Design for repair: ottimizzazione metodologie e caso di studio sottogruppo meccanico

Negli ultimi anni si è visto un forte segnale di cambiamento culturale indirizzato verso la sostenibilità affermando sempre più efficacemente i concetti di riciclaggio, riduzione e riutilizzo. Finora il design dei prodotti si è concentrato su aspetti che sfavorivano tale approccio e piuttosto si ponevano come specifica quella di definire a priori la vita del prodotto. Infatti, si sono sempre più sviluppate tecniche di accoppiamento delle parti che una volta accoppiate non consentivano più il disassemblaggio di queste. L’obiettivo di tale elaborato è stato quello di definire, nella famiglia di metodologie chiamata Design for X, un criterio che possa valutare e guidare la progettazione in ottica più mirata verso la riparabilità del prodotto “Design for Repair”. Aumentare la riparabilità del prodotto vuol dire poter aumentare la sua longevità, così da non avere la necessità di sostituirlo con un componente nuovo causando un impatto ambientale doppio, ossia la mancata necessità sia di sfruttare risorse per la realizzazione del sostituto sia di non dover occuparsi del processo di smaltimento del prodotto sostituito.

Economic design of (X)over-bar and R charts under Weibull shock models

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Joint conomic design of (x)over-bar and R charts under Weibull shock models

This paper deals with the joint economic design of (x) over bar and R charts when the occurrence times of assignable causes follow Weibull distributions with increasing failure rates. The variable quality characteristic is assumed to be normally distributed and the process is subject to two independent assignable causes (such as tool wear-out, overheating, or vibration). One cause changes the process mean and the other changes the process variance. However, the occurrence of one kind of assignable cause does not preclude the occurrence of the other. A cost model is developed and a non-uniform sampling interval scheme is adopted. A two-step search procedure is employed to determine the optimum design parameters. Finally, a sensitivity analysis of the model is conducted, and the cost savings associated with the use of non-uniform sampling intervals instead of constant sampling intervals are evaluated.

Economic design of (X)over-bar charts with variable parameters: the Markov chain approach

This paper presents an economic design of (X) over bar control charts with variable sample sizes, variable sampling intervals, and variable control limits. The sample size n, the sampling interval h, and the control limit coefficient k vary between minimum and maximum values, tightening or relaxing the control. The control is relaxed when an (X) over bar value falls close to the target and is tightened when an (X) over bar value falls far from the target. A cost model is constructed that involves the cost of false alarms, the cost of finding and eliminating the assignable cause, the cost associated with production in an out-of-control state, and the cost of sampling and testing. The assumption of an exponential distribution to describe the length of time the process remains in control allows the application of the Markov chain approach for developing the cost function. A comprehensive study is performed to examine the economic advantages of varying the (X) over bar chart parameters.

Joint conomic design of x̄ and R charts under Weibull shock models

This paper deals with the joint economic design of x̄ and R charts when the occurrence times of assignable causes follow Weibull distributions with increasing failure rates. The variable quality characteristic is assumed to be normally distributed and the process is subject to two independent assignable causes (such as tool wear-out, overheating, or vibration). One cause changes the process mean and the other changes the process variance. However, the occurrence of one kind of assignable cause does not preclude the occurrence of the other. A cost model is developed and a non-uniform sampling interval scheme is adopted. A two-step search procedure is employed to determine the optimum design parameters. Finally, a sensitivity analysis of the model is conducted, and the cost savings associated with the use of non-uniform sampling intervals instead of constant sampling intervals are evaluated.

Joint economic design of X̄ and R control charts for processes subject to two independent assignable causes

A model for the joint economic design of X̄ and R control charts is developed. This model assumes that the process is subject to two assignable causes. One assignable cause shifts the process mean; the other shifts the process variance. The occurrence of the assignable cause of one kind does not block the occurrence of the assignable cause of another kind. Consequently, a second process parameter can go out-of-control after the first process parameter has gone out-of-control. A numerical study of the cost surface to the model considered has revealed that it is convex, at least in the interest region.

Fractal geometry and architecture design: case study review

The idea of buildings in harmony with nature can be traced back to ancient times. The increasing concerns on sustainability oriented buildings have added new challenges in building architectural design and called for new design responses. Sustainable design integrates and balances the human geometries and the natural ones. As the language of nature, it is, therefore, natural to assume that fractal geometry could play a role in developing new forms of aesthetics and sustainable architectural design. This paper gives a brief description of fractal geometry theory and presents its current status and recent developments through illustrative review of some fractal case studies in architecture design, which provides a bridge between fractal geometry and architecture design.

Crystallization, preliminary X-ray analysis and Patterson search of a new aspartic protease isolated from human urine

Aspartic protease (EC 3.4.23) make up a widely distributed class of enzymes in animals, plants, microbes and, viruses. In animals these enzymes perform diverse functions, which range from digestion of food proteins to very specific regulatory roles. In contrast the information about the well-characterized aspartic proteases, very little is known about the corresponding enzyme in urine. A new aspartic protease isolated from human urine has been crystallized and X-ray diffraction data collected to 2.45 Angstrom resolution using a synchrotron radiation source. Crystals belong to the space group P2(1)2(1)2(1) the cell parameters obtained were a=50.99, b=75.56 and c=89.90 Angstrom. Preliminary analysis revealed the presence of one molecule in the asymmetric unit. The structure was determined using the molecular replacement technique and is currently being refined using simulated annealing and conjugate gradient protocols.

Growth performance and body composition of pacu Piaractus mesopotamicus (Holmberg 1887) in response to dietary protein and energy levels

Improper dietary protein and energy levels and their ratio will lead to increased fish production cost. This work evaluated effects of dietary protein : energy ratio on growth and body composition of pacu, Piaractus mesopotamicus. Fingerling pacu (15.5 +/- 0.4 g) were fed twice a day for 10 weeks until apparent satiation with diets containing 220, 260, 300, 340 or 380 g kg-1 crude protein (CP) and 10.9, 11.7, 12.6, 13.4 or 14.2 MJ kg-1 digestible energy (DE) in a totally randomized experimental design, 5 x 5 factorial scheme (n = 3). Weight gain, specific growth rate increased and feed conversion ratio (FCR) decreased significantly (P < 0.05) when CP increased from 220 to 271, 268 and 281 g kg-1 respectively. Pacu was able to adjust feed consumption in a wide range of dietary DE concentration. Fish fed 260 CP diets showed best (P < 0.05) protein efficiency ratio and FCR with 11.7-12.6 MJ kg-1; but for the 380 CP-diets group, significant differences were observed only at 14.2 MJ kg-1 dietary energy level, suggesting that pacu favours protein as energy source. DE was the chief influence on whole body chemical composition. Minimum dietary protein requirement of pacu is 270 g kg-1, with an optimum CP : DE of 22.2 g MJ-1.

Growth and haematology of pacu, Piaractus mesopotamicus, fed diets with varying protein to energy ratio

Haematopoiesis and blood cells` functions can be influenced by dietary concentration of nutrients. This paper studied the effects of dietary protein:energy ratio on the growth and haematology of pacu, Piaractus mesopotamicus. Fingerling pacu (15.5 +/- 0.4 g) were fed twice a day for 10 weeks until apparent saciety with diets containing 220, 260, 300, 340 or 380 g kg(-1) crude protein (CP) and 10.88, 11.72, 12.55, 13.39, 14.22 MJ kg(-1) digestible energy (DE) in a totally randomized experimental design, 5 x 5 factorial scheme (n=3). Weight gain and specific growth rate were affected (P < 0.05) by protein level only. Protein efficiency ratio decreased (P < 0.05) with increasing dietary protein at all levels of dietary energy. Daily feed intake decreased (P < 0.05) with increasing dietary energy. Mean corpuscular haemoglobin concentration was affected (P < 0.05) by DE and interaction between dietary CP and DE. Total plasma protein increased (P < 0.05) with dietary protein and energy levels. Plasma glucose decreased (P < 0.05) with increasing dietary protein. The CP requirement and optimum protein:energy ratio for weight gain of pacu fingerlings, determined using broken-line model, were 271 g kg(-1) and 22.18 g CP MJ(-1) DE respectively. All dietary CP and DE levels studied did not pose damages to fish health.

Rooting of hardwood cuttings of Roxo de Valinhos fig (Ficus carica L.) with different propagation strategies

The objective of this study was to evaluate the substrate, cuttings collection time, the position and the cutting depth, and the propagation environment on rooting of 'Purple Valinhos' fig tree cuttings in Southwestern Paraná, Brazil. Two experiments were carried out at UTFPR, Câmpus Dois Vizinhos, with hardwoods cuttings from Roxo de Valinhos fig tree. The first experiment used a randomized block design, in 3 x 3 x 2 factorial (substrate x environment x collection time), with four replications of 10 cuttings per plot. The cuttings were collected in the first fifteen days of July and August. The substrates were sand, soil and the mixture of these [1:1 (v / v)]. The environments used were open sky, tunnel with plastic cover and tunnel with half-shade black net cover. The second experiment used a randomized block design, 2 x 2 x 3 factorial (shoot cutting position x soil cover x shoot cutting depth), with four replications of 12 cuttings per plot. In the factor position, the vertically (0 º inclination) and inclined (45 º inclination) shoot cuttings were evaluated. Soil cover was tested with mulching plastic cover or not. The tested depths were 1/3, 1/2 and 2/3 in relation to the total length of the shoot cutting. In both experiments, the following were analyzed: rooting and mortality indices, number of leaves and primary shoots, length of the three largest roots per cutting. It was conclude that, the protected environment with plastic cover on sand as substrate must recommended for the rooting of fig estaca, collecting them in the first half of July. The inclination position and cutting depth of the estaca and the substrate coverage with plastic mulching did not influence the results.

Adherence to health-related behaviors: effectiveness of implementation intentions and posthypnotic suggestion in college students

Resumo: Com base no conceito de implementação de intenções (Gollwitzer, 1993, 1999) e na teoria do contexto de resposta de Kirsch & Lynn (1997), o presente trabalho testou a eficácia de uma intervenção combinada de implementação de intenções com hipnose e sugestão pós-hipnótica na promoção da adesão a uma tarefa simples (avaliação do humor) e uma tarefa difícil (actividade física). Os participantes são estudantes universitários de uma universidade na Nova Jérsia, (N=124, Estudo 1, EUA) e em Lisboa (N=323, Estudo 2, Portugal). Em ambos os estudos os participantes foram seleccionados a partir de uma amostra mais vasta baseado num escrutínio da sua sugestibilidade hipnótica avaliada por meio da Escala de Grupo de Sugestibilidade Hipnótica de Waterloo-Stanford (WSGC): Forma C. O Estudo 1 usou um desenho factorial do tipo 2x2x3 (tipo de intenção formada x hipnose x nível de sugestionabilidade) e o Estudo 2 usou um desenho factorial do tipo 2 x 2x 2 x 4 (tipo de tarefa x tipo de intenção formada x hipnose x nível de sugestionabilidade). No Estudo 1 foi pedido aos participantes que corressem todos os dias e durante três semanas durante 5 minutos, que medissem a sua pulsação antes e depois da actividade física e que mandassem um e-mail ao experimentador, fornecendo assim uma medida comportamental e uma medida de auto-relato. Aos participantes no grupo de intenções de meta foi apenas pedido que corressem todos os dias. Aos participantes no grupo de implementação de intenções foi pedido que especificasses com exactidão quando e onde iriam correr e enviar o e-mail. Para além disso, cerca de metade dos participantes foram hipnotizados e receberam uma sugestão pós-hipnótica em que lhes foi sugerido que o pensamento de correr todos os dias lhes viria à mente sem esforço no momento apropriado. A outra metade dos participantes não recebeu qualquer sugestão hipnótica. No Estudo 2 foi seguido o mesmo procedimento, mas a cerca de metade dos participantes foi atribuída uma tarefa fácil (enviar um Adherence to health-related behaviors ix SMS com a avaliação diária do seu estado de humor naquele momento) e à outra metade da amostra foi atribuída a tarefa de exercício físico atrás descrita (tarefa difícil). Os resultados do estudo 1 mostraram uma interacção significativa entre o nível de sugestionabilidade dos participantes e a sugestão pós-hipnótica (p<.01) indicando que a administração da sugestão pós-hipnótica aumentou a adesão nos participantes muito sugestionáveis, mas baixou a adesão nos participantes pouco sugestionáveis. Não se encontraram diferenças entre os grupos que formaram intenções de meta e os que formaram implementação de intenções. No Estudo 2 os resultados indicaram que os participantes aderiram significativamente mais à tarefa fácil do que à tarefa difícil (p<.001). Os resultados não revelaram diferenças significativas entre as condições implementações de intenções, hipnose e as duas estratégias combinadas, indicando que a implementação de intenções não foi eficaz no aumento da adesão às duas tarefas propostas e não beneficiou da combinação com as sugestões pós-hipnóticas. A utilização da hipnose com sugestão pós-hipnótica significativamente reduziu a adesão a ambas as tarefas. Dado que não existiam instrumentos em Português destinados a avaliar a sugestionabilidade hipnótica, traduziu-se e adaptou-se para Português Escala de Grupo de sugestibilidade hipnótica de Waterloo-Stanford (WSGC): Forma C. A amostra Portuguesa (N=625) apresentou resultados semelhantes aos encontrados nas amostras de referência em termos do formato da distribuição dos padrões da pontuação e do índice de dificuldade dos itens. Contudo, a proporção de estudantes portugueses encontrada que pontuaram na zona superior de sugestionabilidade foi significativamente inferior à proporção de participantes na mesma zona encontrada nas amostras de referência. No sentido de lançar alguma luz sobre as razões para este resultado, inquiriu-se alguns dos participantes acerca das suas atitudes face à hipnose utilizando uma versão portuguesa da Escala de Valência de Atitudes e Crenças face à Hipnose e comparou-se com a opinião de Adherence to health-related behaviors xAbstract: On the basis of Gollwitzer’s (1993, 1999) implementation intentions’ concept, and Kirsch & Lynn’s (1997) response set theory, this dissertation tested the effectiveness of a combined intervention of implementation intentions with hypnosis with posthypnotic suggestions in enhancing adherence to a simple (mood report) and a difficult (physical activity) health-related task. Participants were enrolled in a university in New Jersey (N=124, Study 1, USA) and in two universities in Lisbon (N=323, Study 2, Portugal). In both studies participants were selected from a broader sample based on their suggestibility scores using the Waterloo-Stanford Group C (WSGC) scale of hypnotic susceptibility and then randomly assigned to the experimental groups. Study 1 used a 2x2x3 factorial design (instruction x hypnosis x level of suggestibility) and Study 2 used a 2 x 2x 2 x 4 factorial design (task x instructions x hypnosis x level of suggestibility). In Study 1 participants were asked to run in place for 5 minutes each day for a three-week period, to take their pulse rate before and after the activity, and to send a daily email report to the experimenter, thus providing both a self-report and a behavioral measure of adherence. Participants in the goal intention condition were simply asked to run in place and send the e-mail once a day. Those in the implementation intention condition were further asked to specify the exact place and time they would perform the physical activity and send the e-mail. In addition, half of the participants were given a post-hypnotic suggestion indicating that the thought of running in place would come to mind without effort at the appropriate moment. The other half did not receive a posthypnotic suggestion. Study 2 followed the same procedure, but additionally half of the participants were instructed to send a mood report by SMS (easy task) and half were assigned to the physical activity task described above (difficult task). Adherence to health-related behaviors vii Study 1 result’s showed a significant interaction between participant’s suggestibility level and posthypnotic suggestion (p<.01) indicating that posthypnotic suggestion enhanced adherence among highly suggestible participants, but lowered it among low suggestible individuals. No differences between the goal intention and the implementation intentions groups were found. In Study 2, participants adhered significantly more (p<.001) to the easy task than to the difficult task. Results did not revealed significant differences between the implementation intentions, hypnosis and the two conditions combined, indicating that implementation intentions was not enhanced by hypnosis with posthypnotic suggestion, neither was effective as single intervention in enhancing adherence to any of the tasks. Hypnosis with posthypnotic suggestion alone significantly reduced adherence to both tasks in comparison with participants that did not receive hypnosis. Since there were no instruments in Portuguese language to asses hypnotic suggestibility, the Waterloo-Stanford Group C (WSGC) scale of hypnotic susceptibility was translated and adapted to Portuguese and was used in the screening of a sample of college students from Lisbon (N=625). Results showed that the Portuguese sample has distribution shapes and difficulty patterns of hypnotic suggestibility scores similar to the reference samples, with the exception of the proportion of Portuguese students scoring in the high range of hypnotic suggestibility, that was found lower than the in reference samples. In order to shed some light on the reasons for this finding participant’s attitudes toward hypnosis were inquired using a Portuguese translation and adaptation of the Escala de Valencia de Actitudes y Creencias Hacia la Hipnosis, Versión Cliente, and compared with participants with no prior hypnosis experience (N=444). Significant differences were found between the two groups with participants without hypnosis experience scoring higher in factors indicating misconceptions and negative attitudes about hypnosis.

Effect of water and citrate solubility on agronomic effectiveness of acidulated phosphates in three consecutive corn crops

In the process of phosphate rock acidulation, several impure P compounds may be formed along with the desirable Ca and NH4 phosphates. Such compounds normally reduce the content of water-soluble P and thus the agronomic effectiveness of commercial fertilizers. In order to study this problem, a greenhouse experiment consisting of three consecutive corn crops was conducted in samples of a Red-Yellow Latosol (Typical Hapludox) in a completely randomized design (6 x 2 x 2), with four replicates. Six commercial fertilizers were added to 2 kg of soil at a rate of 70 mg kg-1 P, based on the content of soluble P in neutral ammonium citrate plus water (NAC + H2O) of the fertilizers. Fertilizer application occurred either in the original form or leached to remove the water-soluble fraction, either by mixing the fertilizer with the whole soil in the pots or with only 1 % of its volume. The corn plants were harvested 40 days after emergence to determine the shoot dry matter and accumulated P. For the first crop and localized application, the elimination of water-soluble P from the original fertilizers resulted in less bioavailable P for the plants. For the second and third crops, the effects of P source, leaching and application methods were not as evident as for the first, suggesting that the tested P sources may have similar efficiencies when considering successive cropping. The conclusion was drawn that the water-insoluble but NAC-soluble fractions of commercial P fertilizers are not necessarily inert because they can provide P in the long run.

NPK fertilization on initial growth of physic nut seedlings in Quartzarenic Neossol

Balanced fertilization is important for plant growth. There is little information on physic nut (Jatropha curcas L.) and tests with the fertilization of the species are very recent. This study evaluated the initial growth of physic nut seedlings in response to NPK rates to Quartzarenic Neossol in a greenhouse and estimated P and K critical soil levels and N, P and K in shoot dry matter after 120 days of evaluation. The treatments were arranged in a randomized, fractional factorial design (4 x 4 x 4)½, totalizing 32 treatments with three replicates, 96 experimental plots and N rates (0, 75, 150 and 300 mg dm-3) as urea; P rates (0, 45, 90 and 180 mg dm-3) as triple superphosphate and K rates (0, 50, 100 and 200 mg dm-3) as potassium chloride. After 120 days, the plants were harvested and some variables evaluated: plant height, stem diameter, shoot and root dry weight, macro and micronutrient levels in plant shoots, and soil chemical properties. The physic nut seedlings responded to NPK fertilizer in the initial growth phase; the response to N was negative. The recommended P and K rates were 25 and 67 mg dm-3, respectively. The critical levels, corresponding to the recommended P rate were 13 and 74 mg dm-3 for K in soil (Mehlich-1). The N, P and K levels in the shoot dry matter of physic nut were 37.4, 2.1 and 35.7 g kg-1, respectively.

Industrial and urban organic wastes increase soil microbial activity and biomass

Microbial processes have been used as indicators of soil quality, due to the high sensitivity to small changes in management to evaluate, e.g., the impact of applying organic residues to the soil. In an experiment in a completely randomized factorial design 6 x 13 + 4, (pot without soil and residue or absolute control) the effect of following organic wastes was evaluated: pulp mill sludge, petrochemical complex sludge, municipal sewage sludge, dairy factory sewage sludge, waste from pulp industry and control (soil without organic waste) after 2, 4, 6, 12, 14, 20, 28, 36, 44, 60, 74, 86, and 98 days of incubation on some soil microbial properties, with four replications. The soil microbial activity was highly sensitive to the carbon/nitrogen ratio of the organic wastes. The amount of mineralized carbon was proportional to the quantity of soil-applied carbon. The average carbon dioxide emanating from the soil with pulp mill sludge, corresponding to soil basal respiration, was 0.141 mg C-CO2 100 g-1 soil h-1. This value is 6.4 times higher than in the control, resulting in a significant increase in the metabolic quotient from 0.005 in the control to 0.025 mg C-CO2 g-1 Cmic h-1 in the soil with pulp mill sludge. The metabolic quotient in the other treatments did not differ from the control (p < 0.01), demonstrating that these organic wastes cause no disturbance in the microbial community.