The Economic Impact of Climate Change on the Agricultural System in Fiji

Climate change is one of the most crucial challenges identified in this century for the Pacific Region, such as Fiji, Samoa, Solomon Islands and many more. Citizens of Fiji have gone through peculiarly climatic and weather conditions over the past years like globalization, which had led to many consequences, especially in the agricultural sector which is the main income of many livelihoods not only in Fiji but in other Pacific countries as well. Climatic conditions have been changing adversely from past decades, such as temperature, rise in the sea level, precipitation changes, atmospheric composition changes, flooding, and tropical cyclones. These changes have led to alterations in the environment, thus, affecting crop and livestock production in the agricultural system. For instance, crops that require specific soil and temperature situations are vastly influenced when the temperature level changes suddenly, making the crops vulnerable to adapt to the alterations and therefore, the crops eventually die. Likewise, animal species also get affected by temperature changes, such as heat stress which specifically affects the fertility of male and female livestock. Due to these events, Fiji’s economies have also been affected since agriculture plays a vital role in boosting our economy through local market sales and exporting. Thereby, this review illustrates the impacts of climate change and ways to move forward/ solutions, for example, FAO (Food and Agriculture Organization) and Pacific Islands Climate Change Assistance Program (PICCAP) have supported Fiji in bringing adaptation programs for preparing farmers and all other individuals on the upcoming climatic conditions such as adapting tolerant crops that can handle droughts and other adverse weather conditions.

Quality Assurance Methods Applied For Exposed-Aggregate Concrete Pavement Construction

The exposed aggregate pavement technology for construction of concrete highways is used in European countries, including Poland, mostly for heavy trafficked roads. It is mainly a two-lift slip-form technology with a special treatment of the top surface after the final smoothing operation. This is a demanding technology that leaves a little margin for mistakes. When properly done the pavement layer with exposed aggregates ensures designed skid resistance for vehicle wheels even in adverse weather conditions without excessive traffic noise. The challenge is to provide its cost-effective long term performance including both the adequate roughness and the desired smoothness of the pavement. The paper presents tools and methods for construction quality assurance specific for exposed aggregate concrete pavements. Required monitoring of the stability of concrete mix properties is discussed. The importance of concrete curing is analyzed in respect to the long term durability in wet-freeze regions with heavy use of deicing salts. Macrotexture assessment at the early stage of pavement construction is seen as the key factor for assurance of the proper skidding resistance. Local evaluation of smoothness is also a useful approach to assure the target IRI. Examples of quality assurance efforts applied on concrete highways recently constructed in Poland are presented.

Creation and analysis of a flight attendant platform

Flight simulators have been used for a long time to train pilots of any type of aircraft. This type of training is more economical. The flight simulator improves control skills in extreme situations with minimal risks for the future pilot. Training on a flight simulator makes it possible to reproduce adverse weather conditions at any time. The pilot is on the ground in a special cockpit, which is mounted on a movable platform. This system is needed to ensure flight conditions as close to real as possible. The subject of the research in the article is an aviation simulator on the Stewart platform. The aim is to create and analyze an flight simulator platform using software. The paper presents the already existing flight simulator and its characteristics. Taking into account its dimensions and weight, the platform is modeled in SolidWorks. The kinematic diagram of the type design (6-6) is selected and presented. The basic equation of dynamics for calculating platform motion law for given values of the control forces is given. Also using this equation it is possible to find the controlling forces knowing the law of motion. The developed 3D model consists of two platforms, a movable and a stationary one. The legs with automatically variable length are attached to the platform using hinges. Selected material aluminum alloy type 2024 from which the platform is created. Selected material aluminum alloy type 2024 from which the platform is created. Static analysis of the loaded platform was performed. By loaded platform is meant that in the places where the simulator and the pi-lot's seat are installed, loads equal in weight to the simulator and the maximum weight of the seat with the pilot are applied. The anal-ysis includes such epurfaces: loads to assess whether the structure can support a given weight, displacement, deformation, safety margins and a Design Insight plot to evaluate design details. Identification of elements that are most likely to start collapsing under the weight of the simulator. The research was performed using SolidWorks Simulation software. Based on the data obtained from the plot, conclusions were made about the performance and safety of the developed platform.

Effect of Admixtures on Concrete and Superplasticizers on Cementitious Material

Use of chemical and mineral admixtures have proved beneficial in improving quality, workability and have enhanced finish ability of concrete. They also help in maintaining the concrete during its important stages such as mixing, transporting, placing, curing and also in adverse weather conditions. Superplasticizers are super water reducers that allow 15-20% water reducion thereby increasing the workability without any change in the composition of mix.The reduction in water and cement reduces creep, shrinkage and heat of hydration. In this paper effect of different chemical and mineral admixture was studied along with sand to aggregate volume ratio ,cement content and water were analysed by preparing different concrete mixtures using water reducers and superplasticizers. A specimen of 200mm and 300mm was prepared and tested for compressive strength, split tensile strength and young's modulus. Slump test was also performed at 15 min interval. Also superplasticizers (TJ III , LIGNIN-SULPHONATE-based and NAPHTHALENE-SULPHONATE-based) were taken and their effect on the heat of hydration and induction period of cementitious material (portland cement) was studied. Keywords: admixture, workability, superplasticizer, water cement ratio, heat of hydration.

Can the invasive ambrosia beetle Xylosandrus germanus withstand an unusually cold winter in the West Carpathian forest in Central Europe?

The capability of a non-native species to withstand adverse weather is indicative of its establishment in a novel area. An unusually cold winter of 2016/2017 that occurred in the West Carpathians of Slovakia and other regions within Europe provided an opportunity to indirectly assess survival of the invasive ambrosia beetle Xylosandrus germanus (Coleoptera: Curculionidae, Scolytinae). We compared trap captures of this species in the year preceding and succeeding the respective cold winter. Ethanol-baited traps were deployed in 24 oak dominated forest stands within the southern and central area from April to August 2016, and again from April to August 2017 to encompass the seasonal flight activity of X. germanus and to get acquainted with temporal changes in the abundance of this species in these two distant areas. Dispersing X. germanus were recorded in all surveyed stands before and after the aforementioned cold winter. Their total seasonal trap captures were lower in the southern area following low winter temperatures, but remained similar in the central area. Our results suggest that X. germanus can withstand adverse winter weather in oak dominated forests of the West Carpathians within altitudes of 171 and 450 m asl. It is likely that minimum winter temperatures will not reduce the establishment or further spread of this successful invader in forests in Central Europe.

Permitted speed decision of single-unit trucks with emergency braking maneuver on horizontal curves under rainy weather

Under adverse weather conditions, visibility and the available pavement friction are reduced. The improper selection of speed on curved road sections leads to an unreasonable distribution of longitudinal and lateral friction, which is likely to cause rear-end collisions and lateral instability accidents. This study considers the combined braking and turning maneuvers to obtain the permitted vehicle speed under rainy conditions. First, a braking distance computation model was established by simplifying the relationship curve between brake pedal force, vehicle braking deceleration, and braking time. Different from the visibility commonly used in the meteorological field, this paper defines "driver’s sight distance based on real road scenarios" as a threshold to measure the longitudinal safety of the vehicle. Furthermore, the lateral friction and rollover margin is defined to characterize the vehicle’s lateral stability. The corresponding relationship between rainfall intensity-water film thickness-road friction is established to better predict the safe speed based on the information issued by the weather station. It should be noted that since the road friction factor of the wet pavement not only determined the safe vehicle speed but also be determined by the vehicle speed, so we adopt Ferrari’s method to solve the quartic equation about permitted vehicle speed. Finally, the braking and turning maneuvers are considered comprehensively based on the principle of friction ellipse. The results of the TruckSim simulation show that for a single-unit truck, running at the computed permitted speed, both lateral and longitudinal stability meet the requirements. The proposed permitted vehicle speed model on horizontal curves can provide driving guidance for drivers on curves under rainy weather or as a decision-making basis for road managers.

Risk assessment and ranking in the developing countries’ construction industry: the case of Jordan

PurposeRisk impedes the success of construction projects in developing countries due to planning in an unpredictable and poorly resourced environment. Hence, the literature suggests that practitioners are not fully aware of how important the risk identification process is. Some of the prior studies identified risks in developing countries without highlighting how they can be beneficial to the practitioners in the industry. Therefore, this study highlights this process and identifies the key risks that affect the Jordanian construction industry.Design/methodology/approachThis study adopted an exploratory sequential mixed approach, two rounds of face-to-face interviews that were conducted in Jordan among 12 experts followed by a questionnaire randomly distributed to 122 practitioners. This study utilized the relative importance index, coefficient of variation, and Mann–Whitney (U) to analyze the data. Also, the factor analysis technique was used to identify and regroup the risk factors to further understand the correlation among the risks.FindingsThe result revealed an agreement among contractors’ and consultants’ responses toward allocating risks. Furthermore, several risks can be traced back to the project communication management process, highlighting a deficiency in the process. Also, four-factor groups were established, the first group includes the risk of defective design, late decisions making by other project participants and poor coordination with the subcontractor. The second group has only the risk of corruption, including bribery at sites. The third group includes stakeholders’ financial instability and inadequate distribution of responsibilities and risks. The fourth group includes adverse weather conditions and the use of illegal foreign labor.Originality/valueSome of the prior studies identified risks in developing countries without highlighting how they can be beneficial to the practitioners in the industry.