ajer research - Independent Researcher (original) (raw)

Papers by ajer research

The electronic band structure and vibrational properties of SiP 2 and SiAs 2 have been calculated... more The electronic band structure and vibrational properties of SiP 2 and SiAs 2 have been calculated within the framework of the density functional theory (DFT) and the density perturbation functional theory (DPFT) respectively. For exchange and correlation, the local density approximation was used. The structural optimization results agree well with experiment. The calculation showed that both materials are semi-metals with negative band gap values of-0.91 eV and-1.14 eV for SiP 2 and SiAs 2 respectively. The highest frequency mode was observed to be one of the triply degenerated mode T g with vibrational frequency value of 487 cm-1 for SiP 2 and 442 cm-1 for SiAs 2 .

In this work, itwas qualitative measuredthe microstructure of the HAZ(Heat Affected Zone)and WZ(W... more In this work, itwas qualitative measuredthe microstructure of the HAZ(Heat Affected Zone)and WZ(Weld Zone) of AISI 304L Stainless Steel by the GMAW (Gas Metal Arc Welding) processpulsed,using the singlebead-on-plate procedure.For this purpose,was used GMAW process (Gas Metal Arc Welding) was in singlepass deposition on plate of this steel 304L. After the welding process it was observed that the transfer occurred (metal transfer)exercised important effect on some on some properties of the weld joint, such as directing of the grains, inter dendritic spacing and microhardnessVickersduring the welding. In the Centre of the weld bead,heat flow and dendritics structures andthe microstructure is predominantly ferrite and with austeniticas lines because the steel is predominantly austenitic.Growth in weld joints is, being an epitaxial phenomenon, where the grains of the WZ increase with the same crystalline orientation of the grains of the HAZ, as if the grains were planted in BM.

Cooperative communications has recently granted a great attention. High Altitude Platform assiste... more Cooperative communications has recently granted a great attention. High Altitude Platform assisted cooperative spectrum sensing (HAP-ACSS) is adopted as a step towards achieving this goal. This research employ High altitude platform HAP with smart database fusion center FC to control spectrum assignment to secondary users SU according to available spectrum and the received signal to noise ratio SNR from surrounded secondary user equipment SUE. Base station is equipped with Received Signal Strength Indicator (RSSI) and channel allocation mechanism to handle its assigned channels between licensed primary users PU and SUs within the cell. With the aid of collected BSs-RSSI measurements, SU and PU registered information and the other collected information from all BSs in HAP coverage range, the FC can collect the sparse SUE transmitted power and translate it into a spatial spectrum distribution. The proposed network configuration with adopted algorithm is explained, and a simulation of SU localization is provided. The adopted scheme is promising to help the mobile network achieving significantly improved performance with the coexistence of SUs acquiring to share PU spectrum.

Pattern recognition and classification tasks use machine learning that require a suitable represe... more Pattern recognition and classification tasks use machine learning that require a suitable representation of the pattern. Non-negative matrix factorization (NMF) has to be a useful decomposition and representation of multivariate data pattern. Two different multiplicative algorithms for NMF are analyzed. In this paper, we extend the original NMF to 2-Dimensional kernel non-negative matrix factorization (2DKNMF) to improve its performance. 2DKNMF algorithm is derived based on nonlinear kernel function to map patterns to feature space and stepwise method is applied on each individual pattern in feature space to avoid complex computations. The advantages of 2DKNMF algorithm are based on extract more useful feature hidden in the original pattern and it can process data with negative values by using some specific distribution kernel functions. Experimental results on several face databases show that 2DFNMF has better image reconstruction quality than NMF. Also the running time of 2DFNMF is less, and the recognition accuracy higher than that of NMF.

Iron ore is the mineral mineral resource extracted in greater volume from the Earth's crust being... more Iron ore is the mineral mineral resource extracted in greater volume from the Earth's crust being the main raw material used in the steel industry. Research carried out in the period from 2010 to 2015 by the Center for Management and Strategic Studies, titled "steel industry in Brazil", emphasizes that there is a great expectation in raising the levels of phosphorus and alumina in ores to be worked. Iron ore when found with phosphorus contents above 0.05% is considered reject due to its interference in the steel making it increase its hardness and causing its fragility. Therefore, an alternative route of higher efficiency for the production of iron ore concentrates with ultra-low phosphorus is required when compared to the current routes used by the mines (minimum 50% of the levels currently practiced). Therefore, the present work intends to evaluate an integrated route using the acid percolation process in iron ore sample located inside a conventional furnace (acid baking), with the optimum values being the mass values of sulfuric acid in analytical concentration in the proportion 05-1 of iron ore for 30 minutes inside the furnace at 1500C followed by the leaching process in water for 20 minutes where near 100% phosphorus extraction values were reached.

For 2-D vector maps, reversible fragile watermarking is mainly used to protect the integrity and ... more For 2-D vector maps, reversible fragile watermarking is mainly used to protect the integrity and authenticity content of the data. The proposed scheme in this research is introduced in two stages. The first stage will explain how to extract the vector map characteristics embeds them and marks the location of each spatial feature, divides the features of a vector map into blocks; these blocks are then divided into non overlapped equal segments. The integrity watermark for each block is divided into two parts: content authentication and zooming authentication. The zooming authentication is performed by identifying any 2D scaling attempt. The scaling attempt is detected by using the calculated area of a planar non-self-intersecting polygon with arrays of the x and y coordinates of the vertices, traced in a clockwise direction. The second stage in the presented model will explain how to identify and locate tampered features and tampered regions. After this part is completed, it will be integrated other components to establish the complete Digital Watermarking Scheme for Vector Maps.

This study aimed at the reuse of coal ashes produced in Brazil to increasesustainability. Results... more This study aimed at the reuse of coal ashes produced in Brazil to increasesustainability. Results obtained for zeolite synthesis using Brazilian mineral coal ashes at ambient temperature and pressure are reported. The results indicate that the application of ambient temperature at the evaluatedNaOHconcentrations and times resulted in the synthesis of a Na-X (type FAU) zeolite from the ash dissolution. This indicates that zeolite formation is influenced by the process variables. An increase in synthesis time, as well as of NaOH concentrations,in thezeolitic phases resulted in an increase in the ion exchange capacity of the final product.In experiments with 6 M NaOHduring 30 days of reaction, the beginning of the formation of the mineralogical phase of zeolite X was observed. XRD results indicated the transformation of the ashes into zeolite X with increased reaction time, whileSEM micrographs elucidated morphological changes. BET results demonstrate that increases in surface area influencdmanganese cation adsorption properties.

Abstract: The paper, assessing the laboratory safety and security skills among science technology... more Abstract: The paper, assessing the laboratory safety and security skills among science technology and mathematics (STM) teachers in Sokoto State examines STM teachers skills in the state of the art procedures and practices. Descriptive survey design was adopted for the study. A sample of ninety (90) teachers of the core science subjects was selected through stratified random sampling method from the population of science teachers in Sokoto State. Three research questions were answered. Findings of the study indicated that the science laboratories in Sokoto State lack the most essential safety devices. The study also revealed that STM teachers in Sokoto State are safety conscious but they lack the skills for good planning of laboratory activities. Based on the findings of the study, it was recommended among others that there should be effective teacher preparations and training programme that emphasizes on the acquisition of skills, and competencies as against the current system of training which is theoretically oriented.

ABSTRACT: Drying is a determinant process to produce high quality white pepper. This study explor... more ABSTRACT: Drying is a determinant process to produce high quality white pepper. This study explored the utilization of the YSD-UNIB solar dryer to produce dry white pepper grains, aiming to determine the model of the curve of the relationship between moisture content and drying time, to predict the drying time to complete the drying process with respect to the placement of grains on the racks and the thickness of the grains layer, and to describe the resulting grains by using the Indonesian National Standard of white pepper. The results of the experiments showed that the drying air temperature was 12.15oC higher than the ambient air temperature, and the drying air relative humidity was 35.66% lower than the ambient air relative humidity. The solar drying process was 2.17 h faster than the sun drying. The average drying time varied from 12.8 h to 10.0 h from the lower rack to the upper rack, and varying the thickness of the grains layer from 2 cm to 8 cm the average drying time increased 8.7 h to 14.4 h. The dry pepper grains produced by the solar drying was qualified for Grade II but by sorting the unfilled out grains to meet the threshold of less than 1%, the grains from the 2 cm and 4 cm thickness of the grains layers were qualified for Grade I. The suggestion was made to employ the thickness of the grains layers of 4 cm and 8 cm in drying the white pepper for the world markets and the domestic markets respectively.

ABSTRACT: Indoor air pollution sources are divided into two groups as biological resources and no... more ABSTRACT: Indoor air pollution sources are divided into two groups as biological resources and non-biological resources.Bacteria, fungi, mold, viruses, pollen and their fragments have been identified as biological resources.Non-biological resources are determined by different type of gases, particulate matter anddust generated by smoking, heating and cooling systems, building materials and cooking.Presentstudy undertaken in different indoor environments of Ankara to identifing the effects of human activity on indoor airpollutantsinside the flats during 2 years. Concentration of bacteria and fungi identified inside of 119 flats in Ankara city. Also different types of human activities that affect concentration of bacteria and fungi in indoor environments of flats were aimed. Concentration ofbioaerosols was measured by NIOSH Method-0800. According to the obtained results, different human activities such as; number of individuals living at home, ventilation status andnumber of people smoking insideflats severely affect the concentration of bacteria and fungi in an indoor environment. As a result, statistical relationship between concentration of bacteria and fungi and human activity were found in indoor environments.

ABSTRACT: In this article the Differential Transform method is employed for obtaining solutions f... more ABSTRACT: In this article the Differential Transform method is employed for obtaining solutions for initial value problems. This method gives the series of solutions which can be easily converted to exact ones. The differential transform method was successfully applied to initial value problems. The findings of the study has demonstrated that the method is easy , effective and flexible. The results of the differential transform method is in good agreement with those obtained by using the already existing ones. The proposed method is promising to a broad class of linear and nonlinear problems.

ABSTRACT : The meeting between the Europeans and the Küküa, initially based on good neighborly re... more ABSTRACT : The meeting between the Europeans and the Küküa, initially based on good neighborly relations, ended in a total occupation of the territory by the Europeans. The Kibami becaming masters had subjected the Küküa to hard work. The loss of their cultural identity led to acculturation and disorganization of Küküa society. The European presence had led to a generation conflict. The younger generation, who had adhered to the ideas of the newcomers, was at odds with their elders. All classes were forced to work with the Kibami. The latter had installed the Mfumu at the head of each land, spreading the new policy throughout Küküa territory. The grouping of lineages and villages had pushed Kibami to set up the governing bodies acquired for its cause. Kibami sowed desolation throughout Küküa society.

ABSTRACT: Standalone PV system with hybrid energy storage could be a promising solution for power... more ABSTRACT: Standalone PV system with hybrid energy storage could be a promising solution for powering up off-grid or that have no access to grid electricity. The objective of the control of this hybrid energy storage standalone PV system is to maintain the stability of the DC bus voltage, at the same time to supply the desired power to the load of the PV and hybrid energy storage through coordinated control of power electronic converters. In this paper implementation for a hybrid system in a photovoltaic system with battery and supercapacitors to maintain continuity in the supply is presented. Virtual resistance droop (VRD) controller is proposed to regulate battery converter and a virtual capacitance droop (VCD) controller is implemented for supercapacitor (SC) converter. The SC is used to minimize the imbalance power in the system, due to the slow dynamics of the battery. thus Supercapacitors are used to reduce the stress and increase the life of the battery by providing or absorbing peaks powers as demanded by the load. The photovoltaic cells are connected to DC bus with boost converter and controlled with MPPT algorithm, Supercapacitor and batteries are linked to the DC bus through the buck-boost converter and the load is connected to the DC bus. The effectiveness of proposed scheme is shown by simulation studies in MATLAB/SIMULINK

ABSTRACT: Bangka Belitung Island is the largest tin-producing island in Indonesia and second only... more ABSTRACT: Bangka Belitung Island is the largest tin-producing island in Indonesia and second only to Malaysia. With the decline of the tin industry since 1991 due to the decline in world tin prices are resultPT. TimahTbk must stop some mining activities in Bangka Belitung Island to reduce production costs and provide opportunities for tin mining people to mine on traditionally abandoned land. However, over time this lead mining of the people resulted the negative impact on the environment because mining is done not only in the former mining land of PT. Timah, Tbk but began to expand into protected forest areas and conservation forests, as well as near the Watershed (DAS) which ultimately resulted in flooding during the rainy season. This research is a qualitative research aims to analyze the impact of tin mining people against floods in the province of Bangka Belitung Islands and analyze the efforts made by the Provincial Government of Bangka Belitung in flood tackling due to tin mining people. The results showed that human factors greatly affect the environmental damage. It is necessary to formulate policies that regulate the people's tin mining and supervision of the tin mining activities of the people.

ABSTRACT: The development of the technological environment is an indisputable factor that can inf... more ABSTRACT: The development of the technological environment is an indisputable factor that can influence the morale and ethics of a society. This scientific research looks at robotics as a key technological development. Attempts to rank it on the basis of roboethics, or in terms of how people design, construct, use and treat robots, but also on the basis of bioethics or the ethical implications of robotics applications in medicine. Having the focus of the attention on human, the conclusions are the same from both points of view. It is precisely robotics that has enormous potential. It facilitates the provision of care, helps in many medical areas, and also applies to human repair and enhancement. But, robots cannot replace human completely neither in the care provision, nor in the provision of the medical service.

ABSTRACT: The use of low cost materials in the reinforcement of metal matrix composites is increa... more ABSTRACT: The use of low cost materials in the reinforcement of metal matrix composites is increasing rapidly. The present study deals with development of metal matrix composites (MMC) of A356.2 alloy reinforced with locally available inexpensive fly ash (FA) particles. Fly ash particles of 2, 4, 6, 8 and 10% by weight were used to prepare the metal matrix composites by using stir casting method. Various tests such as hardness test, compression test, and tension test were performed to analyze different mechanical properties of the resultant composites. The results of the tests reveal that the hardness, compressive strength and tensile strength of the aluminum alloy increases with the increase in weight fractions of fly ash particles. The resultant composites may be used as replacements of raw aluminum due to their superior mechanical properties.

ABSTRACT: Electrical Power Distribution system in Nigeria is constantly faced with an ever-growin... more ABSTRACT: Electrical Power Distribution system in Nigeria is constantly faced with an ever-growing load demand. The growth in load demand can be ascertained by conducting power flow analysis on the existing distribution system to ascertain the true performance of the network. Existing distribution system infrastructures having stayed for many years, are weak, obsolete and witness high energy losses. Most distribution substations are overloaded and cannot match with the increasing load demand of the consumers. This has resulted to irregular supply and under-voltage in the system which has led to incessant load shedding by the Distribution Company’s (DISCOs) as an alternative to mitigate this challenge. This research involved actual measurement of data from existing Dumez 11KV feeder network, making the best model of the network based on the existing data in two different software environments, viz: DIgsilent Power Factory 2016 and Electrical Transient Analyzer Program (ETAP) 7.0. Load flow analysis was carried out on the 11kv DUMEZ feeder network using Newton-Raphson power flow algorithm embedded in both software’s to determine the disparity in the results obtained from the two software’s, find out the steady state condition of the existing network, suggest ways or adjustments that can be made in the properties of the existing model to improve the entire system. Following the result analysis, the results obtained from both software’s are similar with very slight differences. The result analytically showed violation of voltage statutory limits. Out of a total of 47 load buses, voltage violation occurred in 46 buses (under voltage bus) operating under steady state condition. Only Otovwodo bus was within the marginal voltage acceptable limit of 97.8 %. However, in order to operate the entire system within the marginal voltage acceptable limit (marginal under voltage ˂ 97%; marginal over voltage ˃ 102%), there is need for upgrade in the form of Distributed Generation (DG).

ABSTRACT : Diseases, injuries, fractures, or conditions after operations on fingers and hands oft... more ABSTRACT : Diseases, injuries, fractures, or conditions after operations on fingers and hands often cause loss of muscle strength and limit the mobility of a particular limb. Muscle strength restoration or increasing the range of motion may be achieved by the rehabilitation of the damaged area. The rehabilitation course ensures that a given area returns, in the maximum possible extent, back to the condition existing prior to the injury. To enable correct finger strength assessment or the rehabilitation success evaluation by an examining person, it was required to construct a device capable of measuring the strength of individual fingers. The submitted article deals with the alternative design of such device for the finger strength measurement, it describes the final design of the device and the measurement methodology that must be adhered to when assessing the muscular strength of fingers of a hand.

ABSTRACT : The maintaining of balance when standing is for a person of any age an essential requi... more ABSTRACT : The maintaining of balance when standing is for a person of any age an essential requirement for performing common, every day functions, avocations and activities and for independent mobility. These listed aspects can be considered as primary criteria for evaluating quality of life. Fromstatisti-caldata, approximatelyone in three patients age 65 or older say that they fall at least one time each year, and 70% of all falls cause an injury to health. A broken neck of the thigh bone is among the most complicated and the most dangerous of these injuries. The purpose of this study is an evaluation of the measured parameters using a force plate as the main indicators for the assessment of stability of the human body when standing, which can be predictive for assessing the risk of a fall occurring.

ABSTRACT: It is well known that the developments of global construction technologies and material... more ABSTRACT: It is well known that the developments of global construction technologies and materials are contributing to enhance the competitive advantages for construction companies. This competition seems to be highly evident in the Jordanian market, especially in the field of construction products. For this reason, the design of "geo-synthetic retaining walls" has been presented through the current research to be an alternative to the reinforced concrete wall.In general, this research presents detailed design for implementing both "the geo-synthetic reinforced soil retaining walls" including the use of geogrid layers, soil layers, and facing elements, and "the conventional reinforced concrete retaining walls" for the Jordanian construction sites. A general comparative study regarding the cost and duration of carrying out each technique has also been provided during this investigation.The methodology of this research comprised two parts. The first part included collecting and reviewing for literature concerning the above subject; whereas, the second part concentrated on the design and adoption for a reinforced earth retaining structure as an alternative to the reinforced concrete one, considering the application of the above alternatives for a case study at a proposed road project in Jordan.Out of the current investigation, it was concluded that the design and adoption of geo-synthetic retaining walls in Jordan showed more advantages than the conventional concrete walls, taking into consideration the costs, duration of execution, used materials, labors, and method of implementation.