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This paper aims to review the recent progress in the research carried out by scientists worldwide regarding American Footballers' head injuries and head protective equipment, focusing on the role of computation methods, mainly finite element method application to American Football helmet design and testing as well as head injury biomechanics. The helmet technology has been constantly improved, and it is driven by market competition, medical records, coaches and athletes' self-awareness. With finite element analysis and computational resources development, it is possible to develop more accurate brain models to recreate American Footballers' head impacts. This method seems to be an excellent simulation tool to verify the helmet's ability to absorb energy and enable the researchers to have an insight into head kinematics and tissue-level injuries. The work is focused on head injuries in American Football as the sport becomes more popular across the globe. Additionally, a reference to the development and newest technology is presented. The review's proposed approach gathers studies presented within the last decade regarding the coupling of finite element brain models with helmets in standardised or on-field conditions. The synthesis of the existing state of the art may enhance the researchers to continue investigating the athlete's trauma and improve the protective gear technology to minimise head injuries. The authors presented numerous studies regarding concussions and the newest findings from the last decade, including Finite Element Head models (FEHm) with American Football helmet simulations. All the studies were searched through Google Scholar, Scopus and ResearchGate databases.

Accident reconstructions and numerical simulations are used to evaluate and improve protective systems. Virtual testing and numerical methods can assist in the improvement safety of vulnerable road...

The historical effects of land development on water management currently require a new approach, in many cases involving attempts at the restoration of the quasi-natural state. This is evident in reference to many regions in Poland, where the hydrographic network has been diminishing over the centuries, among others in favour of obtaining new agricultural land. Such activities overlap with natural processes causing transformations of the hydrosphere. The most serious problems currently include water deficits resulting from climate change and human activity. This paper employed archival bathymetric maps from the beginning of the 20th century for the determination of the scale of changes in the morphometric parameters of six lakes in western Poland. It was determined that over a period of more than a hundred years, the surface area (12.2%) and original volume of water bodies (13.9%) were largely reduced. This situation was caused by both natural (overgrowing and shallowing) and anthropogenic (change in water level) factors. The obtained information points to the need of an inventory of historical bathymetric maps of lakes. In combination with modern research, this will allow for the determination of changes in the water resources of lakes and, in a longer-term perspective, potential possibilities of their renaturisation. This knowledge is important in the context of the reconstruction of water resources in the territory of Poland, where their deficits are recorded increasingly frequently. It should also be emphasised that the restoration of the natural capacity of water retention in lakes is a more economical solution and, most importantly, it is not invasive for the environment.

The article presents the analysis of water level fluctuations in Lake Powidzkie in the years 1961–2015. The study shows a considerable decrease in mean water levels in the aforementioned multiannual period, averaging 9 cmꞏdecade−1. Such a situation is caused by natural as well as anthropogenic factors, co-determining water relations in the study area. The natural factors include the amount and distribution of precipitation, increase in air temperature and evaporation size, unfavourable relations between the lake and catchment or hydrogeological conditions. Anthropogenic factors particularly include long-term transformations of the natural environment in the region, currently associated with meliorations accompanying the nearby opencast brown coal mines and exploitation of groundwaters for municipal purposes. Water shortages occurring during dry periods were shown not to be compensated in the study area in humid years. This is particularly related to the regional lowering of the aquifer remaining in close relations with Lake Powidzkie. Counteracting the unfavourable hydrological situation is done through hydrotechnical infrastructure which partially limits water outflow from the lake through damming.

The human head is a complex multi-layered structure of hard and soft tissues, governed by complex materials laws and interactions. Computational models of the human head have been developed over the years, reaching high levels of detail, complexity, and precision. However, most of the attention has been devoted to the brain and other intracranial structures. The skull, despite playing a major role in direct head impacts, is often overlooked and simplified. In this work, a new skull model is developed for the authors&rsquo, head model, the YEAHM, based on the original outer geometry, but segmenting it with sutures, diplo&euml, and cortical bone, having variable thickness across different head sections and based on medical craniometric data. These structures are modeled with constitutive models that consider the non-linear behavior of skull bones and also the nature of their failure. Several validations are performed, comparing the simulation results with experimental results available in the literature at several levels: (i) local material validation, (ii) blunt trauma from direct impact against stationary skull, (iii) three impacts at different velocities simulating falls, (iv) blunt ballistic temporoparietal head impacts. Accelerations, impact forces, and fracture patterns are used to validate the skull model.

Lake water-level fluctuation is a complex and dynamic process, characterized by high stochasticity and nonlinearity, and difficult to model and forecast. In recent years, applications of machine learning (ML) models have yielded substantial progress in forecasting lake water-level fluctuations. This paper presents a comprehensive review of the applications of ML models for modeling water-level dynamics in lakes. Among the many existing ML models, seven popular ML model types are reviewed: (1) artificial neural network (ANN); (2) support vector machine (SVM); (3) artificial neuro-fuzzy inference system (ANFIS); (4) hybrid models, such as hybrid wavelet-artificial neural network (WA-ANN) model, hybrid wavelet-artificial neuro-fuzzy inference system (WA-ANFIS) model, and hybrid wavelet-support vector machine (WA-SVM) model; (5) evolutionary models, such as gene expression programming (GEP) and genetic programming (GP); (6) extreme learning machine (ELM); and (7) deep learning (DL). Model inputs, data split, model performance criteria, and model inter-comparison as well as the associated issues are discussed. The advantages and limitations of the established ML models are also discussed. Some specific directions for future research are also offered. This review provides a new vision for hydrologists and water resources planners for sustainable management of lakes.

Traumatic brain injury (TBI) is a major public health problem among children. The predominant causes of TBI in young children are motor vehicle accidents, firearm incidents, falls, and child abuse. The limitation of in vivo studies on the human brain has made the finite element modelling an important tool to study brain injury. Numerical models based on the finite element approach can provide valuable data on biomechanics of brain tissues and help explain many pathological conditions. This work reviews the existing numerical models of a child&rsquo, s head. However, the existing literature is very limited in reporting proper geometric representation of a small child's head. Therefore, an advanced 2-year-old child&rsquo, s head model, named aHEAD 2yo (aHEAD: advanced Head models for safety Enhancement And medical Development), has been developed, which advances the state-of-the-art. The model is one of the first published in the literature, which entirely consists of hexahedral elements for three-dimensional (3D) structures of the head, such as the cerebellum, skull, and cerebrum with detailed geometry of gyri and sulci. It includes cerebrospinal fluid as Smoothed Particle Hydrodynamics (SPH) and a detailed model of pressurized bringing veins. Moreover, the presented review of the literature showed that material models for children are now one of the major limitations. There is also no unambiguous opinion as to the use of separate materials for gray and white matter. Thus, this work examines the impact of various material models for the brain on the biomechanical response of the brain tissues during the mechanical loading described by Hardy et al. The study compares the inhomogeneous models with the separation of gray and white matter against the homogeneous models, i.e., without the gray/white matter separation. The developed model along with its verification aims to establish a further benchmark in finite element head modelling for children and can potentially provide new insights into injury mechanisms.

The territory of Poland includes more than 7,000 lakes (1 ha or larger) with a total surface area of 281,377.0 ha, translating into the lake density index of 0.90%. The territory of Poland is evidently divided into the northern part, including 95% of all lakes, and the southern part poor in lakes. The situation is related to the last Scandinavian glaciation. Due to this, in terms of genesis of basins, the majority of lakes are of postglacial character, where the occurrence and course of channel lakes is an indicator of the maximum range of the ice sheet. Lakes fulfil a number of important functions in the environment. The functions refer among others to the conditions of water circulation (suppressing extreme situations, both floods and draughts), affect the biodiversity, shape climatic conditions, and are of key importance for the development and functioning of many branches of the economy (agriculture, energy engineering, tourism), etc. Both environmental and anthropogenic effects resulting from the occurrence of lakes can soon be lost as a result of the progressing process of their disappearance. The situation is determined by the natural process of evolution, accelerated by human activity related to the regulation of water relations, and an increase in productivity of agriculture, and consequently an increase in supply of nitrogen and phosphorus compounds to water. It is estimated that from the moment of development of lakes until today, approximately 60% of the surface area of lakes disappeared.

Cork is a sustainable material with remarkable properties. In addition to its main application as wine stoppers, it has also been employed as a sound and thermal insulator in facades, building roofs, aeronautical applications, and, more recently, in impact energy absorption systems. In its natural form, cork is mainly used in wine stopper manufacturing, but for other applications, cork compounds are usually employed, which makes it possible to manufacture complex geometries with nearly isotropic behavior. In this work, an attempt was made to merge the desirable properties of two different cork materials (agglomerated and expanded black) into cork composite sandwich structures. These structures were tested according to impact conditions typically experienced by energy-absorbing liners used in personal safety devices. Additionally, the performance dependency on the working temperature was analyzed. The sole black, expanded cork (EC159) and agglomerated cork (AC199A and AC216) were tested in 500 J impacts. It was found that black cork was characterized by superior thermal stability, while expanded cork allowed absorbing high energies. In the second stage, the composites consisting of both tested materials were tested in 100 J impact scenarios. The combination of two materials of different properties enabled reduction of the peak force exerted on a helmet user&rsquo, s head during the impact by about 10% compared to agglomerated specimens. Additionally, it was proved that there was no influence of the glue used to join different cork types.

The article focusses on the accident reconstruction involving a pedestrian impacting to the bonnet of a sport vehicle. The corresponding simulation has recourse to the YEAHM as a high-detailed FE human head and brain model. Matching thereby the demands of European regulation EC78/2009, the impact scenario is designed in in order to assess the influence of the vehicle’s bonnet design, especially by regarding its stiffening structure underneath the bonnet outer layer in terms of estimated head and brain injuries. The interpretation of the results is based on the injury criteria of H-M-H brain stress and intracranial pressure (ICP). The observation of the results for the affected lobes of the brain revealed an influence of the bonnet design to the severity of the estimated brain injury. Furthermore, the contre-coup phenomenon was noticed in all simulations, which were performed by the authors. The results proved as well, that the finite element method could be used as well as an effective tool in the stage of preliminary part design. In a conclusion, the benefit of taking in this stage of part designing also possible injury severity in expected impact scenarios into account needs to be seen in the possibility of increasing passive safety of vulnerable road users.

The aim of this work was to assess the numerous approaches to structural and material modeling of brain tissue under dynamic loading conditions. The current technological improvements in material modeling have led to various approaches described in the literature. However, the methods used for the determination of the brain’s characteristics have not always been stated or clearly defined and material data are even more scattered. Thus, the research described in this paper explicitly underlines directions for the development of numerical brain models. An important element of this research is the development of a numerical model of the brain based on medical imaging methods. This approach allowed the authors to assess the changes in the mechanical and geometrical parameters of brain tissue caused by the impact of mechanical loads. The developed model was verified through comparison with experimental studies on post-mortem human subjects described in the literature, as well as through numerical tests. Based on the current research, the authors identified important aspects of the modeling of brain tissue that influence the assessment of the actual biomechanical response of the brain for dynamic analyses.

The purpose of this paper is to present the design process and subsequent numerical analysis calculations of a new roof-mounted bicycle carrier for vehicles. The bicycle carrier is mounted on the vehicles longitudinal bars. The designed construction is subjected to both static and dynamic load sets to check if it meets the requirements of ISO 11154 norm – which specifies the minimum safety requests for roof load carrier intended for mounting on the roof of passengers cars and light commercial vehicles with a maximum authorized total mass up to 3,5t. To fulfil the specifications associated to safety, standards and traffic laws test four different software packages were used: CATIA V5 and NACA airfoil generator for designing, Cambridge Engineering Selector for choosing the most suitable materials and Abaqus CAE for Finite Element Analysis.

The paper presents the analysis of tendencies in water level changes in 32 lakes in Poland during 1976–2010. Series of monthly, seasonal, and annual precipitation and air temperature for 9 meteorological stations were also studied. The trend analysis for all of the studied series of water levels in lakes showed high spatial and temporal variability. Series of annual water levels in the case of 6 lakes showed statistically significant increasing tendencies, and in 7 lakes, significant decreasing trends. Series of annual amplitudes in the majority of lakes (22) showed a decreasing trend, but they were statistically significant only in three cases. The tendencies for air temperature fluctuations are more statistically significant than precipitation. The key role in determining water level changes is played by local factors, particularly including human economic activity, obscuring the effect of natural factors on water level changes. The paper describes cases of changes in water levels in lakes under anthropopressure related to among others: agricultural irrigations, hydropower infrastructure, water transfers, navigation, or mining.

Due to global climate change and growing population, fresh water resources are becoming more vulnerable to pollution. Protecting fresh water resources, especially lakes and the associated environment, is one of the key challenges faced by policy makers and water managers. Lake water level is an important physical indicator of lakes, and its fluctuation may significantly impact lake ecosystems. Therefore, reliable forecasting of lake water level is vital for a proper assessment of the health of lake ecosystems and their management. In this study, two machine learning models, including feed forward neural network (FFNN) and Deep Learning (DL) technique, were used to predict monthly lake water level. The two models were employed for one month ahead forecasting of lake water level in 69 temperate lakes in Poland. The results show that both the FFNN and the DL models performed generally well for forecasting of lake water level of the 69 lakes, with only marginal differences. The results also indicate that the DL model did not show significant superiority over the traditional FFNN model; indeed, the FFNN model slightly outperformed the DL model for 33 of the 69 lakes. These results seem to suggest that traditional machine learning models may just be sufficient for forecasting of lake water level when they are properly trained. The outcomes of the present study have important implications for water level forecasting and water resources management of lakes, especially from the perspective of machine learning models and their complexities.

The article suggests and supports a simulation-based methodology for determining whether the dynamic strength of tire inflation restraining devices for tire inflation meet quality requirements and ensure operator safety during a potential tire explosion. Dynamic strength tests using an NM-600 safety shield and NK-0728 safety cage during a 29.5 R25X tire explosion at a pressure of 10 bar were presented as an example application of this methodology. The shield was subjected to destructive tests involving the use of a 2200 kg impactor, dropping it so that the minimum kinetic energy reached 20 kJ at the time of impact. Analyzed devices were constructed of S355 steel in accordance with EN 10025. The Cowper–Symonds model of material for strain rate phenomena was used in the calculations. Simulations of a 20 kJ ring impact against the cage were performed. The equivalent stress distribution was determined, and displacement contour lines for the maximum dynamic deformation value and plastic deformation were calculated. The plastic displacement obtained in numerical tests was equal to the permanent deformation recorded in the experimental test. Further, the simulations showed that the examined cage met the assumed strength criteria. The conducted tests confirmed the usefulness of the proposed methodology for assessing the dynamic strength of safety cages and shields for tire inflation. The full-scale, physical cage testing is difficult to implement because it requires placing a ring impacting the cage wall. This is a major boundary for closed cages, as considered in this publication. Thus, simulation-based methods are becoming a principal tool for safety assessment of tire inflation restraining devices.

The aim of the study was the analysis and enhancement of the passive safety of occupants in heavy good vehicles. The paper presents part of the research covering the design and development process of the suspension system improving the safety of the driver. The authors performed the numerical simulation of the crash-test of the conceptual design absorbing substantial part of the energy during the frontal collision of the heavy good vehicle. Special emphasis has been placed on developing the innovative and integral suspension system, enabling the translation of the cabin in the load box direction. The designed structure should maintain the survival space and structural integrity of the occupied area in the vehicle in case of the accident with the vehicle or the obstacle with similar weights and dimensions. The design and the computational model were performed using CAD/CAE systems. The geometry was developed in software for parametric modelling. Strength analysis of the prototype solution was carried out in a computing system using Finite Element Method (FEM).

This chapter presents a state-of-the-art review on finite element head modelling. In addition, it also includes a review about the parameters used as head injury criteria with finite element head models as well as their respective thresholds. The head injury criteria and the thresholds here summarised are the result of a great number publications available in the literature. These are the output from experimental and numerical research works. The injury thresholds presented in the latter were generally obtained through accident reconstructions with finite element head models. An overview of their evolution over the last decades and an assessment of the more complex ones are also presented.

A demolition robot is a multi-functional, remote-controlled machine, which is designed to be operated in severe work conditions such as high temperature, dust, radiation or noise. The publication presents the approach to enhance both the robustness of the machine—through Finite Element optimization—and the ergonomics of machine operator by implementing Human-Machine Interface (HMI). The combination of performed experimental and numerical research provided the information about the unfavorable effort and frequency states of the machine in the various operation processes. The use of advanced numerical simulations in pair with experimental tests were applied to estimate the dangerous states of the structure of the machine, as the designing stage enables to elaborate the HMI warning control system of the machine operation.

The article presents the modelling of a bus superstructure and its strength analysis and evaluates the requirements of Regulation No. 66 using the finite element method, with consideration of nonlinearity of materials and geometry. The analysis includes a strength test simulation in the form of a rollover test, which was performed in accordance with the requirements specified in Regulation No. 66 of UN/ECE and annex no. 3 of Regulation 66 of UN/ECE. The article presents the results of the dynamic analysis which uses the finite element method.

Tyre replacement and inflation is a common occurrence in the transportation, construction and mining industries, but in commercial, off-highway, or earth-moving vehicles, the rupture of an inflated tyre can cause serious or even fatal injuries to an operator. This paper highlights the consequences of a burst tyre based on a real case. The presented analytical approach is based upon an assumed adiabatic process and continuum mechanics using Bernoulli&rsquo, s flow equations. A numerical analysis of a tyre burst was performed using multibody and finite element methods to reconstruct the fatal accident. It was shown that tyre-blast injuries may lead to lethal head trauma and bodily injuries, since the potential energy stored in large, over-pressured tyres can exceed 1 MJ.

Structures which protect operators of heavy equipment are important elements found on different types of machines used in construction and mining. Their use is intended to protect the operators from injuries caused by vehicle rollovers. Such structures may be an integral part of the cabin or an external structure outside the cabin. This paper presents the methodology of conducting strength tests for protection structures which uses numerical methods.

The paper describes the evaluation of the pedestrian kinematics after a collision with a Sport Utility Vehicle (SUV) with a high bumper. To meet the goal two approaches were chosen. First, the authors carried out the SUV to pedestrian strike simulation using the certified, finite element lower legform impactor. The impact procedure mirrored the car vs. pedestrian collision described in the current Regulation (EC) 78/2009. However, it has been earlier noticed that the overall pedestrian kinematics response may vastly differ if the lower legform impactor hits a car with a high bumper. To evaluate this, an ellipsoid, standing Hybrid III dummy model was also investigated. Subsequent tests of the dummy model, impacted by the high-bonnet vehicle, confirmed that the stand-alone subsystem test with impactors leads to inaccurate assessment of the actual, after impact, pedestrian kinematics.

According to the strategy of Total Quality Management (TQM) [7] effective quality assurance of mechanical objects is maintained by means of permanent monitoring processes carried out in the cycle of product formation. The quality assessment of processes and the optimization of their crucial elements are the necessary condition for the improvement of efficiency and achievement of high level of customer satisfaction [15]. So far most of the techniques used for the process improvement are adopted to Lean Six Sigma methodology [1, 2, 11, 12, 17]. Achieving the quality on the level of 6 sigma is a primary goal of applying this methodology. Opinions exist that Lean Six Sigma should be implemented in the large number of areas of the life, and its effects (essential improvement in financial results through the reduction of poor quality costs) are hard to overrate. High effectiveness of every single process that is possible to achieve by applying the Lean Six Sigma strategy, became a source of inspiration for the study of Design For Six Sigma (DFSS) [4, 8, 12, 13], with purpose to improve object quality by implementing the innovation in product development.

Glacial lakes undergo evolution with their disappearance as the last stage of it. Natural processes which determine the rate of lake shrinking occur rather slowly but they have been increasing their speed with the stronger human interference in the environment. The most drastic effect of anthropogenic pressure exerted on lake ecosystems is their complete disappearance caused by reclamation works. One can state that this process is a change of rapid character (a lake can disappear within a few years or several decades, in extreme cases even within one year). Drainage works are particularly unfavourable in areas with a shortage of water supplies, where rapid lake shallowing reduces water retention even more. A considerable part of Poland suffers from water supply deficiency. Therefore, draining of lakes should be considered as an adverse operation. This study discusses the examples of eleven lakes located in Poland and subjected to reclamation works. Analyses of those cases lead us to the conclusion that drainage aiming to broaden agricultural areas has not always been proper.

Changes in water resources in selected lakes in the middle and lower catchment of the River WartaLakes play a very important function in water retention, particularly in areas with strong water deficiency. Water resources in lakes determine the possibility of using them for different purposes, e.g. economic development (irrigation or drinking water, water supply for industry). With ongoing processes causing a reduction in lake capacity (shrinking and shallowing), it is necessary to investigate the scale and rate of decreasing lake resources, in terms of the economic and natural consequences of this process. The aim of the study was to test changes in water resources in lakes situated in the middle and lower River Warta catchment. Special attention was paid to lakes characterised by reduced water resources in order to identify factors contributing to this phenomenon. Our current studies of 127 lakes showed a 10% decrease in water resources over 50 years (1910-1960) in the analysed part of the catchment. Our results indicated that the predominant process causing the disappearance of lakes is shallowing. This factor should be monitored carefully to avoid further lake loss.

High-energy experiments like Atlas, Alice, CMS or LHCb at the LHC accelerator at CERN will be performed in very harsh conditions for electronic equipment. High radiation level in the experimental halls causes that commonly available electronic devices do not work properly. A specialized optical transmitter--GOL (Gigabit Optical Link) has been designed at CERN to meet the radiation environment requirements. The design goal was to supply device resistant to high radiation, fast, and being able to transmit data through optical links. Transmitter was designed considering two important characteristics of its work environment: high radiation level and gigabit transmission speed. Proper internal structure of GOL chip allows to minimize single event upsets (SEU) caused by ionizing radiation. Unfortunately, the design does not elimiate SEU completely. This paper presents testing system for the GOL. Its main purpose is testing new prototypes of optical fiber gigabit transmission systems using GOL transmitter and commercial receiver components. The system will be implemented in the CMS experiment for control purposes. It will monitor optical link and transmission quality in the RPC detector. System consits of hardware layer and software layer. Hardware layer, based on Latera FPGA programmable devices. Software has been developed using C++ environment integrated with VME controller hardware.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Car-to-pedestrian front impacts have been well described in the papers. However, there is still insufficient data measuring the performance of new type of Frontal Protection Systems (FPS) fitted on Sport Utility Vehicles (SUVs). Therefore, the aim of the studies was to validate the method of the FPS design, complying with the European Commission Regulations. The complete numerical model of the vehicle front with FPS was created and then subjected to a precise pedestrian impactor subtest. The physical experiment results proved good conformity with the outcomes from numerical simulations. Hence, the design of the presented FPS design was a base for legal process such as European Union homologation.