3,527 research outputs found

    Development of inflatable structures at the University of Southampton

    No full text
    Inflatable technology for space applications is under continual development and advances in high strength fibres and rigidizable materials have pushed the limitations of these structures. This has lead to their application in deploying large-aperture antennas, reflectors and solar sails. However, many significant advantages can be achieved by combining inflatable structures with structural stiffeners such as tape springs. These advantages include control of the deployment path of the structure while it is inflating (a past weakness of inflatable structure designs), an increased stiffness of the structure once deployed and a reduction in the required inflation volume. Such structures have been previously constructed at the Jet Propulsion Laboratory focusing on large scale booms. However, due to the high efficiency of these designs they are also appealing to small satellite systems. This article outlines ongoing research work performed at the University of Southampton into the field of small satellite hybrid inflatable structures. Inflatable booms have been constructed and combined with tape spring reinforcements to create simple hybrid structures. These structures have been subjected to bending tests and compared directly to an equivalent inflatable tube without tape spring reinforcement. This enables the stiffness benefits to be determined with respect to the added mass of the tape springs. The paper presents these results, which leads to an initial performance assessment of these structures

    Optimal Strategy Imitation Learning from Differential Games

    Get PDF
    The ability of a vehicle to navigate safely through any environment relies on its driver having an accurate sense of the future positions and goals of other vehicles on the road. A driver does not navigate around where an agent is, but where it is going to be. To avoid collisions, autonomous vehicles should be equipped with the ability to to derive appropriate controls using future estimations for other vehicles, pedestrians, or otherwise intentionally moving agents in a manner similar to or better than human drivers. Differential game theory provides one approach to generate a control strategy by modeling two players with opposing goals. Environments faced by autonomous vehicles, such as merging onto a freeway, are complex, but they can be modeled and solved as a differential game using discrete approximations; these games yield an optimal control policy for both players and can be used to model adversarial driving scenarios rather than average ones, so that autonomous vehicles will be safer on the road in more situations. Further, discrete approximations of solutions to complex games that are computationally tractable and provably asymptotically optimal have been developed, but may not produce usable results in an online fashion. To retrieve an efficient, continuous control policy, we use deep imitation learning to model the discrete approximation of a differential game solution. We successfully learn the policy generated for two games of different complexity, a fence escape and merging game, and show that the imitated policy generates control inputs faster than the differential game generated policy

    The relationship between dietary acid load and intensity of musculoskeletal pain condition:A population‐based study

    Get PDF
    Pain is a globally prevalent problem, and a comprehension of its pathophysiology is important with respect to patient's health. Musculoskeletal pain conditions (MPs) may be associated with physical, lifestyle, and nutrition status, while dietary acid load (DAL) may be inversely associated with musculoskeletal health in adults. This cross‐sectional study consisted of 175 adults experiencing pain. Anthropometric measurements, physical activity (PA), and pain intensity were assessed via specific questionnaires. Dietary data were collected using a 7‐day 24‐h recall. Foods and beverages were analyzed with Nutritionist IV software for extracting the total energy and nutrients. Net endogenous acid production (NEAP) and potential renal acid load (PRAL) were evaluated for assessing the DAL. Linear regression and Spearman correlation were used to investigate the association of exposure and input variables. Linear regression showed a positive relationship between PRAL and NEAP and pain intensity in the crude model. This significant positive relationship remained after adjusting for all confounders. A lower consumption of potassium, magnesium, vitamin B9 and C, and fiber was seen in the following quartiles of PRAL and NEAP. In addition, MPs intensity and PRAL and NEAP had a weak, positive correlation. This study suggests that a higher DAL may be associated with MPs. However, further research is needed

    Εφαρμογή Σύγχρονων Μεθόδων και Εργαλείων Μηχανολογικού Σχεδιασμού στη Συστηματική Προσέγγιση Ανάπτυξης Βιομηχανικών Προιόντων

    Get PDF
    206 σ.Μεθοδολογία ανάπτυξης σχεδιασμού ενός τυπικού βιομηχανικού προιόντος με τη χρήση σύγχρονων εργαλείων (προγράμματα 3D CAD/CAE, συστηματική προσέγγιση προβλημάτων με μοντέλα κ.α). Στο πλαίσιο της ΔΕ γίνεται σύντομη ιστορική ανασκόπηση στον βιομηχανικό σχεδιασμό καθώς και σε προιόντα σταθμούς που καθόρισαν το σύγχονο σχεδιασμό, ανάλυση κάποιων βασικών μεθοδολογικών συστημάτων σχεδιασμού και τέλος ο σχεδιασμός ενός βιομηχανικού προιόντος, συγκεκριμένα ενός καθίσματος εσωτερικού δημόσιου χώρου.Systematic approach of product design using methodologies and 3D CAD/CAE Software.Νίκη-Δανάη Θ. Χανι

    Hubungan Partisipasi Masyarakat dengan Keberfungsian Tempat Pengelolaan Sampah Terpadu (Tpst) Saeman Padangsari, Kota Semarang

    Full text link
    Garbage is currently a key issue in large cities, especially in Indonesia. To reduce waste generation in urban conducted flagship program 3R (Reduce, Reuse, Recycle) are expected waste generation can be reduced or even not left at all. The general requirements for waste management one of them is in terms of public participation aspects. This study aimed determine the relationship between community participation with the functioning IWMS Saeman Padangsari, Semarang. This study was observational analytic with cross sectional approach. Samples in this research were 38 respondent. The results showed that there was a relationship of public participation in segregation from the source to the functioning IWMS Saeman, there is a relationship of community participation in waste management using the concept of 3R with functioning IWMS Saeman, there is public participation in relation to pay contributions to the functioning of IWMS Saeman, there is no relationship of public participation in comply with the rules of landfills that have been assigned to the functioning IWMS Saeman, there is no relationship of community participation in maintaining the cleanliness of the surrounding environment with functioning IWMS Saeman, there is a relationship of community participation in an active role in the socialization of environmental waste management with the functioning IWMS Saeman. The need to increase people's active participation in waste management in the region IWMS Saeman Padangsari and increasing the dissemination of the manager IWMS Saeman are several alternatives that IWMS Saeman Padangsari function properly

    Kemampuan Koagulan Kitosan dengan Variasi Dosis dalam Menurunkan Kandungan Cod dan Kekeruhan pada Limbah Cair Laundry (Studi pada Rahma Laundry, Kecamatan Tembalang, Kota Semarang)

    Full text link
    Laundry liquid waste contains several chemical substances in detergent raw materials such as phosphate, surfactants, ammonia, and total suspended solids. The existence of detergent in high concentrations and exceeds the quality standards that have been estabilished in a body of water can lead to cases of enviromental pollution in the form of increased turbidity an Chemical Oxygen Demands (COD) levels. Therefore in order to maintain and to ensure the availabillity of water in terms of quality, it requires coagulation-flocculation process to laundry liquid waste before discharging into water bodies. This study aims to determine the decrease of COD levels and turbidity level in laundry liquid waste using chitosan coagulant in Rahma Laundry, Tembalang District, Semarang. The research is a quasi experimental study with pretest-posttest with control group research design with 6 times replication. The total samples are 60 in wich 24 tested for the levels of turbidity and 6 controls. The test results of Kruskal-Wallis with significance p-value < 0,05 indicates that dosage variation (p=0,000) gives different levels of COD and dosage variation (p=0,000) provide 755,97 mg/l and the advantage levels of turbidity before treatment was 516,20 NTU. The optimum dosage of chitosan coagulant is on the dose of 200 mg/l with the effectiveness decrease of COD levels and turbidity levels on 72,67% an 98,67% respectively

    Analisis Risiko Kesehatan Lingkungan Pencemaran Nitrat (No3) pada Air Sumur Gali di Kawasan Pertanian Desa Tumpukan Kecamatan Karangdowo Kabupaten Klaten

    Full text link
    In amount of 67.69% Tumpukan village is an agricultural area where has been contribute nitrate in the groundwater through fertilization activity. The use of urea fertilizer in Indonesia 400-600 kg urea / ha, it exceeds the government's recommendation (200-260 kg urea / ha). The aims of this research is to determine the risk level of exposure nitrate in Tumpukan Village. The research uses a descriptive observational with design study cross sectional and field study ARKL approach. The analysis of data use ARKL method (hazard identification, dose-response analysis, exposure analysis and risk characteristics). The object of population is all wells in the Tumpukan village and the subjects of population are people who use wells for drinking water . The sample object of research is 16 wells were used as sources of drinking water with a distance <50 meters from the area of agriculture and the sample subjects were 89 respondents who use the sample object as sources of drinking water. The results showed an average weight, rate, nitrate's concentration is 52.59 kg and 1.89 liter, 21,26 mg/L. There are nine respondents (10.1%) which have RQ> 1. The conclusion is the risk of nitrate exposure in Tumpukan village is quite low (10.1% of research subjects who are at risk of health problems noncarcinogenic), the risk will appear in the next 10 years for children and 52 years for Adult. The suggestions are farmers can fertilize with organic and inorganic N fertilizer in a balanced way and conducted with the dose and the right time

    The Association Between Dietary Energy Density and Musculoskeletal Pain in Adult Men and Women

    Get PDF
    Musculoskeletal pains (MPs), defined as persistent or recurrent pain, is a complex health problem. High overall calorie and fat intake have been related to obesity and MPs. Dietary energy density (DED), defined as energy content of food and beverages (in kcal) per unit total weight, has been associated with chronic muscle, cartilage, bone damage and pain. Thus, the purpose of this study is to investigate the association between DED and MPs in adult men and women. A total of 175 men and women (> 18 years) with MP participated in the study. A validated short form physical activity (PA) questionnaire, demographic, and McGill Pain Questionnaire were used. Anthropometric measurements were evaluated via standard protocols. Furthermore, a seven-day 24-hour recall of diet was used to determine the dietary intake. Total DED was calculated and divided into quartiles. Linear regression was used to discern the association between DED and MPs in adults. Participants assigned in the highest category of DED were characterized by lower intake of potassium, magnesium, vitamin C, folate, and fiber. However, results showed displayed higher intake of sodium, vitamin E, vitamin B3, fat, protein, cholesterol, saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids (p < 0.001). Finally, after adjustment for confounders such as age, gender, PA, body mass index, waist circumference, education, job, marital status, history of some chronic diseases and vitamin C supplementation, a significant positive association was detected between DED and pain intensity. There was no significant association between DED and pain frequency in all models