle is similar to normal distribution and can be described by static load and dynamic load coefficient. The dynamic load coefficient depends on road profile, vehicle speed, properties of suspensions and static load of axle. While for a given road section road profile remains constant, vehicle speed and suspension properties are subject to limited variations, the static loads of particular axle vary significantly. The weigh-inmotion systems are the source of data on static loads, which are characterized by axle load spectra. The axle load spectra are the key data input for pavement design. The article presents a new approach to inclusion of the dynamic loads in axle load spectra. The theoretical explanation is supported by sample calculations. A one-kilometer road section was selected for calculations and its profile was measured using laser road surface profilograph. The dynamic loads were then calculated using the quarter car model and parameters appropriate for heavy vehicle suspensions. This part of calculations proved that dynamic loads significantly increase for less loaded axles. Dynamic axle load spectra were calculated based on static axle load spectra and function of dynamic load coefficient. The load equivalency factors and truck factors were calculated using the fourth power equation and considering both static and dynamic axle load spectra. Contribution of dynamic loads to pavement failure equals up to 19% for the considered example of road profile, which is characterized by IRI = 1.54 m/km.
Control of the bridge span vibration with high coefficient passive damper. Theoretical consideration and application
- Krzysztof Żółtowski
- Anna Banaś
- Mikołaj Binczyk
- Przemysław Kalitowski
2022 Pełny tekst ENGINEERING STRUCTURES
The research was carried out due to the problem of vibration on the lively pedestrian drawbridge across the Motlawa River in the city of Gdansk. In the design stage, the main span of the footbridge showed unfavorable dynamic properties, which may create a comfort problem for pedestrians. The first vertical bending eigenfrequency was recognized as 1.64 Hz. The original design of the footbridge was equipped with a driving cylinder to operate opening of the drawbridge. It was installed between the abutment and the pylon (integrated part of the span). Based on numerical calculations, it turned out that its high overdamping ratio can raise the value of the first vertical natural frequency to the level where pedestrian action has a low influence on the dynamic excitation of the span. It should be noted, the solution does not affect the behavior of the structure under static loads. Therefore, it was decided to modify the existing hydraulic driving cylinder to become a damper also. Analytical and numerical modeling was performed to establish an appropriate range of damper constant values. Finally, this idea was implemented in the structure. The theoretically defined effects of introducing a high ratio damper have been practically confirmed during the field test. The first vertical natural frequency of the span was shifted from 1.64 Hz to 3.1 Hz. The paper presents the work related to the solution of a specific case. However, the presented idea can be used in a wide spectrum of structures subjected to dynamic excitation. In practice, an external damper enables the change of a ”static scheme” of the structure in the selected range of dynamic loads. This idea has a sense only in the case where response amplitude from dynamic loads is smaller than from the static action.
Control Strategy of a Five-Phase Induction Machine Supplied by the Current Source Inverter With the Third Harmonic Injection
- Marcin Morawiec
- Filip Wilczyński
2022 Pełny tekst IEEE TRANSACTIONS ON POWER ELECTRONICS
In the five-phase induction machine (IM), it is possible to better use the electromagnetic circuit than in the three-phase IM. This requires the use of an adequate converter system which will be supplied by an induction machine. The electric drive system described, in this article, includes the five-phase induction machine supplied by the current source inverter (CSI). The proposed novelty—not presented previously—is the control system structures for the five-phase IM, which is supplied by CSI. The proposed control systems allow for independent control of IM state variables in the first and the second system plane to inject the third harmonic. However, the third harmonic must be suitably associated with the fundamental harmonic. In the proposed solution, the machine vector model is not transformed into the (d–q) coordinate system that is connected to the rotor flux vector but utilizes the stationary system (α–β). The nonlinear model linearization is based on the demonstrated nonlinear variables transformation for i-orthogonal (α–β) (i) planes. Voltage control is applied to the control system structure. The control variables of the five-phase IM are the voltage in the dc link and the angular speed of the output current vector. In the control strategy, the control variables are determined for both system planes. Therefore, the transformation of these control variables to the dc link of CSI is proposed. The proposed control structure allows for independent control of variables in the first and second system planes. It leads to the possibility to increase the value of electromagnetic torque up to 12% for the five-phase IM, which has not been used before in the case of the machine supplied by the CSI. All theoretical issues are confirmed by experimental tests in the 5.5 kW five-phase IM.
Contr-rotating eccentric-mass rotors used as exciters of sinusoidal forces applied to elastically supported bodies
- Krzysztof Lipiński
- Mirosław Gerigk
- Rafał Hein
- Grzegorz Banaszek
2022
The work focuses on aspects of multibody dynamics. Investigated object is a mass driven by rotations of an inertial shaker. Resulting vibrational set consists of two counter-rotating identically-unbalanced rotors. Since the mass centres of the rotors do not coincide with the axes of their rotations, significant centrifugal forces arise during rotations. As both rotors are identically unbalanced, the inter-axial force components balance each other, and only the summed transverse components generate the requested resultant of the sinusoidal-variable exciting force. Abovementioned description refers to a simplified theory of the force generation, since it omits several significant aspects which are difficult to their on-hand estimations, e.g., inertial terms created by the inertia products and gyroscopic effects. These effects, reasonable omitted in case of the stationary fixed shakers, are investigated in the paper, as the vibration-based angular motion of the excited base is significant and interacts with the relative spin motion of the rotors. What is more, variability of the angular speed of the spin should be considered, if power of the implemented drives is limited. Also, the angular and the linear kinematics resulting of the two motions are recombined, e.g. centrifugal terms resulting of rotation are modified by accelerations of transport motion of the base. Taking all of the facts under consideration, effective forces of the real exciter can differ from these which was initially requested, and thus, numerical verification of dynamics of the exciter is recommended, especially, if amplitudes of the resulting vibrations are significant. According to the indicated aspects, multibody model of the exciter is proposed and described in the paper. Simulated behaviours of the model are compared with behaviours a reference model interpreted as a rigid body driven by an ideal external exciter able to perfectly create a force which is described by a purely harmonic mathematical formula. Difference of the obtained results and applicability of the investigated exciter is discussed.
Conversion of waste biomass into activated carbon and evaluation of environmental consequences using life cycle assessment
- Muhammad Amin
- Hussain Hamad Shah
- Amjad Iqbal
- Marek Krawczuk
- Ur Zia Rahman Faroogi
- Adeel Zia
2022 Pełny tekst Applied Sciences-Basel
In this article, activated carbon was produced from Lantana camara and olive trees by H3PO4 chemical activation. The prepared activated carbons were analyzed by characterizations such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller, X-ray diffraction, thermogravimetric analysis, and Fourier transform infrared spectroscopy. H3PO4 is used as an activator agent to create an abundant pore structure. According to EDX analysis, the crystalline structure destroys and increases the carbon content of the olive tree and Lantana camara by 77.51 and 76.16%, respectively. SEM images reveal a porous structure formed as a result of H3PO4 activation. The Brunauer–Emmett–Teller (BET) surface area of the olive tree and Lantana camara activated carbon was 611.21 m2/g and 167.47 m2/g, respectively. The TGA analysis of both activated carbons shows their thermal degradation starts at 230 °C but fully degrades at temperatures above 450 °C. To quantify the potential environmental implications related to the production process of the activated carbon (AC) from olive trees, the life cycle assessment (LCA) environmental methodology was employed. For most of the tested indicators, chemical activation using H3PO4 showed the greatest ecological impacts: the ozone layer depletion potential (42.27%), the acidification potential (55.31%), human toxicity (57.00%), freshwater aquatic ecotoxicity (85.01%), terrestrial ecotoxicity (86.17%), and eutrophication (92.20%). The global warming po-tential (5.210 kg CO2 eq), which was evenly weighted between the phases, was shown to be one of the most significant impacts. The total energy demand of the olive tree’s AC producing process was 70.521 MJ per Kg.
Convolutional Neural Networks for C. Elegans Muscle Age Classification Using Only Self-Learned Features
- Bartosz Czaplewski
- Mariusz Dzwonkowski
- Damian Panas
2022 Pełny tekst Journal of Telecommunications and Information Technology
Nematodes Caenorhabditis elegans (C. elegans) have been used as model organisms in a wide variety of biological studies, especially those intended to obtain a better understanding of aging and age-associated diseases. This paper focuses on automating the analysis of C. elegans imagery to classify the muscle age of nematodes based on the known and well established IICBU dataset. Unlike many modern classification methods, the proposed approach relies on deep learning techniques, specifically on convolutional neural networks (CNNs), to solve the problem and achieve high classification accuracy by focusing on non-handcrafted self-learned features. Various networks known from the ImageNet Large Scale Visual Recognition Challenge (ILSVRC) have been investigated and adapted for the purposes of the C. elegans muscle aging dataset by applying transfer learning and data augmentation techniques. The proposed approach of unfreezing different numbers of convolutional layers at the feature extraction stage and introducing different structures of newly trained fully connected layers at the classification stage, enable to better fine-tune the selected networks. The adjusted CNNs, as featured in this paper, have been compared with other state-of-art methods. In anti-aging drug research, the proposed CNNs would serve as a very fast and effective age determination method, thus leading to reductions in time and costs of laboratory research.
Cooperativity of Halogen- and Chalcogen-Bonding Interactions in the Self-Assembly of 4‑Iodoethynyl- and 4,7-Bis(iodoethynyl)benzo-2,1,3-chalcogenadiazoles: Crystal Structures, Hirshfeld Surface Analyses, and Crystal Lattice Energy Calculations
- Jan Alfuth
- Beata Zadykowicz
- Barbara Wicher
- Katarzyna Kazimierczuk
- Tadeusz Połoński
- Teresa Olszewska
2022 Pełny tekst CRYSTAL GROWTH & DESIGN
Several new 4-iodoethynyl- and 4,7-bis- (iodoethynyl)benzo-2,1,3-chalcogenadiazoles were prepared, and a comprehensive analysis of the most prominent secondary bonding interactions responsible for the crystal self-assembly was performed using X-ray diffraction. The presence of both the iodoethynyl and chalcogenadiazole moieties allows an evaluation of the preference of these molecules to aggregate through either chalcogen- or halogen-bonding interactions in the solid state. The crystal structures of the compounds revealed that their solid-state arrangements are influenced by the nature of the chalcogen atom: for the crystals of the thiadiazoles studied, the C−I···N halogen bonds were preferred, whereas in the corresponding 2,1,3-selenadiazole derivatives, the self-complementary [Se···N]2 supramolecular synthons together with the C−I···N halogen-bonding interactions determined the molecular self-assembly. Furthermore, in the case of the bis(iodoethynyl) derivative the crystal structurewas additionally influenced by the C−I···π(ethynyl) halogen bond. Hirshfeld surface and 2D fingerprint plot analyses were used to demonstrate the intermolecular interactions and intercontact distributions. Also, the total lattice energies were calculated using the CRYSTAL09 and CrystalExplorer programs. They both indicated intermolecular π···π interactions as the forces of substantial contribution to the total lattice energies.
Core–shell excitation of isoxazole at the C, N, and O K-edges – an experimental NEXAFS and theoretical TD-DFT study
- Tomasz Wąsowicz
- Ivan Ljubić
- Antti Kivimäki
- Robert Richter
2022 Pełny tekst PHYSICAL CHEMISTRY CHEMICAL PHYSICS
The near-edge X-ray absorption fine structure (NEXAFS) spectra of the gas-phase isoxazole molecule have been measured by collecting total ion yields at the C, N, and O K-edges. The spectral structures have been interpreted using time-dependent density functional theory (TD-DFT) with the short-range corrected SRC2-BLYP exchange–correlation functional. Experimental and calculated energies of core excitations are generally in good agreement, and the nature of observed core-excitation transitions has been elucidated. The experimental C 1s, N 1s, and O 1s core electron binding energies (CEBEs) have additionally been estimated from another yield measurement where the neutral fragments in high-Rydberg (HR) states were ionized by the electric field. For comparison, theoretical CEBEs have been calculated at the DM06-2X//mixed basis set level. We have also calculated the vibrationally resolved spectra pertaining to the lowest C 1s and N 1s core-excited roots in the Franck–Condon–Herzberg–Teller (FCHT) approximation. These spectra correlate well with the observed spectral features and have proven useful in resolving certain ambiguities in the assignment of the low-lying C 1s NEXAFS bands.
Corporate social responsibility and project management: towards a better understanding of their relationship
- Piotr Sliż
- Magdalena Popowska
- Julia Jarzyński
2022 Pełny tekst e-mentor
The main purpose of this article is to identify the fields of convergence, if any, between two management concepts and business practices, namely Corporate Social Responsibility (CSR) and Project Management (PM). To achieve the formulated goal, a systematic literature review (SLR), including bibliometric analysis, LOESS regression analysis, and text mining, was performed. This analysis allowed us to distinguish five categories corresponding to the distinctive, related research areas combining CSR and PM constructs. Within these categories we were able to identify the most important characteristics of the linkages between both concepts.
Correlation between Compressive Strength and Heat of Hydration of Cement Mortars with Siliceous Fly Ash
- Aleksandra Kuryłowicz-Cudowska
2022 Pełny tekst Minerals
This paper presents the results of calorimetric and strength tests of mortars with ordinary Portland cement and two substitution rates (10 and 20%) of cement by siliceous fly ash. The prepared samples were cured under isothermal conditions at four different temperatures: 23, 33, 43 and 53 °C. Heat of hydration was measured using an isothermal calorimeter dedicated to monitor the hydration process of cementitious composites such as paste, mortar and concrete. Thermal data were recorded continuously for 7 days, while compression tests were performed at 6 h and 1, 2, 5, 7 and 14 days of hardening. The studies proved that the amount of heat released correlates with the early-age strength of 50 mm mortar cubes. In the case of samples cured at 23 and 53 °C, a linear relationship between the heat of hydration and compressive strength was observed. The high value of the coefficient of determination (R2) allows one to estimate the mortar compressive strength after 7 and 14 days based on hydration heat tests conducted at standard temperature (23 °C), regardless of the percentage of siliceous fly ash. The increased curing temperatures do not guarantee a high correlation between compressive strength and the amount of heat released.