Development of a renewable hybrid power plant with extended utilization of pumped storage unit equipment

The scheme of a renewable hybrid power plant with the extended use of the installed equipment of the pumped storage unit for the conversion of the photovoltaic and wind generators direct current to the alternating one is proposed. The scheme is based on existing components with widely used proven technology. To output the power of solar and wind generators to the grid and for DC to AC conversion, a synchronous generator of the pumped storage unit is used in addition to grid inverters. An induction motor, powered through a variable frequency drive from a common DC bus, is used together with a hydraulic turbine to rotate the generator. In addition, batteries and capacitors banks are connected to the DC bus. The possibility of using various types of electric machines to drive a synchronous generator is analyzed and the preference of an induction motor is shown. The response of an induction motor to rotational speed fluctuations is modeled and its capability to participate in the network frequency regulation is shown. With the example of a typical daily load and generation profile, it is shown that the proposed solution for DC to AC conversion has an efficiency close to that of the grid inverter. The proposed scheme of the hybrid power plant can increase the reliability of renewable energy sources and the stability of the network frequency. This is achieved due to increasing the inertia of the rotating masses in the power system, the power factor control capabilities of the synchronous generator and the proper response of induction motor to rapid fluctuations of the rotation speed. The creation of such hybrid power plants opens the way for a further increase in the share of renewable energy sources in the power system.Запропоновано схему гібридної відновлюваної електричної станції з розширеним використанням встановленого обладнання гідроакумулюючого блока для перетворення постійного струму фотоелектричних та вітрових генераторів в змінний. Схема базується на наявних компонентах з широко використовуваною відпрацьованою технологією. Для видачі потужності та перетворення постійного струму сонячних та вітрових генераторів в змінний окрім мережевих інверторів використовується синхронний генератор гідроакумулюючого блоку. Для обертання генератора крім гідротурбіни також використовується асинхронний двигун, підключений через частотно-регульований привод до загальної шини постійного струму станції. Крім того, до шини постійного струму підключені електрохімічні акумулятори і батареї конденсаторів. Проаналізовано можливість використання різних типів електричних машин для приводу синхронного генератора і показано перевагу асинхронного двигуна. Змодельовано реакцію асинхронного двигуна на коливання швидкості обертання і показано його здатність брати участь в регулюванні частоти мережі. На прикладі типового добового графіка навантаження і генерації показано, що запропоноване рішення по перетворенню постійного струму в змінний має ККД, близький до ККД мережевого інвертора. Запропонована схема гібридної станції дозволяє підвищити надійність роботи відновлюваних джерел енергії і стабільність частоти мережі. Це досягається завдяки збільшенню інерції обертових мас в енергосистемі, можливості управління коефіцієнтом потужності синхронного генератора і властивій асинхронному двигуну реакції на коливання швидкості обертання. Створення таких гібридних станцій відкриває шлях до подальшого збільшення частки відновлюваних джерел в енергосистемі

Potensi Objek Wisata Toraja Utara Berbasis Kearifan Lokal sebagai Sumber Materi Geografi Pariwisata

This research focused on the tourism potential of North Toraja based on local wisdom. The method of this study implemented qualitative using ethnography approach. The results showed that (1) the tourism objects in North Toraja are potential in the aspect of culture, nature and history (2) the tourism areas in North Toraja must be under supervised and controlled by Foundations, Farmers, Local Government, and family. (3) Development of tourism objects in the basis of local wisdom supports the continuation of tourism in North Toraja. (4) Tourism in North Toraja based on local wisdom can be used as a source of learning materials for Tourism Geography courses in the Department of Geography, State University of Makassar. The implication of this study will be used a source of support materials Tourism Geography subjects particularly in Tourism Potential Local Content.Penelitian tentang potensi obyek wisata Toraja Utara berbasis kearifan lokal. Hasil dari penelitian digunakan sebagai sumber materi pendukung matakuliah Geografi Pariwisata. Penelitian ini menggunakan pendekatan kualitatif, bertujuan menghasilkan laporan etnografi. Hasil penelitian adalah (1) kawasan obyek wisata Toraja Utara memiliki potensi wisata budaya, alam dan sejarah (2) Pengelola kawasan wisata Toraja Utara diantaranya: Yayasan, Petani, Pemda, dan Keluarga. (3) Pengembangan Objek wisata berbasis kearifan lokal setempat mendukung kelangsungan wisata di Toraja Utara. (4) Wisata Toraja Utara berbasis kearifan lokal dapat digunakan sebagai sumber materi belajar M.k Geografi Pariwisata Jurusan Geografi FMIPA Universitas Negeri Makassar yakni Materi Potensi Wisata lokal

The Effect of Time-Delay Feedback Controller on an Electrically Actuated Resonator

This paper presents a study of the effect of a time-delay feedback controller on the dynamics of a Microelectromechanical systems (MEMS) capacitor actuated by DC and AC voltages. It is shown that negative time-delay feedback control gain can lead to an unstable system, even if AC voltage is relatively small compared to DC voltage. Perturbation method is utilized to present analytically the nonlinear dynamic characteristics of the MEMS capacitor. Agreements among the results of a shooting technique, long-time integration, basin of attraction analysis with the perturbation method are achieved

Perilaku Ibu Terhadap Pertumbuhan Balita Dalam Permasalahan Stunting Dan Pencegahannya Di Desa Torosiaje Jaya

The growth process experienced by toddlers is a cumulative result since the toddler was born. From various studies on stunting and existing literature it is known that in addition to infection, stunting is also associated with nutritional deficiencies (micronutrients and macronutrients). There are several nutrients related to stunting such as protein, iron, zinc, calcium, and vitamins D, A and C. at the family level, especially for poor families, low family access to basic health services, and disparities between provinces that need to be addressed specifically for problems in vulnerable areas.6,9,10 Stunting is a sensitive indicator for poor socioeconomic conditions and predictors for long-term morbidity and mortality. Stunting in early childhood is reversible. 1

Ionospheric Effects on GPS Signal in Low-Latitude Region: A Case Study Review of South East Asia and Africa

The ionosphere is a significant source of errors affecting L-Band (1-2 GHz) signal propagation using Global Position System (GPS). The propagated GPS signals that passes through the Earth’s atmosphere where affected by ionosphere and troposphere irregularities and caused the signal propagation delay. However, the velocity of signals that propagate within the atmosphere deviates from vacuum line of sight (LOS), while the refractivity of ionosphere and troposphere influence the signal propagation delay causing atmospheric effects due to high electrons density.  Both affect the signal in different ways due to their particular refractive properties. The review focuses of some of the previous research studies conducted on empirical modeling of the ionospheric effect in low latitude region. The tabulated findings of such models presented in this article.http://dx.doi.org/10.4314/njt.v34i3.1

STATEGI PEMULIHAN USAHA PARIWISATA MICE DI KOTA PAREPARE

Tujuan penelitian ini mengetahui Potensi Kota Parepare sebagai wisata MICE dimasa transisi kenormalan baru. Penelitian menggunakan metode deskriptif kualitatif. Teknik pengumpulan data dalam penelitian ini menggunakan observasi, wawancara dan dokumentasi. Analisis data dengan langkah pengumpulan, reduksi, dan penyajian data, serta penarikan kesimpulan. Berdasarkan hasil penelitian ditemukan bahwa potensi wisata MICE di Kota Parepare mempunyai prospek yang sangat baik dengan berbagai potensi wisata alam dan wisata buatan serta berbagai macam atraksi budaya yang bisa ditampilkan ketika diselenggarakannya event. Pandemi Covid-19 telah berdampak di sector pariwisata yang mengalami penurunan. Dimasa post Covid-19, pemerintah Kota Parepare menyiapkan strategi dalam rangka pemulihan sektor pariwisata

Trichoderma harzianum in combination with sheep manure amendment enhances soil suppressiveness of Fusarium wilt of tomato

The effect that the biocontrol agent Trichoderma harzianum (isolate Jn14) in combination with an amendment of sheep manure has on the soil suppressiveness of Fusarium wilt of tomato was investigated over a 28-month period. A combination of T. harzianum and organic amendment at concentrations (w:w) of 6 and 10% reduced tomato wilt by 21–36 % and 29–36% respectively, after 0–28 months of soil incubation. When the amendment was added at concentration of 2%, the wilt was suppressed only after 18–28 months. A combination of T. harzianum and the amendment at 6% also increased tomato plant fresh weights by 52% after 28 months, and the 10% amendment increased fresh weights by 56, 40, and 63%, after 18, 24, and 28 months respectively, compared to the experimental controls. Organic amendment at the higher concentrations further stimulated T. harzianum populations, enhanced microbial activity against Fusarium oxysporum in the soil and reduced pathogen populations. Without T. harzianum, the organic amendment at a concentration of 10% reduced disease by only 22, 24, and 23% and only after 18, 24 and 28 months of soil incubation respectively, compared with the controls. However, tomato wilt was not reduced at a 2% manure concentration in less than 12 months of incubation. Organic amendment alone at 6 and 10% reduced the pathogen population by 25% and 37% respectively after 28 months of soil incubation compared with the control. T. harzianum produced fungitoxic metabolites that reduced mycelial growth of Fusarium by 37% and conidium germination by 55% when the pathogen was grown on potato dextrose agar amended with a T. harzianum culture filtrate

Biological control of Egyptian broomrape (Orobanche aegyptiaca) using Fusarium spp.

The broomrape (Orobanche spp.) is an obligate holoparasitic weed that causes severe damage to many important vegetable crops. Many broomrape control strategies have been tested over the years. In this investigation, 125 Fusarium spp. isolates were recovered from diseased broomrape spikes collected from fields in agricultural areas near Hebron. The pathogenicity of isolates on broomrape was evaluated using an inoculum suspension containing mycelia and conidia. The most effective Fusarium isolates significantly increased the dead spikes of broomrape by 33.6–72.7% compared to the control; there was no obvious pathogenic effect on the tomato plants. Fusarium spp. isolates Fu 20, 25 and 119 were identified as F. solani, while Fu 30, 52, 59, 87 and 12-04 were F. oxysporum. In addition, the two previously known Fusarium strains, F. oxysporum strain EId (CNCM-I-1622) (Foxy) and F. arthrosporioides strain E4a (CNCM-I-1621) (Farth) were equally effective in controlling broomrape parasitizing tomato plants grown in pots, where the dead spikes of broomrape increased by 50.0 and 51.6%, respectively

Structure and age-dependent growth of the chicken liver together with liver fat quantification: A comparison between a dual-purpose and a broiler chicken line

Rearing dual-purpose chickens is a practicable approach to avoid culling one-day-old male layer chicks. The present study examined the impact of a conventional fattening diet on the liver of a novel dual-purpose chicken line (Lohmann Dual, LD) in comparison to a broiler (Ross 308) chicken line. Age-related changes of structure and lipid content of the liver were assessed. One hundred twenty and newly hatched chicks (LD = 66, Ross = 54) were kept under the same husbandry conditions and fed a commercial diet for 5 weeks for Ross and 9 weeks for LD. Six birds of each line were examined weekly. Their body weight (BW) and liver mass were recorded. Microscopic structure and ultrastructure of the liver were investigated and the liver lipid content was measured using a pre-validated method. During the study period, liver mass increased with age, while normalized liver mass decreased. Furthermore, liver mass of Ross birds was greater than that of LD birds of the same BW. Overall, no significant differences were observed in the hepatic structure or ultrastructure between the two chicken lines. The hepatic lymphatic aggregations were without fibrous capsules and their number and area increased throughout the first week, then the values began to fluctuate with age in both chicken lines. The changes in the liver lipid content of the two chicken lines were within the normal physiological range over the term of the study. The liver lipid content correlated negatively with age and body weight in both lines. It was the highest on the first day then decreased until day 7 and thereafter did not change in both chicken lines. However, given the same body weight, the Ross chickens had a 9% greater liver lipid content than LD chickens. It is concluded that there is no apparent adverse effect of a high-energy diet on the liver of LD chickens