Suns-VOC_\textrm{OC} characteristics of high performance kesterite solar cells

Low open circuit voltage ($V_{OC}$) has been recognized as the number one problem in the current generation of Cu$_{2}$ZnSn(Se,S)$_{4}$ (CZTSSe) solar cells. We report high light intensity and low temperature Suns-$V_{OC}$ measurement in high performance CZTSSe devices. The Suns-$V_{OC}$ curves exhibit bending at high light intensity, which points to several prospective $V_{OC}$ limiting mechanisms that could impact the $V_{OC}$, even at 1 sun for lower performing samples. These V$_{OC}$ limiting mechanisms include low bulk conductivity (because of low hole density or low mobility), bulk or interface defects including tail states, and a non-ohmic back contact for low carrier density CZTSSe. The non-ohmic back contact problem can be detected by Suns-$V_{OC}$ measurements with different monochromatic illumination. These limiting factors may also contribute to an artificially lower $J_{SC}$-$V_{OC}$ diode ideality factor.Comment: 9 pages, 9 figures, 1 supplementary materia

Soil Investigation Gardu Induk Listrik Pasir Pengaraian Kecamatan Rambah Hilir Kabupaten Rokan Hulu

Tanah merupakan tempat bertumpunaya pondasi suatu konstruksi bangunan maupun jalan raya, keberadaannya akan sangat baik apabila kondisi tanah yang berada dibawahnya mempunyai daya dukung yang cukup untuk menahan beratnya suatu bangunan yang berada diatasnya. Oleh sebab itu pelaksanaan survei geologi dan investigasi struktur lapisan tanah sangat penting untuk memperoleh prediksi penurunan dan daya dukung tanah timbunan

Electronic structure and effects of dynamical electron correlation in ferromagnetic bcc-Fe, fcc-Ni and antiferromagnetic NiO

LDA+DMFT method in the framework of the iterative perturbation theory (IPT) with full LDA Hamiltonian without mapping onto the effective Wannier orbitals. We then apply this LDA+DMFT method to ferromagnetic bcc-Fe and fcc-Ni as a test of transition metal, and to antiferromagnetic NiO as an example of transition metal oxide. In Fe and Ni, the width of occupied 3d bands is narrower than those in LDA and Ni 6eV satellite appears. In NiO, the resultant electronic structure is of charge-transfer insulator type and the band gap is 4.3eV. These results are in good agreement with the experimental XPS. The configuration mixing and dynamical correlation effects play a crucial role in these results

Drying of complex suspensions

We investigate the 3D structure and drying dynamics of complex mixtures of emulsion droplets and colloidal particles, using confocal microscopy. Air invades and rapidly collapses large emulsion droplets, forcing their contents into the surrounding porous particle pack at a rate proportional to the square of the droplet radius. By contrast, small droplets do not collapse, but remain intact and are merely deformed. A simple model coupling the Laplace pressure to Darcy's law correctly estimates both the threshold radius separating these two behaviors, and the rate of large-droplet evacuation. Finally, we use these systems to make novel hierarchical structures.Comment: 4 pages, 4 figure

Aplikasi Analisis Faktor Konfirmatori untuk Mengetahui Hubungan Peubah Indikator dengan Peubah Laten yang Mempengaruhi Prestasi Mahasiswa di Jurusan Matematika FMIPA UNSRI

Analisis Faktor Konfirmatori adalah salah satu metode pada analisis multivariat yang digunakan untuk mengkonfirmasikan apakah model yang dibangun sesuai dengan yang dihipotesiskan. Untuk mengetahui hubungan peubah indikator dengan peubah laten yang mempengaruhi prestasi mahasiswa di Jurusan Matematika FMIPA UNSRI digunakan Analisis Faktor Konfirmatori dengan metode kemungkinan maksimum untuk menduga parameter modelnya. Hasil yang diperoleh bahwa peubah laten untuk latar belakang keluarga (Ԑ1) diukur oleh peubah indikator Pendidikan ayah (x1), Pendidikan ibu (x2) dan Penghasilan orang tua (x3), di mana peubah indikator yang memberikan kontribusi terbesar adalah Pendidikan ibu (0,84). Peubah laten lingkungan belajar di luar kampus (Ԑ2) diukur oleh peubah indikator waktu tempuh dari rumah ke kampus (x4), fasilitas belajar di rumah (x5) dan konsentrasi belajar (x8), di mana peubah indikator dengan kontribusi terbesar adalah fasilitas belajar di rumah (0,80). Peubah laten sikap terhadap almamater (Ԑ3) diukur oleh peubah indikator Fasilitas ruang belajar di jurusan (x11), Fasilitas perpustakaan (x12) dan Fasilitas komputer (x13), di mana peubah indikator dengan kontribusi terbesar adalah Fasilitas ruang belajar di jurusan (x11) (1,08). Peubah laten Persepsi terhadap dosen (Ԑ4) diukur oleh peubah indikator Sistem evaluasi oleh dosen (x16), Sistem pembelajaran oleh dosen (x17), Sistem penugasan oleh dosen (x18) dan Hubungan dengan pembimbing akademik (x19), di mana peubah indikator dengan kontribusi terbesar adalah Sistem pembelajaran oleh dosen (x17) (0,73)

Physiological and Canopy Temperature Responses to Drought of Four Penstemon Species

Available water for urban landscape irrigation is likely to become more limited because of inadequate precipitation and the ever-increasing water demand of a growing population. Recent droughts in the western United States have also increased the demand for low-water-use landscapes in urban areas. Penstemon species (beardtongues) are ornamental perennials commonly grown in low-water-use landscapes, but their drought tolerance has not been widely investigated. The objectives of this study were to determine the effects of water availability on the morphology, physiology, and canopy temperature of Penstemon barbatus (Cav.) Roth ‘Novapenblu’ (Rock Candy Blue® penstemon), P. digitalis Nutt. ex Sims ‘TNPENDB’ (Dakota™ Burgundy beardtongue), P. ×mexicali Mitch. ‘P007S’ (Pikes Peak Purple® penstemon), and P. strictus Benth. (Rocky Mountain penstemon). Twenty-four plants of each penstemon species were randomly assigned to blocks in an automated irrigation system, and the substrate volumetric water content was maintained at 0.15 or 0.35 m3⋅m−3 for 50 days. The decreased substrate volumetric water content resulted in a decreased aesthetic appearance of the four penstemon species because of the increased numbers of visibly wilted leaves and chlorosis. Plant growth index [(height + (width 1 + width 2)/2)/2], shoot number, shoot dry weight, leaf size, and total leaf area also decreased as the substrate volumetric water content decreased, but the root-to-shoot ratio and leaf thickness increased. Photosynthesis decreased, stomatal resistance increased, and warmer canopy temperatures were observed when plants were dehydrated. Additionally, as substrate volumetric water content decreased, the leaf reflectance of P. barbatus and P. strictus increased. Penstemon digitalis, which had the highest canopy–air temperature difference, was sensitive to drought stress, exhibiting a large proportion of visibly wilted leaves. Penstemon ×mexicali, which had the lowest root-to-shoot ratio, had the lowest shoot water content of the species studied and more than 65% of leaves visibly wilted when experiencing drought stress. Penstemon barbatus and P. strictus, native to arid regions, exhibited lower canopy–air temperature differences and better aesthetic quality than the other two species. Under the conditions of this study, Penstemon barbatus and P. strictus exhibited better drought tolerance than P. digitalis and P. ×mexicali

[(6-Methyl-2-pyridylmeth­yl)(2-pyridylmeth­yl)amine][(2-pyridylmeth­yl)amine]copper(II) bis­(perchlorate)

The title compound, [Cu(C6H8N2)(C13H15N3)](ClO4)2, is a mixed ligand complex with the CuII atom coordinated by (6-methyl-2-pyridylmeth­yl)(2-pyridylmeth­yl)amine, acting as a tridentate ligand, and 2-(2-amino­meth­yl)pyridine, as a bidentate ligand, leading to an N5 square-pyramidal geometry. The amine H atoms are involved in hydrogen bonding to the perchlorate O atoms and there are extensive but weak inter­molecular C—H⋯O inter­actions in the crystal structure. The perchlorate ions are each disordered over two positions, with site occupancies of 0.601 (8):0.399 (8) and 0.659 (11):0.341 (11)

Evaluasi Spermatozoa Domba Jantan Berekor Tipis yang Digembalakan di Lahan Kering

Penelitian ini bertujuan untuk mengevaluasi spermatozoa ternak domba jantan berekor tipis yang digembalakan di lahan kering. Populasi ternak domba yang ada di wilayah Timor Tengah Utara tergolong kecil yakni 8 ekor domba jantan dan 13 ekor betina sehingga penelitian ini hanya menggunakan 8 ekor pejantan dewasa berumur 2 tahun. Penampungan semen dilakukan seminggu sekali di pagi hari menggunakan vagina buatan. Hasil evaluasi spermatozoa secara makroskopis menunjukkan bahwa rataan volume semen yang diejakulasi mL 0,85 ± 0,09, warnanya putih/krem kekuningan, berbau khas ternak domba, konsistensinya kental, rataan pH : 7,18± 0,19. Penilaian Kualitas Spermatozoa secara  makroskopis diantaranya  nilai motilitas massa: +++ (baik), nilai  motilitas individu: 80%, daya hidup spermatozoa (Viabilitas): 81,5%± 4,54 konsentrasinya : 2,94 x 109/mL ± 0,50  dan abnormalitas spermatozoa: 15,85% ± 7,57.  Berdasarkan hasil penelitian ini dapat disimpulkan bahwa domba jantan berekor tipis yang digembalakan di lahan kering memiliki kualitas spermatozoa yang tinggi dan dapat di lanjutkan tahapan pengeceran semen dan pembekuan semen serta pengujian bioteknologi reproduksi inseminasi buatan

Volatile State Mathematical Models for Predicting Components in Biomass Pyrolysis Products

Volatile state mathematical models for quantifying the chemical components in volatile biomass pyrolysis products were developed. The component mass yield Yi rate depends linearly on its pseudo kinetic constant and the remaining mass yield. The mass fraction rate of each component was modeled from the derivation of its mass yield rate equation. A new mathematical model equation was successfully developed. The involved variables are: biomass number, temperature, heating rate, pre-exponential factor, and pseudo activation energy related to each component. The component mass fraction yi and the mass yield were predicted using this model within a temperature range. Available experimental pyrolysis data for beechwood and rice husk biomass were used to confirm the developed model. The volatile products were separated into bio-pyrolysis gas (BPG) and a bio-pyrolysis oil (BPO). Five components in the BPG and forty in the BPO were quantified. The pseudo activation energy for each pseudo chemical reaction for a specific component was modeled as a polynomial function of temperature. The component mass fraction and yield are quantifiable using this developed mathematical model equation within a temperature range. The predicted component mass fractions and yields agreed excellently with the available experimental data

Volatile State Mathematical Models for Predicting Components in Biomass Pyrolysis Products

Volatile state mathematical models for quantifying the chemical components in volatile biomass pyrolysis products were developed. The component mass yield Yi rate depends linearly on its pseudo kinetic constant and the remaining mass yield. The mass fraction rate of each component was modeled from the derivation of its mass yield rate equation. A new mathematical model equation was successfully developed. The involved variables are: biomass number, temperature, heating rate, pre-exponential factor, and pseudo activation energy related to each component. The component mass fraction yi and the mass yield were predicted using this model within a temperature range. Available experimental pyrolysis data for beechwood and rice husk biomass were used to confirm the developed model. The volatile products were separated into bio-pyrolysis gas (BPG) and a bio-pyrolysis oil (BPO). Five components in the BPG and forty in the BPO were quantified. The pseudo activation energy for each pseudo chemical reaction for a specific component was modeled as a polynomial function of temperature. The component mass fraction and yield are quantifiable using this developed mathematical model equation within a temperature range. The predicted component mass fractions and yields agreed excellently with the available experimental data