Analytical and finite-element study of optimal strain distribution in various beam shapes for energy harvesting applications

Due to the increasing demand for harvesting energy from environmental vibration, for use in self-powered electronic applications, cantilever-based vibration energy harvesting has attracted great interest from various parties and become one of the most common approaches to convert redundant mechanical energy into electrical energy. As the output voltage produces from a piezoelectric material depends greatly on the geometric shape and the size of the beam, there is a need to model and compare the performance of cantilever beams of differing geometries. This paper presents the study of strain distribution in various shapes of cantilever beams, including a convex and concave edge profile elliptical beams that have been overseen in most of the prior literature. Both analytical and finite element models are derived and the resultant strain distributions in the beam are computed based on MATLAB solver and ANSYS finite element analysis tools. An optimum geometry for a vibration-based energy harvester system is verified. Lastly, experimental results comparing the power density for a triangular and rectangular piezoelectric beams are also presented to validate the finding of the study and the claim as suggested in the literature is verified

Machine learning based lightweight interference mitigation scheme for wireless sensor network

The interference issue is most vibrant on low-powered networks like wireless sensor network (WSN). In some cases, the heavy interference on WSN from different technologies and devices result in life threatening situations. In this paper, a machine learning (ML) based lightweight interference mitigation scheme for WSN is proposed. The scheme detects and identifies heterogeneous interference like Wifi, bluetooth and microwave oven using a lightweight feature extraction method and ML lightweight decision tree. It also provides WSN an adaptive interference mitigation solution by helping to choose packet scheduling, Acknowledgement (ACK)-retransmission or channel switching as the best countermeasure. The scheme is simulated with test data to evaluate the accuracy performance and the memory consumption. Evaluation of the proposed scheme’s memory profile shows a 14% memory saving compared to a fast fourier transform (FFT) based periodicity estimation technique and 3% less memory compared to logistic regression-based ML model, hence proving the scheme is lightweight. The validation test shows the scheme has a high accuracy at 95.24%. It shows a precision of 100% in detecting WiFi and microwave oven interference while a 90% precision in detecting bluetooth interference

Effect of Permeable Vessel Closure and Gelling Agent on Reduction of Hyperhydricity in in Vitro Culture of Carnation

Hyperhydricity, an abnormal morphological appearance and physiologicalfunction, is an important problem in carnation tissue culture. The problem causes premature flowering, high occurrence of abnormal shoots, difficulty in transferring hyperhydric plantlets to soil, and low survival rate of plantlets. High relative humidity and the water potential are considered as the key factors involved in the abnormality. Furthermore, permeable culture vessel and gelling agent were assured to be high potential treatment to eliminate it. Objective of this research was to reduce hyperhydricity in regenerants of carnation using different permeable vessel closures and gelling agents and to assess the multiplication and acclimatization abilities of recovered shoots. Experiment was arranged in randomized complete block design with four replications. First factor was different types of closure, i.e. cotton wool, plastic wrap, parafilm and aluminium foil, while second one was gelling agents, i.e. bacto agar, phytagel, swallow agar, and Type 900 agar. The recovered shoots were then multiplied, rooted, and acclimatized. The results showed that hyperhydricity was successfully reduced by applying permeable closure (cotton wool and plastic wrap) in combination with Type 900 agar. The combination of plastic wrap and Type 900 agar was the most appropriate treatment in reducing hyperhydricity and producing good quality shoots. The treatment reduced the problem down to 23% of total condition of hyperhydricity (100%) and increased leaf chlorophyll content from 0.0883 to 0.1288 mg mg-1. The plastic wrap was easily applied and cheaper material compared to cotton wool. The recovered shoots were able to produce 1-3 healthy axillary shoots and easily rooted on half-strength MS. The recovered plantlets were simply acclimatized with survival rate up to 100% on kossas peat + soil (1:1, v/v) and flowered 4-5 months after acclimatization with decreasing in number and size of flower

Perbanyakan Anyelir Secara in VI Tro Melalui Induksi Pembentukan Tu Nas Adventif

Perbanyakan anyelir secara in vi tro melalui induksi pembentukan tu nas adventif sangat potensial untukproduksi masal bahan tanaman. Penelitian ini bertujuan untuk mendapatkan teknik perbanyakan secara in vi tro yangsesuai untuk D. caryophyllus L. cv. Mal dives melalui pembentukan tu nas adventif, penggandaan tu nas, pengakaran,dan aklimatisasinya. Penelitian dilakukan di Laboratorium Kul tur Jaringan, dan rumahkaca IPPT, UPM, Ma lay siadari bulan Mei 2000 hingga No vem ber 2001. Tiga jenis eksplan (daun muda pertama, kedua, dan internodus muda)dan me dia MS dengan lima konsentrasi BA dan NAA yang berbeda (2,0 mg/l + 0,9 mg/l, 0,9 mg/l + 0,3 mg/l, 3,0 mg/l +0,9 mg/l, 0,1 mg/l BA + 0,1 mg/l, dan 0,1 mg/l + 0,01 mg/l) diseleksi, diikuti dengan perbanyakan tu nas pada me diaterseleksi, pengakaran dan diaklimatisasi pada me dia yang berbeda. Percobaan menggunakan rancangan acakkelompok pola faktorial dengan empat ulangan. Hasil penelitian menunjukkan bahwa daun muda pertama yangberkembang penuh dan me dia MS yang mengandung 0,1 mg/l BA dan 0,01 mg/l NAA merupakan eksplan dankonsentrasi hormon yang sesuai untuk induksi pembentukan tu nas adventif. Konsentrasi tersebut juga sesuai untukmempersiapkan tu nas yang diakarkan. Tu nas mudah diakarkan pada me dia setengah MS. Plantlet mudahdiaklimatisasikan pada me dia campuran antara hu mus dan arang sekam (1:1 v/v) dengan ketahanan hidup hingga100%. Me dia tersebut juga menghasilkan plantlet yang vigor dan tumbuh cepat. Abnormalitas tanaman adalah 6%dari to tal plantlet yang diaklimatisasikan. Tanaman berbunga pada 4,5 hingga 5 bulan setelah aklimatisasi. Hasil studiini diharapkan dapat digunakan sebagai salah satu acuan dalam perbanyakan masal anyelir melalui induksi tu nasadventif. In vi tro prop a ga tion of car na tionthrough in duc tion of ad ven ti tious shoot for ma tion. The tech nique has an im por tant role in mass pro duc tion ofplant ing ma te rial. The ob jec tive of this study was to ob tain suit able in vi tro prop a ga tion of D. caryophyllus L. cv. Mal -dives through in duc tion of ad ven ti tious shoot for ma tion, fol lowed by mul ti pli ca tion of shoots, root ing and ac cli ma ti -za tion. The study was con ducted at Tis sue Cul ture Lab o ra tory and Glass house of IPPT, UPM, Ma lay sia from Mei2000 to No vem ber 2001. Three dif fer ent types of explant (first and sec ond young fully de vel oped leaves and younginternodus) and MS me dium at five dif fer ent con cen tra tions of BA and NAA (2.0 mg/l + 0.9 mg/l, 0.9 mg/l + 0.3 mg/l,3.0 mg/l + 0.9 mg/l, 0.1 mg/l + 0.1 mg/l dan 0.1 mg/l + 0.01 mg/l were se lected, shoots ob tained from the sys tem weremultiplied, rooted and acclimatized in different media. Factorial experiment was arranged in randomized com pleteblock de sign with four rep li ca tions. Re sults of the ex per i ment ex hib ited that the first young fully de vel oped leaves andMS me dium con tain ing 0.1 mg/l BA and 0.01 mg/l NAA was the ap pro pri ate explant and con cen tra tion of BA andNAA to pro duce high est num bers of ad ven ti tious shoot. The con cen tra tion of BA and NAA was also suit able for pre -par ing rooted shoots. Shoots were eas ily rooted on half-strength of MS me dia. Plantlets were sim ply ac cli ma tized in amix ture me dium of kossas peat and paddy char coal (1:1 v/v) with 100% of sur viv abil ity. Vig or ous and healthyplantlets were also re sulted in the me dium. Ab nor mal ity of plants was 6% from to tal ac cli ma tized-plantlets. Theplantlets flow ered at 4.5 to 5 months af ter ac cli ma ti za tion. The re sults ex pected can be used as a stan dard pro to col inmass-pro duc tion of car na tion through ad ven ti tious shoot for ma tion

Walking football during Ramadan fasting for cardiometabolic and psychological health benefits to the physically challenged and aged populations

Concurrent exercise and intermittent fasting regimens for long periods have been shown to enhance cardiometabolic health in healthy individuals. As exercise and fasting confer health benefits independently, we propose that Muslims who are fasting, especially those experiencing health and clinical challenges, continually engage in physical activity during the Ramadan month. In this opinion piece, we recommend walking football (WF) as the exercise of choice among Muslims who are fasting. WF can be played by any individual regardless of the level of fitness, skills, and age. WF has been shown to elicit cardiovascular and metabolic stress responses, which are suitable for populations with low fitness levels. Most importantly, WF has the inherent characteristics of being a fun team activity requiring social interactions among participants and, hence, likely to encourage long-term consistent and sustainable participation

Characterization of the Inlet Port Flow under Steady-State Conditions Using PIV and POD

The current study demonstrates an experimental investigation of the tumble flow structures using Particle Image Velocimetry (PIV) under steady-state conditions considering the central vertical tumble plane. The experiments were carried out on a four-valve, pent-roof Gasoline Direct Injection (GDI) engine head at different valve lifts and with a pressure difference of 150 mmH2O across the intake valves. Furthermore, the Proper Orthogonal Decomposition (POD) analytical technique was applied to PIV-measured velocity vector maps to characterize the flow structures at various valve lifts, and hence the different rig tumble values. The results show that at low valve lifts (1 to 5 mm), 48.9 to 46.6% of the flow energy is concentrated in the large (mode 1) eddies with only 8.4 to 11.46% in mode 2 and 7.2 to 7.5 in mode 3. At high valve lifts, it can be clearly seen that some of the energy in the large eddies of mode 1 is transferred to the smaller flow structures of modes 2 and 3. This can be clearly seen at valve lift 10 mm where the values of the flow energy were 40.6%, 17.3%, and 8.0% for modes 1, 2, and 3, respectively

Cogging Force Issues of Permanent Magnet Linear Generator for Electric Vehicle

Alternatives to hydraulic drives that used on vehicles are necessary in order to reduce the Carbon dioxide (CO2) emission and oil consumption. Hence better performance and efficiency of the vehicles can be achieved by using free piston engine, in which the piston reciprocate linearly with a permanent magnet linear generator (PMLG) without the need of a crankshaft. The PMLG has high performance, but suffering from the cogging force. The cogging force induces undesired vibration and acoustic noise and makes a ripple in the thrust force. Moreover, the cogging force deteriorates the control characteristics, particularly in terms of the position control and speed precisely. This paper proposes Somaloy to replace the laminated silicon steel sheets in order to reduce the cogging force in a PMLG. Through a finite-element analysis, it has been shown that, the stator core made of Somaloy minimizes the cogging force of the PMLG, moreover, giving larger flux-linkage and back-electromotive force (B-EMF), respectively