Second-order sliding mode control for offshore container cranes

Open-sea stevedores of containers provide an alternative way to avoid port congestion. This process involves a mobile harbour equipped with a crane which loads/unloads containers from a large cargo ship. However, the presence of ocean waves and gusty winds can produce an excessive sway to the hoisting ropes of the crane system. This paper presents a second-order sliding mode controller for trajectory tracking and sway suppression of an offshore container crane. From the proposed control law, the asymptotic stability of the closed-loop system is guaranteed in the Lyapunov sense. Simulation results indicate that the developed control system can achieve high performance in trajectory tracking and swing angle suppression despite the presence of parameter variations and external disturbances as in the case of offshore cranes

Adaptive fuzzy sliding mode control for uncertain nonlinear underactuated mechanical systems

Sliding mode control has been shown to be a robust and effective control approach for stabilization of nonlinear systems. However the dynamic performance of the controller is a complex function of the system parameters, which is often uncertain or partially known. This paper presents an adaptive fuzzy sliding mode control for a class of underactuated nonlinear mechanical systems. An adaptive fuzzy system is used to approximate the uncertain parts of the underactuated system. The adaptive law is designed based on the Lyapunov method. The proof for the stability and the convergence of the system is presented. Robust performance of the adaptive fuzzy sliding mode control is illustrated using a gantry crane system. Simulation results demonstrate that the system output can track the reference signal in the presence of modelling uncertainties, external disturbances and parameter variation. © 2013 IEEE

Symptomatic Non-parasitic benign hepatic cyst: Evaluation of Management by Deroofing in Ten Consecutive Cases

Background/Purpose: Solitary non-parasitic cysts of the liver are commonly asymptomatic and do not require treatment. Rarely, however, the cysts become symptomatic and are then best treated surgically. The optimal surgical treatment is debatable. The aim of this study was to evaluate the role of deroofing as a safe and effective approach in the management of simple non-parasitic hepatic cysts. Materials & Methods: From January 2002 to October 2008, 10 patients (8 females and 2 males) with histologically proven non-parasitic, benign, simple hepatic cysts underwent deroofing at Tanta University Hospital. Deroofing was achieved by open surgery in 3 cases and by laparoscopic surgery in 7 patients. The principle of both open and laparoscopic approaches was to remove as much as possible of the cyst wall, destroy the endothelial lining and pack the residual cavity with omentum. Results: All of our patients had a solitary cyst with a mean diameter of 12.5 cm (range; 9-18 cm) and all were symptomatic. The most common complaint was upper abdominal pain (n=7, 70%). Age ranged from 1 - 72 year with a median of 15 years. Three patients (30%) were treated with open deroofing while 7 patients (70%) underwent laparoscopic deroofing. One out of these 7 patients was converted to open surgery. Recurrence occurred in 2 patients but was asymptomatic and discovered on follow up because of the small diameter of recurrent cysts (3-4 cm). The follow up period ranged between 12 – 72 months (median 20 months). Conclusion: with proper selection of patients, laparoscopic deroofing of symptomatic, benign, solitary, non-parasitic hepatic cysts is safe, effective and offers all the advantages of minimally invasive surgery. Open deroofing should be reserved for cysts inaccessible by laparoscopy, when the diagnosis is in doubt and for difficulties encountered at laparoscopy.Index Word: hepatic cyst, laparoscopy

Screening the Efficacy of Some Traditional Herbal Drugs for Treatment of Hymenolepis diminuta Infection in Rats

Background: Hymenolepis nana (human infecting tapeworm) and H. diminuta (rodent infecting tapeworm) are currently incriminated to be the cause of non-specific bowel disturbances. They are in most instances resistant to the available anticestodal compounds due to misuse of drugs and probably adaptation of the parasites to the commercially available drugsObjective: Our objective is to study the toxicity and curative efficacy of different medicinal plants that are candidate for the treatment of tapeworm infections in man.Methods: Four medicinal plants were tested for their ability to treat Hymenolepis diminuta tapeworm infection in rats. These plants are Amaranthus viridis, Cucurbita maxima, Hagenia abyssinica and Balanites aegyptiaca. Selection of these plants was based on ethnobotanicalinformation. The evaluation of the efficiency of these medicinal plants was based on the “controlled test design”, modified from Moskey and Harwood10: Following pre-infection screening, and life cycle establishment rats were grouped to six experimental groups for each plant. Stool specimens were collected from all groups, the mean of eggs counts per gram of faeces were counted. The reduction percentage of eggs per gram (EPG) was calculated and time to clear eggs was compared with that of Niclosamide. Niclosamide drug was used in this study as a control treatment14.Results: There were no signs of toxic effect on the rats due to administration of any of the tested medicinal plants. Amaranthus viridis leavs exhibited a very weak efficacy. It did not reduce eggs ineither water or food significantly as compared to the untreated control group (p> 0.05). The deparasitization activity of this plant (35%) was not significant. Similarly, Balanites aegyptiaca seeds were not effective in treatment of the infection in rats. Egg counts and deparasitization infood and water, were not significantly (p> 0.05) different from those of the untreated control group. On the other hand, Cucurbita maxima and Hagenia abyssinica seeds were very effective in the treatment of Hymenolepis diminuta infection in rats. Egg reduction (100%) was highly significant (p< 0.01) in food and water as compared to that of the untreated control group of rats (zero%). C. maxima seeds in food deparasitized 80% of the worms, while Hagenia abyssinica deparasitized 100%.Conclusion: Our conclusion was that Hagenia abyssinica was the most active plant of this group in the treatment of Hymenolepis diminuta infection in rats

The Practices of Green Supply Chain Management towards Corporate Performances in Construction Industry

Green Supply Chain Management (GSCM) practices has different impact on the corporate performances while practitioners are not willing to implement practices that is irrelevant to their organization. Hence, to ensure the most appropriate investment on GSCM is implemented, this study is conducted to identify the relationship between GSCM practices and corporate performances in Malaysia construction industry. To conduct a literature review to figure the relationship between GSCM practices and corporate performances. Systematic literature review method is adopted in data collection stage. The findings of the study show that the green practices are correlated to the corporate performances and a comprehensive conceptual framework is formed from this study to describe the relationships between GSCM practices and corporate performances in Malaysia construction industry. Research on GSCM in Malaysia is still less in construction industry. However, the findings provide crucial insights for potential practitioners due to it consistency with prior studies which are related to GSCM in other industries and countries. Implementation of GSCM improves corporate performances in various dimensions. The construction industry should understand the functions and relationship of each element in GSCM to achieve best performance outcome in the form they desired. A comprehensive conceptual framework which shows the relationships of GSCM and its impact construction industry which allow the potential practitioners to understand the potential improvement in corporate performances is constructed through the systematic literature review

Growth inhibitory activity of biflavonoids and diterpenoids from the leaves of the Libyan Juniperus phoenicea against human cancer cells

Three biflavonoids [cupressuflavone (1), amentoflavone (2)and sumaflavone (3)], four diterpenoids [13-epi-cupressic acid (4), imbricatholic acid (5), 3-hydroxy-sandaracopimaric acid (6)and dehydroabietic acid (7)]and onelignan [β-peltatin methyl ether (8)],were isolated from the cytotoxicfractions of the extracts of the leaves of the Libyan Juniperus phoeniceaL. The structures of these compounds were elucidated by spectroscopic means.Cytotoxicity of the compounds 1-6were assessedagainst the human lung cancer cell lineA549 using the MTT assay. Compounds 1and 3showed cytotoxicityagainst the A549cells(IC50= 65 µMand 77 µM, respectively), whereas, compound 2did not show any activity. Diterpenes4-6exhibited weak cytotoxicity against the A549 cells with the IC50values of 159 µM, 263 µMand 223 µM, respectively. The cytotoxicity of each compound was compared with the anticancer drug,etoposide (IC50=61 µM).Cupressuflavone (1)wasevaluatedalso for cytotoxicity against both the human PC3 cancer cell lineand the normal prostatecell line (PNT2), and this compoundrevealed a high degreeof cytotoxic selectivity towards the prostate cancer cells (PC3), with IC50value of 19.9 µM, without any evidence of cytotoxicity towards the normal prostatecell line(PNT2)

A DEM model for visualising damage evolution and predicting failure envelope of composite laminae under biaxial loads

A two dimensional particle model based on the discrete element method (DEM) is developed for micromechanical modelling of fibre reinforced polymer (FRP) composite laminae under biaxial transverse loads. Random fibre distribution within a representative volume element (RVE) is considered for the micromechanical DEM simulations. In addition to predicting the stress-strain curves of the RVEs subjected to transverse compression and transverse shear stresses against the experimental testing results and other numerical modelling results, the DEM model is also able to capture the initiation and propagation of all micro damage events. Fibre distribution is found to more significantly influence the ultimate failure of composite laminae under transverse shear, while it has much less effect on the failure under transverse compression. The failure envelope of composite laminae under biaxial transverse compression and transverse shear is predicted and compared with Hashin and Puck failure criteria, showing a reasonable agreement. The predicted failure envelope is correlated with the damage evolution and the quantitative analysis of failure events, which improves the understanding of the failure mechanisms

IMPACTS OF GREEN SITE MANAGEMENT PRACTICES ON ENERGY AND WATER CONSUMPTION EFFICIENCY IN THE MALAYSIAN CONSTRUCTION INDUSTRY

This study aims to investigate the impacts of green site management on corporate environmental and economic performances by improving the efficiency of energy and water consumption at construction sites. The identified green site management has been proven to improve both environmental and economic performances. This study allows practitioners to study and advocate for appropriate green site management strategies. A qualitative method was carried out since this research focused on the construction players’ opinions on green site management practices. Five contractors were selected randomly from the construction sites in Malaysia based on the convenience sampling method. All selected respondents were qualified to give opinions as they held management posts. The results have shown green site management practices can reduce the consumption of resources and improve energy efficiency management and water consumption management, which are considered to have a positive impact on the construction project’s environmental and economic performance. The findings also revealed that green site management practices implementation must not affect their economic performance, such as increasing the construction cost with high initial and maintenance costs. As the construction industry consumes a vast amount of water and energy daily, these consumption reductions can help construction sites achieve energy efficiency and utilize natural resources, eventually improving corporate environmental and economic performance. Thus, green practices must be implemented to bring sustainable development to the construction industry

Prey identification of invasive peacock bass from Telabak Lake Malaysia using DNA barcoding technique

Invasive peacock bass Cichla spp. have recently invaded freshwater habitats across Malaysia. Stomach contents of 135 peacock bass captured from the Telabak Lake of East Coast of Peninsular Malaysia were analysed. The preys were examined using visual identification method and mitochondrial DNA barcoding technique to identify the partial digested and decaying preys in the stomach. The current study identified 7 prey species (6 fishes 43.0% and 1 shrimp 5.1%) belongs to 5 families in fishes’ stomach. The results revealed that peacock bass is highly predator and generalist feeder with an opportunistic feeding behaviour. It is highly important to reduce and monitor the abundance of this species for future survival of native species in the lake