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Wyświetlanie 1-15 z 417
Tytuł:
Investigation on the particle size and shape of iron ore pellet feed using ball mill and HPGR grinding methods
Autorzy:
Abazarpoor, A.
Halali, M.
Powiązania:
https://bibliotekanauki.pl/articles/109944.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
HPGR
ball mill
particle size
particle shape
image analysis
SEM
Opis:
An effect of a grinding method, that is ball mill and high pressure grinding rolls (HPGR), on the particle size, specific surface area and particle shape of an iron ore concentrate was studied. The particle size distribution was meticulously examined by sieve, laser and image analyses. To measure the specific surface area of particles, Brunauer-Emmett-Teller (BET) and Blaine methods were used. It was found that for samples having equal Blaine specific surface areas numbers, the amount of fine particles produced in HPGR was higher than that produced in a ball mill. A higher surface area was observed from HPGR treatment in comparison to ball mill grinding, provided by a higher porosity, cracks, roughness and new surfaces. A shape factor of particles was determined using the circularity, roughness, and aspect ratio. It was also observed that HPGR produced particles that were more elongated, less circular and rougher than those processed by the ball mill.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 908-919
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved photoresponse of porous silicon photodetectors by embedding CdS nanoparticles
Autorzy:
Abd, Ahmed N.
Powiązania:
https://bibliotekanauki.pl/articles/1193949.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CdS
Nanoparticles
PSi
Photodetector
SEM
XRD
Opis:
In this research, the nanocrystalline porous silicon (PSi) films are prepared by electrochemical etching of p types silicon wafers with 15 mA/cm2 etching current densities and 15 min etching time on the formation nanosized pore array. PSi was characterized by the measurement of XRD, FTIR spectroscopy and atomic force microscopy properties (AFM). We have estimated crystallites size from X-Ray diffraction about nanoscale for PSi and Atomic Force microscopy confirms the nanometric size Chemical fictionalization during the electrochemical etching show on the surface chemical composition of PSi. The atomic force microscopy investigation shows the rough silicon surface. Also, it is reported the preparation of colloidal CdS nanoparticles NPs prepared by laser ablation in liquid (LAL) technique by irradiating with a Nd:YAG laser pulses CdS target immersed in methanol and varying the laser fluence 1.32 J/cm2. The structural, morphological and optical of CdS NPs has been studied. XRD measurement disclosed that the CdS NPs were of wurtzite hexagonal crystal structure. Transmission electron microscopy (TEM) investigation revealed that the synthesized CdS particles are spherical and have an average particle size in the range of (25 nm). AFM investigations showed that the produced CdS particles have ball-shape with good disposability. The energy band gap of CdS NPs prepared with 1.32 J/cm2 laser fluence has been determined from optical properties and found to be in the range (2.9 eV). Optical constants of CdS NPs were determined from transmittance and reflectance spectra.The effect of CdS NPs diffusion on properties of PSi Photodetector have reported which reveals that improving in (Al/PSi/Si/Al). The results show that a linear relationship between 1/C2 and reverse bias voltage was obtained. The built-in potential have values depending on the etching time current density and laser flunce. Al/CdSe/PSi/Si/Al photodetector hetrojunction have two peaks of response located at 415 nm and (700 -800nm) with max sensitivity 0.6 A/W. The maximum specific detectivity is 6.8×〖10〗^12 cm•〖Hz〗^(1/2) 〖•W〗^(-1) at 770 nm wavelength.
Źródło:
World Scientific News; 2015, 19; 32-49
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the Chemical Unhairing Process on Pulled Wool Characteristics
Autorzy:
Abdellaoui, Olfa
Harizi, Taoufik
Msahli, Slah
Powiązania:
https://bibliotekanauki.pl/articles/2171990.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
ATR-FTIR
red face Barbary sheep
sheep breed
chemical unhairing process
pulled wool
SEM
scanning electron microscopy
X-ray
Opis:
Textile research is being driven to find sustainable materials as an alternative to raw fibers. In fact, reusing fibrous waste, as a byproduct, is one of the most important environmental challenges that confront the world. This research focused on studying pulled wool fibers as a natural fiber to reduce environmental loading. There are large amounts of residual pulled wool fibers that can be recycled and valorised. Therefore, raw and pulled wool fibers were characterized and compared. Scanning Electron Micrographs (SEM) results show that on the pulled wool fiber, the surface became rougher and the scales appear affected and less dense. Based on the X-ray diffraction (XRD) results, the crystallinity of the pulled fiber decreased lightly. Attenuated Total Reflectance-Fourier Transform Infra Red (ATR-FTIR) spectroscopy analyzes presented some changes in chemical composition. A High-Performance Liquid Chromatography (HPLC) test showed an increase in the amount of cystic acids. The pulled wool fiber indicates that it might have damaged some crosslinks of macromolecular chains in the fiber. Thus, physical, chemical and mechanical properties are affected during the chemical unhairing process. This research purpose was to increase the potential for better value of pulled wool as it presents the natural fiber most used in several applications.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 3 (151); 70--78
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Biodegrability of Degradable/Biodegradable Plastic Material in Controlled Composting Environment
Autorzy:
Adamcová, D.
Vaverková, M. D.
Mašíček, T.
Břoušková, E.
Powiązania:
https://bibliotekanauki.pl/articles/124729.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
degradation
controlled environment
thermogravimetrical analysis
SEM photographs
Opis:
We have obtained eight degradable/biodegradable materials based on starch (certified compostable), sample 4–7, HDPE mixed with totally degradable plastic additive (TDPA), sample 2 and polyethylene with the addition of pro-oxidant additive (d2w), sample 1. Composition of sample 3 has not been reported. The materials have been tested as to the rate and character of their degradability/biodegradability in controlled composting conditions. Experiment explored also the effect of degradation/biodegradation of plastic bags on compost quality. The material of the original samples was subjected to assessment using the Nicolet 6700 FT-IR spectrometer, the outcome thereof was obtaining infrared spectra of the samples. For further specification the original samples were tested using the thermogravimetrical analysis. The texture of the foils at different stages of degradation is presented in the Scanning Electron Microscope (SEM) photographs. Plastic bags certified as compostable have degraded in laboratory conditions and their degradation had no impact on the quality and features of compost. Selected samples (4, 6) showed significant erosion on surface when subjected to the SEM analysis. Samples labeled (by their producers) as 100% degradable (samples 1, 2, 3) did not show any visual signs of degradation and the process of degradation had no impact on the quality and features of compost. Only one of the samples (sample 1) showed certain erosion of surface when submitted for the SEM analysis.
Źródło:
Journal of Ecological Engineering; 2016, 17, 4; 1-10
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nieniszczące badania struktury materiałów włóknisto-cementowych z użyciem elektronowego mikroskopu skaningowego
Non-destructive tests of fibre-cement materials structure with the use of scanning electron microscope
Autorzy:
Adamczak-Bugno, A.
Gorzelańczyk, T.
Krampikowska, A.
Szymków, M.
Powiązania:
https://bibliotekanauki.pl/articles/107746.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
badania nieniszczące
płyty włóknisto-cementowe
SEM
non-destructive testing
fiber-cement board
Opis:
W artykule przedstawiono propozycję zastosowania do badania płyt włóknisto-cementowych nieniszczącą metodę mikroskopową z wykorzystaniem elektronowego mikroskopu skaningowego (SE M) z analizatorem EDS. Badaniom poddano 2 rodzaje płyt włóknisto-cementowych poddanych różnym czynnikom środowiskowym (zawilgoceniu, zamrażaniu-rozmrażaniu) oraz czynnikom wyjątkowym (wypalenia w temperaturze 230°C oraz podpalaniu przez 5 i 10 minut). Uzyskano ciekawe rezultaty badań, które pozwoliły zaobserwować zmiany zachodzące w mikrostrukturze badanych płyt pod wpływem różnych czynników.
The article presents the proposal for the application of non-destructive microscope method with the use of scanning electron microscope (SE M) with EDS analyzer in fibre-cement boards tests. The tests were conducted on 2 types of fibre-cement boards that underwent various environmental factors (dampness, freezing-thawing) and unusual factors (burning out in the temperature of 230° and setting on fire for 5 and 10 minutes). Interesting results were obtained and they allowed to observe the changes that took place in the microstructure of the tested boards under the influence of various factors.
Źródło:
Badania Nieniszczące i Diagnostyka; 2017, 3; 20-23
2451-4462
2543-7755
Pojawia się w:
Badania Nieniszczące i Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of traffic rule violations among bike riders. A structural equation model
Autorzy:
Adhikari, Biranchi Narayan
Behera, Ajay Kumar
Mahapatra, Rabindra Narayan
Das, Harish Chandra
Powiązania:
https://bibliotekanauki.pl/articles/2175844.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
traffic rules violation
SEM
bike rider safety
attribute
Opis:
Bikes are becoming an increasingly popular and reliable mode of transportation in developing countries because of their efficiency and ability to navigate through rough terrain and narrow roadways. Bikes are more vulnerable to road accidents and their riders’ safety is the main concern at present days. Hence, it is essential to reduce the possibility of accidents caused by bike riders. The main reason for bike accidents is bike rider behaviours in the form of traffic rules violations. The paper’s main aim is to categorize the importance of seven attributes on traffic rules violations, including bike rider behaviours, road features, ambient conditions, driving skills, type of license, bike age/tenure and riding without a safety device (helmet). Bike riders’ violations that can lead to an accident and the impact of attributes have been analyzed using the structural equation modelling (SEM) technique. To analyze these attributes, 450 bike riders have been interviewed in Bhubaneswar, India. It has been concluded that bike rider behaviours are the most significant attribute of violations. Since most bike riders are young, with low income and education, paying more attention to their training and education before issuing a driving license is necessary. In addition, those who do not use safety devices (helmets) are more susceptible to committing violations. This relates to the lack of enough control and enforcement in developing cities. Also, it shows that the current traffic fines for not using safety devices (helmets) are not enforced enough. Finally, considering this research’s outcomes can help minimize traffic rules violations among bike riders, which is a step towards safer roads.
Źródło:
Operations Research and Decisions; 2022, 32, 3; 16--31
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
ES-QUAL model and customer satisfaction in online banking: evidence from multivariate analysis techniques
Autorzy:
Ahmed, Rizwan Raheem
Romeika, Giedrius
Kauliene, Raimonda
Streimikis, Justas
Dapkus, Rimantas
Powiązania:
https://bibliotekanauki.pl/articles/19233490.pdf
Data publikacji:
2020
Wydawca:
Instytut Badań Gospodarczych
Tematy:
ES-QUAL model
customer satisfaction
financial performance
Internet banking
normal theory method
bootstrapping method
Structural Equation Modeling
SEM
Opis:
Research background: The commercial banks are adopting online services for their transactions to stay competitive and fulfill the customers' needs. There is a dire need to satisfy online customers in a competitive environment. Thus, this paper employed the ES-QUAL model and two mediating variables and outlined the recommendations to the management of the online banking industry to develop effective strategies. Purpose of the article: The undertaken research aimed to examine the electronic banking service quality and customer satisfaction. For this purpose, we employed the ES-QUAL model and examined the direct impact of ES-QUAL dimensions and customer's satisfaction. The secondary task of this paper is to investigate the mediation effect of customer's trust and the perceived value in an association between the ES-QUAL model and customer satisfaction. Finally, we examine and check whether customer satisfaction translates into the business performance of commercial banks or not. Methods: To achieve the overall goal of this research, SEM-based multivariate approach has been used, including confirmatory factor analysis, exploratory factor analysis, and multiple approaches (normal theory, and bootstrapping) to examine the moderation between the exogenous and endogenous variables. For the validation of hypotheses and results, a financial analysis has been performed simultaneously with the primary analysis. The research is done for a sample of 910 respondents of the account holders of five top commercial banks of Pakistan. Findings & Value added: The outcomes of the direct investigation revealed an affirmative, and potent impact of ES-QUAL dimensions on customer's satisfaction. The outcomes of the indirect relationship exhibited that the perceived value and trust mediate ES-QUAL dimensions and customer satisfaction. The secondary data of selected five commercial banks and ratios analysis validated the results of the ES-QUAL model, and it is concluded that the results are linear with the outcomes of customers' satisfaction of primary analysis.
Źródło:
Oeconomia Copernicana; 2020, 11, 1; 59-93
2083-1277
Pojawia się w:
Oeconomia Copernicana
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mycoremediation of Heavy Metals Contaminated Soil by Using Indigenous Metallotolerant Fungi
Autorzy:
Akram, Muhammad Bilal
Khan, Ibrar
Ur Rehman, Mujaddad
Sarwar, Abid
Ullah, Najeeb
ur Rahman, Shafiq
Aziz, Tariq
Alharbi, Metab
Alshammari, Abdulrahman
Alasmari, Abdullah F.
Powiązania:
https://bibliotekanauki.pl/articles/27315654.pdf
Data publikacji:
2023
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Mycoremediation
Heavy Metals Contaminated Soil
Korangi Industrial Estate
FTIR
Fourier Transform Infrared Spectroscopy
SEM
Scanning Electron Microscope
Opis:
The present study was aimed to identify the indigenous fungal strains which could possibly be applied to the bioremediation of heavy metal-contaminated soil. The contaminated soil samples of Korangi Industrial Estate Karachi were found to have total concentration of Cu 1.044 mgL1 , and Pb 0.631 mgL–1. A total of eight indigenous strains of the fungus were isolated and screened for bioremediation capacity from heavy metals-contaminated soil. For the bioremediation of Lead (Pb) these same indigenous eight fungal strains were used for biological remediation. All the fungal isolated with enhanced bioremediation capability were through phenotypic and genotypical characterization. The topology of the phylograms established that the fungal isolates used in this study were allocated to: K1 (Penicillium notatum), K2 (Aspergillus parasiticus), K3 (Aspergillus fumigatus), K4 (Aspergillus flavus), K5 (Aspergillus terries), K6 (Fusarium solani), K7 (Penicillium chrysogenum), K8 (Aspergillus niger), K9 (Penicillium piceum) and K10 (Penicillium restrictum). Thus, K8 fungal isolate was found to be more efficient with maximum bioremediation capacity, for copper and lead removal efficiency, and selected for FTIR and SEM to find out the uptake of Cu and Pb which of the functional groups are involved, and further to detect the effects of bioleaching of both heavy metals on to the surface of K8 fungus biomass. The current study indicates that indigenous fungal isolates could be used with high potency to remediate or clean up the heavy metals-contaminated soil either by the technique of in situ or ex-situ bioremediation.
Źródło:
Polish Journal of Chemical Technology; 2023, 25, 3; 1--13
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Perceived corporate sustainability practices and performance of small and medium enterprises (SMEs) in Qatar
Postrzegane praktyki zrównoważonego rozwoju przedsiębiorstw oraz działalność małych i średnich przedsiębiorstw w Katarze
Autorzy:
Al-Ali Mubarak, Y. M. Noor
Gorgenyi-Hegyes, Eva
Fekete-Farkas, Maria
Powiązania:
https://bibliotekanauki.pl/articles/1826375.pdf
Data publikacji:
2020
Wydawca:
Politechnika Częstochowska
Tematy:
sustainability
perceived corporate sustainability practices
SMEs
performance
Structural Equation Modelling
SEM
Qatar
zrównoważony rozwój
postrzegane korporacyjne praktyki zrównoważonego rozwoju
MŚP
wyniki
modelowanie równań strukturalnych
Katar
Opis:
Nowadays sustainability is a contemporary and current issue that recognized by scholars and practitioners. While the concept of perceived corporate sustainability allows various sustainability views, still a lack of understanding arguably inhibits its practical realization and a proper understanding of sustainability is urgently needed. Therefore, the objectives of this paper are to identify the factors affecting perceived corporate sustainability practices (PCSP) and investigate the relationship between PCSP and organizational performance. A quantitative approach was deployed using Structural Equation Modelling (SEM) to analyse the responses from 203 managers for SMEs in Qatar. The study revealed that CSR practices, green practices, and corporate environmental strategy were found to significantly affect PCSP while top management support does not play an important role in it. Moreover, the study showed that PCSP significantly affects financial performance while the relationship between PCSP and none financial performance was not supported by the results. Furthermore, this research is expected to provide SMEs and sustainability literature with valuable suggestions for management practices.
W dzisiejszych czasach zrównoważony rozwój jest współczesnym i aktualnym zagadnieniem, uznanym przez naukowców i praktyków. Chociaż koncepcja postrzeganego zrównoważonego rozwoju korporacyjnego pozwala na różne spojrzenia na zrównoważony rozwój, nadal brak zrozumienia prawdopodobnie utrudnia jego praktyczną realizację, a właściwe zrozumienie zrównoważonego rozwoju jest pilnie potrzebne. Dlatego celem tego artykułu jest zidentyfikowanie czynników wpływających na postrzegane praktyki korporacyjnego zrównoważonego rozwoju (PCSP) i zbadanie związku między PCSP a wydajnością organizacji. Zastosowano podejście ilościowe, wykorzystując modelowanie równań strukturalnych (SEM), aby przeanalizować odpowiedzi 203 menedżerów MŚP w Katarze. Badanie wykazało, że praktyki CSR, zielone praktyki i korporacyjna strategia środowiskowa znacząco wpływają na PCSP, podczas gdy wsparcie najwyższego kierownictwa nie odgrywa w tym ważnej roli. Ponadto badanie wykazało, że PCSP istotnie wpływa na wyniki finansowe, podczas gdy związek między PCSP a żadnymi wynikami finansowymi nie został poparty wynikami. Ponadto oczekuje się, że badanie to dostarczy MŚP i literaturze dotyczącej zrównoważonego rozwoju cennych sugestii dotyczących praktyk zarządzania.
Źródło:
Polish Journal of Management Studies; 2020, 22, 1; 26-42
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biosynthetic of Titanium Dioxide Nanoparticles Using Zizyphus Spina-Christi Leaves Extract: Properties
Autorzy:
Alobaidi, Tuqa B.
Alwared, Abeer I.
Powiązania:
https://bibliotekanauki.pl/articles/2025518.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
green synthesis
TiO2
Zizyphus Spina-Christi
band gap
XRD
FE-SEM
Opis:
The present project utilizes a straightforward, inexpensive, and environmentally friendly approach to produce Titanium dioxide nanoparticles utilizing Zizyphus Spina-Christi leaves (Z-TiO2). Ultra-Spectrophotometry (UV-Vis) was used to characterize the synthesized nanoparticles, which showed the production of nanoparticles at 320 nm absorbance. To investigate functional groups, Fourier Transform Infrared Spectroscopy (FTIR) has been used. The presence of Titanium Dioxide was verified using Energy Distribution X-ray Spectroscopy (EDS). Surface area is calculated using the Brunauer Emmett Teller (BET) formula. Images from Field Emission Electron Microscopy (FE-SEM) verified the nanoparticles' spherical shape and relatively homogenous size distribution. These findings demonstrated that the production of Z-TiO2 nanoparticles was successful.
Źródło:
Journal of Ecological Engineering; 2022, 23, 1; 315-324
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Contrast enhancement of scanning electron microscopy images using a noncomplex multiphase algorithm
Autorzy:
Alsaygh, Zaid
Al-Ameen, Zohair
Powiązania:
https://bibliotekanauki.pl/articles/2097436.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
image enhancement
SEM images
statistical approaches
contrast enhancement
Opis:
Microscopic technology has recently flourished, allowing unparalleled viewing of microscopic elements invisible to the normal eye. Still, the existence of unavoidable constraints led on many occasions to have low contrast scanning electron microscopic (SEM) images. Thus, a noncomplex multiphase (NM) algorithm is proposed in this study to provide better contrast for various SEM images. The developed algorithm contains the following stages: first, the intensities of the degraded image are modified using a two-step regularization procedure. Next, a gamma-corrected cumulative distribution function of the logarithmic uniform distribution approach is applied for contrast enhancement. Finally, an automated histogram expansion technique is used to redistribute the pixels of the image properly. The NM algorithm is applied to natural-contrast distorted SEM images, as well as its results are compared with six algorithms with different processing notions. To assess the quality of images, three modern metrics are utilized, in that each metric measures the quality based on unique aspects. Extensive appraisals revealed the adequate processing abilities of the NM algorithm, as it can process many images suitably and its performances outperformed many available contrast enhancement algorithms in different aspects.
Źródło:
Applied Computer Science; 2022, 18, 2; 28--42
1895-3735
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of Mineral Wollastonite Particulate Filled Vinyl-Ester Resin Composites
Autorzy:
Amarababu, B.
Rangadu, V. P.
Powiązania:
https://bibliotekanauki.pl/articles/412589.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
vinylester
wollastonite
SEM
TGA
mechanical properties
Opis:
In the present research presents influence of coupling agent 1 % triethoxymethyl silane sprayed on to the wollastonite particulate powder before it dispersed into the vinylester/composites. Firstly two different composites were developed in which wollastonite is filled with vinylester resin and same wollastonite was sprayed with coupling agent 1 % triethoxymethyl silane then filled with vinylester resin. The particle functionalization with a bi-functional coupling agent 1 % triethoxymethyl silane was observed to have a significant effect on the curing process and subsequent physical properties of the composites. Wollastonite functionalization favors the composite fabrication with a lower curing temperature as compared to the as-received particle filled vinyl ester resin composites. Thermogravimetric analysis showed an increased thermo-stability in the particles functionalized filled vinyl ester resin composites as compared to the unmodified particle filled counterparts. The uniform particle dispersion and the chemical bonding between filler and vinyl ester resin matrix were found to contribute to the increased thermal stability and enhanced tensile strength and modulus.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 18; 91-102
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Azotan MDMA (3,4-metylenodioksymetamfetaminy) – nietypowa postać soli czy nowy trend na rynku narkotyków?
MDMA (3,4-methylenedioxymethamphetamine) nitrate – an atypical salt form or a new trend in the drug market?
Autorzy:
Bachliński, Robert
Galarda, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/499846.pdf
Data publikacji:
2017
Wydawca:
Centralne Laboratorium Kryminalistyczne Policji
Tematy:
MDMA
azotan
elektroforeza kapilarna
SEM
nitrate
capillary electrophoresis
Opis:
W niniejszym artykule przedstawiony został przypadek wystąpienia na nielegalnym rynku narkotykowym nietypowej postaci 3,4-metylenodioksymetamfetaminy (MDMA) w formie azotanu. Związek taki bardzo dobrze można zidentyfikować jedynie poprzez zastosowanie metod analitycznych, których nie wykorzystuje się rutynowo w badaniach kryminalistycznych tego typu substancji – elektroforezy kapilarnej (CE) czy skaningowej mikroskopii elektronowej (SEM). Należy więc być bardzo czujnym w przypadkach, gdy badania metodą chromatografii gazowej sprzężonej ze spektrometrią masową (GC-MS) jednoznacznie identyfikują badaną substancję, ale już badania w spektrofotometrii w podczerwieni tego nie potwierdzają.
The article presents a case involving an appearance of an atypical 3,4-methylenedioxymethamphetamine (MDMA) in the form of nitrate on the illicit drug market. This compound can be identified only by using such analytical methods as capillary electrophoresis (CE) or scanning electron microscopy (SEM), which are not routinely applied to forensic analyses of this type of substances. Therefore, particular caution should be exercised whenever a gas chromatography-mass spectrometry (GC-MS) method unambiguously identifies a substance, yet infrared spectroscopy fails to confirm this result.
Źródło:
Problemy Kryminalistyki; 2017, 296; 37-45
0552-2153
Pojawia się w:
Problemy Kryminalistyki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania gleb, wyrobów kamieniarskich i skał – wybrane przypadki opinii wykonywanych w Centralnym Laboratorium Kryminalistycznym Policji w Warszawie
Research on soils, stone products and rocks – selected cases of opinions issued by the Central Forensic Laboratory of the Police in Warsaw
Autorzy:
Bachliński, Robert
Powiązania:
https://bibliotekanauki.pl/articles/23050941.pdf
Data publikacji:
2021
Wydawca:
Centralne Laboratorium Kryminalistyczne Policji
Tematy:
geologia sądowa
beton
gleba
bursztyn
badania mikroskopowe
dyfrakcja rentgenowska
badania SEM
badania FTIR
forensic geology
concrete
soil
amber
microscopic studies
X-ray diffraction
SEM analysis
FTIR analysis
Opis:
Badania gleb, wyrobów kamieniarskich i skał są związane z dyscypliną naukową zwaną geologią sądową. Spośród policyjnych laboratoriów kryminalistycznych badania tego rodzaju wykonywane są jedynie w Zakładzie Chemii Centralnego Laboratorium Kryminalistycznego Policji (CLKP) w Warszawie w liczbie ok. 2% wszystkich ekspertyz rocznie. Pomimo dość niewielkiego napływu tego typu opinii w ostatnich latach z roku na rok rośnie zainteresowanie organów ścigania wykorzystaniem wspomnianych badań w procesie karnym. Poniższy tekst przedstawia przykładowe trzy opinie wykonane w ostatnich latach w CLKP. Pierwsza dotyczy zabójstwa, a do dokonania czynu zabronionego wykorzystano płyty betonowe. Kolejna jest związana z pożarem maszyn rolniczych, materiałem dowodowym są zaś gleby z miejsca zdarzenia i z ubrania podejrzanego. Ostatnia dotyczy fałszowania półproduktów do wytwarzania wyrobów jubilerskich z bursztynu.
Research on soils, stone products and rocks is part of a scientific discipline known as forensic geology. Among the police forensic laboratories, this type of studies are performed only at the Chemistry Department of the Central Forensic Laboratory of the Police (CFLP) in Warsaw and comprise approximately 2% of all opinions issued annually. Despite a relatively low workload in recent years, the interest of law enforcement agencies in the use of this type of analyses in the criminal proceedings is on the rise. This article presents three exemplary opinions issued in recent years at the CFLP. The first opinion relates to murder, whereby concrete slabs were used to commit the criminal act. The second is related to an agricultural machinery fire, whereby evidence included soil samples recovered at the scene and from the suspect’s clothing. The last opinion concerns the falsification of semi-finished products used for amber jewelry craftsmanship.
Źródło:
Problemy Kryminalistyki; 2021, 311; 21-34(pol), 57-70(eng)
0552-2153
Pojawia się w:
Problemy Kryminalistyki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study on damage to PLA knitted fabrics during scouring and bleaching
Autorzy:
Baig, G. A.
Carr, C. M.
Powiązania:
https://bibliotekanauki.pl/articles/778625.pdf
Data publikacji:
2014
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
PLA
Scouring
Bleaching
Weight loss
mechanical properties
SEM
Opis:
Ingeo® PLA (polylactic acid) knitted fabric was scoured through an exhaust technique. The scouring was carried out with sodium carbonate in the presence of a detergent at various concentrations and temperatures. The scoured fabric was bleached with various oxidative bleaching agents. Bleaching was carried out with hydrogen peroxide, sodium chlorite and sodium hypochlorite. Hydrogen peroxide was applied by exhaust and cold pad batch (CPB) techniques. It was observed that during scouring PLA fabric was degraded at high alkali concentrations and processing temperatures. The scouring temperature above 60oC proved to be deleterious due to the scouring solution penetrating into the polymer structure and damaged the fiber. Sodium chlorite and sodium hypochlorite caused little damage to the mechanical properties of PLA. Hydrogen peroxide when applied by the CPB technique did not reduce strength appreciably but when applied by the exhaust technique decreased the strength significantly. SEM analysis revealed that hydrogen peroxide caused holes and slit formation in the fiber structure.
Źródło:
Polish Journal of Chemical Technology; 2014, 16, 3; 45-50
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 417

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