Beliefs About Mathematics And Mathematics Instruction Among Basic Education Mathematics Teachers In Al-Batinah South, Oman

Objektif kajian ini adalah untuk mengenal pasti kepercayaan tentang matematik dan pengajaran matematik dalam kalangan guru matematik pendidikan asas fasa pertama serta untuk menentukan sama ada terdapat perbezaan yang signifikan dalam kepercayaan mereka tentang matematik dan pengajaran matematik dari segi kelayakan akademik, bidang pengkhususan, pengalaman mengajar dan lokasi sekolah di daerah Al-Batinah Selatan, Oman The objectives of this study were to identify Omani basic education first phase mathematics teachers' beliefs about mathematics and mathematics instruction and to determine whether there is a significant difference in their beliefs about mathematics and mathematics instruction in terms of academic qualification, field of specialization, teaching experience and school location in the Al-Batinah South county of Oma

Comparing the Reaction Rates of Plasmonic (Gold) and Non-Plasmonic (Palladium) Metal Particles in Photocatalytic Hydrogen Production

Both Pd and Au metal particles are used in photocatalytic hydrogen generation. Yet while both act as electron sink only gold is poised to respond to visible light due to its plasmonic response. In order to quantitatively gauge their relative contribution into the reaction, the photocatalytic H2 production, from Au/TiO2 and Pd/TiO2 catalysts was studied under UV and UV–Vis light. While under UV light excitation, a weak dependence on the work function of the metal is observed, under UV–Vis light, Au is found to be twice more active than Pd. Under identical UV–Vis light irradiation, the turn over frequency calculated from XPS at.% is found to be 2.8 and 1.8 s−1 for Au and Pd, respectively. The effect is far more pronounced when the rates are normalized to the number of particles of each metal. Both the semiconductor TiO2 (UV light) and the plasmonic metal (visible light) need to be excited for the enhancement to occur; visible light alone causes a negligible reaction rate. Photocurrent measurements further confirmed the difference in the photocatalytic activity under UV and UV–Vis light excitation. Moreover, because of the presence of Au particles responding to visible light the reaction rate is enhanced due to “light penetration depth” effect

PROBAVNI SUSTAV KOŠTUNJAČA PERSORBIRA MIKROČESTICE

The ability of the teleost gut to absorb microparticulate material was examined following rectal intubation (3.5 g kg -1 ) of commercial grade cornstarch (≈21 mm diameter), or potato starch (≈43 mm diameter). Tissue samples were taken from the mid - and hind-gut of control and treated fish 18 h postintubation. Collected samples were processed using standard plastic and staining protocols and resultant photomicrographs examined by computer-assisted image analysis. Cornstarch particles (8-14 mm), were observed to pass from gut lumen to the lamina propria via a paracellular or persorptive route only. No evidence for the like passage of potato starch was found.Mogućnost probavnog sustava koštunjavičastih vrsta riba da apsorbiraju sitne čestice pojedinih tvari bila je istraživana s pomoću rektalne intubacije (3, 5 g kg -1 ) komercijalnoga škroba kukuruza (promjera ≈21 mm) i škroba krumpira (promjera ≈ 43 mm). Uzorci tkiva uzeti su iz srednjeg i stražnjeg dijela crijeva kontrolne i tretirane skupine riba, i to 18 sati nakon intubacije. Sakupljeni su uzorci spremljeni u standardne plastike i obojeni prema protokolu, te fotomikrografski snimljeni na računalu. Čestice škroba kukuruza (8-14 mm) zapažene su da iz lumena crijeva prolaze u laminu propriju samo paracelularnim ili persorptivnim putem. No, nije zapažen prolazak čestica škroba krumpira

An investigation of gas void fraction and transition conditions for two-phase flow in an annular gap bubble column

Gas-liquid flow may be characterised in terms of the gas void fraction, α. This is an important variable in two-phase flow, used in predicting the occurrence of flow regimes, and the associated pressure drop, and mass and heat transfer. The gas void fraction transitions in a two-phase flow system from uniform bubble flow (homogeneous) to churn-turbulent bubble flow (heterogeneous) in an open tube bubble column (OTBC) and an annular gap bubble column (AGBC) have been investigated using a vertical column with an internal diameter of 0.102 m, containing a range of concentric inner tubes which formed an annular gap; the inner tubes had diameter ratios from 0.25 - 0.69. Gas (air) superficial velocities in the range 0.014-0.200 m/s were studied. Tap water and aqueous solutions of ethanol and isopropanol, with concentrations in the range 8 - 300 ppm by mass, were used as the working liquids. Experimental results are presented to show that there are very significant differences in the mean gas void fractions measured in the OTBC and the AGBC, when operated at the same gas superficial velocity using a porous sparger. The mean gas void fraction decreases with increasing ratio of the inner to outer diameter of the annular gap column and the transition to heterogeneous flow occurs at lower gas superficial velocities and lower void fractions. Two reasons are proposed and validated by experimental investigations: (i) the presence of the inner tube causes large bubbles to form near the sparger, which destabilize the homogeneous bubbly flow and reduce the mean void fraction; this was confirmed by deliberately injecting large bubbles into a homogeneous dispersion of smaller bubbles. Moreover, (ii) the shape of the void fraction profiles changes with gap geometry, which affects the distribution parameter in the drift flux model. Radial profiles of the local void fraction were obtained using a two- and four-point conductivity probe, and were cross-sectionally averaged to give mean values that were within 12% of the volume-averaged gas void fractions obtained from changes in aerated level. The presence of alcohol inhibited the coalescence between the bubbles, and consequently increased the mean gas void fraction at a given gas superficial velocity in both the open tube and the annular gap bubble columns. This effect also extended the range of homogeneous bubbly flow and delayed the transition to heterogeneous flow. Moreover, isopropanol results gave slightly higher mean void fractions compared to those for ethanol at the same mass fraction, due to their increased carbon chain length. It was shown that the void fraction profiles in the annular gap bubble column were far from uniform, leading to lower mean void fractions than were obtained in an open tube for the same gas superficial velocity and liquid composition. The chord length measurements in the OTBC for both the tap water and alcohol solutions exhibited two trends with respect to increasing j_g: (i) at low j_g, in the homogeneous flow, an increasing function was obtained; and (ii) with further increase in j_g, a reduction in the chord length was observed. In the presence of the orifice, the results concerning mean chord lengths show a decreasing function of the bubble size with increasing j_g; this was visually demonstrated using photographs. For the AGBC, the chord lengths obtained from the conductivity probe offered evidence of the bubble size decreasing as j_g increased in the heterogeneous regime, which agreed with the findings of the OTBC. This was also confirmed using the results obtained from photographs. A novel approach for bubble size transformation was implemented to process the conductivity probe measurements. An analytical method was used as a forward transform to predict the chord length distribution from the bubble size distribution and an optimisation approach was applied as a backward transform method to obtain the bubble size distribution from the chord length distribution. The challenge was to consider a variable aspect ratio, φ, for the bubble shape, which depended on their size. The model gave excellent and reasonable predictions for the bubble sizes as their trends were identical to the trend of the chord length, and to the bubble size obtained from photographs

Extracting knowledge and its impact on innovation in Rabigh Electricity Company

This study aimed to identify the level of knowledge extraction practice at Rabigh Electricity Company, the extent of application of knowledge extraction techniques and tools, and their impact on innovation. The study sample consisted of (92) employees of the organization under study, Rabigh Electricity Company, Saudi Arabia. The study developed a questionnaire as a tool for collecting demographic data from the sample in the study environment and data for extracting knowledge, its techniques, tools, and methods of use on the one hand, and innovation on the other hand. Through the processes of statistical analysis and statistical indications, the results of the study showed that there is, at a large rate, among the respondents an awareness of the importance and role of knowledge extraction in innovation in the company (significance α≤0.05). This is done by holding periodic meetings and workshops and using automated techniques to extract the stored identifier. Based on these results, the study recommends the establishment of an independent department for knowledge management in the company that includes a team of experts and specialists in the field of knowledge management and innovation to activate the processes of extracting knowledge and enhance the benefit from its applications, which achieves the company's vision and future goals

Knowledge Extraction and Innovation

The study aimed to reveal scientific studies and research that dealt with the relationship between knowledge extraction and innovation in general. The study used inductive and follow-up methods through searching in search engines, databases, and automated indexes. It showed that the practical trend for the study of innovation did not appear until the early fifties of the ninth century. Tenth, as for knowledge extraction, it appeared synonymously with knowledge discovery, knowledge gathering, data mining, and data processing at the end of the nineteenth century. A systematic review of the literature was also conducted to obtain more insight into the relationship between knowledge extraction and innovation, most of which dealt with knowledge management processes in general and their impact on innovation. There are a few studies that focus mainly and specifically on the process of knowledge extraction and its impact on innovation. One of the most prominent results was that information technology and its various techniques have a prominent role in facilitating access to knowledge, extracting it from its sources, and presenting it to the beneficiaries, which enhances the innovation process of employees and organizations

Factors Influencing the Emergence of Collective Action in a Traditional Fishery of Oman: An Empirical Assessment of Three Coastal Fishing Towns in South Al-Batinah

Factors influencing the emergence of collective action are studied using survey data from individual boat owners from Barka, Masn’a and Suwaiq. Fishermen who adopt a cooperative strategy tend to be more risk averse and have high economic dependence on the common property resources. Social identity as a fisherman also appears to predict fishermen's willingness to cooperate to manage their fishery. Resource scarcity and possession of information about the status of the resource is also influential in fishermen’s decision to cooperate. The results strongly suggest that group size does not have any significant influence on fishermen’s willingness to cooperate to manage their fishery. The study findings also indicated that while the first two sources of heterogeneity (cultural division and difference in objectives and interests) are considered as causing a strong obstruction to collective action, the same cannot be said about the difference in the distribution of income. More inequality does not necessarily lead to more efficient use of natural resources. Thus, Olson's (1965) exploitation hypothesis was ruled out.Keywords: Fisheries Economics, fisheries management, Economic Solutions to Customary, Aboriginal and Traditional Fishing Rights, group size, Common property resource

Destabilisation of a homogeneous bubbly flow in an annular gap bubble column

Destabilisation of a homogeneous bubbly flow in an annular gap bubble colum

An experimental study of gas void fraction in dilute alcohol solutions in annular gap bubble columns using a four-point conductivity probe

The influence of alcohol concentration on the gas void fraction in open tube and annular gap bubble columns has been investigated using a vertical column with an internal diameter of 0.102 m, containing a range of concentric inner tubes which formed an annular gap; the inner tubes had diameter ratios from 0.25 - 0.69. Gas (air) superficial velocities in the range 0.014-0.200 m/s were investigated. Tap water and aqueous solutions of ethanol and isopropanol, with concentrations in the range 8 - 300 ppm by mass, were used as the working liquids. Radial profiles of the local void fraction were obtained using a four-point conductivity probe and were crosssectionally averaged to give mean values that were within 12% of the volumeaveraged gas void fractions obtained from changes in aerated level. The presence of alcohol inhibited the coalescence between the bubbles and consequently increased the mean gas void fraction at a given gas superficial velocity in both the open tube and the annular gap bubble columns. This effect also extended the range of homogeneous bubbly flow and delayed the transition to heterogeneous flow. Moreover, isopropanol results gave slightly higher mean void fractions compared to those for ethanol at the same mass fraction, due to their increased carbon chain length. It was shown that the void fraction profiles in the annular gap bubble column were far from uniform, leading to lower mean void fractions than were obtained in an open tube for the same gas superficial velocity and liquid composition

Destabilisation of a homogeneous bubbly flow in an annular gap bubble column

Experimental results are presented to show that there are very significant differences in the mean gas void fractions measured in an open tube and a annular gap bubble column, when operated at the same gas superficial velocity, using a porous sparger. The mean gas void fraction decreases with increasing ratio of the inner to outer diameter of the annular gap column and the transition to heterogeneous flow occurs at lower gas superficial velocities and lower void fractions. Two reasons are proposed and validated by experimental investigations: (1) the presence of the inner tube causes large bubbles to form near the sparger, which destabilize the homogeneous bubbly flow and reduce the mean void fraction; this was confirmed by deliberately injecting large bubbles into a homogeneous dispersion of smaller bubbles and (2) the shape of the void fraction profiles changes with gap geometry and this affects the distribution parameter in the drift flux model