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Real-time calculation of fragment velocity for cylindrical warheads

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Defence Technology（防务技术） 2019年第3期15卷 264-271页

作者： David felix Ian Colwill Elias Stipidis Institution of Engineering and Technology Stevenage England Member of British Computer Society London Institute of Electrical and Electronics Engineers London

To simulate explosion fragments, it is necessary to predict many variables such as fragment velocity, size distribution and projection angle. For active protection systems these predictions need to be made very quickly, before the weapon hits the target. Fast predictions also need to be made in real time simulations when the impact of many different computer models need to be assessed. The research presented in this paper focuses on creating a fast and accurate estimate of one of these variables - the initial fragment velocity. The Gurney equation was the first equation to calculate initial fragment velocity. This equation, sometimes with modifications, is still used today where finite element analysis or complex mathematical approaches are considered too computationally expensive. This paper enhances and improves Breech’s two-dimensional Gurney equation using available empirical data and the principals of conservation of momentum and energy. The results are computationally quick, providing improved accuracy for estimating initial fragment velocity. This will allow the developed model to be available for real-time simulation and fast computation, with improved accuracy when compared to existing approaches.

关键词： Initial fragment velocity Real-time simulation Cylindrical explosion

Turned Trochoidal Disturbance on a Liquid Jet Surface

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Chinese Journal of Mechanical Engineering 2014年第4期27卷 846-852页

作者： SADIK Shalom KIRZHNER felix KRAMARENKO Denis Department of Mechanical Engineering ORT Braude College Division of Environmental Water and Agricultural Engineering Faculty of Civil and Environmental EngineeringTechnion-IIT Haifa 32000 Israel Biotechnology Engineering ORT Braude College

This paper shows that a turned trochoidal function disturbance may lead to peripheral drops production. The resulting model is used to describe that a turned trochoidal disturbance leads to peripheral drops production on the liquid jet surface without the necessity for superimposed disturbances. The trochoid is a non-unique parametric function. Only non-unique parametric functions disturbances may lead to peripheral drops production. The trochoidal function disturbance is decomposed to Fourier series. Every Fourier element receives an amplification factor in accordance to the Rayleigh inviscid jet model. Peripheral drops are received on the jet surface. The paper shows that all trochoidal disturbance functions, prolate cycloid, cycloid and curtate cycloid have a capability of peripheral drops producing. A limited capability of peripheral drops production is introduced for the trochoidal curtate cycloid. Produced drops size are reduced for increasing the jet velocity and wave number. Smaller drops are also received by transition from the prolate cycloid to curtate cycloid disturbance.

关键词： drops liquid jet trochoidal function

Modelling geographic accessibility to Primary Health Care Facilities:combining open data and geospatial analysis

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Geo-Spatial Information Science 2019年第3期22卷 174-184页

作者： Olanrewaju Lawal felix E.Anyiam Department of Geography and Environmental Management Faculty of Social SciencesUniversity of Port HarcourtPort HarcourtNigeria Centre for Health and Development University of Port HarcourtPort HarcourtNigeria

Ensuring healthy lives and promoting well-being for all ages is the 3rd Sustainable Development Goal(SDG).Inequality in access to health care remains one of the primary challenges in achieving the *** the ever-increasing expansion of urban areas and population growth,there is a need to regularly examine the pattern of accessibility of basic amenities across regions,States and urban *** study examined geographic access to Primary Health Care Facilities(PHCF)in Nigeria using the combination of open data and geospatial analysis ***,showcasing an approach can be replicated across different regions in Sub-Saharan Africa due to issues of information *** on elevation,location of health care facilities,population and network data were *** result shows that PHCF aggregate at certain locations,*** urban agglomerations,and transit route leading to these *** concentrations are found in the capital *** average travel time to the nearest PHCF is about 14 min(Standard Deviation±13.30 min)while the maximum is about 2 *** of low accessibility areas exist across the Akwa Ibom State in the Niger Delta region of *** is an indication that most places have good geographic *** the 1787 settlements identified in our dataset,98.3%are with good access(60 min).Geographic access is not the main limiting factor to health care access in the ***,computation of access to health care should take into consideration other dimensions of accessibility,to create a robust measure which will support effective and efficient health care planning and delivery.

关键词： Spatial accessibility geographic accessibility Sustainable Development Goal(SDG) Primary Health Care Facilities(PHCF) Niger Delta geocomputation

Long noncoding RNAs in prostate cancer： overview and clinical implications

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Asian Journal of Andrology 2016年第4期18卷 568-574页

作者： Bhavna Malik felix Y Feng Department of Radiation Oncology University of Michigan Ann Arbor Michigan USA Department of Radiation Oncology Urology and Medicine University of California at San Francisco USA Helen Diller Family Comprehensive Cancer Center University of California at San Francisco USA

Prostate cancer is the second most common cause of cancer mortality among men in the United States. While many prostate cancers are indolent, an important subset of patients experiences disease recurrence after conventional therapy and progresses to castration-resistant prostate cancer （CRPC）, which is currently incurable. Thus, there is a critical need to identify biomarkers that will distinguish indolent from aggressive disease, as well as novel therapeutic targets for the prevention or treatment of CRPC. In recent years, long noncoding RNAs （IncRNAs） have emerged as an important class of biological molecules. LncRNAs are polyadenylated RNA species that share many similarities with protein-coding genes despite the fact that they are noncoding （not translated into proteins）. They are usually transcribed by RNA polymerase II and exhibit the same epigenetic signatures as protein-coding genes. LncRNAs have also been implicated in the development and progression of variety of cancers, including prostate cancer. While a large number of IncRNAs exhibit tissue- and cancer-specific expression, their utility as diagnostic and prognostic biomarkers is just starting to be explored. In this review, we highlight recent findings on the functional role and molecular mechanisms of IncRNAs in the progression of prostate cancer and evaluate their use as potential biomarkers and therapeutic targets.

关键词： biomarker long noncoding RNAs (IncRNAs) prostate cancer

On Some Cycles in Wenger Graphs

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Acta Mathematicae Applicatae Sinica 2020年第2期36卷 492-502页

作者： Ye WANG felix LAZEBNIK Andrew THOMASON College of Mathematical Sciences Harbin Engineering UniversityHarbin 150001China Department of Mathematical Sciences University of DelawareNewark.DE 19716U.S.A. DPMMS Centre for Mathematical SciencesWilberforce RoadCambridgeUK

Let p be a prime,q be a power of p,and let Fq be the field of q *** any positive integer n,the Wenger graph Wn(q)is defined as follows:it is a bipartite graph with the vertex partitions being two copies of the(n+1)-dimensional vector space Fq^n+1,and two vertices p=(p(1),…,p(n+1))and l=[l(1),…,l(n+1)]being adjacent if p(i)+l(i)=p(1)l(1)i-1,for all i=2,3,…,n+*** 2008,Shao,He and Shan showed that for n≥2,Wn(q)contains a cycle of length 2 k where 4≤k≤2 p and k≠*** this paper we extend their results by showing that(i)for n≥2 and p≥3,Wn(q)contains cycles of length 2k,where 4≤k≤4 p+1 and k≠5;(ii)for q≥5,0

关键词： cycle pancyclic finite field Wenger graph graph embeddings

The Hidden Side of the Story between the Placenta and Preeclampsia: Preliminary Results of a Prospective Cohort of Pregnant Women in Cameroon

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Open Journal of Obstetrics and Gynecology 2024年第4期14卷 610-620页

作者： Junie Annick Metogo Ntsama Ambroise Merci Engounou Seme Urielle Julie Tchuente Sutchueng Wilfried Loic Tatsipie Christian Vagoda Henry-Leonard Chatelin Mol Madye Ngo Dingom felix Essiben Cyrille Claude Noa Ndoua Yann chris Eng Odile Fernande Zeh Faculty of Medicine and Biomedical Sciences University of Yaound&#233 I Yaound&#233 Cameroon Faculty of Medicine and Pharmaceutical Sciences University of Dschang Dschang Cameroon

Introduction: Pre-eclampsia is a complication of pregnancy that generally occurs in the third trimester. It is associated with a maternal and foetal mortality rate of around 27%. In view of the grim picture painted by this condition for both mother and newborn, studies have been carried out into the early detection of patients at risk of developing pre-eclampsia. These make it possible to introduce pregnancy-specific monitoring and preventive strategies to reduce the incidence of the condition. Objective: To establish the link between placental ultrasound characteristics and the onset of pre-eclampsia. Methodology: A multicentre prospective cohort study was conducted in two hospitals in Yaoundé, namely the Yaoundé Gynaecological Obstetrics and Paediatrics Hospital and the Nkolndongo Health and Social Animation Centre, in the gynaecology and radiology departments over a period of 11 months, from October 2022 to August 2023. It included pregnant women who had undergone obstetric ultrasound between 12 and 18 weeks’ gestation. In addition to routine obstetric ultrasound, we performed obstetric Doppler measurements in these patients. The resistance index of the left and right uterine arteries, the umbilical artery and the placental volume were the characteristics sought. At the end of this examination, two groups were formed: cases (pathological Doppler group) and controls (normal Doppler group). Blood pressure and urine dipstick were taken at each antenatal visit until delivery, then during the immediate postpartum period and finally at 7 days, 21 days and 42 days after delivery. Results: Sixty-seven (67) patients were included. Of these, 35 (47.8%) had pathological Dopplers. Sixteen patients had arterial hypertension associated with proteinuria and were therefore labelled as pre-eclampsia (PE). This gives a prevalence of 23.9%. Fifteen (42.8%) of these patients belonged to the exposed group and one to the unexposed group. The mean IR of the pre-eclampsia patients was s

关键词： Pre-Eclampsia Doppler Ultrasound Placenta

Optimal Component Types for the Design of Construction Processes

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Tsinghua Science and Technology 2008年第S1期13卷 317-324页

作者： felix Enge Wolfgang Huhnt Chair of Process Modelling in Civil Engineering Berlin Institute of Technology

Within the project preparation phase, experienced professionals manually map design information onto process information with the aim to develop realistic and practical schedules. Unfortunately, the mapping itself is neither part of any underlying data model nor is it supported by current scheduling tools. As a consequence the process of setting up the data model for a schedule is still not supported formally. Huhnt and Enge described a modelling technique that addresses the missing linkage between design and process information[1]. The approach makes use of so called component types. These are template sub-processes that describe the fabrication procedure of typical building components. Decomposing the building into com-ponents and assigning a component type to each component allows for formal support while scheduling. Depending on the decomposition of the building into components and the complexity of the involved component types the specification effort differs. The question about optimal component types arises: Which layout of building components and component types results in minimal specification effort? This paper presents a branch and bound algorithm to determine optimal component types. For a given schedule, which has been modelled based on component types, all possible decompositions into sub-processes are determined. During the decomposition process the encountered configurations are compared. Those with minimal specifica-tion effort are registered. Theoretical and practical examples are examined and discussed.

关键词： scheduling process modelling planning processes construction processes branch and bound pattern matching search algorithm optimization

Less workplace parking with fully autonomous vehicles?

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Journal of Intelligent and Connected Vehicles 2022年第3期5卷 283-301页

作者： Stefan Tscharaktschiew felix Reimann Institute of Transport and Economics Technische Universität DresdenDresdenGermany

Purpose–Recent studies on commuter parking in an age of fully autonomous vehicles(FAVs)suggest,that the number of parking spaces close to the workplace demanded by commuters will decline because of the capability of FAVs to return home,to seek out(free)parking elsewhere or just *** would be good news because,as of today,parking is one of the largest consumers of urban land and is associated with substantial costs to *** of the studies,however,is concerned with the special case of employer-provided parking,although workplace parking is a widespread phenomenon and,in many instances,the dominant form of commuter *** purpose of this paper is to analyze whether commuter parking will decline with the advent of self-driving cars when parking is provided by the ***/methodology/approach–This study looks at commuter parking from the perspective of both the employer and the employee because in the case of employer-provided parking,the firm’s decision to offer a parking space and the incentive of employees to accept that offer are closely interrelated because of the fringe benefit character of workplace *** study develops an economic equilibrium model that explicitly maps the employer–employee relationship,considering the treatment of parking provision and parking policy in the income tax code and accounting for adverse effects from commuting,parking and public *** study determines the market level of employer-provided parking in the absence and presence of FAVs and identifies the factors that drive the *** study then approximates the magnitude of each factor,relying on recent(first)empirical evidence on the impacts of ***–This paper’s analysis suggests that as long as distortive(tax)policy favors employer-provided parking,FAVs are no guarantee to end up with less commuter ***/value–This study’s findings imply that in a world of self-driving cars,policy intervention related to work comm

关键词： Autonomous vehicles Employer-provided parking Fringe benefit Self-driving cars Transport policy

Comparison of manual and automatic barcode detection in rough horticultural production systems

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International Journal of Agricultural and Biological Engineering 2019年第6期12卷 169-176页

作者： felix Eyahanyo Thomas Rath Leibniz University of Hannover Institute of Horticultural Production SystemsBiosystems Engineering SectionHerrenhäuser Straße 230419 HannoverGermany University of Applied Sciences Osnabrück Biosystems Engineering Laboratory(BLab)Oldenburger Landstraße 2449090 OsnabrückGermany

Automation of production in the nurseries of flower producing companies using barcode scanners have been attempted but with little *** laser barcode scanners which have been used for automation have failed due to the close proximity between the barcode and the scanner,and factors such as speed,angle of inclination of the barcode,damage to the barcode and dirt on the ***,laser barcode scanners are still being used manually in the nurseries making work laborious and time consuming,which leading to reduced ***,an automated image-based barcode detection system to help solve the aforementioned problems was *** were conducted under different situations with clean and artificially soiled Code 128 barcodes in both the laboratory and under real production conditions in a flower producing *** images were analyzed with a specific algorithm developed with the software tool *** the results from the company showed that the image-based system has a future prospect for automation in the nursery.

关键词： automation barcode detection horticultural production systems image processing barcode scanners