Wyniki wyszukiwania - Biblioteka Nauki

1

Study of dehydration and water states in new and worn soft contact lens materials

100%

Krysztofiak K. , Szyczewski A.

Optica Applicata

|

2014

|

tom Vol. 44, nr 2

237--250

EN

The purpose of this study was to examine the in vitro dehydration characteristics of new and worn conventional and silicone-hydrogel contact lenses. Four contact lens materials were investigated: three conventional hydrogels (etafilcon, nelfilcon, omafilcon) and one silicone-hydrogel (narafilcon). Gravimetric data were obtained with analytical balance with 1 min intervals. Quantitative parameters of water content and dehydration rate were calculated allowing quantitative description of dehydration process. Differential scanning calorimetry was used to monitor changes in water states in samples studied. As expected, dehydration behavior of each material is different in terms of mean dehydration rate values and phases of dehydration. Gravimetric data allowed us to distinguish three phases of dehydration. Interestingly, the effect of the osmolality of storing solutions on dehydration was found – lenses stored in hyperosmotic solutions needed more time to achieve equilibrium with the environment. Effect of wearing on dehydration patterns and water properties was confirmed. In worn samples, a decrease in water content was observed. Additionally, there was a change in water structure after 6 h of wearing in all lenses studied. This behavior may be ascribed to tear film components deposition and changes in surface wettability that appear during wearing.

2

Assessment of construction workers’ hydration status using urine specific gravity

100%

Montazer S. , Farshad A. A. , Monazzam M. R. , Eyvazlou M. , Yaraghi A. A. , Mirkazemi R.

International Journal of Occupational Medicine and Environmental Health

|

2013

|

tom 26

|

nr 5

762-769

EN

Objectives: The study objective was to assess hydration status by measuring USG among construction workers in Iran. Materials and Methods: The study design was comparative and experimental. Sixty participants were randomly selected from the construction workers from a construction campus with a similar type of work, climate and diet and formed 2 groups (individuals exposed to the sun and non-exposed individuals). TWL and USG were measured in both groups on 2 consequent days, at the beginning, mid and end of the work shift. Results: USG test showed that mean USG was 1.0213±0.0054 in the control group and in the exposed group, where it was significantly higher, it amounted to 1.026±0.005. In the exposed group, 38% of workers had a USG level between 1.026-1.030, representing a higher risk of heat illness and impaired performance and 12.72% had a USG level above 1.030 representing a clinically dehydrated status, while this proportion in the control group was 15.2% and 0.58%, respectively. The mean TWL index measure was 215.8±5.2 W/m² for the control group and 144±9.8 W/m² for the exposed group, where, again, it was significantly higher. The Pearson correlation measure showed a significant correlation between USG and TWL. Conclusions: Strong correlation between TWL, as an indicator of thermal stress and USG shows that USG can be considered as a predictor of thermal stress. The difference between USG among the exposed and non-exposed workers and the increase in USG during midday work show the sensitivity of this measure in different thermal and climatic conditions, whereas, the high level of dehydration among workers despite acceptable TWL level, shows that heat stress management without considering the real hydration status of workers, is insufficient.

3

Hydrothermal preparation and catalytic activity of copper oxide supported on zinc aluminate spinel.

100%

Zawadzki M. , Grabowska H. , Miśta W.

Prace Naukowe Instytutu Chemii i Technologii Nafty i Węgla Politechniki Wrocławskiej. Konferencje

|

2002

|

tom Vol. 10, nr 57

401-406

EN

Copper oxide supported on ZnAl2O4 catalysts with various CuO loading were prepared by wet impregnation method. The effect of copper oxide addition on catalytic performance of ZnAl2O4 in n-hexanol reactions was examined. Experimental data show that the addition of CuO into studied catalysts does improve the activity in dehydrogenation of alcohol. Catalysts containing CuO have mainly dehydrogenation properties whereas ZnAl2O4 carrier dehydrates and dehydrogenates alcohol.

4

Odmiany półwodnego siarczanu wapnia

100%

Pichniarczyk P. , Chłądzyński S.

Izolacje

|

2008

|

tom R. 13, nr 1

48-50

PL

Półwodny siarczan wapnia CaSO4.1/2H2O może występować w dwóch odmianach, które są wynikiem różnic w prowadzeniu procesu dehydratacji. Odmiana 3 powstaje, gdy proces dehydratacji odbywa się w atmosferze powietrza, przy niewielkiej prężności pary wodnej. Odmiana a powstaje, gdy obróbka termiczna przebiega w atmosferze nasyconej pary wodnej. Może być także otrzymywana przez odwadnianie dwuhydratu w roztworach kwasów lub soli. Półwodzian obu odmian występuje ponadto w niewielkich ilościach w przyrodzie.

5

Reagent dla povysenia produktivnosti skvazin na osnove degidratacionnogo fosfokompleksa DFK-12

100%

Svetlickij V. M. , Ivankiv O. A. , Divonak U. I.

Prace Naukowe Instytutu Nafty i Gazu

|

2012

|

tom nr 182 wyd. konferencyjne

773--776

EN

The article provides the results of using of the dehydrating phosphor-соmрlех DFK-12 for restoration and increase of the well’s bottomhole zone permeability. The positive influence is achieved duе to chemical and physical influence at the reservoir.

6

Wody deszczowe sąsiada – część III – Trudności na drodze do państwa prawa

100%

Dąbrowski W.

Instal

|

2012

|

tom nr 1

61-65

PL

Przedstawiono przykłady niskiej świadomości urzędów co do potrzeby właściwego technicznie i zgodnego z prawem odwodnienia inwestycji budowlanych. Jednym ze stwierdzonych problemów było unikanie przez niektórych urzędników obowiązków nakładanych na nich przez prawo w odniesieniu do decyzji, które powinny zostać podjęte w przypadku niewłaściwego gospodarowania wodami opadowymi. Drugim problemem są opóźnienia i udzielanie odpowiedzi wymijających na wnioski petentów.

EN

Some examples of local governments low awareness in respect to the need of technically correct and following law methods of storm water disposal have been presented. One of the problems recognized during the study was avoiding by some local governments of their obligations defined by the law in respect to decisions to be taken if storm water is not managed properly. The second shortcoming are delays in answering the claims and avoiding giving direct answers to citizens.

7

Catalytic Performance of CuO/ZnAl2O4-Al2O3 Catalysts in n-Hexanol Conversion

88%

Grabowska H. , Zawadzki M. , Wrzyszcz J.

Polish Journal of Chemistry

|

2003

|

tom Vol. 77 / nr 5

779-787

EN

Aseries of CuO/ZnAl2O4-Al2O3 catalysts with various CuO loading were prepared by an impregnation method. The effect of copper oxide addition for the reaction of n-hexanol was examined. The reactions were carried out at atmospheric pressure in a fixed bed reactor in the temperature range of 533-663 K. Experimental data show that the addition of copper oxide into studied catalysts does improve the activity in dehydrogenation of alcohol. Catalysts containing CuO have both dehydration and dehydrogenation properties, whereas ZnAl2O4-Al2O3 carrier only dehydrates alcohol. Obtained results indicate that the dehydrogenation of n-hexanol over CuO/ZnAl2O4-Al2O3 catalysts proceeds via carboxy intermediate.

8

Effects of acid leaching on halloysite

88%

Saklar S. , Yorukoglu A.

Physicochemical Problems of Mineral Processing

|

2015

|

tom Vol. 51, iss. 1

83--94

EN

A characteristic iron-containing halloysite sample from Turkey was subjected to acid leaching using organic and inorganic acids for removing iron impurities. The aim of this study was to compare the raw hydrated and dehydrated halloysites with the leached products. Hydrochloric acid and oxalic acid were chosen as leaching agents for the removal of iron impurities at 80 °C for 2.5 h. The physicochemical properties of the acid-treated halloysite were analyzed by XRF, XRD, FTIR, TGA, DTA, SEM, and TEM. The XRF results showed that the acid treatment caused the dissolution of minor amounts of Al3+ ions from the clay layer. The XRD results indicated that the crystalline structure was unchanged after the leaching. However, it was observed that the hydrated (1 nm) halloysite readily lost its interlayer water and was transformed to the dehydrated (0.7 nm) form. In addition, no visible effects of the acid treatment on the tubular structure of halloysite were detected in the SEM and TEM images. Typical pores of varying dimensions were observed in all of the samples regardless of their form or treatment. Furthermore, the TG-DTA and FTIR analysis results were similar for both the raw and the acid-treated samples.

9

PERVAPORATIVE INVESTIGATION OF ETHYL ALCOHOL DEHYDRATION

88%

Gnus M. , Dudek G. , Turczyn R. , Tórz A. , Łącka D. , Konieczny K. , Łapkowski M.

Progress on Chemistry and Application of Chitin and its Derivatives

|

2015

|

tom 20

54-63

EN

Pervaporative separation properties of crosslinked chitosan and alginate membrane on ethanol-water mixture at room temperature was studied. The influence of crosslinking agents on the separation properties were discussed. Selected crosslinking agents were affected differently on used polymer matrices. The better separation properties were obtained for membranes crosslinked by phosphoric (V) acid. The highest pervaporation separation index (309.6 kg/m2·h) and separation factor (52.6) were obtained for phosphoric (V) acid crosslinked alginate membranes, however, the greatest total flux (12.4 kg/m2·h) obtained for phosphoric acid crosslinked chitosan membranes

10

Changes in cell physiology at the stage of dehydration in a cryopreservation protocol

88%

Domzalska L. , Kedracka-Krok S. , Mikula A. , Rybczynski J. J.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

|

2015

|

tom 96

|

nr 1

11

Studies of dehydration kinetics of Li2SO4·H2O by the master plots method

88%

Wanjun T. , Donghua C.

Open Chemistry

|

2007

|

tom 5

|

nr 1

341-348

EN

The kinetics of Li2SO4·H2O dehydration in static air atmosphere was studied on the basis of nonisothermal measurements by differential scanning calorimetry. Dehydration data were subjected to an integral composite procedure, which includes an isoconversional method, a master plots method and a model-fitting method. Avrami-Erofeev equation was found to describe all the experimental data in the range of conversion degrees from 0.1 to 0.9. The determined activation energy equals 65.45 kJ·mol−1 with standard deviation ±0.47 kJ·mol−1. The estimated value of parameter m in Avrami-Erofeev equation is 2.15 with standard deviation ±0.11. Also, the obtained pre-exponential factor is 7.79×105 s−1 with standard deviation ±0.55×105 s−1. The results show that the present integral composite procedure gives self-consistent kinetic parameters.

12

Dehydration-Induced Charge Transfer in Ni3[Fe(CN)6]2ź15H2Oe T

88%

Liu M. , Bian X. F. , Xia Y. F. , Bao Z. , Xu M. X.

Polish Journal of Chemistry

|

2009

|

tom Vol. 83, nr 10

1729-1735

EN

Molecular magnet nickel(II) hexacyanoferrate(III), powder Ni3[Fe(CN)6]2ź15H2O, was prepared by coprecipitation method. The coprecipitated powder was annealed in vacuum at different temperatures of 80, 100, 120, and 140 graduate C. Water molecules contained in Prussian blue analogues were removed by heating. The effects of dehydration on its charge transfer properties were studied by Fourier-transform infrared and Mössbauer measurements. It was found that the FeIII–CN–NiII state is the major structure in the coprecipitated form, while the FeII–CN–NiIII bond is formed in the annealed samples. The dehydration of NiII ferricyanide above 80°C induces an inner charge transfer from NiII towards FeIII to form the mixed valence system Ni(II) Ni(III) ferri-ferro-cyanide.

13

Decomposition of Mg(HSeO3)2x3H2O and Mg(HSeO3)2, IR spectroscopic and thermoanalytical investigations

88%

Engelen B. , Muller H. , Unterderweide K.

Polish Journal of Chemistry

|

1998

|

tom Vol. 72, nr 2

263-268

EN

By crystallization from aqueous Mg(HSeO3)2 solutions, single cristals of Mg(HSeO3)2x3H2O, Mg(HSeO3)2, and MgSe2O5 could be obtained. The compounds have been characterized by means of IR spectroscopy. The dehydration mechanisms of Mg(HSeO3)2x3H2O and Mg(HSeO3)2 have been studied using TG, DTA and high-temperaure Raman techniques. DTA and TG measurements indicate that the thermal decomposition of Mg(HSeO3)2x3H2O results in the direct formation of the diselenite MgSe2O5. High-temperature Raman experiments under quasi static conditions (heating rate<5K/h, isothermal intervals of -1h) show that Mg(HSeO3)2x3H2O decomposes in two steps under the intermediate formation of the anhydrous hydrogenselenite Mg(HSeO3)2.

14

Metrological Aspects of Controlling the Rotational Movement Parameters of the Auger for Dewatering Solid Waste in a Garbage Truck

88%

Wójcik W. , Bereziuk O. V. , Lemeshev M. S. , Bohachuk V. V. , Polishchuk L. K. , Bezsmertna O. , Smailova S. , Kurmagazhanova S.

International Journal of Electronics and Telecommunications

|

2023

|

tom Vol. 69, No. 2

233--238

EN

In the article, a device for measuring the parameters of the rotational movement of the auger for dewatering solid waste is proposed based on the analysis of signal processing methods and measurement of physical quantities. It can be used in the development of high-performance special vehicles for transporting waste as the main link in the structure of machines for the collection and primary processing of solid waste. The structural scheme of the means and block diagram of the microcontroller control program algorithm for implementation of the device for measuring the parameters of the rotational motion are proposed. The main technical characteristics of the proposed means are given. The results of experimental tests for measuring the parameters of rotational motion are shown. The results of experimental studies, which are given in the work, confirmed the reliability of the measured parameters.

15

An Innovative Method for the Dehydration Hardening of Modified Inorganic Binders

88%

Izdebska-Szanda I. , Kamińska J. , Angrecki M. , Palma A. , Madej W.

Archives of Metallurgy and Materials

|

2016

|

tom Vol. 61, iss. 4

2097--2102

EN

The results of research on the possibility of using a gaseous medium (hot air) as a hardening agent for inorganic binders were discussed, and tests on the reclamation of waste moulding sands were carried out. The research programme also included the use of a modernized test stand for hardening of foundry sands with gaseous agents and a pilot plant for the sand reclamation. Cores made on the test stand were examined for the basic technological properties and were also used in moulds for the trial knocking out of castings. Two types of binders were tested, i.e. a modified water glass designated as Binder A and, for comparison, a reference material which was hydrated sodium silicate R145. The hardener for the sand mixtures was hot air (the dehydration of water glass). Trials of the sand reclamation were carried out in a laboratory pilot plant, installed and operating at the Foundry Research Institute. The obtained reclaim was added in different amounts to the sand mixtures subjected to technological tests. The next step included the manufacture of test moulds, pouring them with aluminium alloy, and knocking out of castings to test the collapsibility of moulds and cores.

16

Dehydration of no flotation size coal's slimes on the deck of high-frequency screen with multislopes area's working surface

88%

Eremejev I. , Polulyakh A. , Polulyakh D. , Grachyov O.

Teka Komisji Motoryzacji i Energetyki Rolnictwa

|

2014

|

tom 14

|

nr 2

17

Solar Dryer with Electronic PID Controller for Dry Potato Production

88%

Herrera-Morales J. A. , Carbajal-Morán H. , Almidón-Elescano Á.

Ecological Engineering & Environmental Technology

|

2022

|

tom Vol. 23, iss. 1

223--229

EN

The objective of the research was to determine the amount of moist extractable matter from the precooked potato dough with the cut in the shape of sticks and the acceleration of the subtraction of moisture from the matter to be dried inside the solar dryer, controlling the flow of dry air entering the collector through six fans. The temperature and relative humidity in the dryer vary with the flow of air that enters the interior of the dryer and by the heat of the brass generated by the exposure of the extraction chamber to radiation from the Sun from 9:00 am. to 5:00 pm. The temperature and relative humidity values detected by the DHT 22 sensor were processed by the Arduino based microcontroller that has embedded the PID control program, whose outputs acted on the fans and heaters, fed with conventional energy, with respect to the setpoints of temperature 36.5 °C and relative humidity 33%. 26 temperature and relative humidity samples were taken during the day, inside the solar dryer chamber with electronic PID controller. As a result, an average controlled temperature of 36.36 °C and relative humidity of 33.115% were obtained in the dryer chamber, allowing the extraction of 73.16% of the weight of the wet matter from the precooked potato. Achieving, dry potato weighing 26.84% of the initial mass, in a drying time of 8 hours.

18

The Effect of Different Processing Methods on the Behavior of Minerals Content in Food Products

75%

Alshallash K. S. , Shahat M. , Ibrahim M. I. , Hegazy A. I. , Hamdy A. E. , Elnaggar I. A. , El-Wahed A. E.-W. N. A. , Taha I. M.

Journal of Ecological Engineering

|

2023

|

tom Vol. 24, nr 3

263--275

EN

The goal of the current study was to determine the mineral content of different fruit varieties (Na, K, Ca, P, Mg, Fe, Zn, and Cu), as well as the effects of various processing methods (such as canning, drying, stewing, syrup process, and concentration of juices). All tested fruits that were subjected to various types of processing were exposed to a degree of mineral loss, varying from very little to high reduction. However, it still retains its nutritional value. All fig products have the greatest levels of most tested minerals, compared to other processed fruit products, particularly P and Fe. In turn, orange products supply higher quantities of Ca. On the other hand, apricot products have a comparable value of other minerals with those found in fig and orange products. Among canned juices, guava had the highest contents of Ca, P, and Fe, while mango scored the first juice as Mg and Zn supplying. Canned apricot halves contain the best amounts of K, Ca, P and Mg than the same products of apple and peach. Among jam products, fig jam has higher amounts of Na, Ca, P, Mg, and Fe than those found in other fruit jams. The concentration of fruit juices by vacuum-heating or dehydration of fruit produced higher mineral retentions than the fruit products that were processed by other techniques. The concentrated orange juice by vacuum-heating processing retained most of the minerals found in raw juice, also dried apricot sheet retained higher minerals than those retained in dehydrated whole apricot.

19

Effect of temperature on ethanol conversion over the surface of Zr-modified zeolite ZSM-5

75%

Ivanovna K. R. , Yurievich P. A.

Catalysis for Sustainable Energy

|

2014

|

tom 2

|

nr 1

EN

In this paper, we have shown modification of high-silicon zeolite ZSM-5 by zirconium, and the results of ethanol conversion on this catalyst. Effect of process parameters on the selectivity of ethanol dehydration products was analyzed. In addition, a mechanism of aromatic hydrocarbons formation including reactions of dehydrogenation, dehydrocyclization and alkylation of intermediates was discussed. It was found that with increasing temperature a selectivity decreased for reactions of isomerization and increased selectivity for aromatic products and products of cracking reactions. The data also confirms that hexene-1 is an intermediate in the conversion process of ethanol and the catalyst system with 1% Zr-ZSM-5 has a bi-functionality. Catalytic properties of the system in the conversion of hydrocarbons are determined by the presence on their surface of both Broensted and Lewis acid sites.

20

How does affect thermal processing to functional properties of bean flours?

75%

Aguilera Y. , Esteban R. M. , Benitez V. , Sarmento T. , Molla E. , Lopez-Andreu F. J. , Martin-Cabrejas M. A.

Polish Journal of Food and Nutrition Sciences

|

2011

|

tom 61

|

nr Suppl.1