130 research outputs found
Pengembangan Perangkat Pembelajaran IPA Berbasis Model Pembelajaran Inkuiri Pada Materi Sistem Pencernaan Untuk Melatih Keterampilan Proses Siswa Smp Kelas VIII Dan Meningkatkan Hasil Belajar Siswa
This research has purpose to produces learning materials that proper theoritically and empirically that consists of lesson plan, student work sheet, student book on digestive system that supported by increasing of student achievementand student responses towards learning that try process skils with junior high school research subject in Sidoarjo. This research used 4D development model but this research did not use dissiminate with one group pretes posttest in try out. Data collecting method, questionnaire, test and observation. Data analysis used qualitative descriptive technic. Research findings showed that validation of learning materials, namely syllabus, lesson plan, student book, and student worksheet was 82.5%, 91.3%, 80.3%, 85.0%; respectively lesson plan implementation was high and students response very positive (80.3). Learning materials that developed was proper to be used in learning and increased student achievement
Chemical Investigation of Leaching and Electrochemical Behaviour of Sensor-based Pre-concentrated Copper Ores with Alkaline Lixiviant
OKAbstract
While the production of copper metal from primary ores is still increasing, the gradual depletion of high-grade ores implies that the recovery of the metal from low-grade ores is presenting a challenge. A major problem associated with processing of low-grade copper ores can be their high calcite content and concentration of other metals such as Fe, Mn, Co, As, Pb, and Ni. These other metals make the processing of such ores expensive due to the high cost of the leaching chemicals. Therefore, in this study a novel, integrated copper processing method is developed to enhance the economic extraction of copper from such ores.
This research investigated the chemical leaching behaviour of porphyry copper ore samples from Chile, South America. Ores were pre-concentrated and classified with near infrared sensing into product, middling and waste fractions. Mineralogical analysis of the ore was conducted using QEMSCAN®, XRD and NIR. The elemental investigation of the ore was carried out using PXRF, ICP-MS and SEM. Analyses revealed that the major copper-bearing mineral is chrysocolla and that the ore is composed mainly of silicate, oxide and carbonate gangue. Calcite in the ore is considered problematic due to acid consumption. In terms of abundance of gangue in the classified ore the order is waste > middling and product. A systematic comparison of the complexometric behaviour of the ore was investigated with Na2EDTA reagent while the leaching behaviour of the classified ore was investigated in NH4Cl and H2C2O4 lixiviants. The influence of process variables such as lixiviant concentrations, particle sizes, solid-to-liquid ratio, temperature, time and stirring speed on the behaviour of the classified ore were investigated.
The rate of Cu dissolution and formation of Cu-EDTA complex in Na2EDTA was higher in the product than the middling while that of the waste was found to be insignificant at 0.01 M, even when the concentration of the complexing agent was increased from 0.01 M to 0.05 M. The rate of Cu-EDTA complex formation was found to increase with decreasing particle sizes and solid-to-liquid ratio across the ore categories. Ammonium chloride leaching of the product and middling revealed contrasting behaviour. The rate of Cu extraction was found to increase significantly from 21.5 % to 75.0 % and 27.3 % to 89.0 % when the temperature was increased from 40 ˚C to 90 ˚C, respectively. On increasing the concentration of NH4Cl from 0.5 M to 5 M, the extraction of Cu was found to increase from 20.0 % to 65.0 % and 26.5% to 83.3 %, respectively. It was found that the leaching yield of Cu increased substantially when the particle size was decreased from –125+90 μm to –90+63 μm and –63+45 μm and with decreasing solid-to-liquid ratio (middling and product), respectively. A steady decrease in Cu extraction was obtained when the stirring speed was increased from 300 rpm to 800 rpm. Similarly, the effectiveness of the leaching process was investigated over an extended time period from 2 h to 4 h with an NH4Cl concentration range of 0.55 M to 1.65 M, a temperature of 70 ˚C to 90 ˚C, and at a constant stirring speed of 300 rpm, particle size fraction of -64+45 μm and a solid to liquid volume of 6 g/ 250 mL. It was found that Cu extraction was enhanced by about 90 % during the experiment. The estimated activation energy of the leaching process was characterized using the shrinking core model under the experimental conditions. It was found to range between 45 and 71 KJ/mol in the first and second batch experiments, which is indicative of a chemically controlled leach process. XRD and ICP-MS characterization of mineralogical and chemical composition of residues suggested that the NH4Cl lixiviant leaching is selective for Cu. Examination of leachate with ICP-MS for co-extraction of Mn, Co, Ni and Zn indicated insignificant solubilisation of the metals during leaching. Comparison of Cu extraction in NH4Cl and H2C2O4 under the same experimental conditions revealed that NH4Cl is a better extractant than H2C2O4.
Furthermore, the electrodeposition of Cu metal was studied with ore leachate containing Cu(NH3)42+ complexes and with Cu(NH3)4SO4 synthetic electrolyte. Cyclic voltammetric measurements were conducted across a range of cathodic potentials from 0.8 V to – 1.0 V for selected scan rates of 20, 30, 50, 100 and 200 mV/s. Chemical reduction and electrodeposition of Cu from the complexes was found to proceed via two reversible electrochemical processes, each involving the transfer of a single electron. Cu(NH3)42+ complexes are first reduced to Cu(NH3)2+, which is in turn reduced to metallic Cu. The result is compared with the behaviour of synthetic Cu(NH3)4SO4 electrolyte. It was observed that the reduction of Cu(NH3)4SO4 to metallic Cu proceeds as two sequential, single electron transfer processes. The Cu/Cu(NH3)42+ redox reaction was observed to be fast compared to Cu/Cu2+ redox reaction in the Cu(NH3)4SO4 solution. Investigation of the electrochemical kinetics shows that the cathodic peak current varied linearly with the square root of the scan rate, which is indicative of the Cu(NH3)2+ and Cu(NH3)4SO4 reduction to Cu proceeding through a diffusion-controlled process.
Assessment of the effect of calcite for leaching of copper from classified ore fractions indicated the potential of NH4Cl lixiviant for the leaching application. Three processing routes to handle the ore fractions on the basis of variation in calcite, gangue and copper content are proposed.Nigerian Tertiary Education Trust Fund (TETFund
Idea państwa i władcy w najstarszych "Żywotach" świętych Cyryla i Metodego
W polskiej literaturze przedmiotu dotyczącej sytuacji politycznej na
ziemiach polskich w okresie przedpaństwowym, przede wszystkim zaś
odnoszącej się do dziejów Małopolski w dobie przedpiastowskiej, ważkie
miejsce wśród źródeł je opisujących zajmują najstarsze Żywoty
Konstantyna/Cyryla i Metodego. Spośród nich szczególną uwagę polskich
badaczy przyciąga Żywot Metodego. Powodem tak wielkiego
zainteresowania historyków jest zaledwie jedno zdanie, ów słynny
passus o bardzo silnym (nieznanego imienia) księciu pogańskim „siedzącym
na Wiślech”, a także o proroctwie włożonym przez autora
Żywota w usta Metodego, który przepowiedział owemu księciu niepokojącemu Morawę, że jeśli nie przyjmie dobrowolnie chrztu, wówczas
zostanie pojmany do niewoli i w niej ochrzczony.
Zdanie to, kończące się potwierdzeniem przez autora Żywota prorockiego
daru apostoła Słowian, wypowiedzianego słowami: „tak się
stało”, skłoniło praktycznie wszystkich historyków czeskich i słowackich,
a także znaczną część badaczy dziejów ziem polskich przed
powstaniem państwa polskiego do wyprowadzenia kilku ważkich spostrzeżeń,
z których za najważniejsze uznajemy to dotyczące panowania
Państwa Wielkomorawskiego nad Małopolską oraz wniosek — jakkolwiek
formułowany nieco rzadziej (niekiedy jedynie pośrednio)
— o przyjęciu przez tę właśnie część późniejszej Polski wczesnopiastowskiej
chrztu z rąk Metodego bądź jego uczniów i o rycie słowiańskim
w liturgii. Jednak — co należy wyraźnie podkreślić — znacząca
część polskich uczonych kwestionuje obecnie możliwość opanowania
przez Państwo Wielkomorawskie ziem Polski południowej
Pengaruh Penerapan Media Benda Asli Pada Mata Pelajaran Matematika Terhadap Hasil Belajar Siswa Kelas III Di MI/SD
In a formal educational such as a Madrasah, the success of education can be seen from the student learning outcomes in learning achievement. The quality and success of the students learning is strongly influenced by the ability and accuracy of the teachers choosing , using methods and media that is can be improve the effectiveness of the students learning process. The title of this research is "The Effect of the Application of Original Material Media on Mathematics Subjects to the Learning Outcomes of Thirth Grade Students in elementary school. The research used is an experiment with a quantitative approach. As for the sampling in this study, the authors only take Thirth Grade as an experimental class totaling 27 students based on random sampling and the results of the observation of the author towards third grade students regarding the low student learning outcomes on Mathematics subjects. The data collection technique of this study uses observation, tests (pre-test and post-test). Data analysis to draw conclusions using the "t" test formula for small, interconnected samples.. As for the results of this study, the results of the observations showed that the application of the original object media in Mathematics subjects was good. Student learning outcomes in the post-test have increased mean scores when compared with the pre-test. Whereas for the comparison test obtained a conclusion after comparing the amount of t tabael 1% dan 5% is 2,78 dan 2,06 obtained in the calculation to is 16,23. So that the research concludes that there is an effect of the application of the original object media to the learning outcomes of Thirth Grade students in elementary school
"Iste sunt ville circa..." : z badań nad "Liber fundationis episcopatus Wratislaviensis"
Marek Cetwinski undertook an attempt to describe the terminology concerning the
notion of state and government in Liber fundationis claustri S. Marie Virginis in
Heinrichow which appears as a source of vital importance when presenting the history
of Silesia. Among others it points at the understanding of the term dominus and the fact
that the group of domini, according to the author of Liber fundationis..., was wider than
the circle of the monarch’s closest relatives.
While continuing the studies on one of the most important texts referring to the
history of the Church in Wroclaw diocese and Silesian colonization at the turn of the
13—14th centuries, Idzi Panic undertook an attempt to describe the meaning of bishop’s
writer’s terminology. The research worker comes to the conclusion that the detailed
analysis of the bishop’s writer’s terminology concerning the local terms makes us verify
our knowledge on the number of settlements and, as a consequence, find that this
number exceeds the number of settlements (803) known from the previous research
Pengembangan Lembar Kerja Siswa (LKS) Ipa Berbasis Phet “Optical Geometri” Tema Mata
Developmental research already been done by the title “Development of Student Work Sheet Science basis on PhET ”Optical Geometri” Theme eye.”. This research intent to describe work sheet student feasibility gets basis PhET “Optical is Geometry” theme eye to be sighted bases material component criterion, representation, and language; feasibility is sighted from student response. This research points on developmental model 4D but then just come up develop (development). Analyze of the research was done by descriptive quantitative, one that points out that Student Work Sheet gets basis PhET was reasonable being utilized deep learning is sighted of all aspect covers material with percentage as big as 88.88%, representation as big as 88.88%, and language as big as 85.00%. Besides feasibility also being sighted of student response that cover representation feasibility in learning as big as 93.42%, Representation criterion of Student Work Sheet as big as 80.26%, and language as big as 75.43%. Learned thoroughness individually with percentase as big as 100% complete with up to KKM as big as ≥ 70 and klasical with percentase 100% complete as supporting as feasibilities
Lata 891-892 : ostatnia próba podporządkowania Państwa Wielkomorawskiego przez Wschodnich Franków u schyłku panowania Świętopełka
W ostatnim czasie ożyły badania nad dziejami Europy Środkowej w IX i X
wieku, w jej naddunajskiej strefie. Ożywienie to tylko do pewnego stopnia należy
wiązać z okrągłymi rocznicami powstawania niektórych tutejszych państw
(Austria, Węgry), daleko częściej bowiem studia te, mające bardzo starą tradycję3 są prowadzone w związku z określonymi zainteresowaniami poszczególnych
badaczy. W tym między innymi kontekście należy spojrzeć również
na ostatnie monografie polskich badaczy poświęcone dziejom niektórych
państw tego regionu we wczesnym średniowieczu, a mianowicie Państwa
Wielkomorawskiego oraz Węgier. Autorem pracy poświęconej dziejom
politycznym i społeczno-gospodarczym pierwszego z państw jest K. Polek,
a piszący te słowa skupił swoją uwagę na początkach państwa węgierskiego.
Losy obu wymienionych państw były na przełomie IX i X wieku dość ściśle
złączone. Uważa się powszechnie, że Państwo Wielkomorawskie zostało
zniszczone przez Węgrów, którzy najpierw osiedlili się w jego obrębie, a następnie,
po nieprawnym — w rozumieniu ówczesnego „prawa międzynarodowego”
— opanowaniu Niziny Panońskiej, którą odebrali Państwu Wschodniofrankijskiemu
(pogląd ten — jak wykazałem — jest całkowicie błędny), zwrócili
się przeciw swym niedawnym dobroczyńcom, Wielkiej Morawie. W konsekwencji
działań wojennych, po początkowych sukcesach Morawian, Węgrzy
odnieśli nad wojskami wielkomorawskimi ostateczne zwycięstwo i w roku 902
(jak przypuszczają na ogół badacze węgierscy) lub 906 (jak przyjmują niektórzy
badacze czescy i słowaccy) Państwo Wielkomorawskie przestało istnieć.
Od tych poglądów odbiega stanowisko L. Havlika, który przyjął, że
ostateczny upadek tego państwa miał miejsce na przełomie lat dwudziestych X wieku, opinia ta — dodajmy — spotkała się ze zdecydowanym sprzeciwem
części innych uczonych. Różnica między poglądami formułowanymi przez
L. Havlika a stanowiskiem zajmowanym w omawianej kwestii przez pozostałych
autorów sprowadza się więc w istocie do kwestii chronologicznych, nie dotyczy
natomiast samej genezy załamania się politycznego Wielkiej Morawy, a w konsekwencji
jej definitywnego upadku.
Wspomniana dyskusja, jakkolwiek bez wątpienia bardzo ważna, zepchnęła
nieco w cień pytanie o sytuację zewnętrzną Wielkiej Morawy bezpośrednio przed
osiedleniem się tutaj Węgrów, a więc w ostatnich latach życia Świętopełka, toteż
nad tym problemem zamierzamy się pochyli
Fundacje mieszczan księstwa cieszyńskiego na rzecz szpitali w okresie rządów regencyjnych Jana z Pernstejnu (1528-1544) : z badań nad dziejami Kościoła w księstwie cieszyńskim na przełomie średniowiecza i czasów wczesnonowożytnych
There is an opinion functioning in the literature on the subject that Reformation in the Duchy
of Cieszyn began at the beginning of the twenties of 16th century, which was soon after Martin
Luter’s speech. Referring to this opinion, it had to be emphasised that until 1543, when the last
donation to hospitals in the Duchy o f Cieszyn was registered, all the donations which referred to
Altarists were treated by both parties (donors and beneficiaries) as life-long irrevocable trusts.
It has to be mentioned that catholic priests were treated as rightful members of the community
of the Duchy of Cieszyn. We cannot trace any signs of hostility typical for the times of Reformation.
On the basis of the above information, at least in the light o f the discussed in the article
donations to hospitals in the Duchy of Cieszyn we claim that opinion about Reformation
beginning in the Duchy of Cieszyn thanks to the protector of the princess Anna and Jan from
Pernstejn, coregents governing the Duchy after the death o f Wacław II might be discarded. It did
not happened until Wacław III Adam assumed independent reign
Biases and Uncertainties in Physical Parameter Estimates of Lyman Break Galaxies from Broad-band Photometry
We investigate the biases and uncertainties in estimates of physical
parameters of high-redshift Lyman break galaxies (LBGs), such as stellar mass,
mean stellar population age, and star formation rate (SFR), obtained from
broad-band photometry. By combining LCDM hierarchical structure formation
theory, semi-analytic treatments of baryonic physics, and stellar population
synthesis models, we construct model galaxy catalogs from which we select LBGs
at redshifts z ~ 3.4, 4.0, and 5.0. The broad-band spectral energy
distributions (SEDs) of these model LBGs are then analysed by fitting galaxy
template SEDs derived from stellar population synthesis models with smoothly
declining SFRs. We compare the statistical properties of LBGs' physical
parameters -- such as stellar mass, SFR, and stellar population age -- as
derived from the best-fit galaxy templates with the intrinsic values from the
semi-analytic model. We find some trends in these distributions: first, when
the redshift is known, SED-fitting methods reproduce the input distributions of
LBGs' stellar masses relatively well, with a minor tendency to underestimate
the masses overall, but with substantial scatter. Second, there are large
systematic biases in the distributions of best-fit SFRs and mean ages, in the
sense that single-component SED-fitting methods underestimate SFRs and
overestimate ages. We attribute these trends to the different star formation
histories predicted by the semi-analytic models and assumed in the galaxy
templates used in SED-fitting procedure, and to the fact that light from the
current generation of star-formation can hide older generations of stars. These
biases, which arise from the SED-fitting procedure, can significantly affect
inferences about galaxy evolution from broadband photometry.Comment: 85 pages, 34 figures, submittted to ApJ
- …