Assessment of Conventional Insecticides against Common Bed Bugs Cimex Hemipterus (Hemiptera: Cimicidae) in Jeddah Province, Saudi Arabia

Bed bugs, Cimex hemipterus (Hemiptera: Cimicidae) are small insects that are considered public health pests and cause many health and economic problems. The efficacy of Organophosphorus insecticides (Safrotin and Actikill) and pyrethroids (Project and Cyper Safe) in controlling C. hemipterus adults and nymphs were investigated using contact and dipping methods. The WHO protocol was followed for insecticides application. The results of the current study showed that the project pesticide from the pyrethroids group gave the highest effectiveness against bed bugs, as the value of the concentration that killed 50% (LC50) of insects was of the adults (264.8, 337.5 ppm) when using dipping and contact methods, respectively. while the LC50 value when applying the two methods of the same insecticide against nymphs was 254.7 and 329.3ppm, respectively. However, Safrotin the more effective organophosphorus insecticide. The dipping method was more effective than the contact method for all insecticides, and the nymphs were more susceptible than the adults (LC50= 1502.6 and 1065.28ppm). The pesticides can be arranged in descending order according to their effect as follows: Project> Cyper Safe > Safrotin > Actikill. Our findings suggest that bed bugs in Jeddah Province may have developed resistance to common pesticides used in public health pest management programs. For this reason, this study recommends a periodic evaluation of the effectiveness of pesticides to be used during emergency pest outbreaks

Measurement of tool wear using a non-contact method, using a laser measuring system

Measurement of tool wear using a non-contact method, using a laser measuring system. This article examined the tools - straight cutters with a contactless method using a laser sensor. The first aspect of the research was to determine the influence of the spindle rotational speed on the accuracy of laser measurement. The second aspect of the research was to establish the correlation between the diameter of the tool measured with a laser micrometer and the wear of the tool measured with the microscope. A good (R2> 0.8) Pearson's correlation was found between the measured tool diameter and it’s wear.

Application and Development of Noncontact Detection Method of α-Particles Based on Radioluminescence

The detection of α particles is of great significance in military and civil nuclear facility management. At present, the contact method is mainly used to detect α particles, but its shortcomings limit the broad application of this method. In recent years, preliminary research on noncontact α-particle detection methods has been carried out. In this paper, the theory of noncontact α-particles detection methods is introduced and studied. We also review the direct detection and imaging methods of α particles based on the different wavelengths of fluorescence photons, and analyze the application and development of this method, providing an important reference for researchers to carry out related work.

Assessment of Undergraduate Business Education Students' Usage of Social Networking as a Platform For Entrepreneurship Activities In North-West, Nigeria

The study assessed the undergraduate business education students' usage of social networking as a platform for entrepreneurship activities in North-west, Nigeria. Specifically, the study had five objectives, five research questions and five null hypotheses. The study anchored theory of Technology Acceptance Model of Ajzen and Fishbein's, (1980) and Division of Innovation Theory (DOI) of Rogers (1995). The study adopted a survey research design. The population of this study comprises of all the 407 final undergraduate business education 2019/2020 academic session in North-west Nigeria. The entire population was used for the study. The instrument for the data collection was a structured questionnaire. The instrument was validated by four experts, pilot tested and a reliability coefficient of 0.81 was obtained. The data were collected by the researcher assisted by four research assistants using personal contact method. Descriptive statistics of mean and standard deviation was employed to answer the research questions. The hypotheses were tested using Analysis of Variance (ANOVA) at the 0.05 level of significance. The results revealed among others that the level of students' awareness, perceived ease of use and perceived usefulness of social networking as a platform for entrepreneurship activities in tertiary institutions in North-west Nigeria was low. Based on these, it was concluded that the business education will not reap the benefit of social networking sites to searcher for business opportunities, venture into business and meet the needs of their technologically savvy customers. It was recommended among others that business education lecturers should create awareness on students on the role of social networking as a platform for entrepreneurship activities.

Selected Problems of Power MOSFETs Thermal Parameters Measurements

In the paper, selected problems that are related to the measurements of thermal parameters of power MOSFETs that are placed on a common heat sink are analysed. The application of the indirect electrical method, the contact method, and the optical method in measuring self and mutual transient thermal impedances of these transistors is presented. The circuits that are required to perform measurements are presented and described. The errors of measurements are assessed for each of the considered methods. In the case of the indirect electrical method, an additional influence of the selection of a thermo-sensitive parameter and the function approximating thermometric characteristics on the measurement error are taken into consideration. The measurement results of the thermal parameters of the investigated transistors that were obtained using the considered measurement methods in various supply conditions are presented and discussed.

Laser Processing of Diffusion Boronized Layer Produced on Monel® Alloy 400—Microstructure, Microhardness, Corrosion and Wear Resistance Tests

The paper presents the results of studies of microstructure, mechanical and physicochemical properties of surface layers produced by laser modification of the diffusion boron layer on Monel® Alloy 400. The diffusion boron layers were produced at 950 °C for 6 h. The gas-contact method was used in an open retort furnace. The process was carried out in a powder mixture containing B4C carbide as a boron source. The next stage was the modification of the boron layer with a diode laser beam of a nominal power of 3 kW. A constant power of 1400 W of the laser beam was used. The scanning speed was variable (successively 5 m/min, 25 m/min, 50 m/min). In order to determine the best parameters, single tracks were created, after which multiple tracks were prepared using previously selected parameters. It was found that both the diffusion borided layer and the laser modified layer had better properties than the substrate material. Both these processes contributed to an increase in corrosion resistance, hardness and wear resistance. It was also found that laser modification caused a slight deterioration of the properties in comparison with the diffusion borided layer. However, the laser modification process resulted in the production of a much thicker layer.

The Effect of Spray Distance on Porosity, Surface Roughness and Microhardness of WC-10Co-4Cr Coatings Deposited by HVOF

The paper presents the computational studies on the microstructure of WC-Co-Cr coatings deposited by High Velocity Oxy Fuel spraying (HVOF). The study covers the porosity assessment according to ASTM E2109-01 standard, carried out in ImageJ software, in terms of volume porosity, size and shape of the pores. The evaluation was preceded by scanning electron microscope (SEM) observations at magnifications of 2000x and 5000x. Additionally, topography analysis has been performed by confocal laser scanning microscope (CLSM), and the surface roughness Ra was evaluated by the contact method with use of a stylus profilometer. Finally, the influence of porosity was observed for coatings microhardness HV0.3. According to the results, the total closed porosity was found to be in the range of 5.01 vol.% and 5.38 vol.%. The dominated pores in the coatings were of size 0.1-1.0 μm. Studies showed that HVOF process enabled deposition of dense coatings, characterized by homogenous distribution of pores and low roughness.

Automatic segmentation of the borders of the pathological focus in the macular area of the retina to calculate the area of the pathological focus

Optical coherence tomography (OCT) is a modern, non-contact method of diagnostic examination that enables the visualization of various tissues of the human eye in a cross-sectional view at the microscopic level with the required morphological information. The software pre-installed in such devices contains many different tools for analyzing scans and has almost all the functionality necessary for the doctor to make a correct diagnosis. However, as time passes, more and more advanced methods of analyzing the images appear, which actualizes new tasks of developing additional software that can supplement and expand the functionality of the diagnostic equipment. This paper proposes an algorithm for automatic segmentation of the borders of a pathological focus in the macular area of the retina to calculate the area of the pathological focus, which together with other algorithms for analysis of morphometric parameters of the human eye, which are still under development, will be used for more accurate diagnosis of the stage of age-related macular degeneration.

Hibiscus sabdariffa L. calyces’ and argon DBD plasma: potential eco-friendly cleaners for fire-damaged silver gelatin prints

Purpose This paper aims at examining the potentiality of using Hibiscus sabdariffa L. calyces’ (Hs) aqueous extract to remove soot stains from the surface of fire-damaged silver gelatin prints. It further studies the cleaning efficiency and impact of both a contact method and a noncontact method with argon dielectric barrier discharge plasma (DBD Ar. plasma) on the different properties of silver gelatin prints. Accordingly, it prompts using economic, eco-friendly materials and methods in the photograph conservation field. Design/methodology/approach To achieve the aims of this paper, four silver gelatin prints were stained with soot and treated with the (Hs) aqueous extract as a contact method and DBD Ar. plasma combined with the aqueous extract as a noncontact method. The assessment was carried out using digital microscopy, atomic force microscopy and spectrophotometer to study the efficiency of the tested treatments and their impact on the surface of the photographs. FTIR was used to monitor the state of the binder after cleaning. Furthermore, the pH and the mechanical properties were measured. Findings The contact method resulted in lower concentrations of (Hs) extract that efficiently cleaned the surface without causing any stains or damage to the treated photographs. The noncontact method (plasma with an aqueous extract) proved to be less effective in cleaning and made the binder more susceptible to deterioration. Originality/value This paper reveals the success of (Hs) aqueous extract in cleaning soot on vulnerable photographs’ surfaces.