2020 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2020

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Comparing the permeability of human and porcine small intestinal mucus for particle transport studies
- Lukasz Krupa
- Balazs Bajka
- Robert Staroń
- Didier Dupont
- Harjinder Singh
- Krzysztof Gutkowski
- Adam Macierzanka
2020 Full text Scientific Reports
The gastrointestinal mucus layer represents the last barrier between ingested food or orally administered pharmaceuticals and the mucosal epithelium. This complex gel structure plays an important role in the process of small intestinal absorption. It provides protection against hazardous particles such as bacteria but allows the passage of nutrients and drug molecules towards the intestinal epithelium. In scientific research, mucus from animal sources is usually used to simulate difficult-to-obtain human small intestinal mucus for investigating the intramucus transport of drug delivery systems or food nanoparticles. However, there is a lack of evidence the human mucus can be reliably substituted by animal counterparts for human-relevant transport models. In this report, a procedure for collecting human mucus has been described. More importantly, the permeability characteristics of human and porcine small intestinal mucus secretions to sub-micron sized particles have been compared under simulated intestinal conditions. Negatively charged, 500 nm latex beads were used in multiple-particle tracking experiments to examine the heterogeneity and penetrability of mucus from different sources. Diffusion of the probe particles in adult human ileal mucus and adult pig jejunal and ileal mucus revealed no significant differences in microstructural organisation or microviscosity between the three mucus types (P > 0.05). In contrast to this interspecies similarity, the intraspecies comparison of particle diffusivity in the mucus obtained from adult pigs vs. 2-week old piglets showed better penetrability of the piglet mucus. The mean Stokes–Einstein viscosity of the piglet jejunal mucus was approx. two times lower than the viscosity of the pig jejunal mucus (P < 0.05). All mucus structures were also visualised by scanning electron microscopy. This work validates the use of porcine small intestinal mucus collected from fully-grown pigs for studying colloidal transport of sub-micron sized particles in mucus under conditions mimicking the adult human small intestinal environment.
Comparing traffic intensity estimates employing passive acoustic radar and microwave Doppler radar sensor
- Andrzej Czyżewski
2020 Journal of the Acoustical Society of America
The purpose of our applied research project is to develop an autonomous road sign with built-in radar devices of our design. In this paper, we show that it is possible to calibrate the acoustic vector sensor so that it can be used to measure traffic volume and count the vehicles involved in the traffic through the analysis of the noise emitted by them. Signals obtained from a Doppler radar are used as a reference source. Although the acoustical vector sensor (AVS), being the embodiment of acoustic radar, has a lower accuracy than Doppler radar in vehicle counting and cannot measure the vehicle speed with the same precision has certain advantages over the Doppler sensor. Namely, it does not emit any signals, it is not susceptible to electromagnetic interferences, and it allows for further analysis of audio signals, such as assessment of the road surface state (e.g., wet/dry). The acoustic radar employing AVS we developed is a new proposition of the acoustic method for road traffic monitoring. Our research also allowed a comparison of the efficiency of both methods, namely microwave and acoustic ones. In this paper, we also provide a short review of previous publications on the project.
Comparison of Cadmium Cd2+ and Lead Pb2+ Binding by Fe2O3@SiO2‐EDTA Nanoparticles – Binding Stability and Kinetic Studies
- Amanda Kulpa
- Jacek Ryl
- Grzegorz Skowierzak
- Adrian Koterwa
- Grzegorz Schroeder
- Tadeusz Ossowski
- Paweł Niedziałkowski
2020 Full text ELECTROANALYSIS
This study describes the synthesis and characterization of ethylenediaminetetraacetic acid (EDTA) functionalized magnetic nanoparticles of 20 nm in size – Fe3O4@SiO2‐EDTA – which were used as a novel magnetic adsorbent for Cd(II) and Pb(II) binding in aqueous medium. These nanoparticles were obtained in two‐stage synthesis: covering by tetraethyl orthosilicate and functionalization with EDTA derivatives. Nanoparticles were characterized using TEM, FT‐IR, and XPS methods. Metal ions were detected under optimized experimental conditions using Differential Pulse Anodic Stripping Voltammetry (DPASV) and Hanging Mercury Drop Electrode (HDME) techniques. We compared the ability of Fe3O4@SiO2‐EDTA to bind cadmium and lead in concentration of 553.9 μg L−1 and 647.5 μg L−1, respectively. Obtained results show that the adsorption rate of cadmium binding was very high. The equilibrium for Fe3O4@SiO2‐EDTA‐Cd(II) was reached within 19 min while for the Fe3O4@SiO2‐EDTA‐Pb(II) was reached within 25 minutes. About 2 mg of nanoparticles was enough to bind 87.5 % Cd(II) and 54.1 % Pb(II) content. In the next step the binding capacity of Fe3O4@SiO2‐EDTA nanoparticles was determined. Only 1.265 mg of Fe3O4@SiO2‐EDTA was enough to bind 96.14 % cadmium ions while 5.080 mg of nanoparticles bound 40.83 % lead ions. This phenomenon proves that the studied nanoparticles bind Cd(II) much better than Pb(II). The cadmium ions binding capacity of Fe3O4@SiO2‐EDTA nanoparticles decreased during storage in 0.5 M KCl solution. Two days of Fe3O4@SiO2‐EDTA storage in KCl solution caused the 32 % increase in the amount of nanoparticles required to bind 60 % of cadmium while eight‐days storage caused further increase to 328 %. The performed experiment confirmed that the storage of nanoparticles in solution without any surfactants reduced their binding capacity. The best binding capacity was observed for the nanoparticles prepared directly before the electrochemical measurements.
Comparison of near infrared spectroscopy (NIRS) and near-infrared transillumination-backscattering sounding (NIR-T/BSS) methods
- Agnieszka Gruszecka
- Marcin Gruszecki
- Patric J. Neary
- Jyotpal Singh
- Taylor Teckchandani
- Monika Waskow
- Magdalena Wszedybyl-Winklewska
- Wojciech Gumiński
- Andrzej F. Frydrychowski
- Jacek Rumiński
- Piotr Lass
- Gregory Kratzig
- Paweł J. Winklewski
2020 Full text Scientific Reports
The aim of the study was to compare simultaneously recorded a NIR-T/BSS and NIRS signals from healthy volunteers. NIR-T/BSS is a device which give an ability to non-invasively detect and monitor changes in the subarachnoid space width (SAS). Experiments were performed on a group of 30 healthy volunteers (28 males and 2 females, age 30.8 ± 13.4 years, BMI = 24.5 ± 2.3 kg/m2). We analysed recorded signals using analysis methods based on wavelet transform (WT) for the wide frequency range from 0.0095 to 2 Hz. Despite the fact that both devices use a similar radiation source both signals are distinct from each other. We found statistically significant differences for WT amplitude spectra between both signals. Additionally, we showed different relationships of both signals to blood pressure. Collectively, based on the present findings and those of previous studies, we can conclude that the combination of NIR-T/BSS or NIRS signals and time–frequency analysis opens new frontiers in science, and give possibility to understand and diagnosis of various neurodegenerative and ageing related diseases to improve diagnostic procedures and patient prognosis.
Comparison of sound of organ pipes in contemporary and historical instruments
- Marta Kalman
- Damian Koszewski
- Bartłomiej Mróz
2020
The aim of this research is to examine the differences in the timbre of organ pipes’ sound between a historical and a contemporary organ instrument. The historical instrument is the Oliwa organ from Gdansk, Poland, and the contemporary one is from Kartuzy, Poland. Recordings are made of single notes played by an open labial pipe that belongs to the Principal rank. The analyses and comparison of several sound features compatible with audio descriptors defined in MPEG-7 standard are performed in the MATLAB environment. The influence of the distance between the microphone and the sound source on sound features is also examined, in order to judge whether the comb filter appears in close distances from the sound source.
Comparison of the Physical and Sensory Properties of Hybrid Citrus Fruit Jaffa® Sweetie in Relation to the Parent Fruits
- Martyna Lubinska-Szczygeł
- Żaneta Polkowska
- Tomasz Dymerski
- Shela Gorinstein
2020 Full text MOLECULES
In the presented study, an overall Jaffa sweetie evaluation was made to find a correlation between Citrus grandis Osbeck × Citrus paradisi Macf. and its parent fruits’ (Citrus grandis Osbeck, Citrus paradisi Macf.) properties. Based on the sensory analysis, it was found that the taste and aroma of the new hybrid fruit are close to pummelo. By the use of chromatographic analysis, the selected monoterpenes present in the fruits were quantified. α-terpineol was typed as the main monoterpene compound in the headspace of sweetie and grapefruit, with the concentrations: 20.96 and 87.9 µg/g, respectively. In turn, γ-terpinene was chosen as the most important monoterpene determining the flavor of sweetie fruit. Based on two-dimensional gas chromatography (GC × GC-TOF-MS) and principal component analysis (PCA) of the data, several volatile compounds were associated with analyzed fruits’ aroma. Jaffa Sweetie is the hybrid fruit with sensory properties similar to pummelo with a higher content of monoterpenes, which improves its health benefits compared to the parent fruit. The research presents an instrumental method for assessing the aroma properties of the fruit as a reference method for sensory analysis, commonly used in the industry.
Comparison of two methods of sound extraction from guitar string video recordings
- Marta Stefaniak
- Andrzej Czyżewski
2020
A comparison of two sound extraction methods from guitar string video recordings is presented in the paper. A brief overview of highframe rate camera technology and possible applications are included. The method using the image analysis from two such cameras is presented. The cameras are placed at the angle of 90 degrees for recording the image in three planes. The results achieved with the setup proposed by ourselvesare comparedto the results of recording with a single highframe rate camera used for the Visual Microphone method developed by scientists from MIT. Spectrograms and signal spectra of recordings were compared and discussed, revealing that both methods of sound extraction from video brought the ability to reproduce sound, but with some distortions.Finally, the options for future experiments are considered.
Compensation of supply current harmonics, reactive power, and unbalanced load current balance in the closed-loop control of a shunt active power filter
- Agata Bielecka
- Daniel Wojciechowski
2020 Full text Zeszyty Naukowe Akademii Morskiej w Szczecinie
This paper presents the compensation tasks performed by a shunt active power filter, including compensation of harmonic currents, reactive power, and an unbalanced load current. The paper demonstrates novel control of the shunt active power filter in a closed-loop system. The control algorithm was verified by performing simulations and compared the simulated results with those obtained in an open-loop control system. All simulations were conducted in the PLECS program using a control algorithm written in C programming language.
Competencies of graduates as future labour market participants – preliminary study
- Małgorzata Gawrycka
- Justyna Kujawska
- Michał Tomasz Tomczak
2020 Full text Economic Research-Ekonomska Istrazivanja
The aim of article is to examine and compare the views of employers and future employees on the desirable competencies of the potential labour market participants. The applied research method is a combination of qualitative and quantitative methods – interviews conducted among recruiters (representing potential employers) and a survey of university graduates (future employees). The study shows that both the Polish graduates and the employers identify the deficits of professional competencies. The differences of opinions were related to their assessment of generic competencies, the deficits of which were pointed to by the interviewed recruiters, who described them at the same time as fundamental to obtaining the employment. Meanwhile, the graduates assessed their generic competencies as the highest. According to the recruiters, the future employees lack also practical experience. On the other hand, the employers believe that the graduates are not prepared to using the possessed theoretical knowledge in practice. It should be noted, however, that employers perceive a great potential for the development of graduate competencies, which, together with acquiring practical experience, will probably lead to the narrowing of the competence gap.
Complex Predictive Solution for Computerized Processes in Tire Industry
- Jan Piesik
- Kazimierz Kosmowski
2020 Full text
Following increasing market needs of productivity, cost reduction and safety requirements, computerized industry are faced to finding optimum between economic aspects of business and safety-related risk management. Modern factories equipped with computerized processes and extended diagnostic tools to support operator do not often use of all information’s which comes from the equipment. Some of the relations between the events are also omitted or neglected. Authors after analyzing the defects of modern production lines with batch production, noticed a correlation between the defects and the historical information registered by the supervisory system controlling the production process. The problem is that with the multitude of appearing information, they are not analyzed on an ongoing basis. This article presents a new approach to increase machinery reliability, safety and quality increase through predictive data analysis.
Comprehensive Evaluation of the Biological Properties of Surface-Modified Titanium Alloy Implants
- Piotr Piszczek
- Aleksandra Radtke
- Michalina Ehlert
- Tomasz Jędrzejewski
- Alicja Sznarkowska
- Beata Sadowska
- Michał Bartmański
- Yasar Kemal Erdogan
- Batur Ercan
- Waldemar Jędrzejczyk
2020 Full text Journal of Clinical Medicine
An increasing interest in the fabrication of implants made of titanium and its alloys results from their capacity to be integrated into the bone system. This integration is facilitated by different modifications of the implant surface. Here, we assessed the bioactivity of amorphous titania nanoporous and nanotubular coatings (TNTs), produced by electrochemical oxidation of Ti6Al4V orthopedic implants’ surface. The chemical composition and microstructure of TNT layers was analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). To increase their antimicrobial activity, TNT coatings were enriched with silver nanoparticles (AgNPs) with the chemical vapor deposition (CVD) method and tested against various bacterial and fungal strains for their ability to form a biofilm. The biointegrity and anti-inflammatory properties of these layers were assessed with the use of fibroblast, osteoblast, and macrophage cell lines. To assess and exclude potential genotoxicity issues of the fabricated systems, a mutation reversal test was performed (Ames Assay MPF, OECD TG 471), showing that none of the TNT coatings released mutagenic substances in long-term incubation experiments. The thorough analysis performed in this study indicates that the TNT5 and TNT5/AgNPs coatings (TNT5—the layer obtained upon applying a 5 V potential) present the most suitable physicochemical and biological properties for their potential use in the fabrication of implants for orthopedics. For this reason, their mechanical properties were measured to obtain full system characteristics.
Compressive Sensing Approach to Harmonics Detection in the Ship Electrical Network
- Beata Palczynska
- Romuald Maśnicki
- Janusz Mindykowski
2020 Full text SENSORS
The contribution of this paper is to show the opportunities for using the compressive sensing (CS) technique for detecting harmonics in a frequency sparse signal. The signal in a ship’s electrical network, polluted by harmonic distortions, can be modeled as a superposition of a small number of sinusoids and the discrete Fourier transform (DFT) basis forms its sparse domain. According to the theory of CS, a signal may be reconstructed from under-sampled incoherent linear measurements. This paper highlights the use of the discrete Radon transform (DRT) techniques in the CS scheme. In the reconstruction algorithm section, a fast algorithm based on the inverse DRT is presented, in which a few randomly sampled projections of the input signal are used to correctly reconstruct the original signal. However, DRT requires a very large set of measurements that can defeat the purpose of compressive data acquisition. To acquire the wideband data below the Nyquist frequency, the K-rank-order filter is applied in the sparse transform domain to extract the most significant components and accelerate the convergence of the solution. While most CS research efforts focus on random Gaussian measurements, the Bernoulli matrix with different values of the probability of ones is applied in the presented algorithm. Preliminary results of numerical simulation confirm the effectiveness of the algorithm used, but also indicate its limitations. A significant advantage of the proposed approach is the speed of analysis, which uses fast Fourier transform (FFT) and inverse FFT (IFFT) algorithms widely available in programming environments. Moreover, the data processing algorithm is quite simple, and therefore memory usage and burden of the data processing load are relatively low.
Computational Fluid Dynamics Simulation of Gas–Liquid Multiphase Flow in T-junction for CO2 Separation
- Sylwia Wrzesień
- Paweł Madejski
- Paweł Ziółkowski
2020 Prace Naukowe Wydziału Architektury Politechniki Wrocławskiej
The article presents the results of a computational fluid dynamics (CFD) analysis of gas-liquid multiphase flow. The simulation was conducted using CFD code and the Euler–Euler approach. The presented study relates to the non–reactive, steady-state, turbulent flow of water and carbon dioxide mixture in a 3D pipe. Separation phenomenon between phases is observed. The solution was obtained using a mixture model. Different values of carbon dioxide volume fraction were taken into account in the analysis of the results. The analysed cases were compared thanks to the obtained calculations results. The main purpose of the simulations was to show streamlines, velocity, pressure, and volume fraction distribution that could be useful in developing pipeline systems in many industrial applications, especially for CO2 separator.
Computationally-efficient design optimisation of antennas by accelerated gradient search with sensitivity and design change monitoring
- Anna Pietrenko-Dąbrowska
- Sławomir Kozieł
2020 Full text IET Microwaves Antennas & Propagation
Electromagnetic (EM) simulation tools are of primary importance in the design of contemporary antennas. The necessity of accurate performance evaluation of complex structures is a reason why the final tuning of antenna dimensions, aimed at improvement of electrical and field characteristics, needs to be based on EM analysis. Design automation is highly desirable and can be achieved by coupling EM solvers with numerical optimisation routines. Unfortunately, its computational overhead may be impractically high for conventional algorithms. This study proposes an efficient gradient search algorithm with numerical derivatives. The acceleration of the optimisation process is obtained by means of the two mechanisms developed to suppress some of finite-differentiation-based updates of the antenna response sensitivities that involve monitoring and quantifying the gradient changes as well as design relocation between the consecutive algorithm iterations. Both methods considerably reduce the need for finite differentiation, leading to significant computational savings. At the same time, excellent reliability and repeatability is maintained, which is demonstrated through statistics over multiple algorithm runs with random initial designs. The proposed approach is validated using a benchmark set of wideband antennas. The proposed algorithm is competitive to both the reference trust-region algorithm as well as its recently reported accelerated versions.
Computations of the least number of periodic points of smooth boundary-preserving self-maps of simply-connected manifolds
- Grzegorz Graff
- Jerzy Jezierski
- Adrian Myszkowski
2020 Topological Methods in Nonlinear Analysis
Let $r$ be an odd natural number, $M$ a compact simply-connected smooth manifold, $\dim M\geq 4$, such that its boundary $\partial M$ is also simply-connected. We consider $f$, a $C^1$ self-maps of $M$, preserving $\partial M$. In [G. Graff and J. Jezierski, Geom. Dedicata 187 (2017), 241-258] the smooth Nielsen type periodic number $D_r(f;M,\partial M)$ was defined and proved to be equal to the minimal number of $r$-periodic points for all maps preserving $\partial M$ and $C^1$-homotopic to $f$. In this paper we demonstrate a purely combinatorial method of calculation of the invariant and illustrate it in various cases.
Computed tomography indicators of cerebral microperfusion improve long term after carotid stenting in symptomatic patients
- Paweł J. Winklewski
- Mariusz Kaszubowski
- Grzegorz Halena
- Agnieszka Sabisz
- K Chojnicki
- Jaroslaw Dzierzanowski
- Maciej Piskunowicz
- N. Kurhaluk
- Edyta Szurowska
- Arkadiusz Szarmach
2020 Full text Acta Biochimica Polonica
OBJECTIVES: We tested the hypothesis that computed tomography (CT) perfusion markers of cerebral microcirculation would improve 36 months after internal carotid artery stenting for symptomatic carotid stenosis while results obtained 6-8 weeks after the stenting procedure would yield a predictive value. METHODS: We recruited consecutive eligible patients with >70% symptomatic carotid stenosis with a complete circle of Willis and normal vertebral arteries to the observational cohort study. We detected changes in the cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP) and permeability surface area-product (PS) before and after carotid stenting. We have also compared the absolute differences in the ipsilateral and contralateral CT perfusion markers before and after stenting. The search for regression models of "36 months after stenting" results was based on a stepwise analysis with bidirectional elimination method. RESULTS: A total of 34 patients completed the 36 months follow-up (15 females, mean age of 69.68±S.D. 7.61 years). At 36 months after stenting, the absolute values for CT perfusion markers had improved: CBF (ipsilateral: +7.76%, contralateral: +0.95%); CBV (ipsilateral: +5.13%, contralateral: +3.00%); MTT (ipsilateral: -12.90%; contralateral: -5.63%); TTP (ipsilateral: -2.10%, contralateral: -4.73%) and PS (ipsilateral: -35.21%, contralateral: -35.45%). MTT assessed 6-8 weeks after stenting predicted the MTT value 36 months after stenting (ipsilateral: R2=0.867, contralateral R2=0.688). CONCLUSIONS: We have demonstrated improvements in CT perfusion markers of cerebral microcirculation health that persist for at least 3 years after carotid artery stenting in symptomatic patients. MTT assessed 6-8 weeks after stenting yields a predictive value.
Concentration of Potentially Bioactive Compounds in Italian Extra Virgin Olive Oils from Various Sources by Using LC-MS and Multivariate Data Analysis
- Anna Różańska
- Marina Russo
- Francesco Cacciola
- Fabio Salafia
- Żaneta Polkowska
- Paola Dugo
- Luigi Mondello
2020 Full text Foods
High quality extra virgin olive oils represent an optimal source of nutraceuticals. The European Union (EU) is the world’s leading olive oil producer, with the Mediterranean region as the main contributor. This makes the EU the greatest exporter and consumer of olive oil in the world. However, small olive oil producers also contribute to olive oil production. Beneficial effects on human health of extra virgin olive oil are well known, and these can be correlated to the presence of vitamin E and phenols. Together with the origin of the olives, extraction technology can influence the chemical composition of extra virgin olive oil. The aim of this study was to investigate the concentration of potentially bioactive compounds in Italian extra virgin olive oils from various sources. For this purpose, vitamin E and phenolic fractions were characterized using high-performance liquid chromatography (HPLC) coupled with fluorescence, photodiode array and mass spectrometry detection in fifty samples of oil pressed at industrial plants and sixty-six samples of oil produced in low-scale mills. Multivariate statistical data analysis was used to determine the applicability of selected phenolic compounds as potential quality indicators of extra virgin olive oils.
Concept of a swirling diffuser in batch blending tanks
- Wojciech Artichowicz
- Jerzy Sawicki
2020 Full text CHINESE JOURNAL OF CHEMICAL ENGINEERING
The mixing of two or more components belongs to the category of the most common unit operations, both in technology and in nature. One particular version is homogenization (blending), the effectivity of which is strongly related to the blending time. Among many differentiated individual solutions of mixing systems used in blenders, one should distinguish the class of agitators with diffusers. An analysis of the character of the velocity field during a blending chamber operation leads to the conclusion that it would be of avail to outfit a straight diffuser with different setup of elbows. In consequence, the vertical direction of the inflowing fluid stream would be changed into the horizontal direction of the outflowing stream, which should intensify the blending process. The concept has been verified experimentally, making use of the tracer methodology. The obtained results confirmed the theoretical conclusion, that the blending time for the swirling-diffuser was shorter than for the classical straight one.
Concrete Compressive Strength Under Changing Environmental Conditions During Placement Processes
- Andrzej Ambroziak
- Patryk Ziółkowski
2020 Full text Materials
The technological process of concrete production consists of several parts, including concrete mix design, concrete mix production, transportation of fresh concrete mix to a construction site, placement in concrete framework, and curing. Proper execution of these steps provides good quality concrete. Some factors can disturb the technological process, mainly temperature and excessive precipitation. Changing daily temperature and rainfall during fabrication, transportation, and placement can shape not only the properties of the concrete mix but also the compressive strength of hardened concrete. In this paper, we tried to answer the question of how temperature and precipitation affect concrete production. The scope of this study was to determine the change of compressive strength of the hardened concrete in a specific period for selected concrete mix recipes, taking into account changing daily temperature and precipitation magnitude. The investigated concrete mixes concrete compressive strength beyond that of the concrete grade, termed "concrete superstrength.” This concrete post limiting behaviour of concrete is also discussed.
CONCRETE MIX DESIGN USING SIMPLE EQUATIONS
- Hakim Abdelgader
- Ramadan Suleiman
- Abdalla Adam
- Jamal Khatib
2020 Full text BAU Journal - Science and Technology
The behaviour of concrete, whether fresh or har dened, depends basically on the beha viour of its components and the r elationship between them, ther efore, obtaining a concr ete with cer tain pr operties depends fundamentally on the concr ete mix design. Concr ete mix design gener ally includes two main steps: 1-Selection of the main components suitable for the concr ete (cement, aggr egate, water , and additiv es); 2-Determination of mor e economical mix r atios t o fulfil the workability , str ength and efficiency requirements. Curr ently, ther e ar e many international methods locally appr oved for mix designs. The y are all r elated t o each other , the y giv e r elatively the same quantities of the mix components and the y are all capable of pr oviding a good concr ete mix. It is impor tant t o consider that these methods giv e approximate quantities which should be check ed b y experimental mix es in or der t o obtain r esults suitable for the r equirements of the local envir onment and local materials. The A CI and BS methods ar e the most commonly used. Both of these methods depend on gr aphs and standar d tables deriv ed fr om pr evious research experience and actual concr ete pr oduction as well as studies of the pr operties of the materials used. This paper illustr ates a new appr oach for concr ete mix design named as: “Double Coating Method”, which is curr ently used in some r esearch centers in the r epublic of P oland and was r ecently applied in the laboratories of the Civil Engineering Depar tments in the Univ ersities of T ripoli and Benghazi in Lib ya. This paper describes experiment in which 24 mixtur es wer e used t o assess the usefulness of this technique for problem of pr oportioning concr ete mixtur es in gener