Pacific Science Review A: Natural Science and Engineering最新文献

Heating, Ventilating and Air Conditioning Systems (HVAC) are applied for primarily cooling purpose as well as to maintain quality of air. Since, most of the HVAC company has lack of data for the designing purpose – leads to uncomforting. Less standardization in designing criteria of HVAC Systems (Except ASHRAE which provides data for refrigeration systems) leads to write this paper. There is no any sources available that can exactly says how to design an energy efficient HVAC Systems. This paper provides the mathematical aspects for designing the HVAC Systems. This paper includes the process of designing HVAC with components by using mathematical framework – confirmed by software. This paper provides proper selection of capacity of systems and life cycle cost analysis too. For the simplicity of understanding, we have provided a demonstration with the example of 1000 seats auditorium situated at Vadodara, Gujarat. As the result of this designing, we got an emission free HVAC Systems with low GWP (Global Warming Potential) and ODP (Ozone Depletion Potential) – providing best comfort condition with reduction trunk duct arrangement and low life cycle cost. However production side of the Ducting Systems will become more expensive and complex due to numbers of joints and duct sizes but after applying it properly – better performance and less frictional losses lead the system to high Energy Efficiency Ratio (EER).

Equipment for treatment of rice seeds by laser radiation is designed. The equipment was tested in Emzun (DPRK) with different varieties of rice, namely, Pyongyang 49 and Pyongyang 20. As a result of the laser treatment, the germination of the rice seeds was increased on average by 10–16%, whereas the incidence of seeds was decreased.

Entomopathogenic fungi are well-known biological control agents of insects that have broadly replaced the chemicals used in biopesticides for agricultural purposes. The pathogenicity of entomopathogenic fungi depends on the ability of its enzymatic equipment, consisting of lipases, proteases and chitinases, which degrade the insect's integument. Additionally, the researchers studied the content of β-galactosidase, -glutaminase, and catalase within entomopathogenic fungi. With highly focused investigations on the use of enzymes for green technology, the group of entomopathogens are slowly gaining applications in these areas, even as phytopathogenic fungi (disease originator). This brief review will serve as a reference of the enzymes derived from entomopathogenic fungi and of their current and potential applications.

Today, the world is witnessing more interest in robotics and their application in various fields, such as medicine. Enhancing accuracy, increasing speed of operation and reducing costs are the primary performance objectives in the improvements to design and manufacture of devices or robots. One of the best ways to achieve these aims is using devices or robots instead of human resources. The injection pump we designed and manufactured in this work is a type of robot that has applications in medicine and health centres. This device is used for patients who are unable to receive foods and drugs orally. By examining similar foreign devices in Ardebil health centres, studying their advantages and disadvantages, and researching health centre requirements for these devices, we designed and constructed such a device for the first time in this country. The most important items achieved in these investigations include time, accuracy, speed of drug injection and cost reduction. The shortest time we achieved using this device was approximately 6 s for 1 cc of drug or fluid. We also calculated the speed of injection for 1 cc of drug to be approximately 0.17 cc per second, which was an ideal value compared to that of similar foreign devices. In comparison to the cost of similar foreign devices, our device has a lower cost due to simplicity and high performance. To achieve these results, we designed a new device engine. In this design we used a three-step engine that has a different algorithm than similar devices. In this engine, every cc was injected in 2000 steps of the engine, and each step was 3 ms, achieving 6 s for each cc of injection.

Neem (Azadirachta indica) is widely used in the Ayurvedic medicine system for treating malaria and fever. The present study was undertaken to prepare crude extracts of neem leaves with different polarity organic solvents by using a maceration method and assessing phytochemical screening, the total phenol content and antioxidant activity by the spectroscopic method. The leaf samples collected from the Bahla, Ad Dakliyah region were used for extraction by a maceration method using different organic solvents with increasing polarities. Biochemical screening was determined by established methods. The total phenol content and free radical scavenging activity were assessed by conventional Folin–Ciocalteu reagent (FCR) and α, α-diphenyl-β-picrylhydrazyl (DPPH) methods. Biochemical screening of the crude extracts of neem leaves revealed positive results of flavonoids, saponins, steroids, alkaloids, amino acid and tannins. However, triterpenoid and anthraquinone were not detected in the crude extracts of neem leaves. The total phenol content of crude extracts from the leaves of the plant selected to be the gallic acid equivalent was found to be the highest in the ethyl acetate extract containing phenol compounds (3.58 g/100 g of dry powder) and the lowest in the water extract (0.42 g/100 g of dry powder). The highest antioxidant activity was found in the butanol extract and the lowest was in the hexane extract of the plant selected to be equivalent to DPPH. The crude extracts of neem showed significant antioxidant activity; thus, these extracts could be used as natural antioxidants for the preparation of medicines to treat different diseases.

The structure of the barotropic component of oceanic currents is discussed. First, we present observational evidence against the absence of the vertical shear of horizontal velocity in barotropic flows. We then discuss the Taylor-Proudman theorem, which we base our presumption on. We show that this theorem crudely neglects nonlinear terms of fluid motion equations either through geostrophic approximation or directly through a scale analysis of the vorticity transport equation. However, these terms serve as a mechanism allowing for the vertical shear of horizontal velocity.

The importance of long-term load forecasting in the power industries cannot be over-emphasised, as it provides the industries with future power demand that may be useful in generating, transmitting and distributing power reliably and economically. In recent times, many techniques have been used in load forecasting, but artificial intelligence techniques (fuzzy logic and ANN) provide greater efficiency compared to conventional techniques (e.g., regression and time series). In this paper, a fuzzy logic model for long-term load forecasting is presented. A fuzzy logic model is developed based on the weather parameters (temperature and humidity) and historical load data for the town of Mubi in Adamawa state to forecast a year-ahead load. The fuzzy logic model forecast a year-ahead load with a MAPE of 6.9% and efficiency of 93.1%. The result obtained reveal that the proposed model is capable of predicting future load.

Electronic spam is the most troublesome Internet phenomenon challenging large global companies, including AOL, Google, Yahoo and Microsoft. Spam causes various problems that may, in turn, cause economic losses. Spam causes traffic problems and bottlenecks that limit memory space, computing power and speed. Spam causes users to spend time removing it. Various methods have been developed to filter spam, including black list/white list, Bayesian classification algorithms, keyword matching, header information processing, investigation of spam-sending factors and investigation of received mails. This study describes three machine-learning algorithms to filter spam from valid emails with low error rates and high efficiency using a multilayer perceptron model. Several widely used techniques include C4.5 decision tree classifier, multilayer perceptron and Naïve Bayes classifier, all of which are used for training data whether in the form of spam or valid emails. Finally, the results are discussed, and outputs of considered techniques are examined in relation to the proposed model.

The chemical and biological activities of crude extracts of Andrographis echioides leaves using petroleum (pet) ether, ethyl acetate, methanol and aqueous solvents were assayed.

The total phenol, flavonoid, protein and carbohydrate contents of A. echioides crude extracts were evaluated. The antioxidant activities of the leaf extracts were determined by 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), hydrogen peroxide, metal chelating, reducing power and total antioxidant activity assays. In addition, the crude extracts were screened for antibacterial activity (gram-positive and gram-negative bacteria) by disc diffusion method and the minimum inhibitory concentration was determined.

Of the crude extracts tested, the pet ether extract of A. echioides contained more total phenols (0.01955 ± 0.0012 mg/g), flavonoids (1.2889 ± 0.3606 mg/g) and proteins (1.6065 ± 0.160 mg/mL). The aqueous extract of A. echioides was enriched for carbohydrate (467.6 ± 0.003 mg/mL). The methanol extract of A. echioides exhibited potent antioxidant activity IC50 values (1.14 ± 0.06 to 1.15 ± 0.45 μg/mL), as well as antibacterial activity (16 ± 1.527 mm), than the aqueous extract of A. echioides (20 ± 1.527 mm).

A. echioides has great potential as a source of anti-cancer compounds due to its high antioxidant content and antibacterial activity.

The present work focuses on the dynamics of a two prey and one predator model where the preys are subjected to the logistic growth law and the predator is subjected to the mortality rate and intra specific competition. The effects of time delay and random environmental fluctuations on the stability of the model around the interior equilibrium point are analytically tested using classical mathematical tools. The stable, periodic and chaotic behaviours of the model for different sets of chosen parameters are explored in numerical simulations.