Experimental investigation of feedforward control schemes of a flexible robot manipulator system

This paper presents experimental investigations into the applications of feedforward control schemes for vibration control of a flexible manipulator system. Feedforward control schemes based on input shaping and filtering techniques are to be examined. A constrained planar single-link flexible manipulator is considered in this experimental work. An unshaped bang-bang torque input is used to determine the characteristic parameters of the system for design and evaluation of the input shaping control techniques. The input shapers and filtering techniques are designed based on the properties of the system. Simulation results of the response of the manipulator to the shaped and filtered inputs are presented in time and frequency domains. Performances of the shapers are examined in terms of level of vibration reduction and time response specifications. The effects of derivative order of the input shaper on the performance of the system are investigated. Finally, a comparative assessment of the control strategies is presented and discusse

SIGNAL CONDITIONING OF STRAIN GAUGE SENSORS

Strain gauge sensors are used extensively in industrial machines and testing equipments. The output signal of these sensors is basically an analog voltage in the millivoltage range. Interfacing these sensors to a computer system is used to be a challenging problem. There are many popular solution strategies and designers must always compromise between cost, accuracy, and reliability. In this research a real design problem is presented. It is a rehabilitation of a Materials Testing Machine which is partially destroyed during the last war on Gaza. Many possible solution strategies are described and the most suitable one to the case study is adopted. The proposed design has been successfully implemented and the machine is returned back to work properly

A Demand-Supply Matching-Based Approach for Mapping Renewable Resources towards 100% Renewable Grids in 2050

Recently, many renewable energy (RE) initiatives around the world are based on general frameworks that accommodate the regional assessment taking into account the mismatch of supply and demand with pre-set goals to reduce energy costs and harmful emissions. Hence, relying entirely on individual assessment and RE deployment scenarios may not be effective. Instead, developing a multi-faceted RE assessment framework is vital to achieving these goals. In this study, a regional RE assessment approach is presented taking into account the mismatch of supply and demand with an emphasis on Photovoltaic (PV) and wind turbine systems. The study incorporates mapping of renewable resources optimized capacities for different configurations of PV and wind systems for multiple sites via test case. This approach not only optimizes system size but also provides the appropriate size at which the maximum renewable energy fraction in the regional power generation mix is maximized while reducing energy costs using MATLAB’s ParetoSearch algorithm. The performance of the proposed approach is tested in a realistic test site, and the results demonstrate the potential for maximizing the RE share compared to the achievable previously reported fractions. The results indicate the importance of resource mapping based on energy-demand matching rather than a quantitative assessment of anchorage sites. In the examined case study, the new assessment approach led to the identification of the best location for installing a hybrid PV / wind system with a storage system capable of achieving a nearly 100% autonomous RE system with Levelized cost of electricity of 0.05 USD/kWh

Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis

New α-cyanoketene-N,S-acetals 2(a–g) and β-dialkylamine-α-cyanoacrylates 3(g–i) were synthesized in good to excellent yields by the reaction of ethyl 2-cyano-3,3-bis(methylthio)acrylate 1 with secondary aliphatic amines (i.e., N-methylalkyl- and N-ethylalkylamines), and pyrrolidine, in the presence of triethylamine, under reflux in ethanol, for 1–16 h, depending on the amine used. Five N-methylalkyl amines and pyrrolidine yielded exclusively mono-substituted N,S-acetals 2(a–f) in good yields. On the other hand, N-ethylbenzylamine gave a mixture of monosubstituted products including N,S-acetal 2g in 35% yield and the unexpected product ethyl 3-[benzyl(ethyl)amino]-2-cyanoacrylate 3g in 50% yield. N-Ethylcyclohexylamine and N-ethylbutylamine did not produce N,S-acetals and gave only the unexpected products ethyl 2-cyano-3-[cyclohexyl(ethyl)amino]acrylate 3h and ethyl 3-[butyl(ethyl)amino]-2-cyanoacrylate 3i in good yields. The α-cyanoketene-N,S-acetals 2(a–f), 2j, and 2k underwent cyclization with the binucleophile hydrazine in ethanol under reflux to afford substituted pyrazoles 4(a–f), 4j, and 4k in good yields

An integral equation method for solving neumann problems on simply and multiply connected regions with smooth boundaries

This research presents several new boundary integral equations for the solution of Laplace’s equation with the Neumann boundary condition on both bounded and unbounded multiply connected regions. The integral equations are uniquely solvable Fredholm integral equations of the second kind with the generalized Neumann kernel. The complete discussion of the solvability of the integral equations is also presented. Numerical results obtained show the efficiency of the proposed method when the boundaries of the regions are sufficiently smooth

Extraction of Jatropha curcas fruits for antifungal activity against anthracnose (Colletotrichum gloeosporioides) of papaya

Extracts from seeds and leaves of Jatropha curcas have shown molluscidal, insecticidal and fungicidal properties. J. curcas extracts were found to inhibit the mycelium growth of Colletotrichum musae that causes anthracnose disease in bananas. The antimicrobial activity of crude methanol extracts of J. curcas fruits, pulp and seeds were investigated. J. curcas fruits, pulp and seeds were collected from the farm of Universiti Putra Malaysia. The samples were air dried at ambient temperature, then oven-dried to remove the residual moisture. Equivalent amounts of each ground sample of the J. curcas fruits, pulp and seeds were soaked in methanol solvent and left to stand for 7 days before being filtered and evaporated. The extract was spread over potato dextrose agar (PDA) medium under an aseptic condition and incubated. The zone of inhibition of mycelial growth (mm) around the disc was measured. Both J. curcas seed and pulp extracts had higher antifungal activity than whole fruit extract. J. curcas seed extract showed significant antifungal activities with growth inhibition zone of 5.6 mm or equivalent to 78.87% inhibition followed by pulp with zone of 7.4 mm or equivalent to 72.07%, and whole fruits with zone of 14.2 mm or equivalent to 46.42% as compared to the control with zone of 26.5 mm or equivalent to 100%. Active microbial components in J. curcas have the potential of an antifungal compound to control Colletotrichum gloeosporioides which causes anthracnose disease in papaya in vitro.Key words: Methanol extracts, inhibition zone, postharvest pathogen

Self-efficacy of catering students of Faculty Technical and Vocational Education, University Tun Hussein Onn Malaysia in the Field of Career to be pursued

The increasing rate of unemployed graduates in Malaysia has received alarming attention in recents years. One of the factors that contribute to the unemployment problem is the lack of self-efficacy among graduates in making career choices. Therefore, this study was conducted to identify the self-efficacy of catering students to make decision on career field options to be pursued either as a teacher, hospitality employee or entrepreneur. The design of this study is a quantitative descriptive study through survey and questionnaire is used as research instruments. A total of 66 catering students of year 3 and 4 from Faculty of Technical and Vocational Education (FPTV) were selected as the study sample. The data obtained were analyzed using Statistical Package for Social Science (SPSS) version 22.00 software involving mean, standard deviation, and ANOVA. The results showed that the mean scores of self-efficacy of catering students were high to become teachers (M= 4.11, SD=0.617) and followed by hospitality employee (M= 3.87, SD= 0.574) and entrepreneurs (M= 3.93, SD=0.514). However, there was no significant difference between the three career fields with a value of p = 0.052. In conclusion, catering students have high self-efficacy in venturing into the field of career when graduating from university. Graduates need to see the importance of enhancing self-efficacy because it opens paths for career opportunities and advancement

Standardization of DNA extraction from invasive alien weed Parthenium hysterophorus

DNA isolation from the weed, Parthenium hysterophorus is complicated due to the presence of high amount of allelochemicals in the form of secondary metabolites that causes hindrance in extraction and enzymatic reactions. A modified and efficient DNA extraction from P. hysterophorus leaf has been developed. The present protocol is a modified version of cetyltrimethylammonium bromide (CTAB) method constituting high salt concentration to remove polysaccharides. The increased concentration of β-mercaptoethanol, polyvinylpolypyrrolidone (PVPP), and phenol/chloroform/isoamyl alcohol extractions eliminated protein and phenolic compounds well. Good amount and quality DNA was obtained by this method. The resulted genomic DNA showed fine random amplified polymorphic DNA (RAPD), inter-simple sequence repeat (ISSR) banding pattern, polymerase chain reaction (PCR) amplification of actin gene and restriction digestion confirm the efficiency of modified procedure.Keywords: Allelochemicals, DNA extraction, Parthenium hysterophorus, stress toleranc