AN INNOVATIVE WORKING CONCEPT FOR VARIABLE DELIVERY FLOW EXTERNAL GEAR MACHINE

An innovative and unique working concept for variable delivery external gear machines (VD-EGMs) is presented in this study. The proposed design not only encompasses all the well-known and important advantages of traditional external gear machines but also introduces a feature for varying the displacement (flow delivered per unit revolution). The novel principle of achieving variable displacement in EGMs is based on the variable timing of the connections of the displacement chambers/tooth space volumes (TSVs) with the inlet/outlet ports. The timing variation is obtained by the addition of a simple element (called a “slider”) within the lateral bushings. The position of the slider determines the amount of flow displaced per unit revolution. Starting from the geometry of the design and the proposed concept, analytical expressions for predicting displacement variation, flow rate and input shaft torque were derived. With this working principle, the range of variation of the displacement can be significantly increased by modifying the gear profiles. Therefore, in this work, novel gears with asymmetric teeth profile are designed with the help of a novel tool developed particularly for this process. However, due to the inherent nature of the displacing action of the EGM due to the meshing of the gears, it is not possible to achieve a full flow variation from 0%-100%. Therefore, to maximize the range of flow variation while considering all the other important performance features of the machine to be maintained at an optimum, a multi-objective genetic algorithm based optimization method is used to identify the optimal design of gears and grooves in the lateral bushings. The performance of the desig

A Flow Control System for a Novel Concept of Variable Delivery External Gear Pump

This paper describes a novel concept for a low cost variable delivery external gear pump (VD-EGP). The proposed VD-EGP is based on the realization of a variable timing for the connections of the internal displacement chambers with the inlet and outlet ports. With respect to a standard EGP, an additional element (slider) is used along with asymmetric gears to realize the variable timing principle. Previously performed tests confirmed the validity of the concept, for a design capable of varing the flow in the 65%-100% range. Although the VD-EGP concept is suitable for various flow control system typologies (manual, electro-actuated, hydraulically flow- or pressure- compensated), this paper particularly details the design and the test results for a prototype that includes both a manual flow control system and a pressure compensator. Flow vs pressure and volumetric efficiency curves are discussed along with transient (outlet flow fluctuation) features of the VD-EGP

Microwave assisted enzymatic kinetic resolution of (±)-1-phenyl-2-propyn-1-ol in nonaqueous media

Kinetic resolution of 1-phenyl-2-propyn-1-ol, an important chiral synthon, was studied through trans-esterification with acyl acetate to investigate synergism between microwave irradiation and enzyme catalysis. Lipases from different microbial origins were employed for the kinetic resolution of (R/S)-1-phenyl-2-propyn-1-ol, among which Candida antarctica lipase B, immobilized on acrylic resin (Novozym 435), was found to be the best catalyst in n-hexane as solvent. Vinyl acetate was the most effective among different acyl esters studied. The effect of various parameters was studied in a systematic manner. Definite synergism between microwave and enzyme was observed. The initial rate was improved around 1.28 times under microwave irradiation than conventional heating. Under optimum conditions, maximum conversion (48.78%) and high enantiomeric excess (93.25%) were obtained in 2 h. From modeling studies, it is concluded that the reaction follows the Ping-Pong bi-bi mechanism with dead end alcohol inhibition. Kinetic parameters were obtained by using nonlinear regression. This process is green, clean, and easily scalable as compared to the chemical process

A Comparative study on the Effectiveness of Muscle Energy Techniques and Maitland Mobilization Coupled with Ultrasound in Patients with Periarthritis of the Shoulder Joint

PURPOSE OF THE STUDY: To compare the effectiveness of Muscle Energy Technique and Maitland mobilization coupled with Ultrasound in patients with periarthritis of shoulder joint. MATERIALS AND METHODS: 20 subjects with periarthritis were randomly allocated. The subjects were treated Ultrasound coupled with Muscle Energy Technique (Group I) and Maitland Mobilization (Group II). The treatment was given for 45 minutes a day up to 2 months. The outcome was measured in terms of shoulder pain and disability index (SPADI). RESULTS: Independent "t" test was used to compare the pre test and post test values between each groups. On comparing the mean values of SPADI of two groups, the study shows there is a significant increase in the post test values of ultrasound coupled with muscle energy technique than Ultrasound coupled with Maitland Mobilization. CONCLUSION: Ultrasound coupled with muscle energy technique is more effective than Maitland mobilization in reducing pain and disability, enhancing shoulder function among periarthritis subjects

A Comparative Study of Email Forensic Tools

Over the last decades, email has been the major carrier for transporting spam and malicious contents over the network. Email is also the primary source of numerous criminal activities on the Internet. Computer Forensics is a systematic process to retain and analyze saved emails for the purpose of legal proceedings and other civil matters. Email analysis is challenging due to not only various fields that can be forged by hackers or malicious users, but also the flexibility of composing, editing, deleting of emails using offline (e.g., MS Outlook) or online (e.g., Web mail) email applications. Towards this direction, a number of open source forensics tools have been widely used by the practitioners. However, these tools have been developed in an isolated manner rather than a collaborative approach. Given that email forensic tool users need to understand to what extent a tool would be useful for his/her circumstances and conducting forensic analysis accordingly. In this paper, we examine a set of common features to compare and contrast five popular open source email forensic tools. The study finds that all email forensic tools are not similar, offer diverse types of facility. By combining analysis tools, it may be possible to gain detailed information in the area of email forensic

Genetic analysis of Chaerephon pumilus (Chiroptera: Molossidae) from southern Africa.

Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2008.Chaerephon pumilus, the little free-tailed bat, (family: Molossidae) has a distribution throughout most of sub-Saharan Africa and the eastern region of Madagascar. The vast geographical distribution of this species is accompanied by considerable phenotypic variation, which may conceal cryptic species. The cytochrome b (845 nucleotides) and D-loop (314 nucleotides) regions of the mitochondrial DNA were sequenced to assess phylogenetic relationships within C. pumilus (southern Africa) and in relation to Chaerephon species from Madagascar (C. pumilus, C. leucogaster). Samples were obtained from KwaZulu-Natal, South Africa, and localities in Swaziland. The cytochrome b sample (n = 11) comprised four haplotypes, with a haplotype diversity of 0.6727, whilst the D-loop (n = 34) dataset comprised 13 haplotypes with a haplotype diversity of 0.8342. Neighbour joining, maximum parsimony and Bayesian analyses revealed congruent tree structures for both mtDNA regions. All Chaerephon taxa in this study formed a monophyletic clade with respect to the outgroup Mops midas. Chaerephon pumilus from the eastern side of Madagascar formed a well-supported monophyletic group, sister to a clade comprising C. pumilus (southern Africa) and C. leucogaster, and is suggested to comprise a separate species. Southern African C. pumilus formed two paraphyletic clades, A and B, separated by a genetic distance of 0.9 %. Chaerephon leucogaster formed a monophyletic group nested within southern African C. pumilus, suggesting conspecificity. However, the well-characterized morphology of C. leucogaster lends support to its specific status, and suggests the possible existence of cryptic species among southern African C. pumilus. Population genetic analysis suggests that two C. pumilus (southern African) clades have been expanding, one for between 2432 and 4639 years, and the other for the 11156 to 21280 years. A combined cytochrome b analysis, trimmed to 343 nucleotides, was carried out on the data from this study and that of Jacobs et al. (2004), also on southern African C. pumilus. Haplotypes from the Jacobs et al. (2004) study, which also identified two 0.9 % divergent clades (light- and dark-winged) were found to be identical or very similar to haplotypes from this study and were interspersed among southern African C. pumilus haplotypes in phylogenetic analyses. Chaerephon pumilus haplotypes from Zambia and Tanzania were found to be more closely related to those from southern Africa and to C. leucogaster than to C. pumilus (Madagascar), further indicating that this may be a separate species. Haplotypes from the light-winged clade of Jacobs et al. (2004) were identical to those of dark-winged samples from this study, suggesting that wing shade may not be diagnostic of the two clades

Cassification of breast tumor based on ultrasound images

This research primarily focuses on the predictive technology of identifying the state of tumors in the breast tissues. In breast cancer diagnosis, patients are forced to undergo a series of biopsies just to identify and confirm on the state of tumor, as whether malignant or benign. In this research however, an algorithm will be developed using MATLAB Image Processing Toolbox to indentify the state of a tumor solely based on ultrasound images. Ultrasound images of breast tumors are imported into MATLAB and are passed through a set of filters to remove background noise. Next, the filtered images are run through a set of edge detection algorithms which identifies and defines the region of interest. The processed images are analyzed qualitatively and the following results are obtained; the analysis shows that malignant tumors have well defined boundaries while benign tumors have poorly defined boundaries. To test this theory, the algorithm is used to process another set of ultrasound images of unknown characteristics. The results were analyzed and classified into two groups; malignant and benign. The results are compared with the actual biopsy results from the IIUM Breast Cancer Research Institute, Kuantan and all the analyzed results matched the biopsy results. As a recommendation to improve this study, a quantitative analysis on the ultrasound images is carried out so that more accurate results can be obtained. If the development of this algorithm is proven to be a success, it would be used in every hospital throughout the country to diagnose patients with breast cancer

Comparing Piezoresistive Substrates for Tactile Sensing in Dexterous Hands

While tactile skins have been shown to be useful for detecting collisions between a robotic arm and its environment, they have not been extensively used for improving robotic grasping and in-hand manipulation. We propose a novel sensor design for use in covering existing multi-fingered robot hands. We analyze the performance of four different piezoresistive materials using both fabric and anti-static foam substrates in benchtop experiments. We find that although the piezoresistive foam was designed as packing material and not for use as a sensing substrate, it performs comparably with fabrics specifically designed for this purpose. While these results demonstrate the potential of piezoresistive foams for tactile sensing applications, they do not fully characterize the efficacy of these sensors for use in robot manipulation. As such, we use a high density foam substrate to develop a scalable tactile skin that can be attached to the palm of a robotic hand. We demonstrate several robotic manipulation tasks using this sensor to show its ability to reliably detect and localize contact, as well as analyze contact patterns during grasping and transport tasks.Comment: 10 figures, 8 pages, submitted to ICRA 202