A Brief Review on Aerodynamic Performance of Wingtip Slots and Research Prospect

Wingtip slots, where the outer primary feathers of birds split and spread vertically, are regarded as an evolved favorable feature that could effectively improve their aerodynamic performance. They have inspired many to perform experiments and simulations as well as to relate their results to aircraft design. This paper aims to provide guidance for the research on the aerodynamic mechanism of wingtip slots. Following a review of previous wingtip slot research, four imperfections are put forward: vacancies in research content, inconsistencies in research conclusions, limitations of early research methods, and shortage of the aerodynamic mechanism analysis. On this basis, further explorations and expansion of the influence factors for steady state are needed; more attention should be poured into the application of flow field integration method to decompose drag, and evaluation of variation in induced drag seems a more rational choice. Geometric and kinematic parameters of wingtip slot structure in the unsteady state, as well as the flexibility of wingtips, should be taken into account. As for the aerodynamic mechanism of wingtip slots, the emphasis can be placed on the study of the formation, development, and evolution of wingtip vortices on slotted wings. Besides, some research strategies and feasibility analyses are proposed for each part of the research.

Angular control of differential shape-memory alloy spring actuator for underactuated dynamic system

This article dwells on two technical aspects, the design and implementation of an upgraded version of the differential shape-memory alloy–based revolute actuator/rotary actuating mechanism for stabilization and position control of a two-degree-of-freedom centrally hinged ball on beam system. The actuator is configured with differential and inclined placement of shape-memory alloy springs to provide bidirectional angular shift. The shape-memory alloy spring actuator occupies a smaller space and provides more extensive reformation with justifiable actuation force than an equally able shape-memory alloy wire. The cross or diagonal architecture of shape-memory alloy springs provides force amplification and reduces the actuator’s control effort. The shape-memory alloy spring–embodied actuator’s function is exemplified by the highly dynamic underactuated custom-designed ball balancing system. The ball position control is experimentally demonstrated by cascade control using the control laws that have been unattempted for shape-memory alloy actuated systems; the ball is positioned with linear (integer-order and fractional-order) proportional–integral–derivative controllers optimized with genetic algorithm and particle swarm optimization at the outer/primary loop. Angular control of the shape-memory alloy actuated beam is obtained with nonlinear (integer-order and fractional-order sliding mode control) control algorithms in the inner/secondary loop.

Implemetasi Cascade Control Pada Pengaturan Suhu Steamer BaglogMenggunakan PLC dan HMI

Di dalam budidaya jamur tiram, media tumbuh jamur, yang biasa disebut baglog sebelum melalui proses pembibitan harus dalam kondisi steril. Alat sterilisasi baglog biasanya menggunakan drum berkapasitas besar yang dipanasi di atas kompor atau juga menggunakan oven. Namun, hal ini memakan waktu yang lebih lama dan juga dikendalikan secara manual dengan memutar valve secara manual dengan melihat warna api pada pembakaran.Salah satu solusi dari hal tersebut yaitu menggunakan steamer yang dapat dikendalikan secara otomatis secara cascade control menggunakan metode kontrol PID. Salah satu keuntungan menggunakan cascade yaitu respon yang lebih cepat, error lebih kecil dan lebih presisi. Dalam pembuatannya digunakan PLC, HMI, sensor suhu PT100, sensor tekanan pipa bourdon dan motor dc.Dari hasil perancangan terhadap aplikasi kontroler PID dengan metode Ziegler Nichols ini pada inner secondary diperoleh Kp=5, Ti= 360 dan Td=90 sehingga memiliki performa kontrol td= 1030 s,tr= 3390 detik,ts= 3570 detik, Ess=1% dan parameter PID pada outer primary yaitu Kp=1, Ti=250s, dan Td=50s dan yang mampu memberikan kestabilan pada sistem kontrol suhu steamer untuk mencapai set point dan memiliki performa kontroltd= 1510 s,tr= 1950 detik,ts=2130, Ess= 1%.

Sonations in Migratory and Non-migratory Fork-tailed Flycatchers (Tyrannus savana)

Synopsis Sonations are sounds that animals produce with structures other than the vocal apparatus for communication. In birds, many sonations are usually produced with modified flight feathers through diverse kinematic mechanisms. For instance, aeroelastic fluttering of feathers produces tonal sound when airflow exceeds a threshold velocity and induces flight feathers to oscillate at a constant frequency. The Fork-tailed flycatcher (Tyrannus savana) is a Neotropical bird with both migratory and year-round resident subspecies that differ in the shape of the outer primary feathers of their wings. By integrating behavioral observations, audio recordings, and high-speed videos, we find that male Fork-tailed flycatchers produce sonations with their outer primary feathers P8-10, and possibly P7. These sounds are produced during different behavioral contexts including: the pre-dawn display, intraspecific territorial disputes, when attacking potential nest predators, and when escaping. By placing feathers in a wind tunnel, we elicited flutter at frequencies that matched the acoustic signature of sounds recorded in the wild, indicating that the kinematic mechanism responsible for sound production is aeroelastic flutter. Video of wild birds indicated that sonations were produced during the downstroke. Finally, the feathers of migratory (T.s.savana) and year-round resident (T.s.monachus) Fork-tailed flycatchers flutter in feather locations that differ in shape between the subspecies, and these shape differences between the subspecies result in sounds produced at different frequencies.

Combustion Characteristics and NOx Emission through a Swirling Burner with Adjustable Flaring Angle

A swirling burner with a variable inner secondary air (ISA) flaring angle β is proposed and a laboratory scale opposed-firing furnace is built. Temperature distribution and NOx emission are designedly measured. The combustion characteristics affected by variable β are experimentally evaluated from ignition and burnout data. Meanwhile, NOx reduction by the variable β is analyzed through emissions measurements. Different inner/outer primary coal-air concentration ratios γ, thermal loads and coal types are considered in this study. Results indicate that β variation provides a new approach to promote ignition and burnout, as well as NOx emission reduction under conditions of fuel rich/lean combustion and load variation. The recommended β of a swirling burner under different conditions is not always constant. The optimal βopt of the swirling burner under all conditions for different burning performance are summarized in the form of curves, which could provide reference for exquisite combustion adjustment.

Madeirasquilla tuerkayi, a new genus and species of mantis shrimps from Madeira Island, eastern Atlantic (Crustacea: Stomatopoda: Nannosquillidae)

Madeirasquilla tuerkayi is described as a new genus and species of the nannosquillid mantis shrimps (Stomatopoda) based on a single specimen collected from Madeira, eastern Atlantic. That specimen is remarkable by a combination of the following morphological characters: rostral plate with three sharp anterior projections; antennal protopod with two mesial and one ventral papillae; cornea subglobular; raptorial claw dactylus with 11 or 12 teeth, and with acute proximal tooth on outer margin; pleonite 6 with strong posterolateral spine and two posteriorly directed sternal spines; telson bearing smooth shield-like dorsal prominence with acute median spine posteriorly; four pairs of fixed primary teeth posteriorly on the telson; outer primary spine of uropodal protopod longer than inner primary spine. The separate position of the new genus is supported also by molecular comparison. A key to the genera of the family Nannosquillidae is proposed.

PEMBINAAN PENGELOLAAN MANAJEMEN USAHA DAN E-MARKETING PADA PELAKU USAHA INDUSTRI MIKRO PENGRAJIN SEPATU DI KECAMATAN MEDAN DENAI

AbstrakKegiatan program pengabdian masyarakat dari Lembaga Pengabdian Pada Masyarakat (LPPM) Universitas Muhammadiyah Sumatera Utara ini bertujuan untuk melakukan Pembinaan Pengelolaan Manajemen Usaha dan E-Marketing pada Pelaku Usaha Industri Mikro Pengrajin Sepatu di Kecamatan Medan Denai. Kegiatan pengabdian masyarakat ini melibatkan pengrajin Sepatu yang akan menjadi Mitra pengabdian masyarakat yaitu Jondy Shoes dan Whindy Shoes. Pengabdian masyarakat ini dilaksanakan selama 8 (delapan) bulan dengan target luaran utama adalah publikasi jurnal ilmiah pengabdian masyarakat, memperoleh ijin usaha, mempunyai website dann peningkatan wawasan dan keterampilan. Metode yang digunakan dalam kegiatan pengabdian masyarakat ini adalah pendekatan partisipatif, pendekatan kognitif, pendekatan afektif dan pendekatan keterampilan dan tahapan tahapan yang digunakan adalah persiapan, investigasi, transformasi. Incubation, verification, implementation, evaluasi, pengembangan secara bertahap yang dimulai dengan Plan, do, action, check. Selanjutnya para mitra sudah mempunyai email dan webblog sebagai sarana promosi usaha yang mitra jalankan dan sudah memiliki izin usaha dan telah terdaftar di Dinas Koperasi Kota medan. Kata Kunci: manajemen usaha, e-marketing AbstractThe activities of the public service program of the community service Society or LP2M Univesity of Muhammadiyah Sumatera Utara aims to perform the construction Management Business Management and E-Marketing in Micro Industry Trade Craftsmen shoes in Medan Denai. This outreach activities involving craftsmen shoes that will become a partner of public service i.e. Jondy Whindy Shoes and Shoes. Public service was conducted for 8 (eight) months with the outer primary target was the publication of the scientific journal public service, obtaining a business license, have increased insight and dann website skills. Methods used in this outreach activity is a participatory approach, the approach of cognitive, affective and approach the approach phase and stage skills used are preparation, investigation, transformation. Incubation, verification, implementation, evaluation, development gradually, beginning with a Plan, do, check, action. Furthermore the partners already have email and webblog as a means of promotion of the business partners who run and already have a business license and has been registered with the Department of Cooperatives of medan Keywords: Business Management, E-Marketing

On the autorotation of animal wings

Botanical samaras spin about their centre of mass and create vertical aerodynamic forces which slow their rate of descent. Descending autorotation of animal wings, however, has never been documented. We report here that isolated wings from Anna's hummingbirds, and also from 10 species of insects, can stably autorotate and achieve descent speeds and aerodynamic performance comparable to those of samaras. A hummingbird wing loaded at its base with the equivalent of 50% of the bird's body mass descended only twice as fast as an unloaded wing, and rotated at frequencies similar to those of the wings in flapping flight. We found that even entire dead insects could stably autorotate depending on their wing postures. Feather removal trials showed no effect on descent velocity when the secondary feathers were removed from hummingbird wings. By contrast, partial removal of wing primaries substantially improved performance, except when only the outer primary was present. A scaling law for the aerodynamic performance of autorotating wings is well supported if the wing aspect ratio and the relative position of the spinning axis from the wing base are included. Autorotation is a useful and practical method that can be used to explore the aerodynamics of wing design.

Setting the boundaries: Primary cell wall synthesis and expansion

Mature plant cells typically have two-layered walls: a first-formed thin outer primary wall layer enclosing a later-formed thick inner secondary wall. The surface area of the primary wall limits the size of the cell and thus the maximum amount of biomass that can potentially be accumulated in the secondary wall. By controlling the shape and size of the cell, the primary wall therefore imposes the limits on the amount of inedible biofuel a plant cell can make.

Large-Scale Patterns of Molt Activation in the Flight Feathers of two Albatross Species

Laysan Albatross (Phoebastria immutabilis) and the closely-related Black-footed Albatross (P. nigripes) replace 20%–90% of their 35–41 wing flight feathers every year. Large-scale molt patterns (patterns between rather than within molt series) account for 77% of the variation in the number of flight feathers replaced. We identified four molt series: series A—the five outer primaries; series B—the five inner primaries plus four outer secondaries; series C—the middle secondaries; and series D—the inner secondaries. A fifth molt series may lie between series C and D. Each year, series A and D initiate molt, but series B and C may or may not initiate molt. The result is four “annual molt patterns”: ABCD, ABD, ACD, and AD. Temporally overlapping waves of molt never occur within series A or B, but about one third of the time they occur within series C and D. Multiple, spatially defined waves of molt (replaced feathers separated by unreplaced feathers) never occur within series A, but occur about two thirds of the time within series B, C, and D. The inner primaries and outer secondaries constitute a single molt series, probably to equilibrate between series total feather length, and thus, total molt duration. Studies of foraging range and reproduction in albatrosses would benefit from the development of species-specific indices of molt duration and extent that are biologically as well as statistically defensible. The number of outer primary feathers replaced and the number of molt series that activate molt are two such indices for Laysan and Black-footed Albatrosses.