Almond[Prunus dulcis Miller(D.A.Webb)]is the main tree nut species worldwide.Here,genotyping-by-sequencing(GBS)was applied to 149 almond cultivars from the ex situ collections of the Italian Council for Agricultural R...Almond[Prunus dulcis Miller(D.A.Webb)]is the main tree nut species worldwide.Here,genotyping-by-sequencing(GBS)was applied to 149 almond cultivars from the ex situ collections of the Italian Council for Agricultural Research(CREA)and the Spanish National Research Council(CSIC),leading to the detection of 93,119 single-nucleotide polymorphisms(SNPs).The study of population structure outlined four distinct genetic groups and highlighted diversification between the Mediterranean and Californian gene pools.Data on SNP diversity and runs of homozygosity(ROHs)allowed the definition of kinship,inbreeding,and linkage disequilibrium(LD)decay in almond cultivated germplasm.Four-year phenotypic observations,gathered on 98 cultivars of the CREA collection,were used to perform a genome-wide association study(GWAS)and,for the first time in a crop species,homozygosity mapping(HM),resulting in the identification of genomic associations with nut,shell,and seed weight.Both GWAS and HM suggested that loci controlling nut and seed weight are mostly independent.Overall,this study provides insights on the almond cultivation history and delivers information of major interest for almond genetics and breeding.In a broader perspective,our results encourage the use of ROHs in crop science to estimate inbreeding,choose parental combinations minimizing the risk of inbreeding depression,and identify genomic footprints of selection for specific traits.展开更多
Ageing is associated with several anatomical and physiological changes of the organism, and the increase in global elderly population promotes the research to develop strategies to improve their quality of life. In th...Ageing is associated with several anatomical and physiological changes of the organism, and the increase in global elderly population promotes the research to develop strategies to improve their quality of life. In this work, we characterized the immunological alterations naturally produced during aging in a mice model, and evaluated the effect of probiotic Lactobacillus (L.) rhamnosus CRL1505 administration on those immunological parameters. We demonstrated that L. rhamosus CRL1505 was able to improve peritoneal macrophages phagocytic activity, and the number of intestinal IgA<sup>+</sup> cells in aged mice, reaching values of those parameters similar to young adult mice. The results of this work indicate that is plausible that the immunobiotic CRL1505 strain may find applications as a beneficial immunomodulator in aging to reinforce the intestinal and systemic immunity. The immune modulation in aging induced by L. rhamnosus CRL1505 could lead to the development of new strategies for functional foods specifically tailored for the elderly.展开更多
Introduction: On March 11, 2020, the World Health Organization (WHO) declared that the entire World was overrun by a pandemic. Science has managed, in a short time, to characterize a new disease, sequence a new viral ...Introduction: On March 11, 2020, the World Health Organization (WHO) declared that the entire World was overrun by a pandemic. Science has managed, in a short time, to characterize a new disease, sequence a new viral genome, develop diagnostics, produce treatment protocols and establish the efficacy of drugs and vaccines in randomized controlled trials. In this paper we have dealt with different topics regarding the pandemic linked to COVID-19. Objectives: Aim of this paper is to compare the number of deaths attributable to COVID-19, that occurred in the different Italian macro-areas, in the different pandemic waves;we studied the trend of the curves relating to the proportion of deaths to the number of infected in the Italian macro-areas for the pandemic waves and analysed the mortality data, focusing on the Italian context and comparing it with other foreign countries. We examined the data regarding swabs, hospitalizations, home isolation, admissions to intensive care and deaths registered in pandemic period. Results: Geographically, Italy was differently affected by the pandemic. Northern Italy was the most affected area. In comparison with some foreign countries, Italy is one of the nations that paid the most in terms of deaths, due to: delays in understanding the seriousness of the emergency;the slow management in the tracking systems of contagions;the high number of hospitalizations;a corporate organizational system poorly planned. Conclusion: The years 2020 and 2021 have been dramatic and unprecedented. The year 2021 was the year of redemption, where, despite social, economic and health difficulties, thanks to mass vaccination, we were able to give a real strong response to the pandemic. Trust in science has led to a drastic decrease in mortality throughout the world.展开更多
Cheeses are characterized by several chemical-physical properties that make it difficult for the microorganisms growth, consequently. The actual European legislation allows the addition of few food additives in this t...Cheeses are characterized by several chemical-physical properties that make it difficult for the microorganisms growth, consequently. The actual European legislation allows the addition of few food additives in this type of food products. In this work, the entire procedure of extraction, purification, chromatographic separations and quali/quantitative determination of seven food additives (sorbic acid, benzoic acid, lactic acid, acetic acid, nitrites, nitrates and phosphates) was developed and applied for the analysis of different types of cheese (mozzarella, cheese spread, semi-hard and hard cheeses). Through validation procedure it was possible to evaluate the most important validation parameters. Extended calibration curves (r > 0.990) were obtained for all the analyzed compounds. Recovery values ranged from 72.8% to 98.4% and a good repeatability was obtained, with precision levels in the range of 0.03% - 0.11% (n = 6). The potential and feasibility of the method were tested by analysing real samples, such as mozzarella, cheese spread, semi-hard and hard cheeses, confirming that the method is well suited to satisfy the demands for accurate confirmation analyses of seven food additives in cheeses, which is especially valuable in official check analyses and in monitoring schemes.展开更多
The effect of daily consumption of a yogurt containing Lactobacillus reuteri CRL 1098 on the lipid profile of hypercholesterolemic subjects was evaluated by performing a prospective, randomized, double-blind, cross-ov...The effect of daily consumption of a yogurt containing Lactobacillus reuteri CRL 1098 on the lipid profile of hypercholesterolemic subjects was evaluated by performing a prospective, randomized, double-blind, cross-over placebo controlled clinical study. Participants consumed daily a yogurt containing L. reuteri CRL 1098 or a placebo for four weeks, separated by a wash-out period. Total cholesterol, triacylglycerol, high-density (HDL) and low-density (LDL) lipoprotein levels were assessed at the beginning and at the end of each period. We found a statistically significant reduction of total (–7.86 g/dl) and LDL (–7.02 g/dl) cholesterol in absolute changes (before-after) as well as a decreasing trend in the group receiving the yogurt containing L. reuteri with respect to the placebo group, without detecting changes in HDL-cholesterol and triacylglycerol levels. Our results suggest that low amounts of yogurt (125 g/day) and low doses of the CRL 1098 strain (106 CFU) are sufficient to reduce total and LDL-cholesterol levels in hypercholesterolemic subjects.展开更多
Foxtail millet （Setaria italica） is one of the most valuable species in economic terms in the genus Setaria and plays an important role in human nutrition, animal feed, and agriculture. The present study described c...Foxtail millet （Setaria italica） is one of the most valuable species in economic terms in the genus Setaria and plays an important role in human nutrition, animal feed, and agriculture. The present study described chemical, physical, and quality aspects of seeds of foxtail millet. Furthermore, the fluid-dynamic behavior of the seeds was evaluated in a conical spouted bed, which has advantages in terms of promoting the cyclic and regular movement of the seed particles. Dynamic parameters of spouting （minimum spouting veloc- ity, stable and peak pressure drop） were determined and compared with those obtained from empirical correlations available in the literature. The results obtained from physical characterization showed that the seeds can be classified as belonging to Group D of Geldart, having a non-rough surface, mean diameter of 1.75 mm, and sphericity of 0.74. Fluid-dynamics analysis showed that the seeds are suitable for processing in a spouted bed, which is in agreement with the results of particle physical characterization.展开更多
Dear Editor,Evidence of oculomotor nerve（ON）synkinesis is a common occurrence following both acquired and congenital III nerve palsy[1].It is generally accepted that aberrant regeneration is the likely aetiology of ...Dear Editor,Evidence of oculomotor nerve（ON）synkinesis is a common occurrence following both acquired and congenital III nerve palsy[1].It is generally accepted that aberrant regeneration is the likely aetiology of synkinesis in acquired III nerve palsy,following intracranial aneurysm,trauma,展开更多
RMC （renal medullary carcinoma） is considered a rare entity, corresponding to approximately 2% of primary kidney tumors, usually occurring in the second decade of the patient＇s life and it is closely related with p...RMC （renal medullary carcinoma） is considered a rare entity, corresponding to approximately 2% of primary kidney tumors, usually occurring in the second decade of the patient＇s life and it is closely related with previous history of sickle cell disease. Studies have reported RMC as highly aggressive, poorly responsive to chemotherapy, surgery, radiotherapy or targeted therapy. This disease＇s median overall survival is less than 12 months. We are reporting a case of a 21-year-old woman with sickle cell trait, whose initial clinical presentation was RMC already metastatic to the liver. She underwent total right nephrectomy, and her clinical picture worsened during hospitalization with pneumonia, bowel obstruction, oliguria and death in less than two months after diagnosis, with no performance status to attempt any treatment options to her cancer at any time. Although some cases in the literature had reported good response to neoadjuvant therapy, this disease has early recurrence and little response to treatment. Our objective is to call the attention for this aggressive desease to estimulate new perspectives and further studies with chemotherapy and other different kinds of treatment, mainly because only surgical intervention is an incomplete aproach.展开更多
The treatment of metastic melanoma has rapidly evolved in the last 5 years, giving clinicians and patients the hope for long lasting responses. In the field of modern immunotherapy, we are reaching the point of an exp...The treatment of metastic melanoma has rapidly evolved in the last 5 years, giving clinicians and patients the hope for long lasting responses. In the field of modern immunotherapy, we are reaching the point of an expressive percentage of patients achieving long term survival with anti-CTLA4 and anti-PD1 checkpoint inhibitors. Of note, there is a considerable amount of patients excluded from the checkpoint blockade trials because of comorbidities like chronic viral infections. A precaution to avoid autoimmune induced hepatitis rendered HBV （hepatitis B virus） and HCV （hepatitis C virus） infected patients usually ineligible, but real life data in those patients, who are getting treatment despite of that, is pointing toward the feasibility and safety of immunotherapy in this context. To ilustrate that, we report the case of a metastatic non-BRAF mutated melanoma patient with HCV chronic infection and a surprising benefit derived from ipilimumab and pembrolizumab for his latter condition.展开更多
Pancreatic cancer is an aggressive and lethal disease that affects especially older population. Its more relevant tumor marker is CA 19-9 （carbohydrate antigen 19-9）, although it can be elevated in others clinical s...Pancreatic cancer is an aggressive and lethal disease that affects especially older population. Its more relevant tumor marker is CA 19-9 （carbohydrate antigen 19-9）, although it can be elevated in others clinical situations, like cholangitis and cholestasis. Otherwise, a small people subset, like our patient, do not produce this tumor marker, as on blood as in the tumor, because they are incapable to express the Lewis Antigen. Therefore, this case report is about a patient without Lewis Antigen express and CA 19-9 low levels. We will report a rapid disease progression, despite of low CA 19-9, comparing with available data that often show better prognosis in this setting. Conclusion： Low levels of CA 19-9 do not predict good response or better prognosis in patients that do not express Lewis Antigen.展开更多
Susanna Mancini,a 27-year-old lawyer,sent her boyfriend a photo of herself wearing a swimsuit and sunglasses."Too bad you can’t see my eyes,"she wrote him."I am so proud of my tough yuppie 2 stare!&quo...Susanna Mancini,a 27-year-old lawyer,sent her boyfriend a photo of herself wearing a swimsuit and sunglasses."Too bad you can’t see my eyes,"she wrote him."I am so proud of my tough yuppie 2 stare!"And one tough yuppie she was,Reuters reports:"Her professional pride propelled3her early career as a lawyer.She was successful and well paid for it."That was the late展开更多
The present paper studied numerical and experimentally the transesterification reaction between sunflower oil and ethanol with NaO H catalyst in microchannels with circular obstructions. The micromixer design influenc...The present paper studied numerical and experimentally the transesterification reaction between sunflower oil and ethanol with NaO H catalyst in microchannels with circular obstructions. The micromixer design influence on fluid mixing and oil conversion was investigated for a range of operating conditions: Reynolds number(Re = 0.1–100),Temperature(25–75 °C), ethanol/oil molar ratio(6-12), and catalyst concentration(0.75 wt%–1.25 wt%), using three microchannel configurations(Length = 35 mm; Width = 1500 μm; Height = 200 μm): T-shape – channel without obstructions; MCO – channel with 3 obstructions ensemble – equally disposed over longitudinal length;MWO – channel with 7 obstructions ensemble. The MCO micromixer was based on literature work, and the MWO is a totally new micromixer design. Experimental tests were conducted in similar conditions in microreactors using these micromixers(Length = 411 mm) made of polydimethylsiloxane. The MCO configuration presented the highest performance(mixing index of 0.80 at Re = 100), oil conversion of 81.13% at 75 °C, molar ratio of 9 and catalyst concentration of 1%. Experimental results showed high conversions for MCO and MWO configurations(99.99%) at 50 °C, molar ratio of 9 and catalyst concentration of 1%, with a residence time of 12 s.展开更多
This paper presents a controller model of asymmetric current injection for converter-interfaced generators suitable for root-mean-square(RMS)phasor-domain,fundamentalfrequency,three-phase,and dynamic simulation tools....This paper presents a controller model of asymmetric current injection for converter-interfaced generators suitable for root-mean-square(RMS)phasor-domain,fundamentalfrequency,three-phase,and dynamic simulation tools.The effectiveness of the proposed controller is assessed with simulations in test systems with high percentage of converter-interfaced generation.The simulations focus on the operation of protection relays that use negative-sequence quantities in their directional elements.This paper also presents and compares two strategies to limit reactive negative-sequence currents,and active and reactive positive-sequence currents.A tutorial test system and a regional system part of the actual Brazilian Interconnected Power System are used to assess the correctness of the proposed controller in three-phase fundamental-frequency RMS dynamic simulations.展开更多
The scope of the present research aims at demonstrating the 3D printing use in the manufacturing of microchannels for chemical process applications. A comparison among digital model processing applications for 3D prin...The scope of the present research aims at demonstrating the 3D printing use in the manufacturing of microchannels for chemical process applications. A comparison among digital model processing applications for 3D print(slicers) and a print layer thickness analysis were performed. The 3D print fidelity was verified in several devices, including the microchannels’ printing with and without micromixer zones. In order to highlight the 3D print potential in Chemical Engineering, the biodiesel synthesis was also carried out in a millireactor manufactured by 3D printing. The millireactor operated under laminar flow regime with a total flow rate of 75.25 ml·min^-1(increment of about 130 times over traditional microdevices used for biodiesel production).The printed millireactor provided a maximum yield of Ethyl Esters of 73.51% at 40 ℃, ethanol:oil molar ratio of7 and catalyst concentration of 1.25 wt% and residence time about 10 s. As a result of flow rate increment attained in the millireactor, the number of required units for scaling-up the chemical processes is reduced. Using the approach described in the present research, anyone could produce their own millireactor for chemical process in a simple way with the aid of a 3D printer.展开更多
文摘Almond[Prunus dulcis Miller(D.A.Webb)]is the main tree nut species worldwide.Here,genotyping-by-sequencing(GBS)was applied to 149 almond cultivars from the ex situ collections of the Italian Council for Agricultural Research(CREA)and the Spanish National Research Council(CSIC),leading to the detection of 93,119 single-nucleotide polymorphisms(SNPs).The study of population structure outlined four distinct genetic groups and highlighted diversification between the Mediterranean and Californian gene pools.Data on SNP diversity and runs of homozygosity(ROHs)allowed the definition of kinship,inbreeding,and linkage disequilibrium(LD)decay in almond cultivated germplasm.Four-year phenotypic observations,gathered on 98 cultivars of the CREA collection,were used to perform a genome-wide association study(GWAS)and,for the first time in a crop species,homozygosity mapping(HM),resulting in the identification of genomic associations with nut,shell,and seed weight.Both GWAS and HM suggested that loci controlling nut and seed weight are mostly independent.Overall,this study provides insights on the almond cultivation history and delivers information of major interest for almond genetics and breeding.In a broader perspective,our results encourage the use of ROHs in crop science to estimate inbreeding,choose parental combinations minimizing the risk of inbreeding depression,and identify genomic footprints of selection for specific traits.
文摘Ageing is associated with several anatomical and physiological changes of the organism, and the increase in global elderly population promotes the research to develop strategies to improve their quality of life. In this work, we characterized the immunological alterations naturally produced during aging in a mice model, and evaluated the effect of probiotic Lactobacillus (L.) rhamnosus CRL1505 administration on those immunological parameters. We demonstrated that L. rhamosus CRL1505 was able to improve peritoneal macrophages phagocytic activity, and the number of intestinal IgA<sup>+</sup> cells in aged mice, reaching values of those parameters similar to young adult mice. The results of this work indicate that is plausible that the immunobiotic CRL1505 strain may find applications as a beneficial immunomodulator in aging to reinforce the intestinal and systemic immunity. The immune modulation in aging induced by L. rhamnosus CRL1505 could lead to the development of new strategies for functional foods specifically tailored for the elderly.
文摘Introduction: On March 11, 2020, the World Health Organization (WHO) declared that the entire World was overrun by a pandemic. Science has managed, in a short time, to characterize a new disease, sequence a new viral genome, develop diagnostics, produce treatment protocols and establish the efficacy of drugs and vaccines in randomized controlled trials. In this paper we have dealt with different topics regarding the pandemic linked to COVID-19. Objectives: Aim of this paper is to compare the number of deaths attributable to COVID-19, that occurred in the different Italian macro-areas, in the different pandemic waves;we studied the trend of the curves relating to the proportion of deaths to the number of infected in the Italian macro-areas for the pandemic waves and analysed the mortality data, focusing on the Italian context and comparing it with other foreign countries. We examined the data regarding swabs, hospitalizations, home isolation, admissions to intensive care and deaths registered in pandemic period. Results: Geographically, Italy was differently affected by the pandemic. Northern Italy was the most affected area. In comparison with some foreign countries, Italy is one of the nations that paid the most in terms of deaths, due to: delays in understanding the seriousness of the emergency;the slow management in the tracking systems of contagions;the high number of hospitalizations;a corporate organizational system poorly planned. Conclusion: The years 2020 and 2021 have been dramatic and unprecedented. The year 2021 was the year of redemption, where, despite social, economic and health difficulties, thanks to mass vaccination, we were able to give a real strong response to the pandemic. Trust in science has led to a drastic decrease in mortality throughout the world.
文摘Cheeses are characterized by several chemical-physical properties that make it difficult for the microorganisms growth, consequently. The actual European legislation allows the addition of few food additives in this type of food products. In this work, the entire procedure of extraction, purification, chromatographic separations and quali/quantitative determination of seven food additives (sorbic acid, benzoic acid, lactic acid, acetic acid, nitrites, nitrates and phosphates) was developed and applied for the analysis of different types of cheese (mozzarella, cheese spread, semi-hard and hard cheeses). Through validation procedure it was possible to evaluate the most important validation parameters. Extended calibration curves (r > 0.990) were obtained for all the analyzed compounds. Recovery values ranged from 72.8% to 98.4% and a good repeatability was obtained, with precision levels in the range of 0.03% - 0.11% (n = 6). The potential and feasibility of the method were tested by analysing real samples, such as mozzarella, cheese spread, semi-hard and hard cheeses, confirming that the method is well suited to satisfy the demands for accurate confirmation analyses of seven food additives in cheeses, which is especially valuable in official check analyses and in monitoring schemes.
文摘The effect of daily consumption of a yogurt containing Lactobacillus reuteri CRL 1098 on the lipid profile of hypercholesterolemic subjects was evaluated by performing a prospective, randomized, double-blind, cross-over placebo controlled clinical study. Participants consumed daily a yogurt containing L. reuteri CRL 1098 or a placebo for four weeks, separated by a wash-out period. Total cholesterol, triacylglycerol, high-density (HDL) and low-density (LDL) lipoprotein levels were assessed at the beginning and at the end of each period. We found a statistically significant reduction of total (–7.86 g/dl) and LDL (–7.02 g/dl) cholesterol in absolute changes (before-after) as well as a decreasing trend in the group receiving the yogurt containing L. reuteri with respect to the placebo group, without detecting changes in HDL-cholesterol and triacylglycerol levels. Our results suggest that low amounts of yogurt (125 g/day) and low doses of the CRL 1098 strain (106 CFU) are sufficient to reduce total and LDL-cholesterol levels in hypercholesterolemic subjects.
文摘Foxtail millet （Setaria italica） is one of the most valuable species in economic terms in the genus Setaria and plays an important role in human nutrition, animal feed, and agriculture. The present study described chemical, physical, and quality aspects of seeds of foxtail millet. Furthermore, the fluid-dynamic behavior of the seeds was evaluated in a conical spouted bed, which has advantages in terms of promoting the cyclic and regular movement of the seed particles. Dynamic parameters of spouting （minimum spouting veloc- ity, stable and peak pressure drop） were determined and compared with those obtained from empirical correlations available in the literature. The results obtained from physical characterization showed that the seeds can be classified as belonging to Group D of Geldart, having a non-rough surface, mean diameter of 1.75 mm, and sphericity of 0.74. Fluid-dynamics analysis showed that the seeds are suitable for processing in a spouted bed, which is in agreement with the results of particle physical characterization.
文摘Dear Editor,Evidence of oculomotor nerve（ON）synkinesis is a common occurrence following both acquired and congenital III nerve palsy[1].It is generally accepted that aberrant regeneration is the likely aetiology of synkinesis in acquired III nerve palsy,following intracranial aneurysm,trauma,
文摘RMC （renal medullary carcinoma） is considered a rare entity, corresponding to approximately 2% of primary kidney tumors, usually occurring in the second decade of the patient＇s life and it is closely related with previous history of sickle cell disease. Studies have reported RMC as highly aggressive, poorly responsive to chemotherapy, surgery, radiotherapy or targeted therapy. This disease＇s median overall survival is less than 12 months. We are reporting a case of a 21-year-old woman with sickle cell trait, whose initial clinical presentation was RMC already metastatic to the liver. She underwent total right nephrectomy, and her clinical picture worsened during hospitalization with pneumonia, bowel obstruction, oliguria and death in less than two months after diagnosis, with no performance status to attempt any treatment options to her cancer at any time. Although some cases in the literature had reported good response to neoadjuvant therapy, this disease has early recurrence and little response to treatment. Our objective is to call the attention for this aggressive desease to estimulate new perspectives and further studies with chemotherapy and other different kinds of treatment, mainly because only surgical intervention is an incomplete aproach.
文摘The treatment of metastic melanoma has rapidly evolved in the last 5 years, giving clinicians and patients the hope for long lasting responses. In the field of modern immunotherapy, we are reaching the point of an expressive percentage of patients achieving long term survival with anti-CTLA4 and anti-PD1 checkpoint inhibitors. Of note, there is a considerable amount of patients excluded from the checkpoint blockade trials because of comorbidities like chronic viral infections. A precaution to avoid autoimmune induced hepatitis rendered HBV （hepatitis B virus） and HCV （hepatitis C virus） infected patients usually ineligible, but real life data in those patients, who are getting treatment despite of that, is pointing toward the feasibility and safety of immunotherapy in this context. To ilustrate that, we report the case of a metastatic non-BRAF mutated melanoma patient with HCV chronic infection and a surprising benefit derived from ipilimumab and pembrolizumab for his latter condition.
文摘Pancreatic cancer is an aggressive and lethal disease that affects especially older population. Its more relevant tumor marker is CA 19-9 （carbohydrate antigen 19-9）, although it can be elevated in others clinical situations, like cholangitis and cholestasis. Otherwise, a small people subset, like our patient, do not produce this tumor marker, as on blood as in the tumor, because they are incapable to express the Lewis Antigen. Therefore, this case report is about a patient without Lewis Antigen express and CA 19-9 low levels. We will report a rapid disease progression, despite of low CA 19-9, comparing with available data that often show better prognosis in this setting. Conclusion： Low levels of CA 19-9 do not predict good response or better prognosis in patients that do not express Lewis Antigen.
文摘Susanna Mancini,a 27-year-old lawyer,sent her boyfriend a photo of herself wearing a swimsuit and sunglasses."Too bad you can’t see my eyes,"she wrote him."I am so proud of my tough yuppie 2 stare!"And one tough yuppie she was,Reuters reports:"Her professional pride propelled3her early career as a lawyer.She was successful and well paid for it."That was the late
基金the Unicamp Scholarship Program,CAPES and the financial support provided by FAPESP(Sao Paulo Research Foundation,Process 2013/25850-7)Prof.Dr.Milton Mori for giving space to perform the simulations and the Microfabrication Laboratory(Proposal LMF-19844)
文摘The present paper studied numerical and experimentally the transesterification reaction between sunflower oil and ethanol with NaO H catalyst in microchannels with circular obstructions. The micromixer design influence on fluid mixing and oil conversion was investigated for a range of operating conditions: Reynolds number(Re = 0.1–100),Temperature(25–75 °C), ethanol/oil molar ratio(6-12), and catalyst concentration(0.75 wt%–1.25 wt%), using three microchannel configurations(Length = 35 mm; Width = 1500 μm; Height = 200 μm): T-shape – channel without obstructions; MCO – channel with 3 obstructions ensemble – equally disposed over longitudinal length;MWO – channel with 7 obstructions ensemble. The MCO micromixer was based on literature work, and the MWO is a totally new micromixer design. Experimental tests were conducted in similar conditions in microreactors using these micromixers(Length = 411 mm) made of polydimethylsiloxane. The MCO configuration presented the highest performance(mixing index of 0.80 at Re = 100), oil conversion of 81.13% at 75 °C, molar ratio of 9 and catalyst concentration of 1%. Experimental results showed high conversions for MCO and MWO configurations(99.99%) at 50 °C, molar ratio of 9 and catalyst concentration of 1%, with a residence time of 12 s.
基金supported by CNPQ,FAPERJ and Coordenacao de Aperfeicoamento de Pessoal de Nível Superior–Brasil(CAPES)Finance Code 001。
文摘This paper presents a controller model of asymmetric current injection for converter-interfaced generators suitable for root-mean-square(RMS)phasor-domain,fundamentalfrequency,three-phase,and dynamic simulation tools.The effectiveness of the proposed controller is assessed with simulations in test systems with high percentage of converter-interfaced generation.The simulations focus on the operation of protection relays that use negative-sequence quantities in their directional elements.This paper also presents and compares two strategies to limit reactive negative-sequence currents,and active and reactive positive-sequence currents.A tutorial test system and a regional system part of the actual Brazilian Interconnected Power System are used to assess the correctness of the proposed controller in three-phase fundamental-frequency RMS dynamic simulations.
基金the National Postdoctoral Program(PNPD/CAPES)the UNICAMP Scholarship Program+2 种基金FUNCAMP(UNICAMP Foundation)the financial support provided by CNPq(National Council for Scientific and Technological Development,Process404760/2016-3)FAPESP(Sao Paulo Research Foundation,Process 2016/20842-4).
文摘The scope of the present research aims at demonstrating the 3D printing use in the manufacturing of microchannels for chemical process applications. A comparison among digital model processing applications for 3D print(slicers) and a print layer thickness analysis were performed. The 3D print fidelity was verified in several devices, including the microchannels’ printing with and without micromixer zones. In order to highlight the 3D print potential in Chemical Engineering, the biodiesel synthesis was also carried out in a millireactor manufactured by 3D printing. The millireactor operated under laminar flow regime with a total flow rate of 75.25 ml·min^-1(increment of about 130 times over traditional microdevices used for biodiesel production).The printed millireactor provided a maximum yield of Ethyl Esters of 73.51% at 40 ℃, ethanol:oil molar ratio of7 and catalyst concentration of 1.25 wt% and residence time about 10 s. As a result of flow rate increment attained in the millireactor, the number of required units for scaling-up the chemical processes is reduced. Using the approach described in the present research, anyone could produce their own millireactor for chemical process in a simple way with the aid of a 3D printer.
