Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 6
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

The expected demand for hard coal intended for the households will progressively be decreasing. This is directly related to the introduced anti-smog resolutions, as well as the growing level of environmental awareness. However, it should be noted, that the use of the modern home heating boilers will result in an increase in the demand for medium coal sizes. The shortfall of this type of coal is already observed on the market. Therefore, its import is necessary. One of the solutions to increase the supply of the medium coal sizes is the production of coal briquettes. Moreover, their use will consequently lead to reduced emissions.

The paper presents a comparison of emissions from the combustion of coal briquettes and hard coal in home heating boilers. The briquettes were characterized by significantly lower emissions than hard coal (by 52% on average). The particulate matter emissions were lower by 70%. This may significantly contribute to improving air quality in Poland and in addition, limit the occurrence of smog. The possibility of further emission reduction by using low-emission fuels as briquette components was presented. The average relative emission reduction compared to hard coal for the analyzed fuels was estimated as follows: 62% for coal char, 57% for coke, 51% for charcoal/biocarbon, 49% for anthracite, 45% for torrefied biomass, and 33% for peat.

Furthermore, the issue of the mercury content in the analyzed fuels was discussed. The lowest mercury content was found in biomass fuels, in particular biomass after thermal treatment (torrefied biomass, biocarbon, and charcoal). Fuels produced from hard coal in the pyrolysis process (coal char and coke) were characterized by very low mercury content as well.

Go to article

Authors and Affiliations

Tadeusz Dziok
Krystian Penkała
Download PDF Download RIS Download Bibtex

Abstract

This paper focuses on the global practical Mittag-Leffler feedback stabilization problem for a class of uncertain fractional-order systems. This class of systems is a larger class of nonlinearities than the Lipschitz ones. Based on the quasi-one-sided Lipschitz condition, firstly, we provide sufficient conditions for the practical observer design. Then, we exhibit that practical Mittag-Leffler stability of the closed loop system with a linear, state feedback is attained. Finally, a separation principle is established and we prove that the closed loop system is practical Mittag-Leffler stable.
Go to article

Authors and Affiliations

Imed Basdouri
1
ORCID: ORCID
Souad Kasmi
2
Jean Lerbet
3

  1. Gafsa University, Faculty of Sciences of Gafsa, Department of Mathematics, Zarroug Gafsa 2112 Tunisia
  2. Sfax University, Faculty of Sciences of Sfax, Department of Mathematics, BP 1171 Sfax 3000 Tunisia
  3. Laboratoire de Mathématiques et de Modélisation d’Evry, Univ d’Evry, Université Paris Saclay, France
Download PDF Download RIS Download Bibtex

Abstract

The paper discusses the principles of the Critical Shear Crack Theory (CSCT) in terms of the punching shear analysis of flat slabs made from lightweight aggregate concretes. The basic assumptions of the CSCT were discussed, explaining the differences with regard to the calculation of ordinary concrete flat slabs, relating mainly to the adopted failure criterion associated with ultimate slab rotation. Taking into account the observations and conclusions from the previous experimental investigations, it was confirmed, that contribution of lightweight aggregate particles in the aggregate interlock effect should be ignored, due to possibility of aggregate breaking. However, the analysis of the profile of failure surface confirmed, that particles of the natural fine aggregate increase the roughness of the surface and should be included by formulating failure criterion for LWAC slabs.
The theoretical load-rotation relationships were compared with the results of measurements, confirming good agreement in most cases. The theoretical ultimate rotations were lower on average by about 11% than the experimental ones. The analysis of 57 results of the experimental investigations on punching shear of LWAC slabs made from various types of artificial aggregates showed a very good agreement with predictions of the CSCT. The obtained ratio of the experimental to theoretical load was 1.06 with a coefficient of variation of 9.1%. The performed parametric study demonstrated a low sensitivity of the correctness of the CSCT predictions to a change in a fairly wide range of parameters such as: the longitudinal reinforcement ratio, concrete compressive strength and concrete density.
Go to article

Authors and Affiliations

Michał Gołdyn
1
ORCID: ORCID

  1. Lodz University of Technology, Department of Concrete Structures, al. Politechniki 6, 93-590 Łódz, Poland
Download PDF Download RIS Download Bibtex

Abstract

I n t r o d u c t i o n: A high neutrophil-to-lymphocyte ratio (NLR) has been reported to be a strong biomarker of inflammation.

A i m: We sought to evaluate the impact of NLR on long-term all-cause and cardio-vascular (CV) mortality in hemodialysis (HD) patients.

Ma t e r i a l a n d Me t h o d s: A total of 84 chronic kidney disease (CKD) stage 5 patients with 54 of them on HD, with a median age of 61.5 (51.3–74.8) years were enrolled. The association between NLR and clinical biomarkers was investigated. Multivariable Cox regression analysis was used to find significant predictors of all-cause and CV mortality at follow-up.

R e s u l t s: The median NLR (interquartile range) was 3.0 (2.1–4.1). Patients with NLR ≥3.9 (the highest tertile) had higher five-year all-cause mortality then remaining patients (53.6% vs. 30.4%; p = 0.039). On the contrary, only a trend towards increased CV mortality was observed (25.0% vs. 42.9%; p = 0.10). NLR ≥3.9 was a significant predictor of all-cause mortality at five years [hazard ratio (95%CI): 2.23 (1.10– 4.50); p = 0.025] in Cox regression model adjusted for age, gender, and diabetes status. Similarly, while using NLR as continuous variable a significant association between NLR and all-cause mortality was confirmed even after adjustment for covariates [hazard ratio per 1 unit increase (95%CI): 1.26 (1.06–1.51); p = 0.009] with the area under the receiver operating characteristic (ROC) curve of 0.64. Correlations between NLR and WBC, concentration of fibrinogen, albumin were observed.

C o n c l u s i o n s: Asymptomatic inflammation measured by NLR showed an association with long-term all-cause mortality in stage 5 CKD patients, even while white blood cell count was in the normal range.

Go to article

Authors and Affiliations

Karolina Woziwodzka
Artur Dziewierz
Magdalena Pawica
Agnieszka Panek
Marcin Krzanowski
Paulina Gołasa
Paweł Latacz
Magdalena Burkat
Marek Kuźniewski
Katarzyna Krzanowska
Download PDF Download RIS Download Bibtex

Abstract

Authors, mostly specialists on rehabilitation and orthopedic surgery prove that arthrofibrosis is a commonly overlooked phenomenon, which may lead to serious limitation in the range of movement, leading to limitation in patients quality of functioning. The main goal of this article is to emphasize the importance of understanding a such complex condition. Non typical patomechanism, lack of biomarkers dedicated to this dysfunction and general lack of under-standing in this pathology causes that risk factors and the most effective strategies remain vastly unknown. Pathophysiology of the arthrofibrosis in the joints is definitely multifactorial, but intense production of collagen seems to be the main factor. Most modern pharmacological methods concentrate on the regula-tion of collagen fiber production and reducing the inflammation. Inflammation from joint contractures stimulates the proliferation of activated cells that results in the production of extracellular matrix macromolecules to form fibrotic tissue that is deposited into the capsule, thereby resulting in fibrosis.
Lack of unified classification scale is caused by relatively high variation of the functions fulfilled by particular joints and each treatment plan should be constructed individually. Quality of surgical treatment and physical therapy play a major role in both prevention and treatment of such complex condition as arthrofibrosis.
Both iatrogenic mistakes and overly aggressive manual therapy are some of main factors increasing the risk of this pathological condition. Introducing properly conducted physical therapy treatment in the early stage is crucial to main the range of movement and preventing this significant problem.
Go to article

Authors and Affiliations

Andrzej Walocha
1
Bartosz Rutowicz
2
Wojciech Przybycień
2
Michał Zarzecki
2
Michał Kłosiński
2
Paweł Depukat
2
Bernard Solewski
2
Ewa Mizia
2
Anna Gil
2
Ewa Walocha
3

  1. Boom Boxing Studio, Kraków, Poland
  2. Department of Anatomy, Jagiellonian University Medical College, Kraków, Poland
  3. Laboratory of Nursing Theory and Fundamentals, Institute of Nursing and Midwifery, Faculty of Health Sciences, Jagiellonian University Medical College, Kraków, Poland
Download PDF Download RIS Download Bibtex

Abstract

In the austral summer of 1977/78 phytoplankton populations in Ezcurra Inlet, Admiralty Bay, reached maximum abundance at the end of February; two smaller peaks of growth occurred in January. Flagellates and "monads" were dominant in the plankton, except two days in December, when diatoms were prevalent. Thalassiosira untarctica and a few species of the genera Nilzschia and Chaeloceros were the major diatoms during the summer. Several other diatoms. Corethron criophilum. Eucampia bulaustium. and Rhizosolenia spp. together with the all-summer dominants, contributed to the diatom peak in December, following the breaking of ice. Algal peaks always followed periods of calm days and stable atmospheric pressure; the increased stability of the water column at such times appears to be the factor determining the onset of the periods of phytoplankton maxima. Decline of algal peaks could be largely attributed to grazing by Euphausia superba and E. crystallorophias.

Go to article

Authors and Affiliations

Elżbieta E. Kopczyńska

This page uses 'cookies'. Learn more