Effect of rapid thermal processing conditions on the properties of Cu2ZnSnS4 thin films and solar cell performance

In the present work, we have studied the effect of several sulphurization conditions on the properties of Cu2ZnSnS4 thin films obtained through rapid thermal processing (RTP) of multi-period precursors with 8 periods of Zn/SnS2/CuS. In this study we varied the heating rate, the maximum sulphurization temperature, the time at maximum temperature and the amount of evaporated sulphur. The samples were characterized through scanning electron microscopy, energy dispersive spectroscopy, Raman scattering spectroscopy, X-ray diffraction, photoluminescence and I–V measurements. We have observed that at heating rates above 0.5 1C/s the samples delaminated severely. As a result further tests were carried out at 0.2 1C/s heating rate. The morphological studies revealed that the samples sulphurized at higher temperatures, shorter times and higher amount of evaporated sulphur exhibited larger grain sizes. The structural analysis based on Raman scattering and XRD did not lead to a clear distinction between the samples. Photoluminescence spectroscopy studies showed an asymmetric broad band characteristic of CZTS, which occurs in the range of 1.0–1.4 eV and a second band, on the high energy side of the previous one, peaking at around 1.41 eV. The intensity of this latter band varies from sample to sample revealing substantial differences in their optical properties. This band appears to originate either from the surface of the absorber or from the CdS layer and has a clear correlation with cell efficiency. The higher the intensity of this band the lower the cell efficiency, presumably due to the increase in recombination resulting from CZTS surface decomposition and eventually from the CdS with modified optoelectronic properties. The cell results hint toward a detrimental effect of long sulphuriza-tion times and a positive effect of higher sulphur vapour pressure and higher sulphurization temperature. Solar cell efficiencies improved with increased grain size in the absorber layer. The highest cell efficiency obtained in this study was 3.1%.info:eu-repo/semantics/publishedVersio

Influence of a low magnetic field on the thermal diffusivity of Bi-2212

The thermal diffusivity of a Bi-2212 polycrystalline sample has been measured under a 1T magnetic field applied perpendicularly to the heat flux. The magnetic contribution to the heat carrier mean free path has been extracted and is found to behave as a simple power law. This behavior can be attributed to a percolation process of electrons in the vortex lattice created by the magnetic field.Comment: 10 pages, 3 figures; to be published in Phys. Rev.

Effects of starch/polycaprolactone-based blends for spinal cord injury regeneration in neurons/glial cells viability and proliferation

Spinal cord injury (SCI) leads to drastic alterations on the quality of life of afflicted individuals. With the advent of Tissue Engineering and Regenerative Medicine where approaches combining biomaterials, cells and growth factors are used, one can envisage novel strategies that can adequately tackle this problem. The objective of this study was to evaluate a blend of starch with poly(ε-caprolactone) (SPCL) aimed to be used for the development of scaffolds spinal cord injury (SCI) repair. SPCL linear parallel filaments were deposited on polystyrene coverslips and assays were carried out using primary cultures of hippocampal neurons and glial cells. Light and fluorescence microscopy observations revealed that both cell populations were not negatively affected by the SPCL-based biomaterial. MTS and total protein quantification indicated that both cell viability and proliferation rates were similar to controls. Both neurons and astrocytes occasionally contacted the surface of SPCL filaments through their dendrites and cytoplasmatic processes, respectively, while microglial cells were unable to do so. Using single cell [Ca2+ ]i imaging, hippocampal neurons were observed growing within the patterned channels and were functional as assessed by the response to a 30 mM KCl stimulus. The present data demonstrated that SPCL-based blends are potentially suitable for the development of scaffolds in SCI regenerative medicine.Portuguese Foundation for Science and Technology through funds from POCTI and/or FEDER programs (Funding to ICVS, 3B's Research Group and post doctoral fellowship to A.J. Salgado-SFRH/BPD/17595/2004)

Temperature-responsive nanomagnetic logic gates for cellular hyperthermia

While a continuous monitoring of temperature at the micro- and nano-scales is clearly of interest in many contexts, in many others a yes or no answer to the question "did the system locally exceed a certain temperature threshold?" can be more accurate and useful. This is the case of hard-to-detect events, such as those where temperature fluctuations above a defined threshold are shorter than the typical integration time of micro/nanothermometers and systems where fluctuations are rare events in a wide time frame. Herein we present the synthesis of iron selenide magnetic nanoplatelets and their use as non-volatile logic gates recording the near infrared (NIR) dose that triggers a temperature increase above a critical temperature around 42 °C in prostate cancer cell cultures. This use is based on the bistable behavior shown by the nanoplatelets below a magnetic phase transition at a tunable temperature T C and on their photothermal response under NIR light. The obtained results indicate that the synthesized nanomagnets may be employed in the future as both local heaters and temperature monitoring tools in a wide range of contexts involving systems which, as cells, are temperature-sensitive around the tunable T C

Technical and economic pre-feasibility study for the construction of septic tank-filter-sinkhole with alternative material

Received: February 2nd, 2021 ; Accepted: August 3rd, 2021 ; Published: August 24th, 2021 ; Correspondence: [email protected] study of the different materials used in the construction of septic tanks aims to facilitate and spread the use of this sewage treatment system in places that are not assisted by municipal sewage systems and in the rural area, which despite having a smaller number of inhabitants compared to the urban area This study aims to carry out a technical and economic evaluation of the concrete and tires using in the construction of septic tanks-filter-sinkhole. The wastewater treatment systems were built according to the recommendations in NBR 7229/93 and 13969/97. To evaluate the efficiency of each system built, the following parameters were analyzed: chemical oxygen demand (COD), the potential of hydrogen (pH), alkalinity, acidity, and temperature. In the economic evaluation, the materials and labor required to install the systems were considered using the Brazilian cost database (SINAPI), and an economic and financial feasibility study was carried out. According to the technical and economic analysis of construction, both systems showed the same technical performance, however, the concrete design proved to be more advantageous than the tire design, considering the difficulty in acquiring the tires and the high cost if it is necessary to buy them, in addition to the greater difficulty in handling and installing the tire system compared to the concrete one

AVALIAÇÃO HISTOPATOLÓGICA, HORMONAL E BACTERIOLÓGICA DA PIOMETRA NA CADELA

O presente estudo teve como objetivo analisar os níveis hormonais, as alterações histopatológicas e os agentes etiológicos encontrados na piometra aberta e fechada em cadelas. Foram colhidas 30 amostras de fêmeas ovariohisterectomizadas em clínicas veterinárias da cidade de Curitiba, no Estado do Paraná, no período de outubro de 2002 a maio de 2003. Procedeu-se a exames bacteriológicos, análises histopatológicas dos cornos uterinos e dosagem hormonal da progesterona e do estradiol pela quimioluminescência. A bactéria isolada em maior porcentagem (36%) foi a Escherichia coli, e a alteração histológica de hiperplasia cística endometrial encontrada variou do grau I ao grau III. A proporção entre a progesterona e estradiol teve uma variação significativa nos dois tipos de piometra, porém não foi possível relacionar o agente etiológico, o tipo de lesão e a dosagem hormonal com o tipo de piometra, aberta ou fechada. Histopathological, hormonal, bacterial evaluation in the bitch pyometra Abstract The aim of the present study was to carry out an evaluation of the hormone levels, the histological changes and the etiological agents found in the open and closed pyometra. The uterine horns were collected from 30 bitches subjected to ovariectomy in different veterinary clinics from Curitiba, State of Parana, during the period of October 2002 to May, 2003. Bacteriological cultures, histological analysis and assays of progesterone and estradiol by the chemoluminescent method were performed. Escherichia coli showed to be the most frequent (36%) of the isolated bateria. It has been found the histological analysis that cystic endometrial hyperplasia varied from type I to type III. The progesterone/ estradiol ratio showed a significant variation in regard to the two types of piometra. However, it was not possible to corrrelate the etiological agent, the lesion and the hormonal levels with the open or closed pyometra

Controlling Bovine Brucellosis In The State Of São Paulo, Brazil: Results After Ten Years Of A Vaccination Program

A cross- sectional study was carried out, between May and November 2011, to estimate the situation of the bovine brucellosis in São Paulo State, 10 years after the commencement of the vaccination of the heifers with the S19 strain. The State was divided into seven regions and in each of them, 300 farms with reproductive activity were randomly chosen and considered as primary sample units. A fixed number of cows was randomly selected and tested for antibodies against Brucella spp. A farm was considered infected if at least one female tested positive. In the selected farms, an epidemiological questionnaire was administered which focused on herd traits as well as husbandry and sanitary practices that could be associated with the risk of infection. The prevalence (percentile, [95% confidence interval]) of infected herds was 10.2% [8.8-11.8] for the State, and for the regions, it varied from 7.3% [4.7-11.2] to 12.3% [8.8-16.8], not showing significant difference between different regions. The apparent prevalence of positive farms in the State and regions remained similar to the prevalence observed 10 years before. The prevalence of positive animals was 2.4% [1.8-3.1] in the State and varied from 1.1% [0.6-2] to 3.5% [1.7-7.1] in the regions, not showing significant difference between regions. Again, there was no difference in the prevalence of positive animals after 10 years of the vaccination program. The risk factors (odds ratio, 95% confidence interval) associated with bovine brucellosis in the State included number of cows = 24 (3.08, 2.22-4.27) and the acquisition of breeding animals (1.33, 0.95-1.87). The São Paulo State should conduct systematic vaccination coverage of above 80% of the eligible heifers with the S19 strain vaccine annually. Moreover, the State should emphatically use RB51 strain vaccine in females above 8 months of age not vaccinated with S19 strain vaccine. An efficient animal health education program to orientate farmers to test replacement animals for brucellosis prior to introduction in their herds should also be implemented.3753505351

Hypersensitivity reaction after intravenous administration of meloxicam in dogs - case report

ABSTRACT Although rarely reported in veterinary medicine, this article shows three cases of dogs that presented anaphylactic reactions after intravenous administration of meloxicam at therapeutic doses. Three dogs of different breeds and ages were submitted to anesthesia for surgical procedures of ovariohysterectomy and repair of patellar luxation. The animals were classified as ASA I and did not present changes in clinical and laboratory tests. All dogs were anesthetized and monitored by anesthesiologists, with careful multiparametric evaluation. Near the end of the procedures, meloxicam was administered intravenously in all dogs, and the drug used had the same commercial presentation and concentration, but with different lot numbers and with different months. For less than a minute, the animals showed significant hypotension, with pressure values close to 30 mmHg or inaudible by Doppler. The animals had no skin signs, only hypotension and a decrease in heart rate in one of them. All dogs were immediately treated with intravenous ephedrine and atropine in the bradycardic patient. After the emergency treatment, the dogs showed stabilized vital signs, with no complications or need for additional intervention. After the event, the three dogs showed no signs of clinical, behavioral or laboratory changes

Correlation effects in ionic crystals: I. The cohesive energy of MgO

High-level quantum-chemical calculations, using the coupled-cluster approach and extended one-particle basis sets, have been performed for (Mg2+)n (O2-)m clusters embedded in a Madelung potential. The results of these calculations are used for setting up an incremental expansion for the correlation energy of bulk MgO. This way, 96% of the experimental cohesive energy of the MgO crystal is recovered. It is shown that only 60% of the correlation contribution to the cohesive energy is of intra-ionic origin, the remaining part being caused by van der Waals-like inter-ionic excitations.Comment: LaTeX, 20 pages, no figure