Academic literature on the topic 'Fasi solide naturali'
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Journal articles on the topic "Fasi solide naturali"
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Silva, F. M., D. C. Coelho, A. V. Machado, and R. O. Costa. "Detecção de Resíduos de Agrotóxicos no Mel de Abelha." ACTA Apicola Brasilica 2, no. 2 (October 17, 2014): 17. http://dx.doi.org/10.18378/aab.v2i2.3738.
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<p>As abelhas A. melífera são uns dos mais importantes polinizadores de culturas, além disso, elas produzem mel, própolis, geleia real e cera. O mel, principal produto da atividade apícola, utilizado como alimento, adoçante e para fins terapêuticos (apiterapia), tem a imagem de ser natural, saudável e limpo sendo esse um produto muito valorizado no mercado externo por isso, a busca por rigorosos padrões de qualidade se torna necessária para atender a um mercado consumidor cada vez mais exigente. Dessa forma a identificação da origem floral e geográfica, a ocorrência de adulterações e as contaminações, principalmente com antibióticos e agrotóxicos no mel tem se tornado uma rota importante devido os quais podem acarretar problemas de saúde ao consumidor. A dispersão da matriz em fase sólida (MSPD) combinada às técnicas cromatográficas modernas como cromatografia a gás (GC) e cromatografia a líquido (HPLC) é uma alternativa para evitar os diversos inconvenientes encontrados nos métodos clássicos de extração. A proposta desse trabalho foi pesquisar os diferentes tipos de Análises e metodologias de detecção de resíduos de agrotóxicos no mel de abelha Apresentando diferentes metodologias para a execução de estudos para validação de metodologia em métodos analítico, utilizando as técnicas de dispersão da matriz em fase sólida, cromatografia a gás acoplada à espectrometria de massas e cromatografia líquida de alta eficiência com detector espectrofotométrico com arranjo de diodos.</p><p><strong>Pesticide Residues in Honey Pesticide Residues detection in Bee honey</strong></p><pre> </pre><p><strong> </strong>A. mellifera bees are one of the most important pollinators of crops in addition they produce honey, propolis, royal jelly and wax. Honey, the main product of beekeeping, used as food, sweetener and in therapy (apitherapy), has the image of being natural, healthy and clean making a highly valued product in the foreign market so the search for rigorous standards of quality is needed to meet a consumer market increasingly demanding. Thus the identification of floral and geographical origin, the occurrence of tampering and contamination, especially with antibiotics and pesticides in honey has become an important route because which can cause health problems to consumers. The dispersion of the solid phase matrix (PDDM) combined with modern chromatographic techniques as gas chromatography (GC) and liquid chromatography (HPLC) is an alternative to avoid the various drawbacks found in classical extraction methods. The purpose of this study was to investigate the different types of analyzes and pesticide residue detection methodologies in honey Introducing different methodologies for carrying out studies for validation of a method in analytical methods, using the matrix dispersion techniques in solid phase, gas chromatography coupled to mass spectrometry and high-performance liquid chromatography with UV detector with diode array.</p>
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Wahyuningtyas, Eka Sakti, Nasruddin Nasruddin, Heni Setyowati Esti Rahayu, Heni Lutfiyati, Isabella Meliawati Sikumbang, Laela Hayu Nurani, Afiana Rohmani, Nia Salsabila, and Gela Setya Ayu Putri. "Efektivitas Perlakuan Kombinatif Plasma Medis dan Ekstrak Daun Sirih untuk Mempercepat Penyembuhan Luka Fase Proliferasi pada Model Mencit Diabetik." Jurnal Ilmiah Kesehatan Keperawatan 15, no. 2 (December 29, 2019): 81. http://dx.doi.org/10.26753/jikk.v15i2.378.
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The continued increase in the number of people with Diabetes Mellitus (DM) in Indonesia is a serious problem. One of the big problems for people with Diabetes Mellitus (DM) is the emergence of complications of diabetic wounds. To date the strategy for treatment of diabetic wounds has been limited to the use of wound dressing, cell therapy and oxygen therapy. The problem is that the strategy is not fully successful. Thus, it is very important to look for new strategies to improve the quality of diabetic wound healing, such as by applying a combination of plasma medicine and local natural product, like the extraction of Daun sirih (Piper betle) leaves. Plasma medicine is a relatively new and multidisciplinary study involving plasma science, biomedical, pharmaceutical and other health sciences aimed at applying plasma to therapeutic health. Plasma is the fourth phase of matter, after the solid, liquid and gas phase. The medical aspects of plasma are related to the ability of plasma to produce biological molecules Reactive Oxygen and Nitrogen Species (RONS). If RONS is controlled in the right dosage it can be efficacious for health therapy. This study intends to examine the effects of combinative treatment of plasma medicine and Piper betel leaf extract for proliferation phase of wound healing in diabetic small animal model. This study used male Balb c mice with acute wounds which were divided into 5 groups, namely groups of untreated normal mice (ND-TP), groups of untreated diabetic mice (D-TP), groups of diabetic mice wounds with Piper betel leaf extract (DS ), the wound group of diabetic mice with plasma medicine (DP) and the wound group of diabetic mice with plasma medicine and Piper betel leaf (DPS). The plasma medicine was treated on wound with condition non-contact style (the plasma jet did not touch the wound) with a distance of plasma jet reactor nozzle to the surface of wound about 20 mm, for 2 minutes, every day. Macroscopic observation of wounds is carried out every day from day 0 to 7. On day 7 it was seen that the size of the wound area for D-P-S was smaller than the other groups. The results of this study indicated that Piper betel leaf extract can potentially be used to optimize the performance of plasma medicine in accelerating diabetic wound healing during the proliferation phase. Further investigation, however, is important to be conducted to study the effect for all phases of wound healing and its mechanism histo-pathologically.
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Berghuis, Nila Tanyela, Mutaqqin Mutaqqin, Farid Imam Hidayat, Sugianto Sugianto, Harbi Pratama, Anggun Kirana, David Aji Rifaldi, Abelia Jesica, Paradigma Maulana, and Afif Thufail. "Perbandingan Penggunaan Katalis Alam (Zeolit dan Bentonit) dalam Sintesis Biodiesel dari Minyak Goreng Komersil." ALCHEMY Jurnal Penelitian Kimia 18, no. 2 (September 23, 2022): 174. http://dx.doi.org/10.20961/alchemy.18.2.57616.174-182.
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<p>Biodiesel merupakan suatu senyawa metil ester berantai panjang yang mengandung asam lemak yang diperoleh melalui reaksi transesterifikasi. Bahan bakar alternatif ini dapat disintesis dari minyak goreng komersial dengan bantuan katalis. Katalis basa sering digunakan dalam reaksi transesterifikasi pada sintesis biodiesel. Penggunaan katalis akan meningkatkan persentase dari produk biodiesel yang dihasilkan. Katalis berfasa solid atau padat menjadi pilihan yang tepat untuk memudahkan proses pemisahan produk akhir reaksi dengan katalis. Katalis fasa padat yang dapat digunakan adalah zeolit dan bentonit alam. Penelitian ini bertujuan untuk menentukan pengaruh kinerja katalis zeolit dan bentonit yang telah diaktivasi terhadap produksi biodiesel dengan bahan dasar minyak goreng komersial serta menentukan rendemen hasil sintesis biodiesel melalui penggunaan katalis alam. Aktivasi dengan KOH dapat meningkatkan aktivitas katalisis dengan memperbesar luas permukaan dari katalis alam (bentonit dan zeolit). Analisis FTIR dan XRD terhadap katalis alam, pemurnian, aktivasi dan <em>recycle</em> menunjukkan adanya perubahan struktur kristalin dari katalis yang digunakan. Rendemen hasil sintesis biodiesel melalui penggunaan katalis bentonit dan zeolit berturut-turut adalah 91,75% dan 86,05%. Berdasarkan data persen rendemen hasil sintesis biodiesel, maka penggunaan katalis bentonit lebih baik di bandingkan dengan katalis zeolit. Analisis spektrum FTIR dari sintesis biodiesel yang berasal dari minyak jelantah menunjukkan hilangnya gugus OH yang memastikan bahwa reaksi transesterifikasi terjadi. Kualitas biodiesel yang dihasilkan memenuhi persyaratan Standar Nasional Indonesia (SNI) 04-7182-2006. Massa jenis biodiesel yang diproduksi menggunakan zeolit dan bentonit sebesar 868,54 kg/m<sup>3 </sup>dan 863,50 kg/m<sup>3</sup>. Sementara itu, viskositas biodiesel yang dihasilkan menggunakan zeolit dan bentonit berturut-turut sebesar 2,92 mm<sup>2</sup>/s dan 2,58 mm<sup>2</sup>/s.</p><p><strong>Comparison of Using Natural Catalysts (Zeolite and Bentonite) in <strong>Biodiesel </strong>Synthesis from Commercial Cooking Oil. </strong>Biodiesel is a long-chain methyl ester compound that contains fatty acids obtained through a transesterification reaction. This alternative fuel can be synthesized from commercial cooking oil with the help of a catalyst. Base catalysts are often used in transesterification reactions in biodiesel synthesis. Using a catalyst will increase the percentage of the biodiesel product produced. Solid or solid-phase catalysts are the right choice to facilitate separating the final reaction product from a catalyst. Solid-phase catalysts that can be used are zeolite and natural bentonite. This study aims to determine the effect of activated zeolite and bentonite catalysts on biodiesel production using commercial cooking oil as a base material and determine biodiesel synthesis yield using natural catalysts. The catalyst activation with KOH can increase catalytic activity by increasing the surface area of natural catalysts. FTIR and XRD analysis of natural catalysts, purification, activation, and recycling showed a change in the crystalline structure of the catalyst used. The yield of biodiesel synthesis by using bentonite catalyst was 91.75%. Meanwhile, the use of zeolite catalysts produced 86.05% biodiesel. Based on the percent yield data from biodiesel synthesis, the use of bentonite catalyst is better than zeolite catalyst. FTIR spectrum analysis of biodiesel synthesis from used cooking oil showed the loss of the OH group, which confirmed that the transesterification reaction occurred. The quality of the biodiesel produced meets the requirements of the Indonesian National Standard (SNI) 04-7182-2006. The biodiesel densities produced using zeolite and bentonite are 868.54 kg/m<sup>3</sup> and 863.50 kg/m<sup>3</sup>. Meanwhile, the biodiesel viscosities produced using zeolite and bentonite are 2.92 mm<sup>2</sup>/s and 2.58 mm<sup>2</sup>/s, respectively.</p>
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Eka Nurjanah and Nety Kurniaty. "Sintesis Tetrapeptida Linear Phe-Leu-Ala-Pro (FLAP) sebagai Kandidat Antioksidan dengan Metode Solid Phase Peptide Synthesis (SPPS)." Jurnal Riset Farmasi 1, no. 2 (December 31, 2021): 89–96. http://dx.doi.org/10.29313/jrf.v1i2.452.
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Abstract. Antioxidants are compounds that can prevent or inhibit oxidation in a cell caused by free radicals. Based on previous study, one of the natural antioxidant peptides is a tetrapeptide (Phe-Leu- Ala-Pro), which was isolated from Sea Cucumber Collagen (Acaudina Molpadiodes) in Zheijing Province, China. In this study, a tetrapeptide (Phe-Leu-Ala-Pro) has been successfully synthesized using the solid phase peptide synthesis method (SPPS) with the strategy by using a protective group Fmoc, 2-chlorotrityl chloride resin as a buffer and coupling reagents including HBTU, HOBt and DIPEA. FLAP tetrapeptide compound has been formed which is characterized by mass spectrophotometer with an m/z value of 447.2608 for peak of [M+H]+ ion. The results of the RP- HPLC analysis showed that the FLAP tetrapeptide compound was not pure because there were still minor peaks, the target compound retention time was 2 minute. The FLAP tetrapeptide compound has antioxidant activity with an IC50 value of 9376.6 ppm based on DPPH test.
Abstrak. Antioksidan adalah suatu senyawa yang dapat mencegah atau menghambat oksidasi pada suatu sel yang disebabkan oleh radikal bebas. Salah satu peptida antioksidan alami yang ditemukan pada penelitian sebelumnya adalah tetrapeptida (Phe-Leu-Ala-Pro) yang diisolasi dari Kolagen Teripang (Acaudina Molpadiodes) di Provinsi Zheijing Cina yang memiliki aktivitas antioksidan. Pada penelitian ini tetrapeptida (Phe-Leu-Ala-Pro) telah berhasil disintesis menggunakan metode sintesis peptida fase padat (SPPS) dengan strategi pemakaian gugus pelindung Fmoc, penyangga yaitu resin 2-klorotritil klorida dan reagen pengkopling diantaranya yaitu HBTU, HOBt dan DIPEA. Senyawa tetrapeptida FLAP telah terbentuk yang ditandai dengan hasil karakterisasi menggunakan spektrofotometer massa dengan nilai m/z 447,2608 pada puncak ion [M+H]+. Pada hasil analisis RP-HPLC menunjukkan bahwa senyawa tetrapeptida FLAP belum murni karena masih adanya puncak-puncak minor, senyawa target berada pada waktu retensi menit ke-2. Senyawa tetrapeptida FLAP memiliki aktivitas antioksidan dengan nilai IC50 sebesar 9376,6 ppm pada uji DPPH.
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Miniati, Mara. "Birth and life of Scientific Collections in Florence." Museologia & Interdisciplinaridade 5, no. 9 (April 30, 2017): 14–41. http://dx.doi.org/10.26512/museologia.v5i9.17201.
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O artigo centra-se na história das coleções científicas em Florença. Na era dos Medici, Florença foi um importante centro de pesquisa científica e de coleções. Este aspecto da cultura florentina é geralmente menos conhecido, mas a ciência e coleções científicas foram uma parte consistente da história da cidade. O recolhimento de instrumentos científicos era um componente importante das estratégias políticas dos grão-duques florentinos, convencidos de que o conhecimento científico e controle tecnológico sobre a natureza conferiria solidez e prestígio ao seu poder político. De Cosimo I a Cosimo III, os grão-duques Médici concederam o seu patrocínio e comissões sobre gerações de engenheiros e cientistas, formando uma coleção de instrumentos matemáticos e astronômicos, os modelos científicos e produtos naturais, exibidos ao lado das mais famosas coleções de arte na Galleria Uffizi, no Palazzo Pitti, e em torno da cidade de Florença e outros lugares da Toscana. Esta coleção soberba, ainda existente, é uma expressão não só do "gosto" dos tempos, mas também dos interesses multifacetados do grão-duques. Após o fim da era Medici, no século 18, a dinastia Lorena Florence separou as coleções artísticas das coleções científicas e estas últimas foram colocados no novo Museu Imperial e Real de Física e História Natural, pelo Grão-Duque Pedro Leopoldo de Lorena e aberta ao público em 1775. A fundação deste museu pela dinastia Lorena representou um novo desenvolvimento e uma nova fase para esse material de interesse científico em Florença. Este artigo descreve as transformações ocorridas entre os séculos 18 e 19 na vida cultural da capital da Toscana: as artes e ciências foram promovidos, e os florentinos cultivados estavam interessadas no desenvolvimento recente da física, na Itália e no exterior. Nesse período, numerosas coleções científicas privadas e públicas de Florença existentes, que eram menos famosas, mas não menos importantes do que as coleções Médici e Lorena se destacaram. Finalmente, o artigo descreve como as coleções florentinas se desenvolveram. A fundação do Instituto e Museu de História da Ciência deu nova atenção aos instrumentos científicos antigos. Sua intensa atividade de pesquisa teve um impacto sobre a organização do Museu. Novos estudos levaram a novas atribuições aos instrumentos científicos, as investigações de arquivamento contribuiram para um melhor conhecimento da coleção, e os contactos crescentes com instituições italianas e internacionais feitas do Museu tornaram-no cada vez mais ativo em uma ampla rede de empreendimentos cooperativos sobre temas específicos. A última alteração de sua denominação (Museo Galileo) e a reorganização moderna são a expressão de uma "continuidade" do patrimônio histórico-científico, preservado pelo Museu, e do "Inovação" para permiti-lo "falar" e torna-lo inteligível a um público contemporâneo.
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Setyawan, Teddy, Lilis Sugiarti, and Supriyono Eko Wardoyo. "KAJIAN BANYAKNYA PUPUK KANDANG TERHADAP PERKEMBANGBIAKAN KUTU AIR (Daphnia sp.) DI RUMAH KACA SEBAGAI PAKAN ALAMI DALAM BUDIDAYA IKAN." Jurnal Sains Natural 4, no. 1 (December 1, 2017): 1. http://dx.doi.org/10.31938/jsn.v4i1.70.
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Study of manure amount for kutu air (Daphnia sp.) reproduction in green house as natural food in fish culture Daphnia sp. is zooplankton used as natural food fish that have a complete nutrient content and easily digested in the gastro intestinal tract because it is solid and has a thin wall, otherwise it does not cause a decline of water quality and can improve the durability of fish seed to disease or changes in water quality, because it is always in living conditions. Levels of nutrient content consists of 42.65% protein, 8% fat, fiber and ash 4%. In the farming activities either fish growth or fish hatcheries 2.58% and ornament fish consumption, the daphnia is very desirable as a source of natural food and fresh for fish.The research result showed that the treatment with fertilizer concentration of 3 g / l gave the highest average number of Daphnia sp. on the sixth day. The highest was 344,000 head in the water volume of 30 liters using aquariums in the greenhouse environment. Water quality during the study was an average water temperature of 33 ° C and an average pH of 6.45 and the water quality was an optimum condition for the growth of Daphnia sp. There was a negative correlation significantly between the average member of Daphnia sp. with a concentration of manure and pH, but there was no correlation between the member of Daphnia sp. with the water temperature.Keywords : Daphnia sp., manure amount, natural food, fish culture ABSTRAK Daphnia sp. adalah zooplankton digunakan sebagai pakan alami ikan yang mempunyai kandungan gizi yang lengkap mudah dicerna dalam saluran pencernaan karena isinya padat dan mempunyai dinding yang tipis, selain itu tidak menyebabkan penurunan kualitas air dan dapat meningkatkan daya tahan benih ikan terhadap penyakit maupun perubahan kualitas air karena selalu dalam keadaan hidup dan kadar kandungan gizi terdiri dari protein 42,65 %, lemak 8 %, serat 2,58 % dan abu 4 % (Darmanto, dkk., 2000). Didalam kegiatan usaha budidaya atau pembenihan ikan baik ikan konsumsi maupun ikan hias, pakan alami ini sangat diperlukan sekali sebagai sumber makanan dari alam karena segar sesuai kesukaan ikan. Hasil penelitian bahwa perlakuan menghasilkan rata-rata jumlah Daphnia sp. pada fase stasioner hari keenam dengan konsentrasi pupuk 3 g/L merupakan perkembangbiakkan Daphnia sp. tertinggi yaitu 344.000 ekor dalam volume air 30 liter menggunakan akuarium di dalam lingkungan rumah kaca. Kualitas air selama penelitian adalah rata-rata suhu air 33 °C dan rata-rata pH 6,45 dan kualitas air ini merupakan kondisi optimum untuk pertumbuhan Daphnia sp. Ada korelasi negatif (berlawanan) secara nyata antara rata-rata perkembangbiakkan Daphnia sp. dengan konsentrasi pupuk kandang dan pH, tetapi tidak ada korelasi antara perkembangbiakkan Daphnia sp. dengan suhu air.Kata kunci: Daphnia sp., Konsentrasi Pupuk Kandang, pakan alami, budidaya ikan
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Fitriana Asni and Nety Kurniaty. "Sintesis Senyawa Heksapeptida Siklik Analog Pipecolisporin (Pro-Lys-Pipe-Trp-β-Ala-Phe) dengan Metode Kombinasi Fasa Padat dan Fasa Larutan sebagai Kandidat Antimalaria." Bandung Conference Series: Pharmacy 2, no. 2 (July 31, 2022). http://dx.doi.org/10.29313/bcsp.v2i2.4453.
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Abstract. Malaria is an infectious disease caused by protozoa of the genus Plasmodium and then transmitted to humans through the Anopheles mosquito. One of the natural peptides found in previous studies is cyclic hexapeptide (Pro-Leu-Pipe-Trp- -Ala-Ile) from endophytic fungi isolated from the roots of Tritikum sp and produced pipecolisporin isolation which has been proven to have antimalarial activity. In this study the cyclic hexapeptide analogue pipecolisporin (Pro-Lys-Pipe-Trp- -Ala-Phe) has been successfully synthesized using a solid phase combination method (Solid Phase Peptide Synthesis) and a solution phase with a strategy of using Fmoc protective groups, solid phase buffers namely 2-chlorotrityl chloride resin and coupling reagents namely HATU, HOAt, and DIPEA. A linear hexapeptide compound has been formed which is indicated by the results of characterization using a mass spectrophotometer with an m/z value of 959.4612 at the ion peak and also a cyclic hexapeptide compound has been formed which is indicated by an m/z value of 741.4842 at the peak of the molecular ion [M+H].
Abstrak. Malaria merupakan penyakit menular yang disebabkan oleh protozoa dari genus Plasmodium dan kemudian ditularkan ke manusia melalui nyamuk anopheles. salah satu peptida alami yang ditemukan pada penelitian sebelumnya adalah heksapeptida siklik (Pro-Leu-Pipe-Trp- -Ala-Ile) dari jamur endofit yang diisolasi dari akar Tritikum sp dan menghasilkan isolasi pipecolisporin yang sudah terbukti memiliki aktivitas antimalaria. Pada penelitian ini heksapeptida siklik analog pipecolisporin (Pro-Lys-Pipe-Trp- -Ala-Phe) telah berhasil disintesis dengan menggunakan metode kombinasi fasa padat (Solid Phase Peptide Synthesis) dan fasa larutan dengan strategi penggunaan gugus pelindung Fmoc, penyangga fasa padat yaitu resin 2-klorotritil klorida serta reagen pengkopling yaitu HATU, HOAt, dan DIPEA. Senyawa heksapeptida linear telah terbentuk yang ditandai dengan hasil karakterisasi menggunakan spektrofotometer masasa dengan nilai m/z 959,4612 pada puncak ion dan juga Senyawa heksapeptida siklik telah terbentuk yang ditandai dengan nilai m/z 741,4842 pada puncak ion molekul [M+H].
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Ph.D, Rani Maharani, Dadan Sumiarsa, Christina Marpaung, Achmad Zainuddin, Ace Tatang Hidayat, Desi Harneti, Nurlelasari Nurlelasari, and Unang Supratman. "Sintesis Tetrapeptida PADY menggunakan Metode Fasa Padat dan Aktivitas Antioksidannya." Jurnal Kimia Valensi 5, no. 1 (May 27, 2019). http://dx.doi.org/10.15408/jkv.v5i1.10500.
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Peptida antioksidan merupakan kelompok peptida yang berperan penting karena dapat menetralkan radikal bebas, sehingga dapat mencegah dan mengobati penyakit kronis. Salah satu senyawa peptida antioksidan alami yang telah ditemukan peneliti sebelumnya adalah senyawa tetrapeptida PAGY (Pro-Ala-Gly-Tyr) yang diisolasi dari gelatin kulit ikan amur sturgeon (Acipenser schrenckii) dan dilaporkan memiliki aktivitas antioksidannya dengan IC50 5.38 mg/mL dalam uji DPPH dan 0,008 mg/mL dalam uji ABTS berturut-turut. Kelompok kami telah berhasil mensintesis PAGY bersama dengan analognya yakni PSGY, PFFY, PAFY, dan PAIY dengan menggunakan metode sintesis peptida fase padat (SPPS). Pengujian aktivitas antioksidan pada senyawa hasil sintesis menunjukkan bahwa PSGY memiliki aktivitas antioksidan lebih baik dari PAGY. Pencarian analog tetrapeptida antioksidan yang lebih baik hingga saat ini masih terus dilakukan. Pada penelitian ini telah berhasil disintesis analog tetrapeptida lainnya PADY (Pro-Ala-Asp-Tyr) dengan metode sintesis peptida fase padat menggunakan strategi Fmoc/t-Bu pada resin 2-klorotritilklorida dilanjutkan dengan pengujian aktivitas antioksidannya. HATU/HOAT digunakan sebagai reagen pengkopling dalam sintesis PADY. Pemurnian krud PADY dilakukan menggunakan RP-HPLC preparatif sehingga diperoleh PADY murni seberat 14.7 mg (12.6%). Penentuan struktur peptida hasil sintesis dianalisis dengan menggunakan spektroskopi 1H-NMR dan TOF-MS. Pada pengujian aktivitas antioksidan dengan metode DPPH, PADY hasil sintesis memberikan nilai IC50 sebesar 1.850 mg/mL, yang mengindikasikan bahwa PADY menunjukkan aktivitas antioksidan yang lebih rendah daripada PAGY hasil sintesis peneliti sebelumnya. Kata kunci: Antioksidan, tetrapeptida, sintesis peptida fase padat. Antioxidant peptide is a class of peptides that play an important in neutralizing free radicals, therefore this compound can be used to prevent and treat chronic diseases. One of the natural antioxidant peptides reported by previous researcher is PAGY (Pro-Ala-Gly-Tyr), which is isolated from amur sturgeon fish (Acipenser schrenckii) gelatin that showed antioxidant activity with IC50 5.38 and 0.008 mg/mL using DPPH and ABTS assay, respectively. Our group has successfully synthesized PAGY, along with its analogues of PSGY, PFFY, PAFY, and PAIY using solid phase peptide synthesis method (SPPS). Antioxidant assay on synthesised compounds showed that PSGY has better antioxidant activity than PAGY. The search on the analogues of the antioxidant tetrapeptide was continued. From this study, a tetrapeptide analogue PADY (Pro-Ala-Asp-Tyr) has been successfully synthesised by solid phase peptide synthesis method with Fmoc/t-Bu strategy on 2-chlorotrityl chloride resin and tested for its antioxidant activity. HATU and HOAt reagents were used as the coupling reagent for the synthesis of PADY. The resulting PADY peptide solid was then purified using preparative RP-HPLC yielding PADY of 14.7 mg (12.6%). Characterisation of the synthesized compound was analysed by 1H-NMR and TOF-MS. On the antioxidant assay using DPPH method, PADY showed IC50 value of 1.850 mg/mLindicating a lower activity than the synthetic PAGY. Keywords: Antioxidant, tetrapeptide, solid phase peptide synthesis (SPPS).
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Salgado, Tatiane Totta, Marina Gatti, Katia Flores Genaro, Luiz Fernando Pegoraro, and Giédre Berretin-Felix. "Duration of mastication and oral phase of swallowing in the elderly with different dental conditions: a clinical analysis." Revista CEFAC 24, no. 5 (2022). http://dx.doi.org/10.1590/1982-0216/20222458122.
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ABSTRACT Purpose: to measure the total time of mastication and oral phase of swallowing in healthy elderly people, considering different food consistency, the presence of natural teeth, and the type of prosthetic oral rehabilitation, as well to compare dental conditions and consistencies. Methods: a cross-sectional study with 57 healthy elderly people, aged between 60 and 82 years, divided into: dentate group (D) (n=15); and rehabilitated groups; PD: fixed or removable partial dentures in one or both arches (n=15); CRD: maxillary and mandibular complete removable dentures (n=15); ISCD: complete dentures - maxillary removable denture and mandibular implant-supported dentures (n=12). The duration time (seconds) of chewing and of the oral phase of swallowing was measured in the consistencies: solid (a roll slice), pudding (10 ml) and liquid (10 ml). Results: healthy dentate elderly subjects had the following intervals: liquid=1.07±0.35 s; pudding=3.48±1.76 s; and solid=27.88±7.11 s. Statistically significant differences were observed between the D and ISCD groups (p=0.0056) and between D and CRD (p=0.0056) for liquid. For all groups, there was a statistically significant increase between liquid and solid consistencies and between pasty and solid ones (p<0.001). Conclusions: the dentate elderly had shorter oral phase time of swallowing for liquids than the rehabilitated edentulous elderly, but not different from the elderly with partial dentures. Chewing and swallowing time for solid food was longer than that for the other consistencies, regardless of dental condition.
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Siti Nurhalizah and Nety Kurniaty. "Sintesis Senyawa Heksapeptida Siklik Analog Pipecolisporin (Phe--ala-Trp-Pip-Arg-Pro) sebagai Kandidat Antimalari dengan Metode Kombinasi Fase Padat dan Fase Larutan." Bandung Conference Series: Pharmacy 2, no. 2 (July 31, 2022). http://dx.doi.org/10.29313/bcsp.v2i2.4380.
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Abstract. Malaria is a parasitic disease that is still a major health problem in the world, especially in tropical and sub-tropical countries. Malaria is a health disorder that occurs when red blood cells (erythrocytes) are infected with a protozoan parasite of the genus Plasmodium which is inoculated into the host through the bite of female Anopheles mosquito. Based of previously study, one of the natural antioxidant peptides is cylic hexapeptide (Phe- -ala-Trp-Pip-Arg-Pro), which was isolated from fungus Nigrospora oryzaea which has antimalarial activity. In this study, a cylic hezapeptide analogue of pipecolisporin (Phe- -ala-Trp-Pip-Arg-Pro) has been successfully synthesized using the combination methods of solid phase and liquid phase with strategy by using a protective group Fmoc, 2-chlorotrityl chloride resin as a buffer and coupling reagents including HATU, HOAt, and DIPEA. Cylic hezapeptide analogue of pipecolisporin (Phe- -ala-Trp-Pip-Arg-Pro) compound has been formed which is characterized by mass spectrophotometer with an m/z value of 794,18. The result of the RP-HPLC analysis showed that the cylic hezapeptide analogue of pipecolisporin (Phe- -ala-Trp-Pip-Arg-Pro) compund was not pure because there were still minor peaks.
Abstrak. Malaria merupakan salah satu penyakit parasit yang masih menjadi persoalan kesehatan yang utama di dunia terutama di Negara tropis dan sub tropis. Malaria merupakan suatu gangguan kesehatan yang terjadi pada saat sel darah merah (eritrosit) terinfeksi parasit protozoa dari genus Plasmodium yang diinokulasikan ke inang melalui gigitan nyamuk Anopheles betina. Salah satu peptida antimalaria alami yang ditemukan pada penelitian sebelunnya adalah heksapeptida siklik (Pro-Leu-Pip-Trp- -ala-Iso) yang diisolisasi dari jamur NIigrospora oryzae yang memiliki aktivitas antimalaria. Pada penelitian ini heksapeptida siklik analog pipecolisporin (Phe- -ala-Trp-Pip-Arg-Pro) telah berhasil disintesis menggunakan metode kombinasi fase padat dan fase larutan dengan strategi pemakaian gugus pelindung Fmoc, penyangga yaitu resin 2-klorotritil klorida dan reagen pengkopking diantaranya HATU, HOAt, dan DIPEA. Senyawa heksapeptida siklik analog pipecolisporin (Phe- -ala-Trp-Pip-Arg-Pro) telah terbentuk dengan ditandai dengan hasil karakterisasi menggunakan spektrometer massa dengan nilai m/z 794,18. Pada hasil analisis RP-HPLC menunjukkan bahwa senyawa heksapeptida siklik analog pipecolisporin (Phe- -ala-Trp-Pip-Arg-Pro) belum murni karena masih adanya puncak-puncak minor.
Dissertations / Theses on the topic "Fasi solide naturali"
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Rizzi, Luca. "Validazione di modelli numerici per lo studio del cambiamento di fase solido/liquido in leghe metalliche in regime di convezione naturale." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5985/.
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Il lavoro svolto ha come scopo l’implementazione e la validazione di un modello di cambiamento di fase mediante l’utilizzo del codice commerciale Comsol Multiphysics, che permette la modellazione e la risoluzione di equazioni matematiche che governano ambienti multifisici.
La validazione dei modelli sviluppati è stata effettuata mediante confronto sia con soluzioni analitiche di riferimento, sia con soluzioni numeriche ottenute utilizzando il codice commerciale ProCAST, sviluppato appositamente per simulazioni di processi fusori
I problemi analizzati hanno riguardato lo scambio termico sia in regime di sola conduzione, sia in presenza di convezione naturale all’interno di un materiale in cambiamento di fase solido-liquido. È stato considerato sia il caso di sostanze pure, quindi con un’unica temperatura di cambiamento di fase, sia il caso di leghe metalliche, la cui transizione di fase avviene in un intervallo di temperatura.
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Mosco, Alessandro. "Sviluppo di un bioindicatore naturale per il monitoraggio della qualità delle acque." Doctoral thesis, Università degli studi di Trieste, 2013. http://hdl.handle.net/10077/8557.
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2011/2012La concentrazione del glucosio emolinfatico è regolata nei Crostacei dal crustacean Hyperglycemic Hormone (cHH), un neuropeptide prodotto e rilasciato in circolo nel complesso organo X-ghiandola del seno, localizzato nei peduncoli oculari. Il cHH, oltre a essere coinvolto nella regolazione di diversi processi fisiologici, è implicato anche nelle risposte da stress di origine ambientale o dovute all’esposizione a xenobiotici, il cui risultato finale è un aumento della glicemia. In numerose specie di crostacei sono state identificate più forme circolanti del cHH, alcune delle quali derivano da geni diversi e si differenziano per la sequenza amminoacidica, altre invece risultano da processi di maturazione post-traduzionale dei peptidi come l’isomerizzazione della L-Phe3 con la conseguente formazione di D-Phe3. Le eventuali differenze nella funzione biologica di queste due isoforme chirali sono ancora poco chiare, ma gli scarsi studi sin qui condotti indicano che il D-cHH ha una maggiore e più prolungata attività iperglicemizzante. Inoltre, è stato proposto un suo coinvolgimento sia nell’inibizione della sintesi degli ecdisteroidi sia nella regolazione osmotica. Due sono stati gli indirizzi principali di ricerca sviluppati in questi anni di dottorato. Il primo è consistito nel gettare le basi per la realizzazione di un organismo bioindicatore capace di rilevare la presenza di sostanze tossiche cambiando la propria colorazione in modo facilmente visualizzabile, ed è stato completato con il clonaggio e l’identificazione del promotore del cHH di Astacus leptodactylus (Crustacea, Decapoda), la verifica in vitro della sua funzionalità e l’identificazione di possibili siti di legame per dei fattori di trascrizione. L’obiettivo finale è la modifica in via transiente di Palaemon elegans e Palaemonetes antennarius (Crustacea, Decapoda) mediante l’iniezione di emociti trasfettati con il plasmide veicolante il promotore del cHH ed un gene reporter che visualizza la risposta mediante colorazione dell’animale. Il secondo progetto ha riguardato la sintesi chimica di alcune forme chirali del cHH di A. leptodactylus che è l’unica strategia possibile per ottenere peptidi identici all’ormone nativo, essendo la sola capace di consentire l’introduzione di tutte le modificazioni post-traduzionali necessarie. I peptidi ottenuti sono stati quindi adoperati in saggi biologici in vivo per provare la loro funzionalità. Inoltre, è stato fatto uno studio per appurare il possibile ruolo del cHH nel controllo dell’aggressività in Procambarus clarkii (Crustacea, Decapoda). Per ottenere una quantità sufficiente delle forme chirali del cHH in modo da poterne studiare la funzione biologica, abbiamo scelto la strada della sintesi chimica in fase solida (SPPS). La SPPS è generalmente limitata alla sintesi di peptidi non più lunghi di 40 amminoacidi. Per ottenere sequenze più lunghe è necessario sintetizzare segmenti diversi e quindi ligarli assieme attraverso delle reazioni chimiche. In questo caso si è adoperata la native chemical ligation. Il primo passo ha riguardato la sintesi di sei segmenti (QVF-cHH4-38, QVdF-cHH4-38, pEVF-cHH4-38, pEVdF-cHH4-38, pEVdA-cHH4-38, cHH-39-72) che legati fra loro in maniera diversa avrebbero portato alla formazione di cinque peptidi ammidati al C-terminale, due con la L-Phe3 e la parte N-terminale libera oppure bloccata con il piroglutammato, due con la D-Phe3 e la parte N-terminale anch’essa libera oppure bloccata, e uno con la D-Phe3 sostituita dalla D-Ala3 e l’N-terminale bloccato dal piroglutammato. La sintesi dei diversi segmenti non ha dato particolari problemi, ma la purificazione del segmento cHH-39-72 è risultata particolarmente difficile, in quanto questo peptide è risultato essere molto poco solubile. Questo problema è stato risolto con l’aggiunta di gruppi –SO3 allo zolfo delle cisteine che ha reso solubile il segmento cHH-39-72. Sono stati quindi sintetizzati in quantità sufficienti, dell’ordine di un centinaio di microgrammi, le seguenti forme chirali del cHH: QVdF-cHH, QVF-cHH, pEVF-cHH, pEVdF-CHH e pEVdA-cHH. In quest’ultima isoforma la D-fenilalanina in posizione 3 è stata sostituita dalla D-alanina, per verificare se la fenilalanina avesse un ruolo fondamentale nella funzionalità del peptide. I peptidi di sintesi sono stati quindi utilizzati per eseguire dei saggi in vivo su A. leptodactylus, iniettando nei gamberi il cHH sintetico e verificando la risposta biologica indotta attraverso il dosaggio della glicemia. I prelievi per il dosaggio del glucosio sono stati fatti ai tempi 0 h, 1 h, 2 h, 4 h, 8 h e 24 h. Il profilo temporale della risposta glicemica indotta dalle due forme chirali è diverso, con il L-cHH avente un picco di risposta tra le 2 h e le 4 h, mentre il picco massimo della risposta del D-cHH è più tardivo, situandosi tra le 4 h e le 8 h. Invece, la differenza nella risposta iperglicemica tra la forma bloccata all’N-terminale (Glp-D-cHH) e la forma non bloccata (D-cHH) non è stata significativa a dimostrazione che la presenza del piroglutammato non influenza la risposta biologica indotta dal cHH. L’attività biologica dell’isomero Glp-dA-cHH è stata verificata usando il medesimo protocollo. L’attività iperglicemizzante di questo peptide è risultata essere significativamente inferiore a quella indotta dal Glp-D-cHH. Il risultato ottenuto dimostra che la porzione N-terminale del cHH è fondamentale per la funzionalità del peptide. Lo studio del promotore del cHH è stato effettuato su una sequenza clonata di 176 nucleotidi a monte della regione 5’ del gene per il cHH di A. leptodactylus, che è stata inserita in un vettore senza promotore (pGL3-Basic) a monte del gene reporter per la luciferasi. Con questo vettore sono state trasfettate cellule HEK 293T e la funzionalità del promotore è stata dimostrata da un incremento di circa 1000 volte nell’espressione della luciferasi rispetto a pGL3-Basic. La ricerca di eventuali siti di legame per elementi di regolazione presenti nella sequenza clonata ha consentito di identificare numerosi possibili siti di legame, inclusi una TATA box a -23, una CCAAT box a -78, due GC box a -63 e -70, ed altri per specifici elementi di trascrizione, più precisamente una sequenza a -91 dove i siti di legame per il cAMP response element-binding (CREB), l’elemento di risposta all’ipossia (HRE), il recettore per l’estrogeno (ER-alpha) si sovrappongono, mentre a -160 è stato identificato un possibile sito di legame per il recettore dell’ecdisone (EcR). L’influenza del cHH sull’aggressività in P. clarkii è stata studiata iniettando negli animali il cHH nativo estratto dalle ghiandole del seno. In generale gli animali in cui era stato iniettato il cHH hanno mostrato un aumento nell’espressione della dominanza, gli alfa attraverso un aumento della durata dei combattimenti e i beta per la maggiore intensità dei combattimenti che ne aumentava la dominanza fino a raggiungere una temporanea inversione della gerarchia. Il potenziamento del comportamento aggressivo potrebbe essere dovuto o a una modulazione da parte del cHH dei neuroni che controllano l’espressione del comportamento agonistico, oppure essere dovuto a una maggiore mobilizzazione delle risorse energetiche necessarie per la lotta. Per la prima volta sono state ottenute diverse isoforme del cHH mediante la sintesi peptidica in fase solida accoppiata alla native chemical ligation. I dati ottenuti indicano che questa è la strategia appropriata per la sintesi dei peptidi della famiglia del cHH, essendo l’unica in grado di consentire l’introduzione di tutte le modifiche post-traduzionali per ottenere un peptide identico all’ormone nativo. L’ottimizzazione del presente protocollo consente di rendere disponibili adeguate quantità di peptidi per esperimenti su larga scala, in vivo e in vitro, che possono portare a una migliore conoscenza della funzione del cHH e della relazione tra funzione e struttura. Inoltre sono state gettate le basi per la realizzazione di un organismo bioindicatore per monitorare l’inquinamento delle acque. È stato clonato il promotore del cHH di A. leptodactylus e per la prima volta la funzionalità di un promotore di un peptide della famiglia del cHH è stata verificata in un saggio in vitro. L’identificazione di diversi possibili siti di legame per gli elementi di regolazione nel promotore del cHH suggerisce che l’espressione del cHH sia regolata da svariati fattori fisiologici e ambientali. I risultati ottenuti sono rilevanti per futuri studi indirizzati alla comprensione del ruolo che i fattori di trascrizione identificati possono avere nella regolazione del promotore del cHH. Infine, lo studio sulla relazione di dominanza in Procambarus clarkii ha dimostrato, per la prima volta, che un neuropeptide, nella fattispecie il cHH, è in grado di modulare il comportamento aggressivo, sino a invertire, sia pur temporaneamente, il rango.
XXIV Ciclo
1955
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Pimenta, Eli Fernando. "Investigação das condições de crescimento e produção de metabólitos secundários das linhagens de fungos Penicillium citrinum e Penicillium oxalicum." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/75/75131/tde-03032011-163613/.
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No presente estudo, duas espécies de fungos isoladas do ambiente marinho tiveram seus extratos brutos ativos contra Staphylococcus aureus e Candida albicans para uma espécie de P. citrinum e, atividade citotóxica e contra Mycobacterium tuberculosis para uma espécie de P. oxalicum. Estas foram estudadas com a finalidade de otimizar suas condições de crescimento para produção de metabólitos secundários. Foram realizadas análises multivariadas utilizando planejamento fatorial fracionário. Foram obtidas duas condições ótimas de crescimento para as duas linhagens de Penicillium. O crescimento em maior volume em condições de cultura otimizadas para P. oxalicum permitiu observar a presença de três metabólitos secundários no extrato do meio de cultura. Dois puderam ser isolados e identificados: a meleagrina 52 e a oxalina 26. A metodologia utilizada para se obter uma maior quantidade de metabólitos secundários proporcionou, ainda, o incremento em cerca de 150% na área do pico da oxalina. A partir do crescimento em maior volume em condições de cultura otimizadas para P. citrinum foi possível observar presença de pelo menos onze diferentes metabólitos na análise dos extratos obtidos do meio de cultura. Foi possível identificar e isolar quatro compostos já conhecidos: a (8E)-1-(2,3-diidropirrol-1-il)-2-metildec-8-eno-1,3-diona 56; a 1-(2,3-diidropirrol-1-il)-2-metildecano-1,3-diona 58; a 2-((E)-hept-5-enil)-6,7,8,8a-tetraidro-3-metilpirrolo[2,1-b][1,3]oxazin-4-ona 59 e a citrinina 31. Também foram isolados dois novos alcalóides indólicos contendo um grupo nitro na molécula que foram nomeadas de citrinalinas A 60 e B 62. Foi realizado, também, um estudo com P. citrinum visando a maior produção das citrinalinas, que possibilitou o incremento na produção da citrinalina B.In this study, two species of fungi isolated from the marine environment had their active extracts against Staphylococcus aureus and Candida albicans to a strain of P. citrinum, and activity cytotoxic and against Mycobacterium tuberculosis to a strain of P. oxalicum. This studied aims the optimization their growth conditions for the production of secondary metabolites. Multivariate analysis using a fractional factorial design were used to establish optimal growth conditions for both Penicillium strains. Two optimal growth conditions were obtained for both Penicillium strains. A largest growth volume of P. oxalicum using optimized conditions enabled the detection of three secondary metabolites in the culture media crude extract. Two of such compounds were isolated and identified: meleagrin 52 and oxaline 26. The methodology used to increase the production of secondary metabolites by P. citrinum enabled an increase of 150% in the peak area of oxaline. A largest growth volume of P. citrinum led to the detection of eleven different metabolites in the culture media. Four of these compounds were isolated and identified as the known (8E)-1-(2,3-dihydropyrrol-1-yl)-2-methyldec-8-ene-1,3-dione 56; the 1-(2,3-dihydropyrrol-1-yl)-2-methyldecane-1,3-dione 58; the 2-((E)-hept-5-enyl)-6,7,8,8a-tetrahydro-3-methylpyrrolo[2,1-b][1,3]oxazin-4-one 59 and citrinin 31. Two new indole alkaloids containing a nitro group were also isolated and identified, named citrinalins A 60 and B 62. A further study with P. citrinum aiming an enhanced production of citrinalins allowed a significant increase in the production of citrinalin B.
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Silva, Darlan Ferreira da. "DESENVOLVIMENTO DE MÉTODOS EMPREGANDO SPME-GC/MS E BIOSSENSORES AMPEROMÉTRICOS PARA ANÁLISE DO INSETICIDA PARATION METÍLICO EM AMOSTRAS DE ARROZ IN NATURA." Universidade Federal do Maranhão, 2010. http://tedebc.ufma.br:8080/jspui/handle/tede/915.
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Previous issue date: 2010-10-11Organophosphate insecticides, especially those based on the active ingredient methyl parathion, have been extensively used in crop protection of rice in the State of Maranhão. In this work, an optimized chromatographic method for determination of the methyl parathion insecticide by using solid phase microextraction in a confined environment (headspace) followed by analysis employing gas chromatography with mass spectrometric detection (HS-SPME-GC/MS). Electroanalytical methods using amperometric biosensors were also developed and used to analyze the composite samples of fresh rice. The optimized method using SPME resulted in satisfactory results for sensitivity (limit of detection: 0.026 mg/L-1), precision (coefficients of variation between 6.1 and 22.4%, 8.8% and 32.5 and 19.7 and 24.6%, for milled rice samples, rice with shells and full rice, respectively) and accuracy (recoveries ranging from 73.2 to 90% for milled rice samples, from 88.7 to 89.5%, for paddy rice samples and from 59.5 to 60.6% for full rice samples). In the case of biosensors, these have been built based on acetylcholinesterase enzyme (AChE), commercially obtained or genetically modified, having the sensors prepared with carbon paste modified with TCNQ (tetracyanoquinodimethane) mediator. Better sensitivities were observed with sensors based on AChE enzymes extracted from Drosophila melanogaster. Detection limits of 10.0, 0.05 and 0.001 μg.L-1 were found for the sensors based on AChE (ee), AChE (eb) and mutant enzymes (AChE (Dros) B08 e B12), respectively. The efficiency of the detection method of the methyl parathion insecticide in rice samples without any previous treatment was evidenced by an average recovery of 103.9%, 101%, 102.3% and 105.6%, for the sensors prepared with AChE (ee), AChE (eb), AChE (Dros) B08 and B12 enzymes, respectively. In general, the chromatographic technique used was practical and efficient for direct detection of insecticide residues in rice samples in a wider range of concentration (0.1 a 1 mg.Kg-1). Since the biosensor was more sensitive and effective in smaller amounts (0.0005 a 0.01 mg.Kg-1) of such insecticide in rice, considering the additional advantage of speed and decreasing cost of the analytical technology.
Os inseticidas organofosforados, em especial aqueles à base do princípio ativo paration metílico, têm sido extensivamente usados na proteção de cultivos de arroz no Estado do Maranhão. Neste trabalho, foi otimizado um método cromatográfico para determinação do inseticida paration metílico usando microextração em fase sólida em ambiente confinado (headspace), seguido de análise empregando cromatografia a gás com detecção por espectrometira de massas (HS-SPME-GC/MS). Métodos eletroanalíticos empregando biossensores amperométricos também foram desenvolvidos, tendo sido empregados para análise do composto em amostras de arroz in natura. O método otimizado empregando SPME resultou em resultados satisfatórios quanto à sensibilidade (limite de detecção: 0,026 mg/L-1), precisão (coeficientes de variação entre 6,1 e 22,4%; 8,8 e 32,5% e 19,7 a 24,6%, para as amostras de arroz polido, arroz com casca e arroz integral respectivamente) e exatidão (recuperações na faixa de 73,2 a 90%, para as amostras de arroz polido; de 88,7 a 89,5 %, para as amostras de arroz com casca e de 59,5 a 60,6%, para as amostras de arroz integral). No caso dos biossensores, estes foram construídos à base de enzimas acetilcolinesterase (AChE), comerciais e geneticamente modificadas, tendo sido os sensores preparados com pasta de carbono modificada com o mediador TCNQ (tetracianoquinodimetano). Melhores sensibilidades foram verificadas com sensores preparados à base de enzimas AChE extraídas da Drosophila Melanogaster. Limites de detecção de 10; 0,05 e 0,001μg.L-1 foram encontrados para os sensores preparados com as enzimas AChE (ee), AChE (eb) e mutantes (AChE (Dros) B08 e B12), respectivamente. A eficiência do método de detecção do inseticida paration metílico em amostras de arroz sem nenhum prévio tratamento foi comprovada pelas recuperações médias de 103,9%; 101 %; 102,3% e 105,6 % para os sensores preparados com as enzimas AChE (ee), AChE (eb), AChE (Dros) B08 e B12 respectivamente. De modo geral, a técnica cromatográfica empregada foi prática e eficiente para detecção direta de resíduos do inseticida em amostras de arroz, em uma faixa maior de concentração (0,1 a 1 mg.Kg-1). Já os biossensores foram mais sensíveis e eficientes em teores menores (0,0005 a 0,01 mg.Kg-1) do inseticida no arroz, considerando ainda a vantagem adicional da rapidez e menor custo da técnica analítica.
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Wondracek, Marcos Henrique Pereira [UNESP]. "Síntese e aplicação de sílica modificada na adsorção de Cu(II), Cd(II) e As(V) em meio aquoso: pré-concentração em amostras de águas naturais." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/152253.
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Este trabalho relata o desenvolvido de métodos analíticos que visa à determinação de algumas espécies tóxicas e potencialmente tóxicas de metais e metalóides em níveis ultra-traço em amostra de água naturais, utilizando uma técnica analítica menos sensível, como a espectrometria de absorção atômica em chama (FAAS). Essa técnica foi escolhida por ser relativamente simples e possuir baixo custo operacional. A técnica de extração em fase sólida (EFS), utilizando um novo material sorvente, foi utilizada para separar e pré-concentrar os analitos. Este estudo demonstra o procedimento de uma nova rota sintética via co-condensação visando à produção de uma sílica mesoporosa organofuncionalizada com o ligante 4-amino-3-hidrazino-5-mercapto-1,2,4-triazole e, sua utilização como sorvente para pré-concentração/análise de especiação de íons metálicos em amostras de água. O material produzido foi caracterizado por espectroscopia na região do infravermelho (FTIR), BET, ressonância magnética nuclear (RMN) de 29Si e 13C, dentre outras. As características adsortivas desse material foram estabelecidas em estudos de batelada, onde se estudou o efeito do pH, cinética de adsorção e capacidade máxima de adsorção. A otimização multivariada foi utilizada para obtenção das melhores condições químicas e de fluxo no sistema de pré-concentração, permitindo avaliar as interações principais e secundárias entre os fatores. Por meio da análise dos espectros obtidos por FTIR foi possível observar bandas de estiramento C–H, C–Cl e (NH2) oriundos da fração orgânica do material. A área superficial foi de 369,84 m2 g-1com diâmetro médio de poros em 7,1 nm, relacionados a materiais mesoporosos. Os resultados obtidos por RMN de 29Si comprovam a formação do material híbrido, sintetizado por co-condensação, e o RMN de 13C confirma o ancoramento do ligante na matriz. O pH que favorece a adsorção dos íons foi 5,0 para Cu(II) e 3,0 para Cd(II) e As(V). O modelo cinético de pseudo segunda ordem apresentou melhor ajuste aos dados experimentais, indicando adsorção química. Os dados de sorção desses íons metálicos mostraram bom ajuste ao modelo de Langmuir, com capacidade máxima de adsorção próxima aos valores obtidos experimentalmente, 0,057, 0,018 e 0,060 mmol g-1 para Cu(II), Cd(II) e As(V), respectivamente, indicando que a sorção ocorre em monocamada. Os parâmetros analíticos encontrados para o Cu(II) foram: fator de pré-concentração de 18,1; intervalo linear de 10,0 – 200,0 µg L-1 (R = 0,999) e LD de 1,45 µg L-1. Para o Cd(II): fator de pré-concentração de 15,8; intervalo linear de 2,0 – 100,0 µg L-1 (R = 0,999) e LD de 0,38 µg L-1. Para o As(V): fator de pré-concentração de 5,0; intervalo linear de 0,25 – 2,5 µg L-1 (R = 0,999) e LD de 0,039 µg L-1. A exatidão foi checada pelo método de adição e recuperação e/ou método comparativo com GFAAS ou ICP OES. As recuperações variaram de 97 – 106% (Cu), 100 – 105% (Cd), 88 – 103% (As(V)) e 96 – 106% (As(total)). Os resultados para Cu(II) determinados com os métodos propostos foram concordantes com os obtidos com o método comparativo. Conclui-se que o material produzido apresenta bom potencial para ser aplicado na extração/pré-concentração de cobre, cádmio e análise de especiação inorgânica de arsênio. Provou-se também que baixos limites de detecção e quantificação podem ser obtidos mesmo utilizando uma técnica menos sensível como a FAAS.
This paper reports on the development of analytical methods for the determination of some toxic and potentially toxic species in ultra - trace levels in natural water samples using a less sensitive analytical technique such as flame atomic absorpti on spectrometry (FAAS). This technique was chosen because it is relatively simple and has a low operating cost. The solid phase extraction technique (SPE) using a new sorbent material was used to separate and preconcentrate the analyte. This study demonstr ates the procedure of a new synthetic route using the technique of the co - condensation for the production of a mesoporous organo - functionalised silica with the 4 - amino - 3 - hydrazino - 5 - mercapto - 1,2,4 - triazole ligant and its use as a sorbent for preconcentrati on/ analysis of metal ion s speciation in water samples. The material produced was characterized by infra - red spectroscopy (FTIR), BET, 29 Si and 13 C nuclear magnetic resonance (NMR), among others. The adsorptive characteristics of this material were establis hed in batch studies, where the effect of pH, adsorption kinetics and maximum adsorption capacity were studied. Multivariate optimization was used to obtain the best chemical and flow conditions in the preconcentration system, allowing the evaluation of th e main and secondary interactions among the factors. By means of the analysis of the spectra obtained by FTIR, it was possible to observe C - H, C - Cl and (NH 2 ) stretch bands from the organic fraction of the material. The surface area was 369.84 m 2 g - 1 with a verage pore diameter at 7.1 nm related to mesoporous materials. The results obtained by 29 Si NMR prove the formation of the hybrid material, synthesized by co - condensation, and the 13 C NMR confirms the anchoring of the ligan t in the matrix. The pH 5.0 it w as favors the adsorption of the ions Cu (II), the pH 3.0 it was favors the adsorption of the Cd (II) and As (V). The kinetic model of pseudo second order showed better adjustment to the experimental data, indicating chemical adsorption. The adsorption data of Cu (II), Cd (II), and As (V) were similar to those of the Langmuir model, with a maximum adsorption capacity of 0.057, 0.018 and 0.060 mmol g - 1 for Cu (II), Cd(III) and As(V) , respectively, indicating that the sorption occurs in monolayer. The analyt ical parameters for Cu (II) were: preconcentration factor of 18.1; linear range of 10.0 - 200.0 μg L - 1 (R = 0.999) and LD of 1.45 μg L - 1 . For Cd (II): preconcentration factor of 15.8; linear range of 2.0 - 100.0 μg L - 1 (R = 0.999) and LD of 0.38 μg L - 1 . Fo r As (V): preconcentration factor of 5.0; linear range of 0.25 - 2.5 μg L - 1 (R = 0.999) and LD of 0.039 μg L - 1 . Accuracy was checked by addi tion and recovery method of the standard and/ or comparative method with GFAAS or ICP OES. The recovery ranged from 97 - 106% Cu(II), 100 - 105% Cd (II), 88 - 103% As (V) and 96 - 106% As (total)). The results for Cu (II) determined with the proposed methods were concordant with those obtained with the comparative. It is concluded that the material produced can be successfully applied in the extraction / preconcentration of copper, cadmium and analysis of inorganic speciation of arsenic and low limits of detection and quantification can be obtained even using a less sensitive technique such as FAAS.
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Papic, Morales Jorge. "Determinación de Fe III y/o Fe total en Aguas Potables y Naturales por Medio de Extracción en Fase Sólida." Tesis, 2018. http://repositorio.uchile.cl/handle/2250/152933.
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Seminario de Título entregado a la Universidad de Chile en cumplimiento parcial de los requisitos para optar al Título de Químico AmbientalIron (Fe) is a transition metal usually found in potable water at low concentrations, whose concentration limit is 0.3 mg / L according to NCh 409, and due to its common use mainly in pipelines and industries, it must be constantly monitored, in order to keep its concentration under the limits and guarantee the welfare of people. The aim of this work is to promote an easy method to identify and extract Fe from potable and natural waters through solid phase extraction. This was done both for acid and basic mediums. 0.4 mL of sulfosalicylic acid (SSA) at 2.5% w/v was used as a ligand, adding 3 mL of a monochloroacetic acid buffer for the samples in acid medium and 3 mL of concentrated NH3 (12,66 M) for samples in basic medium and form a complex, either Fe(III)-SSA or Fetotal-SSA, in 100 mL total solution. Then, an anion exchange solid resin was added, called AG 2-x8 from BIORAD, in order to preconcentrate the complex. Previous studies were conducted without the addition of resin to observe the formation of the complex and study its characteristics. The quantification limits were 0.56 ppm and 0.28 ppm, which are very high or too close to the concentration limit of Fe allowed in potable water, that is, 0.3 ppm (NCh 409). Solid phase studies were carried out in order to decrease the quantification limits of the method. Then the chemical variables involved in obtaining the complex were optimized, such as the amount of SSA, anionic resin, buffer and total volume. Thus obtaining the adequate amounts for each analyte, mentioned above. The extraction of the Fe-ASS complex was possible for both media. However, in a basic medium it requires much higher Fe concentrations for its formation and presented a constant turbidity in the form of a colloidal compound of gray tone mainly referred so the procedure was more thoroughly studied in acid medium. The Fe(III)-SSA complex presented good linearity throughout the measurement range with an DL of 7.32 x 10-3 ppm and an QL of 0.024 ppm achieving a good sensitivity and a recovery percentage of 99.7%. Only SO4-2 presented interference in the sample with a tolerance limit of only 100 ppm. The standard addition method was effective to eliminate this interference by treating the entire matrix in the same way throughout the measurement range. Potable water samples were taken from different sources, such as, from the Analytic Chemistry Laboratory (Ñuñoa), Quinta Normal and from a construction zone adjacent of the the Faculty of Sciences of the University of Chile. Fe is generally found at concentrations below the norm (23.38 ppb and 172 ppb), but is sensitive to climatic factors (522 ppb after a very rainy day) and construction places with little waste treatment (342.3 ppb), so it must be constantly monitored. Solid phase extraction is a simple, fast and efficient method and has a wide range of applications for different compounds or chemical substances.
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Pedro, Tânia Cristina Ferreira Ribas Vaz. "Development of solid phase extraction flow-based tools for environmental monitoring." Doctoral thesis, 2020. http://hdl.handle.net/10400.14/32160.
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The development of new analytical tools can be considered a non-stop challenge due to the constant search for new improved features and also to the emerging environmental contaminants. Flow-based methodologies stand out in contributing for this analytical challenge, providing the automation and miniaturization of the analysis including sample pre-treatment.
This thesis was developed based on two major objectives, one of them was to develop new miniaturized and automated analytical tools based on flow analysis for environmental monitoring. When designing new methodologies, another essential objective was to simplify sample preparation by coupling these techniques, based on solid phase extraction (SPE), within the developed flow-based system. The developed methodologies were optimized based on the same principles: minimize the use of reagent, make greener choices of the reagents, minimize the effluent production, lower the limits of detection and quantification, simplify and minimize sample/reagent handling. The use of the in-line SPE strategy showed to bring advantageous features to the analytical method (lowering limits of detection and quantification). The in-line SPE was achieved by using commercial resins (NTA and Chelex 100) and also a lab-made polymer inclusion membrane (Chapter 3).
A biparametric sequential injection system for the determination of copper and zinc in water and soil leachates was developed (Chapter 3). The strategy was to use a non-specific coulour reagent (4-(2-Pyridylazo)resorcinol – PAR) and explore the use of two different sorbent materials to selectively separate the two different metal ions in the same manifold. A polymer inclusion membrane (PIM) and the commercial resin Chelex 100 were the chosen materials to selectively retain zinc and copper, respectively. It was the first time that a PIM was used with this purpose in a flow system.
A spectrophotometric method for iron quantification using a newly designed chromogenic chelator was developed (Chapter 4). This low toxicity iron chelator was a specially designed 3-hydroxy-4-pyrydinone functionalized with ethers. Furthermore, this reagent demonstrated to display high affinity and specificity for iron ions. With the main objective of quantifying iron in a variety of water samples (fresh and marine water) a strategy including SPE was added to the manifold. By using an in-line SPE process, resorting to a NTA resin column coupled to the flow system, sample matrix clean-up and also the enrichment of the analyte was achieved.
A method for the screening of biogenic amines in waters was developed (Chapter 5). The system was divided in two analytical parts. The first one was devoted to the pre-concentration of the analyte using a column packed with Chelex 100; the second was the derivatization of the biogenic amines using fluorescamine for the fluorescent detection of the analyte. This method intended to be a suitable and ease to operate system to obtain real-time information about biogenic amines content in water.
A flow injection system for the spectrophotometric determination of the total zinc content in plant digests was developed (Chapter 6). By using a NTA resin column, zinc pre-concentration and the removal of possible interferences was accomplished. A specially designed multi-reflection flow cell coupled with a light emitting diode was the chosen detection system for the spectrophotometric determination of zinc using Zincon as colour reagent. The physical configuration of the flow cell contributed to improve the limit of detection and minimize refractive index gradients produced by the mixture of the reagents.O desenvolvimento de novas ferramentas analíticas pode ser considerado um desafio constante, devendo-se tal à busca incessante de características analíticas cada vez melhores e também ao surgimento de novos contaminantes ambientais. Os métodos em fluxo destacam-se ao contribuir para este desafio analítico, nomeadamente na automatização e miniaturização da análise, incluindo o tratamento da amostra. A tese foi desenvolvida com base em dois objetivos principais, um dos quais se centrou no desenvolvimento de novos métodos analíticos em fluxo para a monitorização ambiental. No planeamento de novos métodos teve-se em consideração outro grande objetivo, a simplificação do tratamento da amostra, associando para tal técnicas de extração em fase sólida ao sistema de fluxo desenvolvido. A otimização dos sistemas analíticos teve por base os mesmos conceitos: minimizar o consumo de reagentes; fazer uma escolha mais ecológica relativamente aos reagentes; minimizar a produção de efluentes, melhorar limites de deteção e quantificação; simplificar e minimizar o manuseamento de amostras/reagentes. Ao recorrer a processos de extração em fase sólida em linha, conseguiu-se uma melhoria das características analíticas associadas ao método (baixando o limite de deteção e quantificação). De uma forma geral, a extração em fase sólida em linha foi realizada recorrendo à utilização de resinas comerciais (NTA e Chelex 100), mas também foi utilizada uma membrana produzida em laboratório (Capítulo 3; membrana de inclusão de polímeros – PIM). Foi desenvolvido um sistema biparamétrico por injeção sequencial para a determinação de cobre e zinco em águas e lixiviados de solos (Capítulo 3). A estratégia usada para o desenvolvimento deste método envolveu o uso de um reagente de desenvolvimento de cor não específico - (4-(2-piridilazo)resorcinol – PAR) - e o explorar da utilização de diferentes materiais adsorventes para separar seletivamente os dois iões metálicos no mesmo sistema. Para tal recorreu-se a uma membrana de inclusão de polímeros (PIM) e a uma resina comercial (Chelex 100) com o intuito de reter e separar o zinco e o cobre, respetivamente. De salientar que foi a primeira vez que uma PIM foi utilizada com este objetivo num sistema de fluxo. No Capítulo 4 foi desenvolvido um método espectrofotométrico para a determinação de ferro em águas naturais utilizando um quelante cromogéneo desenvolvido recentemente. O quelante de ferro de toxicidade baixa pertence ao grupo das 3-hidroxi-4-piridinonas funcionalizado com éteres. Este reagente demonstrou ainda ter uma elevada afinidade e especificidade para o ferro. Com o objetivo de aplicar o método à determinação de ferro em diferentes tipos de águas naturais (doces e salinas), foi incluído no sistema de fluxo um passo adicional de extração em fase sólida. Para tal, utilizou-se uma coluna empacotada com resina de NTA, a qual permitiu realizar a limpeza da matriz da amostra e também a possibilidade de se concentrar o analito de interesse. viii Foi desenvolvido um método para o despiste de aminas biogénicas em águas (Capítulo 5). O sistema foi dividido em duas fases fundamentais. A primeira fase consistiu na pré-concentração do analito recorrendo a uma coluna empacotada com Chelex 100 acoplada ao sistema de fluxo; de seguida procedeu-se à derivatização das aminas com fluorescamina para a sua deteção fluorimétrica. O método desenvolvido tinha como principal objetivo ser de fácil execução, mas que desse uma resposta em tempo real sobre o conteúdo em aminas biogénicas em águas. Foi desenvolvido um sistema por injeção em fluxo para a determinação de zinco total em plantas (Capítulo 6). Com a implementação de uma coluna de NTA no sistema de fluxo conseguiu-se a pré-concentração de zinco e também a remoção de possíveis interferentes presentes na amostra. Como sistema de deteção foi utilizada uma célula de fluxo multi-reflexão acoplada a um LED, visando a determinação espectrofotométrica do zinco utilizando Zincon como reagente de desenvolvimento de cor. Devido à configuração física da célula de fluxo, esta contribuiu para a minimização da influência da refração produzida pela mistura dos reagentes e para o melhoramento do limite de deteção do método.
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Machado, Marta Daniela Valença. "Deteção de antidepressivos em águas superficiais e residuais." Master's thesis, 2013. http://hdl.handle.net/1822/30107.
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Dissertação de mestrado em Química MedicinalNos últimos anos o consumo de antidepressivos em Portugal tem vindo a aumentar. Segundo estudos realizados pela Autoridade Nacional do Medicamento e Produtos de Saúde (INFARMED) desde 2010 este sofreu um incremento de cerca de 73%, sendo superior em indivíduos do sexo feminino, de meia-idade, desempregados e divorciados. Pelo facto de parte da substância ativa da maioria dos antidepressivos ser metabolizada pelo organismo e da parte restante ser excretada sem qualquer tipo de degradação, o elevado consumo deste tipo de fármacos tem originado contaminações do meio ambiente com quantidades significativas em particular em águas superficiais e residuais. Estes compostos exibem caraterísticas físico-químicas e biológicas que os tornam resistentes à biodegradação e, uma vez nas águas, causam dificuldades às estações de tratamento de águas residuais (ETARs) durante a sua remoção. Assim, a contaminação do meio ambiente por antidepressivos é por vezes elevada, atingindo águas, solos e organismos aquáticos. Com este estudo pretende-se desenvolver um método de análise para a quantificação de três antidepressivos, fluoxetina, citalopram, sertralina e um metabolito, a norsertralina, em águas superficiais. A metodologia analítica desenvolvida utiliza a cromatografia líquida de ultra elevada eficiência acoplada à espetrometria de massa em tandem (UHPLC-MS/MS) precedida de extração em fase sólida (SPE). O procedimento desenvolvido foi aplicado à determinação de antidepressivos inibidores seletivos da recaptação de serotonina numa amostra de água de um rio (rio Lima). A análise efetuada mostra que estes fármacos existem em quantidades muito reduzidas no rio em estudo.
There has been a rapid increase in the use of antidepressants in Portugal. In fact, several INFARMED studies showed increased consumptions of about 73% since 2010, being this consumption higher among the female population, particularly the middle aged, unemployed and divorced individuals. As the consumed active ingredients of most antidepressants are not fully metabolized, the excess is excreted without degradation, contaminating the environment with important impact on wastewaters. Once in the environment, these compounds exhibit physicochemical and biological characteristics that make them resistant to biodegradation, resulting in the inefficient removal of these compounds by wastewater treatment plants (WWTPs). Therefore, the antidepressant contamination can easily reach waters, soils and aquatic organisms. This study was focused on the implementation of an analytical method to the quantification of three antidepressants, sertraline, fluoxetine, citalopram and a metabolite norsertraline, in surface waters. The developed analytical methodology uses ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) preceded by solid phase extraction (SPE). The developed procedure was applied to the determination of serotonin selective reuptake inhibitors in a sample of water from a river (Lima River). The analysis performed shows that these pharmaceuticals exist in very small quantities in the river under study.
Books on the topic "Fasi solide naturali"
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Anderson, Ray C. Berkshire Encyclopedia of Sustainability. Berkshire Publishing Group, 2016. http://dx.doi.org/10.1093/acref/9780190622664.001.0001.
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887 entriesIn this seminal work, experts from around the world provide authoritative coverage of the growing body of knowledge about ways to restore the planet. Focused on solutions, this interdisciplinary publication draws from the natural, physical, and social sciences to bring readers an unprecedented array of 887 articles from over 900 contributors from 53 countries on environmental law and ethics, green business practices, regional sustainability issues, and resource and ecosystem management.There is no shortage of information about environmental problems and no dearth of people calling themselves experts on sustainability. In fact, there is all too much information, and strident voices with opposing claims and frightening predictions. This encyclopedia solves the problem of information overload with concise overviews from experts on an array of sustainability-related topics. The reader will find solid research data, thorough analyses, and jargon-free discussion, effectively transforming a fast-developing research domain.
Book chapters on the topic "Fasi solide naturali"
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Bleakley, Chris. "Needles in Haystacks." In Poems That Solve Puzzles, 93–116. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198853732.003.0006.
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Chapter 6 examines one of the greatest unsolved challenges in mathematics - the problem of finding the best solution from a large number of possibilities. The Traveling Salesman Problem requires that the shortest tour of a group of cities is determined. Surprisingly, the only way to guarantee finding the shortest tour is to measure the length of all possible tours. Exhaustive search such as this is very slow. For centuries, mathematicians have sought to find fast algorithms for solving combinatorial search problems. The most famous was invented by Edsger Dijkstra in 1956. Dijkstra’s algorithm finds the shortest route between cities on a roadmap and is now used in all satellite navigation apps. The Gale-Shapley algorithm solves the problem of matching pairs of items according to user preferences. John Holland took the radical step of accelerating combinatorial search by mimicking natural evolution in a computer.
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Shan, Yao, and Jianjun Shi. "Data Mining for Source Apportionment of Trace Elements in Water and Solid Matrix." In Trace Metals in the Environment - New Approaches and Recent Advances. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.88818.
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Trace elements migrate among different environment bodies with the natural geochemical reactions, and impacted by human industrial, agricultural, and civil activities. High load of trace elements in water, river and lake sediment, soil and air particle lead to potential to health of human being and ecological system. To control the impact on environment, source apportionment is a meaningful, and also a challenging task. Traditional methods to make source apportionment are usually based on geochemical techniques, or univariate analysis techniques. In recently years, the methods of multivariate analysis, and the related concepts data mining, machine learning, big data, are developing fast, which provide a novel route that combing the geochemical and data mining techniques together. These methods have been proved successful to deal with the source apportionment issue. In this chapter, the data mining methods used on this topic and implementations in recent years are reviewed. The basic method includes principal component analysis, factor analysis, clustering analysis, positive matrix fractionation, decision tree, Bayesian network, artificial neural network, etc. Source apportionment of trace elements in surface water, ground water, river and lake sediment, soil, air particles, dust are discussed.
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Greenlaw, Raymond, H. James Hoover, and Walter L. Ruzzo. "Evidence That NC Does Not Equal P." In Limits to Parallel Computation. Oxford University Press, 1995. http://dx.doi.org/10.1093/oso/9780195085914.003.0009.
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Why should we believe that NC does not equal P? One form of evidence is that many people have tried, but failed, to show them equal. More persuasive, perhaps, is the way they have failed, or rather, the character of the limited successes. Specifically, known approaches consistently leave a large gap between what we know how to solve by highly parallel algorithms, and general problems in P. In outline, the state of the art is as follows. General simulations are not fast: The best known parallel simulations of general sequential models give very modest improvements, basically reducing sequential time T to parallel time T/logT or √T, depending on the parallel model. Furthermore, 2TΩ(1) processors are needed to achieve even these modest improvements. Fast simulations are not general: Rapid simulations of sequential models by highly parallel models are known only for rather weak sequential models. Natural approaches provably fail: Certain natural approaches to highly parallel simulation are provably insufficient. Equivalently, in certain natural structured models of computation (Borodin [41]), one can prove that the analogs of NC and P are not equal, and indeed are separated by a nearly exponential gap, as suggested by the two points above. In this chapter we will present this evidence in more detail. The nature of the available evidence renders this chapter, especially Section 5.4, somewhat more technical than the rest of Part I. The reader may wish to skim or skip it, at least on first reading. First, consider the Generic Machine Simulation Problem introduced in Section 4.1. Intuitively, why should we expect this problem to be hard to parallelize? Notice that we defined the problem in terms of Turing machines as a technical convenience; they are not in any way fundamental to the result.
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bin Samsuri, Azemi. "Evaluation of Recycled Carbon Black (r-CB) Based on Styrene Butadiene Rubber, Natural Rubber and Nitrile Rubber Compounds." In Rubber Materials [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.107421.
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The enormous accumulation of used tyres has long been a threat to the environment. Pyrolysis is a process of chemically decomposing organic materials at elevated temperatures above 430°C in the absence of oxygen. Pyrolysis can be used to reprocess the tyres into fuel gas, oils, solid residue (char) and low-grade carbon black, which cannot be used in tyre manufacture. Rubber compounds containing r-CB were prepared based on Styrene Butadiene Rubber, Natural Rubber and Nitrile Rubber. Specific formulations were selected for each of the rubber. Natural Rubber was mixed with r-CB to produce pre-cured tread compound for retreading, Nitrile Rubber was mixed with r-CB to produce hose and seals compounds, and finally, r-CB was compounded in accordance to the Standard Test Methods for Styrene-Butadiene Rubber Recipe and Evaluation Procedures. The quality and performance of r-CB in these rubber compounds were compared with the commercial virgin carbon black. The results show that r-CB matches the quality of virgin carbon black such as High Abrasion Furnace (N330) and Fast Extrusion Furnace (FEF, N550) in terms of hardness, tensile strength, abrasion resistance and other relevant physical properties. The prospects of r-CB are very bright and promising. The challenges ahead are to maintain high quality of r-CB, to be competitive in cost in relation to virgin carbon black.
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Brezonik, Patrick L., and William A. Arnold. "Complexation Reactions and Metal Ion Speciation." In Water Chemistry, 333–88. 2nd ed. Oxford University PressNew York, 2022. http://dx.doi.org/10.1093/oso/9780197604700.003.0009.
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Abstract This chapter deals with the second associative reaction type in ionic equilibria: complexation. After presenting definitions, the chapter describes ways to express equilibria of complexes and their components: metal ions and ligands. The chemical and ecological significance of complexes is summarized, along with the two types of complexes—inner and outer sphere. Factors affecting binding strengths of complexes are described, with attention to predictive relationships. Methods to solve and display complexation equilibria are explained, including simple examples solvable manually and computer methods for complicated situations in many natural waters. The roles of inorganic and organic ligands in metal ion speciation are described using examples ranging from soft to hard waters and high-ionic-strength seawater. The kinetics of complex formation and dissociation is treated. Although most formation reactions are fast, dissociation can be slow for strong complexes. Some metal-ligand exchange processes are slow enough to maintain non-equilibrium conditions for extended periods.
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"Appendix." In My Life with Science (extendes English edition), 103–96. GNT-Verlag GmbH, 2023. http://dx.doi.org/10.47261/1558-a.
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Epiloge: ... “Sometimes one observes that the assessment of a scientist is based on the amount of third-party funding raised. I think this is wrong and go so far as to claim that sometimes too much money can even be harmful, because it does not promote one’s own creativity (The “golden years” of today’s FHI were the 1920s, when inflation and the looming Great Depression forced severe financial constraints.)” ... Vita, Chemistree Holographs: Essay “The physical worldview in the light of relativity and quantum theory”—“This shows that I probably recognized the field of interest of my later life already at the age of 16.“ ...; “In September 1959 I asked Heinz Gerischer for a topic for my diploma (i.e. master’s) thesis and he proposed to me to develop a novel technique for investigating the kinetics of very fast chemical reactions in aqueous solution based on the principle of chemical relaxation as pioneered by Manfred Eigen. In June 1960 I reported on this concept in a seminar for which my manuscript follows. My thesis was successfully finished after 18 months in spring 1961.” ... “The ‘Habilitation’, i.e. promotion to the rank of lecturer (“Privatdozent”) required another thesis on my own research with solid surfaces and a lecture presented to the assembly of the professors of the faculty of natural sciences. This lecture had to be on a different topic and was hence on my previous experience with reactions in solution and took place in summer 1967.” Publications, Links and literature, Image sources, Index.
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Arzberger, Fabian, Jasper Zevering, Anton Bredenbeck, Dorit Borrmann, and Andreas Nüchter. "Unconventional Trajectories for Mobile 3D Scanning and Mapping." In Autonomous Mobile Mapping Robots [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.108132.
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State-of-the-art LiDAR-based 3D scanning and mapping systems focus on scenarios where good sensing coverage is ensured, such as drones, wheeled robots, cars, or backpack-mounted systems. However, in some scenarios more unconventional sensor trajectories come naturally, e.g., rolling, descending, or oscillating back and forth, but the literature on these is relatively sparse. As a result, most implementations developed in the past are not able to solve the SLAM problem in such conditions. In this chapter, we propose a robust offline-batch SLAM system that is able to address more challenging trajectories, which are characterized by weak angles of incidence and limited FOV while scanning. The proposed SLAM system is an upgraded version of our previous work and takes as input the raw points and prior pose estimates, yet the latter are subject to large amounts of drift. Our approach is a two-staged algorithm where in the first stage coarse alignment is fast achieved by matching planar polygons. In the second stage, we utilize a graph-based SLAM algorithm for further refinement. We evaluate the mapping accuracy of the algorithm on our own recorded datasets using high-resolution ground truth maps, which are available from a TLS.
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Greenlaw, Raymond, H. James Hoover, and Walter L. Ruzzo. "Approximating P-Complete Problems." In Limits to Parallel Computation. Oxford University Press, 1995. http://dx.doi.org/10.1093/oso/9780195085914.003.0014.
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Suppose that finding the solution to a problem is P-complete. It is natural to ask if it is any easier to obtain an approximate solution. For decision problems this might mean considering the corresponding combinatorial optimization problem. That is, a problem in which we try to minimize or maximize a given quantity. As one might expect from the theory of NP-completeness, the answer is both yes (for example in the case of Bin Packing, Problem A.4.7) and no (for example in the case of the Lexicographically First Maximal Independent Set Size Problem, see Lemma 10.2.2.). There are several motivations for developing good NC approximation algorithms. First, in all likelihood P-complete problems cannot be solved fast in parallel. Therefore, it may be useful to approximate them quickly in parallel. Second, problems that are P- complete but that can be approximated well seem to be special boundary cases. Perhaps by examining these types of problems more closely we can improve our understanding of parallelism. Third, it is important to build a theoretical foundation for studying and classifying additional approximation problems. Finally, it may be possible to speed up sequential approximation algorithms, of NP-complete problems, using fast parallel approximations. Our goal in this section is to develop the basic theory of parallel approximation algorithms. We begin by showing that certain P-complete problems are not amenable to NC approximation algorithms. Later we present examples of P-complete problems that can be approximated well in parallel. We start by considering the Lexicographically First Maximal Independent Set Problem, introduced in Definition 7.1.1, and proven P-complete in Problem A.2.1. As defined, LFMIS it is not directly amenable to approximation. We can phrase the problem in terms of computing the size of the independent set. Definition 10.2.1 Lexicographically First Maximal Independent Set Size (LFMISsize) Given: An undirected graph G = (V, E) with an ordering on the vertices and an integer k. Problem: Is the size of the lexicographically first maximal independent set of G less than or equal to k ? The following lemma shows that computing just the size of the lexicographically first maximal independent set is P-complete.
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Beßler, Daniel, Robert Porzel, Mihai Pomarlan, Abhijit Vyas, Sebastian Höffner, Michael Beetz, Rainer Malaka, and John Bateman. "Foundations of the Socio-Physical Model of Activities (SOMA) for Autonomous Robotic Agents1." In Frontiers in Artificial Intelligence and Applications. IOS Press, 2021. http://dx.doi.org/10.3233/faia210379.
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In this paper, we present foundations of the Socio-physical Model of Activities (SOMA). SOMA represents both the physical as well as the social context of everyday activities. Such tasks seem to be trivial for humans, however, they pose severe problems for artificial agents. For starters, a natural language command requesting something will leave many pieces of information necessary for performing the task unspecified. Humans can solve such problems fast as we reduce the search space by recourse to prior knowledge such as a connected collection of plans that describe how certain goals can be achieved at various levels of abstraction. Rather than enumerating fine-grained physical contexts SOMA sets out to include socially constructed knowledge about the functions of actions to achieve a variety of goals or the roles objects can play in a given situation. As the human cognition system is capable of generalizing experiences into abstract knowledge pieces applicable to novel situations, we argue that both physical and social context need be modeled to tackle these challenges in a general manner. The central contribution of this work, therefore, lies in a comprehensive model connecting physical and social entities, that enables flexibility of executions by the robotic agents via symbolic reasoning with the model. This is, by and large, facilitated by the link between the physical and social context in SOMA where relationships are established between occurrences and generalizations of them, which has been demonstrated in several use cases in the domain of everyday activites that validate SOMA.
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Wilshire, Howard G., Richard W. Hazlett, and Jane E. Nielson. "Routes of Ruin." In The American West at Risk. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195142051.003.0010.
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The United States is more wedded to vehicles than is any other nation, and “freedom” to many Americans seemingly means driving their individual vehicles anywhere they choose. Opinion polls commonly show high proportions of U.S. citizens more concerned about gas prices, potholed highways, or restrictions on vehicle access to backcountry washes and dirt roads than about government scandals, stolen elections, or environmental damage. Unfortunately, vehicles and roads exact a huge toll on lives and health and threaten our future well-being. Driving wheeled vehicles, and constructing roads to support them, comes close to topping the list of humankind’s most environmentally damaging activities. On most soils, even foot traffic creates tracks, trails, and roads. After ancient people invented wheeled vehicles to carry their burdens and themselves, they found that running water quickly rutted and potholed the cart tracks, and gully erosion chopped them up on slopes. Rainstorms eroded the tracks, flooding the dislodged sediment into streams and creeks and burying downslope croplands. Rutted tracks prevented Roman chariots from driving as fast as they were designed to go, so the talented Roman engineers quite naturally invented paved roads—some with better staying power than asphalt highways. But Roman paving did not solve the erosion problems that roads created, and in some ways made it worse. Today, some parts of the United States contain more motorized vehicles than people. The varied vehicle uses, including military training, have vastly proliferated roads and roadlike corridors—especially numerous utility routes—across every type of American landscape. Erosional forces and their effects have not changed since Roman times, but modern engineers still fail to choose transportation routes or build roads to minimize environmental damages. The roads spread severe erosional effects everywhere, along with pervasive pollution. On top of it all, television images encourage Americans to take recreational cars, trucks, motorcycles, and all-terrain vehicles anywhere we wish. The naked ruts they create are an insidious form of road building.
Conference papers on the topic "Fasi solide naturali"
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Fadl, M., and L. He. "On LES Based Conjugate Heat Transfer Procedure for Transient Natural Convection." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63600.
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Natural convection prediction closely relevant to flexible operations (e.g. fast and frequent startups and showdowns) of gas turbines and steam turbines presents considerable challenges. The strong inter-dependence between fluid and solid parts points to the need for conjugate heat-transfer (CHT) methods. However, the long time scales of the practical operation processes of interest, and the fundamental fluid-solid time scale disparity raise general issues regarding the computational costs of the CHT methods. In particular, if a high-fidelity flow model (e.g. LES) needing to resolve smaller time scales of turbulence is adopted, we also face an additional question regarding the consistency and accuracy of the fluid-solid interface treatment. In this paper, we address the issues by the means of a loosely coupled CHT procedure based on the multi-scale methodology recently proposed for transient conjugate heat transfer predictions. The multi-scale framework provides an efficient way for accurately solving problems with a huge scale disparity. A particular emphasis of the present work is on efficient and accurate transient CHT solutions in conjunction with the turbulence eddy resolved modelling (LES) for natural convection. A multi-scale flow decomposition associated with the corresponding time step split is adopted. The resultant triple timing formation of the flow equations can be solved efficiently for the fluid-solid coupled system with very disparate time scales. The methodology will be presented with case studies supported by a new interface analysis to underpin the problem statement and motivation of the present work, and to demonstrate the validity and effectiveness of the methodology and implemented procedure.
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Kennedy, Rory C., Dillon Helfers, and Yin Lu Young. "A Reduced-Order Model for an Oscillating Hydrofoil Near the Free Surface." In SNAME 13th International Conference on Fast Sea Transportation. SNAME, 2015. http://dx.doi.org/10.5957/fast-2015-062.
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The first objective of this work is to numerically investigate how the proximity to the free surface influences the hydrodynamic response and susceptibility to cavitation of a hydrofoil undergoing controlled pitching oscillations, for high-speed full-scale operating conditions. A second objective is to develop a time-domain Reduced Order Model (ROM) to predict the unsteady hydrodynamic loads (for rapid exploration of the design space and for real-time active/passive actuation/control). The ROM delineates the fluid-structure interaction (FSI) forces into fluid inertial, damping, and disturbing force components, and only predicts the primary oscillation frequency. In addition to predicting the unsteady loads, when coupled with the solid equations of motion, the ROM can also be used to calculate the natural resonance frequencies and damping characteristics with consideration for viscous and free surface effects. This will allow designers to better predict and control the dynamic response of lifting surfaces operating near the free surface.
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Jing, Shuxu, Fazhi He, Xiantao Cai, and Huajun Liu. "Collaborative Naming for Replicated Collaborative Solid Modeling System." In ASME 2008 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/detc2008-49223.
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In this paper, a framework of full replicated collaborative solid modeling and a method for multi-user interaction to support natural, free, fast and less-constrained multi-user human-to-human interaction is proposed. Particularly, the challenges and problems of topological entity correspondence by name across collaborative modeling sites in replicated CSM system is analyzed. And a method to achieve name correspondence during collaborative modeling sessions in replicated CSM system is proposed. The proposed method is tested in a prototype system of replicated CSM, which employs ACIS as the geometric modeling kernel and adopts winsocket API for communication purpose, developed by our research group.
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Haus, H. A. "Additive Pulse Modelocking and Kerr Lens Modelocking." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/up.1992.ma1.
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Additive Pulse Modelocking (APM)[1,2,3] and Kerr Lens Modelocking (KLM)[4] are fairly new methods of generating short pulses from solid state lasers. Both produce an effective fast saturable absorber action (response time shorter than the pulse-width) that can be tailored to the system at hand. For this reason it was possible to modelock solid state lasers with long gain relaxation times that prevented stable operation with available “natural” saturable absorbers. .
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Duan, Wenshun, Kefan Zhang, and Hongli Chen. "Fluid-Thermal-Mechanical Coupling Analysis of the Reactor Vessel of Natural Circulation Lead-Cooled Fast Reactor SNCLFR-100." In 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-91709.
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Abstract Lead-based reactors mostly adopt integrated pool structures to simplify the design of reactor and have high inherent safety. As an important safety facility in the primary circuit, the reliability of the reactor vessel is critical for the safe operation of the whole reactor. The reactor vessel of natural circulation lead-cooled fast reactor SNCLFR-100 was taken as the object, and the corresponding simplified model was established. Based on ANSYS, the fluid-thermal-mechanical coupling analysis was carried out under the steady-state to study the influence of flow field and temperature field on the reactor vessel, and to reveal the distribution law of key thermal and mechanical parameters under the steady-state operation in this paper. The results of mechanical calculations were evaluated based on American society of Mechanical Engineers (ASME) standards, and the preliminary design scheme of reactor solid structure was optimized. The results showed that the stress evaluation results of the SNCLFR-100 reactor vessel meet the requirements of ASME standards in steady-state operation conditions. After optimizing the original solid structure, the stress evaluation results show that the maximum stress value was reduced by 43.3%, and the stress concentration was obviously suppressed, which indicates that the reactor container has a higher safety margin under the optimization scheme. The Steady-state calculation based on normal operation conditions provides a certain research basis for the subsequent transient calculation under accident conditions.
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Chiaramonti, David, Anja Oasmaa, and Yrjo¨ Solantausta. "Fast Pyrolysis Oil for Power Generation." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90245.
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Biomass fast-pyrolysis oil (PO) is a liquid biofuel derived from lignocellulosic biomass: it offers several advantages compared to the direct us of solid bio fuels, such as high energy density, storability and transportability typical of liquid fuels, possibility to use the fuel in engines and turbines, easier downscaling of plants (which is a very important aspect for decentralized energy generation schemes). In addition, PO is the lowest cost biofuel, thus offering the possibility to penetrate also the large scale power generation market. Biomass POs have been studied and applications tested for many years, either for heat generation in medium-scale boilers or power generation. The present works reviews and analyses the most relevant experiences carried out so far and published results in power production from biomass PO. Power generation systems (PGS) which are here examined are gas turbines, diesel engines, stirling engines, as well as co-firing applications in large scale power plants (coal or natural gas plants). The main techniques for upgrading this biofuel and their impact on technologies are also shortly introduced and considered. The current status of development for each PO-based power generation option is discussed. This review work showed that long term demonstration (either technical or economical) is however still needed, even for the most developed technologies (use of PO in modified gas turbines and cofiring in natural gas stations): projects are on going to achieve long term demonstration.
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Maffulli, R., L. He, P. Stein, and G. Marinescu. "Fast Conjugate Heat Transfer Simulation of Long Transient Flexible Operations Using Adaptive Time Stepping." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75740.
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The emerging renewable energy market calls for more advanced prediction tools for turbine transient operations in fast startup/shutdown cycles. Reliable numerical analysis of such transient cycles is complicated by the disparity in time scales of the thermal responses in fluid and solid domains. Obtaining fully-coupled time-accurate unsteady Conjugate Heat Transfer (CHT) results under these conditions would require to march in both domains using the time step dictated by the fluid domain: typically, several orders of magnitude smaller than the one required by the solid. This requirement has strong impact on the computational cost of the simulation as well as being potentially detrimental to the accuracy of the solution due to accumulation of round-off errors in the solid. A novel loosely coupled CHT methodology has been recently proposed, and successfully applied to both natural and forced convection cases that removes these requirements through a source-term based modelling approach of the physical time derivative terms in the relevant equations. The method has been shown to be numerically stable for very large time steps with adequate accuracy. The present effort is aimed at further exploiting the potential of the methodology through a new adaptive time stepping approach. The proposed method allows for automatic time step adjustment based on estimating the magnitude of the truncation error of the time discretization. The developed automatic time stepping strategy is applied to natural convection cases under long (2000 s) transients: relevant to the prediction of turbine thermal loads during fast startups/shutdowns. The results of the method are compared with fully coupled unsteady simulations showing comparable accuracy with a significant reduction of the computational costs.
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Zagar, Philipp, and Rudolf Scheidl. "The Connection Between Sliding Mode Analysis and Singular Perturbation Theory for Modeling Fast Hydraulically Fed-Back Switching Valves." In BATH/ASME 2022 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/fpmc2022-89105.
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Abstract In most cases modeling of fast switching valves in hydraulics results in fast and slow subsystems. System equations which incorporate fast and slow dynamics are called stiff systems and one can apply singular perturbation theory to reduce the system order and get handy approximate expressions in a lower-order description. This is not only useful to reduce complexity to numerically solve the system efficiently, but also to understand the system’s key parameters and how they affect the behavior which is of great interest during design phase. In a previous paper the authors published an approach which uses switched systems and sliding modes to get a reduced system description of hydraulically fed-back switching. There, one models a hydraulic valve as either completely open or closed. A partially opened valve is then modelled as a sliding mode which can be interpreted as a pulse-width modulation of a fast switching digital valve. Even though, the resulting sliding mode dynamics approximation does not preserve topological properties of the full system dynamics an advantage of this approach is that the system incorporates the nonlinearities which arise due to end-stops of valves in a very natural way. Therefore, it is capable of describing system dynamics which results from such non-smooth properties. In this paper the authors work out the naturally suggested — even though not obvious — connection between both approaches for reducing systems with hydraulically fed-back switching valves.
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Haseltalab, A., L. van Biert, and BTW Mestemaker. "Energy Management for Hybrid Power Generation Using Solid Oxide Fuel Cell." In International Ship Control Systems Symposium. IMarEST, 2020. http://dx.doi.org/10.24868/issn.2631-8741.2020.006.
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The shipping industry is facing increasing requirements to decrease its environmental footprints. This challenge is being addressed through the use of alternative fuels and adoption of novel energy sources in advanced power and propulsion systems. In this paper, an energy management approach is proposed to determine the optimal split between different energy sources of a vessel with hybrid power generation. The power and propulsion system of the vessel consists of a gas engine-generator set and a solid oxide fuel cell, both fed with liquefied natural gas, and a battery. Specific fuel consumption curves and transient capabilities of the engine and fuel cell are used to determine the optimal split and the battery is used to deal with the fast load transients during heavy operations and also providing power during low power demanding activities. The performance of the proposed approach is evaluated for a dredging vessel with a DC power and propulsion system and compared to a benchmark vessel powered by gas engine-generator sets only. The results indicate a 16.5% reduction in fuel consumption compared to a benchmark non-hybrid power system and conventional power management.
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Tanasescu, Elena-Cornelia, Mihaela-Cristina Lite, Elena Perdum, Lucia Oana Secăreanu, Ovidiu Iordache, Irina-Mariana Sandulache, and Lucian Gabriel Radu. "Overview on the New Generation of Extraction Technique: Fabric Solid-Phase Extraction." In The 9th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2022. http://dx.doi.org/10.24264/icams-2022.v.8.
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Fabric phase sorptive extraction (FPSE) is a new-generation of sample preparation technique that effectively combines representative characteristics of solid-phase microextraction – SPME (equilibrium-based extraction) and solid phase extraction – SPE (exhaustive extraction). FPSE was introduced in 2014 by Kabir A. and Furon K.G. FPSE utilizes a fabric substrate (natural or synthetic such as cotton or polyester) that is chemically coated with a hybrid sorbent (organic-inorganic sol-gel). The entire assembly (fabric substrate coated with the sol-gel polymer) results in a fast and sensitive micro-extraction device. The FPSE development process can be described in 3 main steps: (1) Preparation of the fabric substrate for sol-gel coating, (2) preparation of the sol-solution for coating the substrate, and (3) formation of sol-gel coatings on the fabric substrate. Using this technique can be ensured a faster, cleaner, and with a high concentration of analyte solution. FPSE is a method that can be easily modified and used in different types of applications. For this reason, FPSE is increasingly used in the scientific community dealing with sample pretreatment. By using this technique, promising results have been obtained both for the extraction and determination of certain analytes from environmental samples, as well as from other types of samples, with complex matrices (food and biological samples). This study aims to summarize the existing data on FPSE and to briefly present this innovative method.