Scientific Research and Essays

  • Research Status of Purification Process of Eutrophicated Water

    There are widespread eutrophication problems in lakes and rivers in China. Eutrophication means that the water body receives too much nutrients such as nitrogen and phosphorus, and the organic matter is excessive. When the algae dies, it rots, causing the water quality to deteriorate, thereby causing damage and destruction of the ecological functions of the water, bringing huge use of water resources. loss. While a considerable number of countries or regions use lakes, rivers, etc. as drinking water sources, the problems caused by eutrophication cannot be ignored, and it is urgent to find a reliable and effective method to provide safe water supply. The combination process with ultrafiltration as the core removes algae and has good effects, low energy consumption, simple process and easy control, and has broad application prospects in the future water treatment industry. However, the problem of membrane fouling is still seriously hindering the further development of membrane technology in the water treatment industry.

  • Risk Perception and Evaluation of Supervision: A Study on Chinese Consumer Trust in Food Safety

    Food safety has always been the focus of attention from all walks of life as it has been treated as one of the important indicators of the development of a country, concerning national health, industrial security and social stability. On the basis of empirical data, this study analyzed consumer trust in food safety from the perspective of consumers’ risk perception, consumer behavior and food safety regulation. It is found that consumers’ trust in food safety in China is not optimistic and governance of food safety remains to be improved.

  • Research on Quality Behavior Coordination of Service Manufacturing Network Node Based on AHP and Fuzzy Mathematics

    Service-oriented manufacturing network (SMN) is a network organization model under the background of industrial integration development. Based on the quality coordination characteristics of SMN nodes, the method of hierarchical analysis and fuzzy comprehensive evaluation is introduced to study the cooperative membership of SMN nodes. This paper first constructs a three-dimensional service-oriented manufacturing network node quality behavior coordination index system including collaborative efficiency, collaborative structure and collaborative quality. Secondly, it combines analytic hierarchy process and fuzzy mathematics to determine the optimal membership degree of node indicators. Finally, it is carried out by a textile machinery enterprise. Evolutionary simulation yields the optimal membership node.

  • Concrete Strength Variations of Unwashed and Processed Coarse Aggregate Sizes

    This project aims to determine the effect of different coarse aggregate sizes and type on the compressive strength of concrete. The most important property of concrete is its compressive strength. The exceeding strength of concrete is as a result of the presence of coarse aggregate. Normal concrete is being produced from different types of aggregate and size and this imparts different property to the resulting concrete. The research has established that the coarse aggregates and their sizes play critical roles in the development of adequate strength in concrete. Fine aggregate is normal sand obtained from a borrow pit. Preliminary laboratory investigation was conducted to ascertain the suitability of using the aggregates for construction work. Tests conducted include sieve analysis, bulk density, and specific gravity. From the graph of the sieve analysis for fine and coarse aggregate, the coefficient of uniformity calculated was 1.5 and 3.45 respectively. It was observed that with proper mixing, the slump test results did not witness shear or collapse type of slump rather there were true slump in all cases of the test. The result of the slump test for 12.5mm, 19.5mm, and 25mm coarse aggregate were 60, 100, and 90. The workability decreased with slight differences when the coarse aggregate size was increased. Three different sizes of coarse aggregates with 25mm maximum size for both processed (granite) and sand stone (Local stone) were employed in the investigation, namely; 12.5mm, 19.5mm and 25mm. The grading and relative densities of the aggregates were studied. The mix ratio and water / cement ratio adopted for the study was 1:2:4 and 0.5 respectively. Twelve concrete cubes (72 total) (150mm× 150mm×150mm) were cast for each coarse aggregate size and type of which three were crushed at each maturity age namely; 7, 14, 21 and 28 days. The 28 day strength…

  • Simulation analysis of impact grounding resistance of transmission lines

    In this paper, some methods of lightning protection measures are expounded in this paper, and then the influence of grounding resistance on ground resistance with current changing with current is revised by means of incomplete consideration of the influence factors of the impact grounding resistance in the standard.

  • Research on the application of wheel pile foundation for transmission lines

    Under the action of low pressure, the wheel pile foundation bears most or even all the downward pressure. When the wheel pile foundation is subjected to uplift force, the uplift force is supported by the short pile, and the ring frame and the 4 flange mainly play the role of transfer pulling force, while the main bearing force is short and short pile. When the wheel pile foundation is subjected to horizontal forces, the horizontal force is mainly borne by the flange and the ring frame. Therefore, only downward pressure and horizontal force should be considered for the ring frame and flange, while uplift force should be considered for the design of thin and short piles. The basic design is simple and the transmission path is clear. The ring frame, flange and short pile of the wheel pile foundation are prefabricated. The foundation can take different prefabricated installation methods with the mechanized construction conditions. It can not only guarantee the quality of the concrete slab, but also speed up the construction speed of the foundation. By comparing with the economic technology of the plate foundation, it is found that under the same geological conditions, the use of wheel pile foundation can reduce the concrete earthwork and the increase of the load, the decrease of concrete is also increased, and the amount of steel is saved, and the economic benefit is remarkable.

  • Implementation of IFOC Algorithm for a Three-Phase Induction Motor Embedded on DSP Microcontroller

    Asynchronous machines are well known to have natural limitations because of the highly nonlinearity and complexity of their motor models. To resolve these problems, an indirect field-oriented control (IFOC) algorithm is applied to control the instantaneous electrical quantities such as torque and flux component. Medium-voltage drives are generally based on either voltage-source inverter (VSI) or current-source inverter (CSI). This paper presents a high-performance CSI-fed IFOC method. By the decoupled control of the machine flux and torque, the performance of the conventional direct field-oriented control (DFOC) CSI-fed induction motor drives has improved; however, this scheme presents a low dynamic response and machine parameter dependence. A squirrel-cage induction motor drive system that provides the proposed IFOC algorithm is tested. The IFOC algorithm has a good dynamic performance and stability. Graphs with measured and estimated values of torque and speed are presented. The results demonstrate the efficiency of the proposed torque control embedded on a digital signal processor (DSP) microcontroller.

  • Design and adaptive control of omni-directional mobile platform with four driving wheels

    In this paper, a general kinematic model of the four drive wheel omnidirectional mobile platform is established, and the CMAC (Cerebellar model articulation controller) +PID joint control strategy is used to design the embedded adaptive control of the omnidirectional mobile platform in view of the problem that the conventional control can not be self-tuning online and the real-time response of the response needs to be improved. The MATLAB simulation and experimental analysis of DC motor speed regulation were carried out, and the motion performance of the prototype was tested by a series of typical experiments. The results show that the kinematic model of the mecanum wheel omnidirectional moving platform is reasonable. The dynamic response of the CMAC+PID adaptive controller is fast, the control precision is high, and the robustness is good. The prototype can achieve the horizontal / vertical translation, the original rotation and the omni-directional motion in the plane. The overall performance can meet the requirements of the engineering application.

  • The Importance of Dental Activity in Patients Inside in Intensive Therapy Unit

    Introduction: Poor oral hygiene is common in ICU patients, which leads to colonization of the oral biofilm by pathogenic microorganisms, especially respiratory pathogens, which may be a source of nosocomial infection. Once the bacteria present in the mouth can be aspirated and cause aspiration pneumonia. Objective: Review of the literature regarding the importance of dental intervention in patients hospitalized in intensive care units. Methodology: An integrative review was carried out in the LILACS databases and in the SCIELO Virtual Library, using the descriptors: Dental care, Periodontal diseases and ICU. Inclusion criteria were: full-text articles available in Portuguese or English and with a temporal cut between 2013 and 2017. Results: Three articles were selected to meet the criteria for inclusion. Discussion: The oral cavity is the first portal of entry for respiratory pathogenic organisms that cause systemic infections, with pneumonia being one of them. Aspiration pneumonia is the most common type of nosocomial or hospital pneumonia and is an infection of the pulmonary parenchyma caused by different types of etiological agents including bacteria, fungi and viruses. This disease is of high cost and represents a significant cause of morbidity and mortality, diagnosed 48 hours after the patient’s hospitalization in the ICU. The absence of attention with oral hygiene and the reduction of salivary flow results in an increase in the quantity and complexity of dental plaque, which may favor bacterial interaction between native plaque bacteria and respiratory pathogens such as P. aeruginosa and enteric bacilli. Conclusion: The evaluation of the oral condition and the need for dental treatment in hospitalized patients require follow-up by a dental surgeon qualified in hospital dentistry avoiding an increase in the proliferation of fungi and bacteria and, consequently, infections and systemic diseases.

  • Clinical Conduct for a Bruxist Patient: Clinical Case Report

    Introduction: Sleep bruxism is an activity of stereotyped movements promoted by the subconscious in the masticatory system that includes the functions of clenching and / or grinding, where neuromuscular protection mechanisms are absent, which can lead to damages to the masticatory system and temporomandibular disorders. Aim: This article aims to demonstrate conducts used in a clinical case to assist in similar case planning. Case report: A 58-year-old male patient required an appointment at the Federal University of Pernambuco integrated dentistry clinic, presenting a complaint of pain in the face region and lack of adaptation with prostheses, he had posterior maxillary edentulism, loss of vertical dimension and severe wear on the remaining teeth. The anamnesis was made in his initial clinical examination, later, was prepared the diagnostic wax-up, the waxing was moulded with condensation silicone for restoration in composite resin with prefabricated pins. Afterward the molding were made to prepare removable partial dentures for the patient. In the old prostheses overlays were prepared to slide between them forming a type of plaque, reprogramming the jaw and avoiding that the patient destroyed the already made restorations. In the following session, the well-adapted prostheses were delivered and the occlusal adjustment was properly performed with intraoral test. Results: The patient reported aesthetic improvement, total pain reduction and better adaptation with the prostheses, he also related comfort in using them. Conclusion: It is possible to perform the rehabilitation of partial edentulous bruxers, approximating the patient to his or her centric relation, without the necessity of plaques and maintaining a quality treatment.