Designing a robotic port system for laparo-endoscopic single-site surgery

Current research and development in the field of surgical interventions aim to reduce the invasiveness by using few incisions or natural orifices in the body to access the surgical site. Considering surgeries in the abdominal cavity, the Laparo-Endoscopic Single-site Surgery (LESS) can be performed through a single incision in the navel, reducing blood loss, post-operative trauma, and improving the cosmetic outcome. However, LESS results in less intuitive instrument control, impaired ergonomic, loss of depth and haptic perception, and restriction of instrument positioning by a single incision. Robot-assisted surgery addresses these shortcomings, by introducing highly articulated, flexible robotic instruments, ergonomic control consoles with 3D visualization, and intuitive instrument control algorithms. The flexible robotic instruments are usually introduced into the abdomen via a rigid straight port, such that the positioning of the tools and therefore the accessibility of anatomical structures is still constrained by the incision location. To address this limitation, articulated ports for LESS are proposed by recent research works. However, they focus on only a few aspects, which are relevant to the surgery, such that a design considering all requirements for LESS has not been proposed yet. This partially originates in the lack of anatomical data of specific applications. Further, no general design guidelines exist and only a few evaluation metrics are proposed. To target these challenges, this thesis focuses on the design of an articulated robotic port for LESS partial nephrectomy. A novel approach is introduced, acquiring the available abdominal workspace, integrated into the surgical workflow. Based on several generated patient datasets and developed metrics, design parameter optimization is conducted. Analyzing the surgical procedure, a comprehensive requirement list is established and applied to design a robotic system, proposing a tendon-driven continuum robot as the articulated port structure. Especially, the aspects of stiffening and sterile design are addressed. In various experimental evaluations, the reachability, the stiffness, and the overall design are evaluated. The findings identify layer jamming as the superior stiffening method. Further, the articulated port is proven to enhance the accessibility of anatomical structures and offer a patient and incision location independent design

The Analyses of Hard- and Soft- Switching SiC Schottky- Buck Converter Performance

In this project two types ofbuck converters, hard switching and soft switching buck converters are compared in term of power lossand reverse recovery current of diode in DC applications. The test circuit used is dc to dc buck converter circuit. The main switch ofcircuit is the IGBT and the same type ofIGBT is used for both techniques. The diode used is fastswitching type Silicon Carbide Schottky (SiC) diode. First semester theory research has been verified with simulations, which were conducted in Cadence Pspice 14.2. The power loss waveforms of diode and IGBT transistor were obtained. Using those power waveforms the energy loss of both circuits were calculated. Second semester, hard and soft switching choppercircuitswere constructed on PCB (Printed Circuit Boards), so that simulation results can be compared with experimentation results. All the PCB layouts were prepared in ARES IV. Powerloss waveforms were obtained from digital oscilloscope. The simulation and experimentation values are found to be quite close to one another. It has found that hard switching chopper has more energy losses comparing soft switching chopper. The main losses occur during SiC diode turn-off (caused by reverse recovery current), IGBT transistor turn-on (caused by ICe current spike) and the highest main loss is IGBT turn-off (caused by tailing time, tailing current). Reducing the turn-off and turn-on switching losses of the IGBT would imply decreasing of the total loss of the system. Thatcould be done by implementing zero voltage switching across the IGBT transistor which would decrease IGBT turn-on and turn-off losses

Designing a cement program for Extended Reach Drilling well using Landmark software

Extended-Reach Drilling (ERD) is essentially an advanced form of directional drilling. ERD employs both directional and horizontal drilling techniques and has the ability to achieve horizontal well departures and total vertical depth-to-horizontal distance ratios well beyond conventional directional drilling. Acceptable production from horizontal well needs successful drilling and completion operation. Hence, cementing of an ERD and horizontal well is an essential part of completion and it influences the future production from the well. Designing proper cement program which is compatible with formation conditions is one of the most significant factors for a successful cement job. This study aims on two problematic parameters of cementing in ERD well. The main objectives of the study is designing cement program which can prevent the presence of the mud channeling on the lower side of the annulus and the water channeling on the opposite side which is top part of the annulus during the casing cementing operation. The study of research papers and other related works showed that creation of turbulent flow regime of pumped cement slurry in the annulus is the best way to remove the settled mud in the lower side of the annulus. Turbulent flow behavior breaks the mud gel and acts as a pushing force for the removal of settled particles from mud. As for the water channeling, the presence of it is mostly affected by the free water content of the cement as the research papers claim. Thus the maintaining the percentage of free water content in cement slurry must be minimum and close to zero. Through my research and studies I try to resolve those problems by designing the suitable cement program. Calculations were made with Excel Macros spreadsheet results. Overall data was used in OptiCem module to simulate and observe casing cementing procedures. The main concern during cementing operation found out to be ECD, which is highly affected by the flowrate of pumping. Critical flowrate values showed very similar results from both of the ways of obtaining the results, OptiCem and Excel Macros. Overall studies showed that proper flowrate only is not enough for creating turbulent flow and that ECD’s high values on higher flowrates disable us to reach the turbulent flow regime without breaking the formation due to fracture gradient’s reaching

Exploring the Multifaceted Nature of Complex Syntactic Units in Linguistic Texts

This research delves into the intricate realm of complex syntactic units, emphasizing their role as pivotal linguistic and methodological entities. By intertwining the planes of expression and content, the study underscores the structural and semantic markers that define these units. A comprehensive review of existing literature on the subject reveals the depth and breadth of understanding surrounding complex syntactic units. The paper further highlights the primary characteristics of these units, emphasizing their role in bridging individual sentences and facilitating coherent communication. Special focus is given to the concluding sentences within these units, which play a crucial role in connecting and contextualizing disparate sentences

The Adoption of E-Business Practices among SME's in Uzbekistan

These researches explore adoption of e-business practice in Uzbekistan and as well SME's attitude toward e-business. Methods of research use quantitative related on questionnaires, where 150 respondents that we provide questionnaires only 132 respondents give feedback and data analysis based on it. Research paper developed is framework where main independent variables (Organizational context, technological context, environmental context) and dependent variable (Adoption of e-business). Finding shows relationship between independent variable to dependent variable. The study revealed that organizational context, technological context, environmental context with adoption of e-business. However, the findings are only applicable on e-business practice in Uzbekistan understudy. It is beneficial for future research to examine the relationship between organizational context, technological context, and environmental context during adoption of e-business in other country and industries

Initial-Boundary Value Problem for Fractional Partial Differential Equations of Higher Order

The initial-boundary value problem for partial differential equations of higher-order involving the Caputo fractional derivative is studied. Theorems on existence and uniqueness of a solution and its continuous dependence on the initial data and on the right-hand side of the equation are established

Fundamental invariants of tensors, Latin hypercubes, and rectangular Kronecker coefficients

We study polynomial SL-invariants of tensors, mainly focusing on fundamental invariants which are of smallest degrees. In particular, we prove that certain 3-dimensional analogue of the Alon--Tarsi conjecture on Latin cubes considered previously by B\"urgisser and Ikenmeyer, implies positivity of (generalized) Kronecker coefficients at rectangular partitions and as a result provides values for degree sequences of fundamental invariants.Comment: Theorem 1.1 is improved, new sec. 8.3 and Theorem 8.12 are added in v2. The final version (after referee's comments) to appear in IMR