The "hit" problem of five variables in the generic degree and its application

Let $P_s:= \mathbb F_2[x_1,x_2,\ldots ,x_s]$ be the graded polynomial algebra over the prime field of two elements, $\mathbb F_2$, in $s$ variables $x_1, x_2, \ldots , x_s$, each of degree $1$. We are interested in the Peterson "hit" problem of finding a minimal set of generators for $P_s$ as a graded left module over the mod-2 Steenrod algebra, $\mathscr {A}$. For $s\geqslant 5,$ it is still open. In this paper, we study the hit problem of five variables in a generic degree. By using this result, we survey Singer's conjecture for the fifth algebraic transfer in the respective degrees. This gives an efficient method to study the algebraic transfer and it is different from the ones of Singer.Comment: 29 page

Using Network Analysis to Understand and Advance Falls Prevention Services and Programs

The purpose of this study was to understand referral linkages that exist among falls prevention agencies in a southern Ontario region using network analysis theory. This was a single case study which included fifteen individual interviews. The data was analyzed through the constant comparative approach. Ten themes emerged and are classified into internal and external factors. Themes associated with internal factors are: 1) health professionals initiating services; 2) communication strategies; 3) formal partnerships; 4) trust; 5) program awareness; and 6) referral policies. Themes associated with external factors are: 1) client characteristics; 2) primary and community care collaboration; 3) networking; and 4) funding. Recommendations to improve the referral pathway are: 1) electronic database; 2) electronic referral forms; 3) educating office staff; and 4) education days. This study outlined the benefit of using network analysis to understand referral pathways and the importance of implementing strategies that will improve falls prevention referral pathways

Calculating the energy yield of Si-based solar cells for Belgium and Vietnam regions at arbitrary tilt and orientation under actual weather conditions

Predicting actual energy harvesting of a photovoltaic (PV) installation as per site-specific conditions is essential, from the customer's point of view, to choose suitable PV technologies as well as orientations, since most PVs usually have been designed and evaluated under standard illumination. Hence, the tendency lives in the PV community to evaluate the performance on the energy yield and not purely on the efficiency. The major drawback is that weather conditions play an important role, and recording solar spectra in different orientations is an expensive and time-consuming business. We, therefore, present a model to calculate the daily, monthly and annual energy yield of Si-based PV installations included in commercial panels as well as tandem solar cells. This methodology will be used to evaluate the benefit of potential new technologies for domestic and building integrated applications. The first advantage of such a numerical model is that the orientation of solar panels and their properties can be easily varied without extra experiments. The second advantage is that this method can be transferred to other locations since it is based on a minimum of input parameters. In this paper, the energy yield of PV installations for different regions in Belgium and Vietnam will be calculated

Predicting energy yield of outdoor Si-based PV installations for Belgium and Vietnam regions at arbitrary tilt and orientation

Over the past decade, photovoltaic solar energy (PV) has been achieved great developments in terms of performance enhancement, cost reduction and scale of deployment. A wide range of materials, device technologies and architectures have been applied to fabricate higher efficiency and lower cost PV. Consequently, Silicon-based single-junction PV, which are dominating the PV industry, are approaching their fundamental efficiency limit of 29.4%. To overcome this barrier, multi-junction or tandem solar cells, which consist of a thin film wide-bandgap top cell and a silicon bottom cell, are very promising. Recently, record efficiencies of 32.5% and 32.8% were achieved for III-V/Si dual-junction solar cells based on stacking of GaInP and GaAs top cells on silicon heterojunction bottom cells, respectively. However, the performance of PV is frequently measured and evaluated under standard test conditions which are considerably different from outdoor operating conditions. In addition, predicting actual harvesting energy of a PV installation as per site-specific conditions is essential for customer’s point of view to choose suitable PV technologies as well as orientation. We, therefore, propose a model to calculate the daily, monthly and annual energy yield of outdoor Si-based PV installations included commercial panels as well as tandem solar cells operating at arbitrary tilt and orientation. This methodology will be used to evaluate the benefit of potential new PV technologies for outdoor domestic and building integrated applications. The advantage of this method is that the orientation of solar panels and their properties can be adjusted quickly without extra experiments and transferring to other locations can be done easily since it based on a minimum of input parameters. In this presentation, the energy yield calculation of outdoor PV installations for different regions in Belgium and Vietnam will be carried out

Application of BaY2F8:Er3+,Yb3+ and Mg8Ge2O11F2:Mn4+ in improving the lighting quality of phosphor-in-glass based white light-emitting diodes with the dual-convex design

Although the luminous of the remote phosphor structure tends to be better than that of the in-cup or conformal phosphor structures, the poor light quality prevents this lighting method from being widely used. It is recognized through experiments that the two-layer remote phosphorus structure should be used to improve color rendering index (CRI) and color quality ratio (CQS) for WLEDs. In the experiments, WLED structures containing green BaY2F8:Er3+,Yb3+ or red Mg8Ge2O11F2:Mn4+ phosphor on the yellow YAG:Ce3+ phosphor were performed at 8500 K.. After that, Mg8Ge2O11F2:Mn4+ and BaY2F8:Er3+,Yb3+ concentrations in each WLED structure is adjusted until chromatic performance reached the finest quality. As a result, Mg8Ge2O11F2:Mn4+is proved to bring great benefits to the increase of CRI and CQS. Specifically, the greater the concentration of Mg8Ge2O11F2:Mn4+, the better CRI and CQS because of the additional red-light material from this phosphor. The other phosphor material, green BaY2F8:Er3+,Yb3+ phosphor, is beneficial for the expansion of luminous flux. However, if the concentration of Mg8Ge2O11F2:Mn4+ or BaY2F8:Er3+,Yb3+ is over the limit, the decrease in lumen output and chromatic quality will occur. While doing the experiment, Mie-scattering theory and the Beer’s law are great tools to verify the accuracy of results. The results of this article can serve the purpose of improving WLEDs fabrication to produce higher quality product