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Effects of Froude number and geometry on water entry of a 2-D ellipse

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Journal of Hydrodynamics 2018年第4期30卷 738-749页

作者：张旭刘沛清屈秋林王睿 Ramesh k.agarwal School of Aeronautic Science and Engineering Beihang University School of Engineering and Applied Science Washington University in St.Louis

By using the finite volume method with volume of fluid model and global dynamic mesh technique, the effects of Froude number and geometry on the water entry process of a 2-D ellipse are investigated numerically. For the time history of the vertical force, the computational fluid dynamics（CFD） results match the experimental data much better than the classical potential-flow theories due to the consideration of the viscosity, turbulence, surface tension, gravity, and compressibility. The results show that the position of peak pressure on ellipse shifts from the spray root to the bottom of ellipse at a critical time. The critical time changes with the geometry and Froude number. By studying the vertical force, the ellipse water entry process can be divided into the initial and late stages based on the critical dimensionless time of about 0.1. The geometry of the ellipse plays a dominant role in the initial stage, while the Froude number is more important in the late stage of entry. The classical Wagner theory is extended to the ellipse water entry, and the predicted maximum value of vertical force coefficient in the initial stage is 4？a/b that matches the CFD results very well, where a and b are the horizontal axis and vertical axis of the ellipse parallel and perpendicular to the initial calm water surface, respectively.

关键词： Water impact water entry fluid-structure interaction Froude number

Generalized Boltzmann solution for non-equilibrium flows and the computation of flowfields of binary gas mixture

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Propulsion and Power Research 2012年第1期1卷 48-57页

作者： Baoguo Wang Geng Qian Ramesh k.agarwal Christopher D.Wilson School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Department of Mechanical Engineering and Materials Science Washington UniversitySt.LouisMO 63130USA Boeing Company St.LouisMO 63166USA

Hypersonic flows about space vehicles produce flowfields in thermodynamic non-equilibrium with the local knudsen numbers kn which may lie in all the three regimes:continuum,transition and *** flows can be modeled accurately by solving the Navier–Stokes(NS)equations;however,the flows in transition and rarefied regimes require a kinetic approach such as the direct simulation Monte Carlo(DSMC)method or the solution of the Boltzmann *** Boltzmann equation and the general solution approach,using the splitting method,will be introduced in this *** of the method used for solving both the classical Boltzmann equation(CBE)and the generalized Boltzmann equation(GBE)are also *** gas mixture discussed in this paper may consist of both monoatomic and diatomic *** particular,the method is applied to simulate two of the three primary constituents of air(N_(2),O_(2),and Ar)in a binary mixture at 1:1 density ratio at Mach 2 and 5,with gases in translational,rotational and vibrational non-equilibrium.

关键词： Generalized Boltzmann equation Non-equilibrium flow Monoatomic gas Diatomic gas Splitting method

Experimental study and Shannon entropy analysis of pressure fluctuations and flow mode transition in fluidized dense phase pneumatic conveying of fly ash

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Particuology 2020年第2期18卷 169-178页

作者： Yassin Alkassar Vijay kagarwal RkPandey Niranjana Behera Industrial Tribology Machine Dynamic and Maintenance Engineering CentreIndian Institute of Technology DelhiNew Delhi 110016India Department of Mechanical Engineering Indian Institute of Technology DelhiNew Delhi 110016India School of Mechanical Engineering Vellore Institute of Technology UniversityVellore 632014India

The objective of this study was to relate experimental pressure fluctuation behavior to the transition in mode of flow observed in fluidized dense phase pneumatic conveying of fly *** entropy and wavelet analysis were utilized to extract features of the flow *** db4 wavelet analysis of pulsating air pressure revealed that the flow mechanism of fly ash in a fluidized dense phase possessed non-steady characteristics associated with gradual aeration of dunes along the direction of *** of Shannon entropy values along the length of the pipeline were assessed to determine the location at which the flow converted from dense to dilute phase *** effects of conveying parameters and specific power consumption on Shannon entropy and variations of the local power consumption coefficient are discussed.

关键词： Fluidized dense phase Mode transition Wavelet Shannon entropy

Reinforced tissue matrix to strengthen the abdominal wall following reversal of temporary ostomies or to treat incisional hernias

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World Journal of Gastrointestinal Surgery 2024年第3期16卷 823-832页

作者： Spencer P Lake Corey R Deeken amit k.agarwal Mechanical Engineering&Materials Science Washington University in St.LouisSt.LouisMO 63130United States Covalent Bio LLCSt.LouisMO 63025United States Department of Surgery McGovern Medical School at UTHealthHoustonTX 77026United States

BACkGROUND Abdominal wall deficiencies or weakness are a common complication of tem-porary ostomies,and incisional hernias frequently develop after colostomy or ileostomy *** use of synthetic meshes to reinforce the abdominal wall has reduced hernia *** meshes have also been used to enhance healing,particularly in contaminated *** tissue matrices(R-TMs),which include a biologic scaffold of native extracellular matrix and a syn-thetic component for added strength/durability,are designed to take advantage of aspects of both synthetic and biologic *** date,RTMs have not been reported to reinforce the abdominal wall following stoma *** Twenty-eight patients were selected with a parastomal and/or incisional hernia who had received a temporary ileostomy or colostomy for fecal diversion after rectal cancer treatment or *** hernia repair and proximal stoma closure,RTM(OviTex®1S permanent or OviTex®LPR)was placed to reinforce the abdominal wall using a laparoscopic,robotic,or open surgical ***-operative follow-up was performed at 1 month and 1 *** recurrence was determined by physical examination and,when necessary,via computed tomo-graphy *** endpoints included length of hospital stay,time to return to work,and hospital *** complications of the wound/repair site included presence of surgical site infection,seroma,hematoma,wound dehiscence,or fistula *** The observational study cohort included 16 male and 12 female patients with average age of 58.5 years±16.3 years and average body mass index of 26.2 kg/m^(2)±4.1 kg/m^(2).Patients presented with a parastomal hernia(75.0%),in-cisional hernia(14.3%),or combined parastomal/incisional hernia(10.7%).Using a laparoscopic(53.6%),robotic(35.7%),or open(10.7%)technique,RTMs(OviTex®LPR:82.1%,OviTex®1S:17.9%)were placed using sublay(82.1%)or intraperitoneal onlay(IPOM;17.9%)mesh *** 1-mo

关键词： Reinforced tissue matrix Reinforced forestomach matrix Ileostomy Colostomy Ostomy takedown Incisional hernia Abdominal wall

Novel technique for anastomotic salvage using transanal minimally invasive surgery:A case report

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World Journal of Gastrointestinal Surgery 2019年第5期11卷 271-278页

作者： Oscar A Olavarria Robert L kress Shinil k Shah amit k.agarwal Center for Surgical Trials and Evidence-Based Practice McGovern Medical School at the University of Texas Health Science Center at HoustonHoustonTX 77033United States Department of Surgery McGovern Medical School at the University of Texas Health Science Center HoustonHoustonTX 77033United States

BACkGROUND Anastomotic leak(AL) after low anterior resection(LAR) can be a highly morbid *** incidence of AL ranges from 5% to 20% depending on patient characteristics and the distance of the anastomosis from the anal *** anastomoses and leaks pose technical challenges for endoscopic *** aim of this report was to describe the use of a commercially available laparoscopic energy device through a transanal minimally invasive surgery(TAMIS) port for the management of a symptomatic leak not requiring relaparotomy(grade B) after a LAR with diverting loop *** SUMMARY A TAMIS GelPOINT Path port was inserted into the anus to access the distal *** was achieved with AirSeal insufflation and a 30 degree laparoscope was introduced through a trocar.A LigaSure TM Retractable L-Hook device was then used to perform a septotomy of the chronic sinus tract identified posterior to the *** procedure was then repeated twice in three weeks intervals with ultimate resolution of the chronic leak *** months after serial TAMIS septotomies,barium enema demonstrated a patent anastomosis with no evidence of persistent leak or *** patient subsequently underwent ileostomy reversal and has had no significant postoperative *** TAMIS septotomy with the LigaSure TM Retractable L-Hook is a feasible andeffective,minimally invasive salvage technique for the treatment of grade B *** studies are needed to assess the generalizability and long-term results of this technique.

关键词： Transanal minimally invasive surgery Ligasure hook Anastomotic leak Low anterior resection Septotomy Case report

Nonmuscle invasive bladder cancer: a primer on immunotherapy

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Cancer Biology & Medicine 2016年第2期13卷 194-205页

作者： Mahir Maruf Sam J.Brancato Piyush k.agarwal Urologic Oncology Branch National Cancer Institute National Institutes of Health

Intravesical Bacillus Calmette-Guerin （BCG） has long been the gold standard treatment of nonmuscle invasive bladder cancer. Recently, there has been an emergence of novel immunotherapeutic agents, which have shown promise in the treatment of urothelial cell carcinoma. These agents aim to augment, modify, or enhance the immune response. Such strategies include recombinant BCG, monoclonal antibodies, vaccines, gene therapy, and adoptive T-cell therapy. Here, we review the emerging immunotherapeutics in the treatment of nonmuscle invasive bladder cancer.

关键词： Urothelial cell carcinoma Bacillus Calmette-Guerin (BCG) immunotherapy bladder cancer

Development and validation of microbial bioassay for quantification of Levofloxacin in pharmaceutical preparations

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Journal of Pharmaceutical Analysis 2015年第1期5卷 18-26页

作者： Nishant A.Dafale Uttam P.Semwal Piyush k.agarwal Pradeep Sharma G.N.Singh Microbiology Division Indian Pharmacopoeia Commission

The aim of this study was to develop and validate a simple,sensitive,precise and cost-effective onelevel agar diffusion（5＋1） bioassay for estimation of potency and bioactivity of Levofioxacin in pharmaceutical preparation which has not yet been reported in any *** 16 microbial *** pumilus ATCC-14884 was selected as the most significant strain against *** was optimized by investigating several factors such as buffer pH,inoculums concentration and reference standard *** of Levofioxacin in commercial sample Levoflox tablet was done by FTIR *** potency recovery value for Levofioxacin in Levoflox tablet was estimated as 100.90%.A validated bioassay method showed linearity（r^2 = 0.988）,precision（Interday RSD=1.05%,between analyst RSD=1.02%） and accuracy（101.23%,RSD=0.72%）.Bioassay was correlated with HPLC using same sample and estimated potencies were 100.90% and 99.37%.*** show that bioassay is a suitable method for estimation of potency and bioactivity of Levofioxacin pharmaceutical preparations.

关键词： Levofloxacin Antibiotic resistance Microbiological bioassay HPLC Pharmacopoeia

Computerized tomography based “patient specific blocks” improve postoperative mechanical alignment in primary total knee arthroplasty

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World Journal of Orthopedics 2016年第7期7卷 426-433页

作者： Raju Vaishya Vipul Vijay Vikas P Birla amit k.agarwal Department of Orthopaedics Joint Replacement and ArthroscopyIndraprastha Apollo Hospital

AIM: To compare the postoperative mechanical alignment achieved after total knee arthroplasty(TkA) using computer tomography(CT) based patient specific blocks(PSB) to conventional instruments(CI).METHODS: Total 80 knees were included in the study, with 40 knees in both the groups operated using PSB and CI. All the knees were performed by a single surgeon using the same cruciate sacrificing implants. In our study we used CT based PSB to compare with CI. Postoperative mechanical femoro-tibial angle(MFT angle) was measured on long leg x-rays using picture archiving and communication system(PACS). We compared mechanical alignment achieved using PSB and CI in TkA using statistical ***: The PSB group(group 1) included 17 females and seven males while in CI group(group 2) there were 15 females and eight males. The mean age of patients in group 1 was 60.5 years and in group 2 it was 60.2 years. The mean postoperative MFT angle measured on long-leg radiographs in group 1 was 178.23°(SD = 2.67°, range: 171.9° to 182.5°) while in group 2, the mean MFT angle was 175.73°(SD = 3.62°, range: 166.0° to 179.8°). There was significant improvement in postoperative mechanical alignment(P value = 0.001), in PSB group compared to CI. Number of outliers were also found to be less in group operated with PSB(7 knee) compared to those operated with CI(17 knee).CONCLUSION: PSB improve mechanical alignment after total knee arthroplasty, compared to CI. This may lead to lower rates of revision in the PSB based TkA as compared to the conventional instrumentation.

关键词： knee Replacement Arthroplasty Patient specific jigs Conventional jigs

Routine colonic endoscopic evaluation following resolution of acute diverticulitis:Is it necessary?

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World Journal of Gastroenterology 2014年第35期20卷 12509-12516页

作者： amit k.agarwal Burzeen E karanjawala Justin A Maykel Eric k Johnson Scott R Steele Department of Surgery University of Texas Health Science Center-Houston Department of Surgery University of Texas Health Science Center-Houston and Lyndon B.Johnson General Hospital University of Massachusetts Memorial Medical Center Colon Rectal Surgery Department of SurgeryMadigan Army Medical Center

Diverticular disease incidence is increasing up to 65% by age 85 in industrialized nations,low fiber diets,and in younger and obese ***-five percent of patients with diverticulosis will develop acute *** imposes a significant burden on healthcare systems,resulting in greater than 300000 admissions per year with an estimated annual cost of $3 billion *** computed tomography(CT) is the diagnostic study of choice,with a sensitivity and specificity greater than 95%.Unfortunately,similar CT findings can be present in colonic neoplasia,especially when perforated or *** prompted professional societies such as the American Society of Colon Rectal Surgeons to recommend patients undergo routine colonoscopy after an episode of acute diverticulitis to rule out ***,the data supporting routine colonoscopy after acute diverticulitis is sparse and based small cohort studies utilizing outdated *** any patient with an indication for a colonoscopy should undergo appropriate endoscopic evaluation,in the era of widespread use of high-resolution computed tomography,routine colonic endoscopic evaluation following resolution of acute uncomplicated diverticulitis poses additional costs,comes with inherent risks,and may require further *** this manuscript,we review the current data related to this recommendation.

关键词： Colonic evaluation Colonoscopy Diverticulitis Acute diverticulitis Colonic neoplasia Endoscopy