Programmable rate modem utilizing digital signal processing techniques

The engineering development study to follow was written to address the need for a Programmable Rate Digital Satellite Modem capable of supporting both burst and continuous transmission modes with either binary phase shift keying (BPSK) or quadrature phase shift keying (QPSK) modulation. The preferred implementation technique is an all digital one which utilizes as much digital signal processing (DSP) as possible. Here design tradeoffs in each portion of the modulator and demodulator subsystem are outlined, and viable circuit approaches which are easily repeatable, have low implementation losses and have low production costs are identified. The research involved for this study was divided into nine technical papers, each addressing a significant region of concern in a variable rate modem design. Trivial portions and basic support logic designs surrounding the nine major modem blocks were omitted. In brief, the nine topic areas were: (1) Transmit Data Filtering; (2) Transmit Clock Generation; (3) Carrier Synthesizer; (4) Receive AGC; (5) Receive Data Filtering; (6) RF Oscillator Phase Noise; (7) Receive Carrier Selectivity; (8) Carrier Recovery; and (9) Timing Recovery

Ueber die Reizleitungsbahn beim Goltz'schen Klopfversuch

Verursacht man durch schnell aufeinander folgende Schläge eine mechanische Reizung auf der Bauchdecke oder auf die Eingeweide des Frosches, so fällt das Herz in Erschlaffungszustand und steht still. Dabei habe ich die Bahn der Reizleitung unter-sucht. Die Ergebnisse sind: 1. Der Stillstand des Herzens beim Klopfversuch wird durch die reflektorische Erregung des N. vagus hervorgerufen. 2. Der zentripetale Impuls, welcher von den gereizten Baucheingeweiden des Frosches ausgeht, tritt ins Rückenmark meistens durch die 6. Kommissurenfaser, aber bisweilen durch die 5. oder die 7. Auch seltenerweise nimmt der Impuls den Weg durch die 7. bis 9. Kommissurenfaser, steigt in ihr auf und gelangt endlich zum herzhemmenden Vaguskern in Medulla oblongata. 3. Die elektorische Reizung des sympatischen Nervenstammes ist nicht geeignet reflektorischen Herzstillstand herbeizuführen. 4. Der Klopfversuch bei Säugetieren (Kaninchen und Meerschweinchen) ist niemals geglückt. 5. Beim Riesensalamander (Cryptobronchus japonicus) gelingt der Klopfversuch sehr leicht. Die zentripetale Bahn geht bei diesem Tier über die 9. bis 11. Kommissurenfaser. 6. Narkose beeinträchtigt das Gelingen des Versuches wesentlich

Experimental and Numerical Study on Cold-formed Steel Built-up Box Beams

In this paper, a study of flexural behavior of cold-formed steel built-up box beam which is commonly used in low rise and residential building is presented. Experimental investigation is conducted to understand about the failure mode and the load capacity of the beam in this study. Numerical analysis by using ABAQUS program was performed in order to verify with experimental result. In addition, influence of thickness, connection spacing, and web height and flange width to thickness ratio, affecting load capacity and buckling behavior of the beam, were discussed. The result shows that the finite element analysis can well predict the flexural strength of the beam and the thickness and connection spacing are the key factors to improve load capacity of the beam

Análise termodinâmica de sistemas BECCS no setor sucroenergético

In the 2015 Paris Agreement, Brazil pledged to reduce its GHG (greenhouse gas) emissions by 37% by 2050 and by 43% by 2030 compared to 2005, reinforcing its targets for reduction to zero emissions by 2050. Bioenergy systems with carbon capture and storage (BECCS) will be essential for countries to be able to meet the gas emission reduction targets established in the Paris Agreement. Brazil is considered the world's largest sugarcane producer with a 39% share. For BECCS systems, the carbon dioxide (CO2) capture method by chemical absorption is the most promising approach among the commercially available technologies in the short and medium term. This work aims to carry out a thermodynamic analysis of different configurations of a BECCS system with a chemical absorption post-combustion capture method (Monoethanolamine-MEA) from the burning of sugarcane bagasse and straw. Commercial software Aspen Plus®, Aspen Hysys® and Matlab were used to simulate different configurations of the BECCS system, covering biomass combustion, CCS (Carbon Capture System) and seven different configurations of the Rankine cycle with cogeneration. Three scenarios of technological maturity of the alcohol and sugar production process were considered in the analysis. Stochastic method and parametric analysis were applied having as main performance indicators evaluated the generation of net electric power, CO2 capture and specific emission per unit of energy generated annually. The analyzes evidenced a tradeoff between net electric power generation and carbon capture for all evaluated scenarios and configurations. Scenarios where there is greater availability of heat as a result of the alcohol and sugar production process being more efficient have been shown to favor carbon capture. Extracting steam from the turbines to supply the thermal and electrical demand of the CCS together with the process implied a high net electrical power penalty generated by the plant.No Acordo de Paris de 2015 o Brasil se comprometeu a reduzir suas emissões de GEE (gases de efeito estufa) em 37% até 2030 e de 43% até 2050 em relação a 2005, reforçando no evento da Cúpula do Clima de 2021 suas metas de redução a emissões zero até 2050. Sistemas de bioenergia com captura de carbono e armazenagem (BECCS) serão fundamentais para que os países consigam cumprir com as metas de redução de emissões de gases estabelecidas no Acordo de Paris. O Brasil é considerado o maior produtor mundial de cana-de-açúcar com 39% de participação. Para sistemas BECCS, o método de captura de dióxido de carbono (CO2) por absorção química é a abordagem mais promissora entre as tecnologias disponíveis comercialmente no curto e médio prazo. Este trabalho tem como objetivo realizar uma análise termodinâmica de diferentes configurações de um sistema BECCS com método de captura pós combustão por absorção química (Monoetanolamina-MEA) a partir da queima do bagaço e palha de cana-de-açúcar. Softwares comerciais Aspen Plus®, Aspen Hysys® e Matlab foram utilizados para a simulação de diferentes configurações do sistema BECCS, abrangendo a combustão da biomassa, CCS (Sistema de Captura de Carbono) e sete diferentes configurações do ciclo Rankine com cogeração. Três cenários de maturidade tecnológica do processo de produção de álcool e açúcar foram considerados na análise. Método estocástico e análise paramétrica foram aplicados tendo como principais indicadores de desempenho avaliados a geração de potência elétrica líquida, captura de CO2 e emissão específica por unidade de energia gerada. As análises evidenciaram um conflito entre geração de potência elétrica líquida e captura de carbono para todos os cenários e configurações avaliadas. Cenários onde há maior disponibilidade de calor em decorrência do processo de produção de álcool e açúcar serem mais eficientes permitiram favorecer a captura de carbono. Extrair vapor das turbinas para suprir a demanda térmica e elétrica do CCS juntamente com o processo implicaram em alta penalidade de potência elétrica líquida gerada pela planta

A Modified Underwater Weighing Method Without Complete Immersion

This study was designed to examine the validity of a modified underwater weighing method for measuring human body volume (BV) that does not require head submersion (MUW). Results were compared with those obtained by the underwater weighing method (UW). The true head volume was calculated from the difference in BV, with and without head submersion. Stepwise regression analysis provided an equation to predict the head volume (HV) from the head girth (HG), the head length (HL), the head breadth (HB), the neck girth (NG), the face length I (FLI), the face length II (FLII), and the cheek girth. The equation for males was HV=0.185^*(HG) +0.122^*(FLII) -8.925, r^2=0.678, SEE=0.216. The equation for females was HV=0.131^*(HG) -0.026^*(NG) +0.112^*(FLI) -6.760, r^2=0.747, SEE=0.154. Cross-validation of predicted HV showed that the correlation coefficients were r=0.759, SEE=0.193 and r=0.749, SEE=0.193, for males and females respectively. Correlation coefficients and SEE between MUW and MW for body volume and % body fat were r=1.000, SEE=0.207 and r=0.983, SEE=1.339 for males and r=1.000, SEE=0.196 and r=0.946, SEE=1.915 for females. It can be concluded that this new method offers promising possibilities for future research with people who are unable to submerge their heads