Actual Supply Research Articles

English

The State Department of Housing in Kenya puts the housing demand in the country at 250,000 housing units per year, while actual supply is 50,000 units p.a. This demand for housing has accumulated to 1.85 million units as at 2018. This has led to the growing proliferation of slums and informal settlements, with the Department showing that there are over 500 such settlements. This state of affairs has been partly attributed to under-investment in low cost housing by both public and private entities. Stakeholders have therefore recommended the application of Public Private Partnerships (PPPs), which increases the role of the private entities in housing production beyond the traditional procurement method. Under PPPs, the public sector cedes the duty of actual housing development and concentrates on creating an enabling environment for the private party to effectively and efficiently perform the function of shelter provision. In addition to creating an enabling environment, the governments undertake monitoring, evaluation, creation of standards and enforcement. This study utilized secondary review of the literature on the evolution on PPPs and focused group discussion with selected officials at the State Department for Housing in Kenya. The purpose was to juxtapose the secondary literature review on how the concept of PPPs has been appreciated as an alternative to the traditional procurement methods.  It was found out that private participation in infrastructure development has evolved over time, assuming many forms like: contracting out, privatization and lately PPPs. Kenya has been applying PPPs since the liberalization of the economy in 1994, though there are were earlier applications of the concept. The country has used PPPs in the hard infrastructure sectors like energy and transport, but little success has been recorded in housing development. It was concluded that PPPs are applicable in down market urban housing in Kenya since the concept has been successfully applied in other areas. Through PPPs, a sector like down market urban housing can access more capital resources, technology, innovation, efficiency and effectiveness. The implication of this finding is that more down market urban housing can be developed to address the huge gap witnessed in Kenya.   Key words: Public private partnerships, public sector/government, private sector/private parties, down market urban housing, low income urban households, evolution.

Resistance and tolerance to mixed nematode infections in chicken genotypes with extremely different growth rates

Fast growing broilers are less able to cope with fitness related challenges. As the allocation of metabolic resources may be traded off between performance and defence functions in parasitized hosts, we hypothesized that fast growing broilers are more sensitive to mixed nematode infections compared with slower growing genotypes under the same environmental conditions. Therefore, we compared male birds of genotypes selected for either meat production (Ross-308, R) or egg production (Lohmann Brown Plus, LB) or for both purposes (Lohmann Dual, LD), to assess their resistance and tolerance to mixed nematode infections with Ascaridia galli and Heterakis gallinarum. While infections reduced feed intake in all three genotypes, feed conversion efficiency was not affected. Infections impaired growth performance only in R birds, indicating lower tolerance in the fast growing genotype compared with slower growing LB and LD genotypes. Impaired tolerance in R birds was associated with a relative nutrient scarcity due to an infection-induced lower feed intake. Resistance to experimentally induced infections depended on host genotype as well as on the worm species involved. Overall, the A. galli burden was higher in R than LB, whereas the burden of LD was not different from that of R and LB. In contrast, the H. gallinarum burden of first generation worms was similar in the three genotypes. Susceptibility to re-infection with H. gallinarum was higher in LB than in LD, whereas very low levels of re-infection were observed in R birds. Our data collectively suggest that resistance and tolerance to mixed nematode infections are sensitive to growth rate in chickens. These differences amongst genotypes may partly be associated with a mismatch between the actual nutrient supply and genotype-specific nutrient requirements.

Experimental investigation of water quality responses to inorganic pollutants for the establishment of a contamination warning system

Abstract In this study, batch and simulated pipeline experiments were conducted to investigate the response of water quality parameters (pH, conductivity, residual chlorine, turbidity, total organic carbon, UV 254, and oxidation reduction potential (ORP)) to various concentrations of four inorganic pollutants (Cd, Cr, Mn, and Pb). In addition, the possibility of detecting incidents of contamination in the actual water supply system was evaluated by deriving the response intensities of each factor to the concentrations of the pollutants. As a result, pH and ORP were identified as the major water quality parameters responsive to the four inorganic pollutants in this study. The responses were more intense (more sensitive) in pure water than in tap water. The results of the batch and simulated pipeline experiments for tap water showed almost identical tendencies, except for the second level of Mn injection (concentration 0.5 mg/L).

Changing of the riverine sediment load supply into Lake Baikal: The natural and anthropogenic causes (Russia)

The influences of natural and anthropogenic factors on temporal changes in sediment load of the main Baikal rivers (Upper Angara River and Barguzin River) were analyzed through the relationship between hydro-climatic parameters (air temperature, precipitation, water discharge and sediment load) and their variation tendencies for the periods of 1945–2014, 1945–1975 and 1976–2014. Mann–Kendall test, abrupt change test were employed to analyze the hydro-climatic data. The results indicated that the air temperature increased on 1.0–1.1 °C in the watersheds over the warming period (1976–2014), and the precipitation had an insignificant decreasing trend in this period, and the reduction was −2.6% and −4.9%. The statistically insignificant increasing in water discharge was 4.2% and 1.3% in the Upper Angara and Barguzin over the period 1976–2014, respectively. Meanwhile, there was a strong decrease in sediment load of −66% and −70%. The abrupt decrease the sediment load in the Upper Angara since the mid-1970s was caused by the combination of human activities in river basin and changes of natural processes. In the Barguzin basin, the significant anthropogenic impact against the background the changes of natural processes in the mid-1980s was began. In the Upper Angara, the period of rapid decline of sediment load from 1976 to 1984 continued, in the Barguzin – from 1976 to 1991, after that, the other regime of sediment load had established. In recent decades, the actual sediment load supply from the Upper Angara and Barguzin into Lake Baikal are 92 × 103 t y−1 and 27 × 103 t y−1 or 22% and 18% of the 1945–1975, respectively.

Pricing strategy of cab aggregators in India

Cab aggregators are making rapid waves across India and the world. Ola and Uber have seized the opportunity with both the hands through startup and stand up India campaign to tap the potential of the Indian market. The article critically evaluates the pricing strategy employed by and Ola and Uber in India, from an economic perspective. It underlines surge pricing as a strategic business tool vis-a-vis revenue management model and analyses the reasons behind it, including challenges to its application from a legal and a consumer standpoint. It also dwells on the alternative mechanisms such as ‘concealed’ surge pricing, and the effect of such selective pricing on actual demand and supply of cabs on the road and driver incentives. Finally, it prescribes policy solutions, and outlines future questions which can be derived from this study.

НЕЛИНЕЙНАЯ МОДЕЛЬ СИСТЕМЫ ЭЛЕКТРОПИТАНИЯ ПОГРУЖНЫХ ОБЪЕКТОВ С УЧЕТОМ ИЗМЕНЕНИЯ ДЛИНЫ КАБЕЛЬ-ТРОСА

Актуальность работы определяется необходимостью создания адекватных математических моделей систем электропитания сложного погружного технологического оборудования, например электроцентробежных насосов и автономных подводных аппаратов, получающих энергию переменного тока по достаточно протяженной кабельной линии. Приемлемая адекватность характеристик модели и реальной системы электропитания данного класса объектов может быть достигнута в результате учета изменяемой длины кабельной линии и различных режимов работы погружного оборудования. Использование передаточных функций в качестве промежуточных моделей основных элементов системы электропитания и операторного метода является достаточно приемлемым решением для адекватного отражения процессов изменения напряжения на нагрузке. Далее путем преобразования передаточной функции записывается нелинейная математическая модель системы электропитания в пространстве переменных состояния, которая позволяет аналитическим образом решить задачу робастной стабилизации неизмеряемого напряжения на полезной электромеханической нагрузке. Цель работы: построение нелинейной математической модели системы электропитания с передачей энергии переменного тока по кабель-тросу с учетом изменения его длины в пространстве переменных состояния. Методы: операторный метод, методы пространства состояния и математического моделирования. Результаты. Разработана методика определения параметров устройства компенсации реактивной мощности в кабель-тросе для увеличения его пропускной способности при передаче мощности на дальние расстояния при повышенной частоте. Определена аналитическая зависимость, позволяющая рассчитать индуктивность компенсирующего устройства во всем диапазоне изменения длины кабель-троса. Для построения оптимального регулятора получены полиномы, позволяющие определять коэффициенты передаточных функций при изменении длины кабеля и сопротивления нагрузки системы электропитания. На основании передаточных функций, полученных для различных режимов работы системы электропитания, определены параметры схемы замещения, позволяющей записать нелинейную математическую модель системы электропитания пониженного порядка. Проведена сравнительная оценка результатов моделирования системы электропитания с передачей энергии переменного тока по кабель-тросу, подтверждающая возможность ее описания моделью пониженного порядка в пространстве состояний. Выводы. В работе предложена методика определения параметров устройства компенсации реактивной мощности, позволяющего увеличить пропускную способность кабель-троса. На основании передаточных функций, коэффициенты которых зависят от длины кабель-троса, записана упрощенная нелинейная математическая модель системы электропитания погружного технологического оборудования. В результате полученная модель системы электропитания может быть использована для последующего синтеза оптимального регулятора напряжения в классе нелинейных систем управления.

Nonlinear Effects of Three-Level Neutral-Point Clamped Inverter on Speed Sensorless Control of Induction Motor

In the model reference adaptive speed observer, the induction motor supply voltage is used as the input of the reference model. However, measuring the supply voltage complicates the system and increases the cost, so the command voltage calculated by the controller is generally used instead of the actual supply voltage in the drive system. However, due to the nonlinear effects of the inverter, the voltage calculated by the controller is different from the actual supply voltage, resulting in a speed observation deviation. This paper analyzes the multiple effects that cause the three-level neutral-point clamped (TL-NPC) inverter output voltage and command voltage deviation. A voltage deviation compensation measure based on the volt-second balance principle is proposed. In this context, the expression of the rotational speed deviation caused by the voltage deviation is derived rigorously and in detail. Finally, the effectiveness of the voltage compensation measure is verified by experiments. The experimental results are basically consistent with the theoretical derivation expressions. The method and analysis in this paper is applicable to induction motor speed sensorless control systems driven by two-level and other multilevel inverters.

Research of Water supply pipeline correlator

Compared with traditional leak detector, correlator has obvious advantages. Based on the study of acoustic leak detection, IT technology and mathematical analysis model are added to locate the leak point more quickly, accurately and reliably. On the basis of studying the characteristics of sound wave propagation in the pipeline and filtering and noise elimination, a correlator is developed and tested in the actual water supply pipeline. Many experimental results can accurately locate the leakage point of water supply pipeline, which fully verifies the feasibility of this study.

Change from agricultural to touristic use: Effects on the aesthetic value of landscapes over the last 150 years

The demand for cultural ecosystem services (CES) is increasing, and aesthetic values contribute substantially to attract visitors to mountain regions, enhancing the socio-economic well-being. While most studies focused on the assessment of aesthetic values under current conditions, this study aimed to evaluate the historic development of aesthetic values from the perspective of today by analysing changes in the actual supply of this CES along roads and paths in Sölden in the Ötztal valley (Austria) since the beginning of tourism. We first mapped roads and paths for five time steps over the last 150 years to then estimate aesthetic values along these infrastructures, using a spatially explicit modelling approach. Furthermore, we compared spatial patterns of visitation preferences derived from social media data with predicted aesthetic values. Our results indicate that an increased access to areas of high aesthetic values was related to general increases in the supply of aesthetic values until 1950. Although the accessibility to high-elevation areas continued to increase until 2017, aesthetic values generally decreased due to landscape changes induced by the shift from mainly agricultural to touristic use. The abandonment of alpine pastures occurred mainly above the forest belt, which coincides with high levels of photo density, as most pictures were taken around mountain huts and on mountain peaks. If carefully planned and managed, mountain regions may actively enhance aesthetic experiences and foster the touristic use by providing good infrastructure, but land use policies and landscape management should support agricultural activities to maintain high levels of aesthetic values.

HYGIENIC ASSESSMENT OF NUTRITION STATUS OF THE POPULATION OF THE GERONTOLOGICAL GROUP

Among many environmental factors nutrition is paramount, permanently and exclusively affecting in multidisciplinary mode on the biological and social essence of the human body. Therefore, this article describes the results of the actual supply of people aged of 60-89 years taking into account their eating habits associated with age-related changes in the gastrointestinal tract and metabolism. The study involved 611 respondents aged of 60-89 years, including men (23.9%) and women - 76.1%, living in Astana, the average age accounts of 73 ± 0.41years. The actual food was studied by frequency and a 24-hour simulation, recommended by the WHO for epidemiological studies. In assessing the adequacy of the supply of the reference values there were taken norms of physiological requirements in energy and nutrients for the population of gerontological groups of the Republic of Kazakhstan, as well as the norms of consumption of micronutrients on a scale of FAO / WHO. The study of the actual nutrition of the category of persons of Astana showed the diet of elderly people to be consisted of foods containing mostly protein and animal fats and digestible carbohydrates, while two latters were characterized by an excess of saturated fatty acids, the lack of polyunsaturated fatty acids, a high level of simple consumption carbohydrates from refined foods such as sugar, refined cereals, flour and poly- micronutrient failure of the nutrition on vitamins (deficiency of vitamin D, a, B1, E, C, biotin, folic and pantothenic acid) and minerals (calcium deficiency, potassium).

Analysis of Electric Power Quantities of Road LED Luminaires under Sinusoidal and Non-Sinusoidal Conditions

The paper presents the results of laboratory tests concerning the measurements of electrical parameters of road lighting luminaires. These measurements were focused on determining the dependence of the electrical parameters of the luminaires versus the changes of the RMS (Root Mean Square) value of the supply voltage and the level of disturbances in the supply voltage. The basic electrical parameters for light-emitting diode (LED) luminaires were analysed with the option of luminous flux adjustment if it existed. During the laboratory measurements, the luminaires were powered from the Agilent 6834B distorted voltage generator within the assumed acceptable range of the changes in the deformation level resulting from the applicable legal provisions for the reproduction of actual power supply conditions.

Propagation of negative shocks across nation-wide firm networks.

This study examines how negative shocks due to, for example, natural disasters propagate through supply chains. We apply a simulation technique to actual supply chain data covering most Japanese firms. To investigate the property of the propagation in the network, we test different types of artificial negative shocks. We find that, first, network structures severely affect the speed of propagation in the short run, and the total loss in the long run. The scale-free nature of the actual supply-chain network—that is, the power-law degree distribution—leads to faster propagation. Second, more intensive damages—that is, more damages suffered by fewer firms—result in faster propagation than extensive damages of the same total size. Third, the actual supply-chain network has innate robustness that comes from substitutability of supplies. If the supply-chain network has severe substitutability, the propagation of negative shocks becomes substantially large. Fourth, direct damages in urban regions promote faster propagation than those in rural regions. Fifth, different sectoral damages show significant differences in the speed of propagation. Finally, we check the indirect damage triggered by a single firm’s loss: 9.7% of all firms contribute to significant loss, and this loss accounts for more than 10% of the damage to the entire production. The simulations conspicuously show that different direct damages, even if they have the same total magnitude of damages, can generate considerably different damages because of the structure of the supply-chain network.

A stochastic reverse logistics production routing model with emissions control policy selection

Carbon emission control policies have emerged in response to the growing global concerns of environmental problems. These regulations should be considered when operational decisions on production, inventory, and routing are being made as emission costs are incurred. In this study, we introduce a reverse logistics supply chain model with remanufacturing and simultaneous pickup and delivery. The problem considers different carbon emission control policies with heterogeneous transportation fleets and allows for lost sales. The aim is to select the optimal carbon control policy with optimal production, inventory, and delivery quantities. The proposed model is formulated as both a deterministic and a two-stage stochastic mixed-integer programming problem. The proposed formulations are demonstrated through two case studies, a simulated reverse logistics supply chain and an actual home appliances production supply chain with remanufacturing options. Sensitivity analyses are conducted to test for the effect of different parameters on the optimal solution. Results indicate that the carbon policy selected has significant effect on the supply chain performance with carbon price being the most significant parameter.

Are the existing EU Ecolabel criteria for furniture products too complex? An analysis of complexity from a material and a supply chain perspective and suggestions for ways ahead

PurposeOne possible reason for the poor uptake of the EU Ecolabel for furniture products may be that the criteria are too complex for applicants. Consequently, it was decided to develop a method which quantifies criteria complexity and subsequently, to propose ways for its reduction, which could be considered in future criteria revision.MethodsThe requirements behind the voluntary EU Ecolabel criteria for furniture products set out in Commission Decision (EU) 2016/1332 have been scored with a “criteria complexity index” (CCI), based on the answers to a series of six questions that relate to the effort required for proper assessment and verification. The criteria, and associated CCI values, have been grouped on a per material basis, allowing a “material complexity index” (MCI) to be calculated and consequently, a “furniture complexity index” (FCI) has been calculated as a function of the materials in different furniture products.Results and discussionOverall, it was found that CCI values can differ depending on the actual supply chain scenario, that textiles and leather had much higher MCI values than all other materials and that the FCI was completely dependent on the materials the furniture product was composed of. FCI values were much lower in general for non-upholstered furniture.ConclusionsThe FCI scores can be greatly reduced by the following: (i) using fewer materials in the product; (ii) having shorter supply chains; (iii) using uncoated metals, or at least carrying out coating in-house; (iv) using solid wood instead of wood-based panels; and (v) identifying competent and communicative suppliers who are especially well-informed about chemicals used. Since furniture manufacturers only have limited scope to make these changes, it is more effective to change the way the criteria are structured in future revisions in order to make the criteria more fairly balanced and flexible for potential applicants. Key points about any future restructuring would be to make the chemical requirements more SME friendly and to consider moving away from a rigid pass–fail approach to a more flexible scoring approach.

Integrating supply and demand in cultural ecosystem services assessment: a case study of Cuihua Mountain (China).

As human demand for ecosystem services (ES) continues to increase, ES assessments have gradually become a popular research topic. Among ES, cultural ES (CES) are often overlooked and are difficult to measure during research because of their invisibility. However, the importance and usage of CES increase with supply and demand, which is key to linking the ecosystem with human well-being. This paper quantitatively evaluates various cultural services and generates corresponding Value Index (VI) maps; it then further explores the current dynamics of supply and demand. We selected Cuihua Mountain (CM) as the study area, and we applied the Social Values of Ecosystem Services (SolVES) model to evaluate CES and generated five specific VI maps to indicate the potential service stock (ES capacity). The actual supply (ES supply) is based on the attribute of the visibility of observation points on leisure routes, and the visitors (ES demand) to the service come from socio-economic data as a measure of the rates of access to entertainment venues. The supply and demand relationship (ES budget) solves the significant problems related to the oversupply and shortage of ES in space. The results showed that the CES supply power of CM is greater than the actual demand; thus, there is great potential for future development. This study also provided a reference and guidance for environmental decision-making and development in other regions.

Profit allocation in agricultural supply chain considering risk factors

For agricultural products, 'agricultural super-docking' is the best way to connect farmers and consumers in agricultural supply chain, the major factor of the implementation of 'agricultural super-docking' is a reasonable profit allocation. In this paper, based on traditional Shapley profit allocation method, a modified profit allocation method is proposed considering risk factors for participants in agricultural supply chain. It is more reasonable for profit allocation because there are different risks for different participants in actual agricultural supply chain system. Compared to traditional Shapley profit allocation method, the obtained profits for farmers by using the proposed profit allocation method increase because of his higher risk than cooperatives and supermarkets. More reasonable profit allocation is helpful to heighten the enthusiasm of farmers to join 'agricultural super-docking' and maintain long-term stability of 'agricultural super-docking'.

Влияние фактического питания, энерготрат, соматотипа на формирование синдрома белково-энергетической недостаточности у тамбовских студенток в возрасте 18-22 лет

The purpose of the study: to study the peculiarities of the influence of nutrition, energotrate, somatotype on the formation of anthropometric syndrome protein-energy insufficiency (SPEI) among female students. Material and methods: we examined 236 girls at the age of 18-22. We studied anthropometric features of physical development, body weight components, actual nutrition and energy resources. We evaluated the 25 of somatometric signs measured using the automated complex «Healthy Child» (TVES, Russia). Diagnosis of SBEN syndrome happened by body-weight index (BWI). We carried out evaluation of actual power supply and power consumption by frequency method with subsequent application of computer program «Analysis of human power supply condition» (version 1.2.4) of Scientific Research Institute of Nutrition. Results: girls with SPEI have significantly reduced morphological status, including component composition of body weight, compared to the control group. Girls with SPEI have a decrease in daily energy consumption against the background of similar levels of energy value of diets and consumption of basic nutrients compared to the control group. One of the main factors in the formation of girls' SPEI is constitutional: 95.6 % of them are asthenics. Discussion: Energy consumption, including physical load, and nutrition are regulated factors of formation of female students' SPEI and somatometric signs of this syndrome should control their usage. Whereas hereditary factors determine somatotype and the mechanisms of its influence on physical development require in-depth study.

Performance investigation of indoor thermal environment and air handling unit in a hub airport terminal

Airport terminal is a typical large space building with large high interspaces and multitudinous functional zones. The task of heating, ventilation and air conditioning (HVAC) system is to ensure the thermal environment of these zones with different functions. A typical terminal in cold region of China is investigated in present paper, where indoor environment and performance of air conditioning system in summer are emphasized. The results indicate that the indoor temperature and humidity parameters at a height of 1.5 m in each zone of the terminal can be effectively controlled. The indoor temperature at a height of 1.5 varies in the range of 24~27°C, and the temperature difference is 0.5~4.9°C in the vertical direction. The temperature at the top of the terminal is greatly affected by the outdoor temperature where is higher and fluctuates obviously, while the temperature at the height of the occupant area is lower and more stable under the control of the air-conditioning system. The indoor carbon dioxide concentration is also at a reasonable level, all below 900 ppm, indicating that the equivalent outdoor air volume per capita is greater than 35 m3/h. Even in the case of high load caused by flight delays, the thermal environment in the terminal can be basically controlled at a comfortable level. As for the air handling unit, air handling process is tested to investigate the cooling capacity. The results show that the actual water supply of the AHU is relatively higher than the set value, but the air volume is almost equal to the set value which leads to an unsatisfactory energy efficiency. The tested energy efficiency ratio (EER) of AHU is only 5~7, almost approaching to that of the cooling plant. Reducing air flow rate could greatly improve the EER of the current air-conditioning system.

Health, Cognition and Work Capacity Beyond the Age of 50. International Evidence on the Extensive and Intensive Margin of Work

The cost of old-age dependency leads to reforms aimed at raising the age or retirement. But do older individuals have the health/cognitive capacity to work longer? This paper asks how much older individuals (55-75) could work if they worked as much as their younger (50-54) counterparts in similar health/with equal cognition. It uses international, European, comparable panel evidence available in the Survey of Health, Ageing and Retirement in Europe (SHARE). It considers both physical and cognition. And consists of subjective and objective measures. Also, it examines the extensive and intensive margins of work. Results are essentially fourfold. First, physical deteriorates with age, but there is less evidence of cognitive decline. Second, ill negatively impacts employment, but less the hours worked. People with ill rarely adjust labour supply at the extensive margin; they rather stop working altogether. Third, we do not find evidence of health justification bias (Bound, 1991); rather of proxying problems when people describe their health, leading to attenuation bias. Finally, declining health/cognition explain at most 31% of the actual labour supply reduction between the age of 50 and 70. This confirms the existence of a, currently largely underused, work capacity among older Europeans.

Power Factor Correction of Three-Phase PWM AC Chopper Fed Induction Motor Drive System Using HBCC Technique

In this paper, a new control strategy for an induction motor (IM) drive system fed from three-phase pulse width modulation (PWM) ac chopper is proposed. The main objective of the proposed control scheme is to achieve input power factor correction (PFC) of the IM drive system under different operating conditions. PFC is achieved by continuously forcing the actual three-phase supply currents with the corresponding reference currents, which are generated in phase with the supply voltages, using hysteresis band current control (HBCC) technique. The proposed control strategy has two loops: the inner loop and outer loop. The output of the outer loop is the magnitude of the supply reference current resulting from either speed controller or startup controller, whereas the output of the inner loop is PWM signals of the ac chopper. The proposed ac chopper features a smaller number of active semiconductor switches, four IGBTs, with only two PWM gate signals. As a result, the proposed system is simple, reliable, highly efficient, and cost effective. Mathematical analysis of the drive system is presented. Components of the input LC filter are designed using frequency response. The IM drive system is modeled using MATLAB/SIMULINK, and a laboratory prototype was built and tested. The simulation and experimental results confirm the validity and robustness of the proposed control strategy.