Background: Small bowel adenocarcinoma is a rare malignant tumor, with the typical age of diagnosis being 60 years old. In the field of risk factors, we can distinguish, between genetic disorders, inflammatory bowel diseases, smoking, and alcohol abuse. Guidelines for the screening methods are very wide, hence it may be difficult to make the right diagnosis at the early stages of cancer. Additional difficulties can be caused by similarities to inflammatory processes in the gastrointestinal tract. Case report: We present a case of a 22-year-old male patient, with the symptoms of weight loss, stool retention, abdominal pain, and vomiting. The patient was initially misdiagnosed with inflammatory bowel disease and received the first dose of anti-inflammatory treatment. At that point, the diagnostic process and the workflow of medical care were delayed due to the COVID-19 pandemic. After receiving the x-ray and computed tomography, the obstruction of the ileum was found, and an urgent operation was performed. Tissue samples obtained during surgery revealed the proper diagnosis, a low-differentiated adenocarcinoma (G3) of the small intestine, stage T4Nx. Conclusion: Taking into consideration the patient’s condition, age, and symptoms, we should always think about the probable malignant process. Inflammatory diseases are known for increasing cancer risk and should always be the indication of this disease. The age of onset of the disease is very unusual, however, we must be aware of such cases in our clinical practice.

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An energy model of stabilized friction and wear is presented. Heating of a definite mass of surface material to the flash point, in consideration of the mass’s specific heat and wear, is assumed to provide the basis for thermal processes. An energy balance is presented in the form of a first law of thermodynamics formula for open systems. Two new magnitudes, referred to as complex systemic constants C and D, are developed and their physical meaning is interpreted. These complex systemic constants are subsequently employed to describe the tribological system. Among other magnitudes in the model, density of thermal dissipation and enthalpy flux, power density of mechanical dissipation, wear severity, and specific work of wear are described. Friction and wear testing results [Ciecieląg, 1994, “Energy Conditions of Metal Resistance to Tribological Wear,” Ph.D. thesis, Świętokrzyska Technical University, Kielce; Żurowski, 1996, “Energy Aspect of Increasing Wear-Resistance of Metals in the Process of Engineering Dry Friction,” Ph.D. thesis, Świętokrzyska Technical University, Kielce; Sadowski and Żurowski, 1992, “Thermodynamic Aspects of Metals' Wear-Resistance,” Tribology and Lubrication Engineering, 3, pp. 152–159] are employed to describe, in quantitative terms, selected tribological systems on the basis of the presented thermodynamic model. A method of determining the complex systemic constants C and D is developed. Specific work of wear, wear severity, probability of emergence of a flux of tribological wear products, and relation of worn mass to heated mass and flash temperature as functions of temperature are defined. This paper concludes with application, significance, and advantages of the complex systemic constants C and D, and phenomena arising in frictional contact between two metals.

Stationary processes of solid friction, heating and wear are analyzed in this paper on the basis of the first principle of thermodynamics. Analytical dependences between physical parameters of a tribological system have been determined. Densities of extensive quantity fluxes are referred to elementary surface and elementary time, which has permitted to include intensive quantities, especially temperature, in the model presented here. Although the discussion is restricted to the phenomenological approach, conclusions regarding some microscopic properties of the matter in the process of fragmentation are drawn directly from the laws of energy and mass conservation. Differences between specific heat of the starting material cp and of the debris produced cp′ are emphasized. The model of the friction process described by Maciąg, M. (2010, “Thermodynamic Model of the Metallic Friction Process,” ASME J. Tribol., 132(3), pp. 1–7) has been modified and a new method of evaluating cp′ is proposed. Results of standard friction and wear testing are used to describe selected tribological systems in quantitative terms based on the thermodynamic model discussed here (Sadowski, J., and Żurowski, W., 1992, “Thermodynamic Aspects of Metals' Wear-Resistance,” Tribol. Lubr. Eng., 3, pp. 152–159). Very high specific heat of tribological wear debris material is found at the moment of the material's production. To conclude, results of theoretical and experimental analysis are discussed and their interpretation is proposed. Applicability of the system magnitudes C and D to modeling of friction and wear is highlighted.

Friction, its concomitant thermal processes and wear are analyzed in a tribological system which is formed by a separate fragment of a friction pair element where mechanical energy is dissipated. A phenomenological (macroscopic) interpretation of stationary processes in a thermodynamic perspective is proposed. The tribological system is assumed to form an open thermodynamic system. An original model of a frictional source of heat is formulated. Balancing of mass and energy, especially the first law of thermodynamics, is employed in the discussion. Analytical dependences are found between work of friction, wear, heat of friction, heat carried away to the environment, and physical properties of the system material are determined. Variation of the system temperature and dimensions of the energy dissipation region are taken into consideration. The proposed model is illustrated by means of selected tests. Reference is made to an earlier, energetic interpretation of friction and its associated processes (Maciąg, M., 2010, “Thermodynamic Model of the Metallic Friction Process,” ASME J. Tribol., 132(3), pp. 1–7). A method of defining a tribological system and a new mechanism of frictional heating are some of the original elements. Introduction of these elements to equations of mass and energy balances resulted in new analytical dependences characterizing properties of a tribological system.