**2.3 Additional analysis methods**

## *2.3.1 Decomposing the analysis across sphere regions*

Several studies have shown variations in localisation accuracy as a function of region on the sphere due to, amongst other things, cue interpretation [3] or reporting method [32]. In these cases, decomposition schemes were used to better characterise those variations and understand their origins. As mentioned in Section 2.1.5, Van Wanrooij and Van Opstal [25] for example decomposed the analysis of elevation gain across azimuthal regions. Later, Majdak et al. [14] proposed an analysis split into hemi-fields to detect higher accuracy variations for targets in the rear region. Middlebrooks [12] applied a similar spatial decomposition to detect high variability for responses in the upper-rear quadrant, temporarily excluding them from the analysis to better assess variations in remaining regions. The principal drawback of decomposition is that it reduces the statistical power of the analysis, and can result in unbalanced data sets if responses are not evenly spread across the regions under consideration.

### *2.3.2 Performance evolution modelling and analysis*

For the evaluation of HRTF learning, it is essential to assess the progression of participant performance over multiple sessions. On the assumption that any adaptation to an HRTF is a process with diminishing returns with repeated training sessions, localisation performances may be modelled as an exponential decay *y* ¼ *y*0 exp ð Þþ �*t=τ c* [15, 31]. Here *y*0 is the initial performance, *t* is the time (training day, session, *etc.*), *τ* is the improvement time constant, and *c* is the long term performance. This model of performance over time allows for comparisons between studies, such as determining if different protocols lead to faster learning rates or if better long term performance can be achieved. If the training duration proves insufficient to reach a performance plateau/asymptote, like that seen in Stitt et al., [10], the improvement data may be better modelled using the linear form *ax* þ *b* [9, 31]. In addition to performance modelling, the correlation between training duration and performance metrics has been used to determine if factors other than training duration, like participant attention, should be considered to explain performance evolution [33].

Analysis of performance evolution can be performed per condition (grouping participants) [8, 10] or per participant [23]. Participant performance evaluation makes it harder to draw general conclusions, but potentially provides deeper insight into performance as not all participants exhibit the same ability to adapt to a new HRTF [24]. This adaptation capacity appears to be a function of initial HRTF affinity or "perceptual quality" [10]. For inter-study comparisons, some form of performance scaling or normalisation may first be required to compensate for such affinities, highlighting performance improvement rather than absolute value [10].

### **3. Methodology for assessing localisation performance**

From the literature review in the previous section, a methodology is derived for assessing binaural localisation accuracy. Though it was designed with a focus on HRTF training programs, it should be applicable to any HRTF-related study interested in localisation performance assessment. Section 3.1 introduces the conventions and metrics used in the methodology, itself detailed in Section 3.2. The metrics


**4. Socioeconomic impacts on local population**

Early irrigation system in the Indus basin was developed for irrigational purposes. Due to the development of canals in the Kashmir region, the agricultural production was increased many folds [39]. The Indus basin irrigation system is one of the largest, complex irrigation networks and the largest weir-controlled system in the world with large reservoirs, barrages, syphons, and many types of canals and their watercourses [40]. Construction of new canals created favorable conditions for the colonies to be developed in the basin. Best examples can be seen as Lyallpur (Faisalabad) developed in the vicinity of the Lower Chenab Canal. Similarly, Sargodha and Montgomery (Sahiwal) were developed along the lower Jhelum Canal and the Lower Bari Doab Canal, respectively [25]. High crop productivity was found in irrigated areas than in the rainfed areas. High crop production leads to high per hectare employment. Additionally, irrigation system also made it possible for an extra crop to be raised, hence increasing per year yield, increasing household income, and decreasing poverty in irrigated areas [41].

Development of irrigation system benefited both at the local and governmental levels. A famine-prone area was converted into an area with high grain productivity that helped to prevent the famine conditions. Living style of the inhabitants was improved, and starvation was minimized. At the same time when the common population was benefitted, the British Government harvested a large volume of cotton crops from the irrigated areas, which provided them with a golden opportunity to cash the results of irrigation system development. Furthermore, the railway network increased access to agricultural products. Railway network facilitated the transport of food grains and cotton to local and international markets. Food grains produced from the area also helped to meet the food demands of other regions, hence making the region of South Asia's "breadbasket."  Similarly, livestock transformed from nomadic form to an organized industry to rear animals for milk and meat production as more fodder crops were available.

Construction of dams provided a platform for the production of electricity from river water. In order to fulfill the commercial and domestic electric requirements in the region, turbines were installed to produce the hydroelectric power. Industrial production increased due to the availability of a cheaper electric supply subsequently increasing the revenue from the industrial sector. Agricultural-based industrial development produced a large number of jobs to boost the local economy. Poverty was reduced, and livelihood increased favoring a better lifestyle in the families living near industrial areas.


**1. Introduction**

The extensive utilization of nonrenewable fossil fuels sources such as petroleum, coal and others has imposed a serious problem of energy depletion beyond the 21st century. Currently, our environment has been severely polluted and the instant effect such as climate change, acid rain, greenhouse effect, etc were the results of these problems. Therefore, it is crucial to balance between exploitation of energy resources and environment protection so that development can be sustainable for the human beings. Thus, a new alternative method should be proposed to overcome this problem, especially in the area of renewable ener‐ gy. In many developing countries, there is an abundance of biomass and agricultural wastes like sawdust, rice and coconut husks, bagasse and animal dung. Unfortunately, these renewable sources were discharged daily due to its properties (wastes) and too expensive to dispose off. For instance, in Malaysia, a huge amount of biomass wastes from oil palm and rubber industries are being produced daily, estimated at not less than 4.5 million metric tonnes effluent per year.

The simplest way for the farmers to discharge the agricultural waste is by burning them. This practice will contribute to air pollution and increase the greenhouse gases effect. To overcome the waste properties of biomass, they are treated in two senses. First, biomass plant matter is used to generate electricity with steam turbines and gasifiers or produce heat, usually by direct

© 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

combustion. Second, biomass which includes plant or animal matter can be converted into fibers or other industrial chemicals, including biofuels. Vegetative biomass is generally composed of lignin, cellulose and hemicelluloses and varies in composition depending on plant species. Because of the nature of their chemical structures, biomass materials can easily be converted into biofuels and other useful chemicals in comparison to coals and other fossil energy sources. For instance, in Malaysia, rubber trees plantation cover more than 1.7 million hectares all over the country. These plantations produced agricultural waste that includes rubber seed, rubber seed pod, and rubberwood. Each hectare can produce an approximately amount of 150 – 160 kg of seeds. The search for a low-cost raw material with adequate fuel characteristics for biofuels production is an important step toward establishing a successful biofuels industry. Typically, rubber seed oil, which is nonedible, is considered as a prospective feedstock for alternative fuels production.

In recent years, the liquefaction potential of coals has been investigated to increase the yield of coal conversion processes and the quality of liquid fuels obtained from coal. However, the liquefaction process of coal and biomass materials known as co-liquefaction has not been developed in Malaysia. Typically, rubber seed oil, which is nonedible, obtained from rubber seed is considered as a prospective feedstock for alternative fuels production since it has been found to be rich in oil. Thus, these abundant biomass sources are potential candidates for the production of alternative fuels via co-liquefaction process, and the development of this technology becomes significant in both efficient utilization of resources and improvement of ecological environment. Owing to the fact that energy composition properties are rich in coal, poor in oil and little in gas [1], coal liquefaction to produce alternative petroleum in Malaysia is of great significance to energy security. Malaysian low-rank coals are chosen as the starting material in this study due to the fact that these coals are abundant, low grade and have lower energy content because of their low carbon composition. They are lighter (earthier) and have higher moisture levels. Hence, an attempt should be made for co-liquefaction of Malaysian coals and rubber tree wastes (rubber seed, rubber seed pod or rubberwood), especially for the production of alternative fuels or other chemical feedstocks.

### **2. World energy supply**

Since 2004, there was no increase in world's oil supply because of the unavailability of finding new sources and the declining output from older oil fields. The increasing production difficulties mean that the supply of oil will soon begin to decline and that, month by month, the decline will be at an accelerating pace [2]. World energy supply is largely dependent on conventional petroleum products and most of the expected increas‐ es in oil demand come from the motorized transport sector, with the largest growth from developing countries. Consequently, the transport sector will become responsible for about one-third of the world's future greenhouse gas (GHG) emission growth and oil prices may reach dramatically high levels [3].

Coincidentally, a growing concern for fossil fuels exhaustion has shown up in the scientific community in the last decade or so. Because of oil, natural gas and coal are finite natural resources; thus the production of these fossil fuels will reach a peak and eventually start to drop. Then, the process of declining will be accelerated because extraction costs will increase after the fossil fuel resources have been consumed. Thus, the implementation of alternative sources becomes more and more important [4].

The depletion of fossil fuels and tighter environmental regulations has forced the world to adopt alternative renewable fuel sources such as hydro, wind and biomass [5], or others. The government expects that an investment through RM9.7 billion is required for the development of the electric utility sector until 2010 [6]. Analysts predicted that the government's aim for 2, 080 MW or 11% of all electricity generated nationwide in 2020 to be sourced from environment-friendly renewable energy and this will be a challenging and long-term task [7]. Hence, due to current demands in electricity and with recent develop‐ ments in the energy sector, alternative renewable fuels must be recognized as an impor‐ tant energy source for the foreseeable future.

### **2.1. Biomass**

combustion. Second, biomass which includes plant or animal matter can be converted into fibers or other industrial chemicals, including biofuels. Vegetative biomass is generally composed of lignin, cellulose and hemicelluloses and varies in composition depending on plant species. Because of the nature of their chemical structures, biomass materials can easily be converted into biofuels and other useful chemicals in comparison to coals and other fossil energy sources. For instance, in Malaysia, rubber trees plantation cover more than 1.7 million hectares all over the country. These plantations produced agricultural waste that includes rubber seed, rubber seed pod, and rubberwood. Each hectare can produce an approximately amount of 150 – 160 kg of seeds. The search for a low-cost raw material with adequate fuel characteristics for biofuels production is an important step toward establishing a successful biofuels industry. Typically, rubber seed oil, which is nonedible, is considered as a prospective

In recent years, the liquefaction potential of coals has been investigated to increase the yield of coal conversion processes and the quality of liquid fuels obtained from coal. However, the liquefaction process of coal and biomass materials known as co-liquefaction has not been developed in Malaysia. Typically, rubber seed oil, which is nonedible, obtained from rubber seed is considered as a prospective feedstock for alternative fuels production since it has been found to be rich in oil. Thus, these abundant biomass sources are potential candidates for the production of alternative fuels via co-liquefaction process, and the development of this technology becomes significant in both efficient utilization of resources and improvement of ecological environment. Owing to the fact that energy composition properties are rich in coal, poor in oil and little in gas [1], coal liquefaction to produce alternative petroleum in Malaysia is of great significance to energy security. Malaysian low-rank coals are chosen as the starting material in this study due to the fact that these coals are abundant, low grade and have lower energy content because of their low carbon composition. They are lighter (earthier) and have higher moisture levels. Hence, an attempt should be made for co-liquefaction of Malaysian coals and rubber tree wastes (rubber seed, rubber seed pod or rubberwood), especially for the

Since 2004, there was no increase in world's oil supply because of the unavailability of finding new sources and the declining output from older oil fields. The increasing production difficulties mean that the supply of oil will soon begin to decline and that, month by month, the decline will be at an accelerating pace [2]. World energy supply is largely dependent on conventional petroleum products and most of the expected increas‐ es in oil demand come from the motorized transport sector, with the largest growth from developing countries. Consequently, the transport sector will become responsible for about one-third of the world's future greenhouse gas (GHG) emission growth and oil prices may

feedstock for alternative fuels production.

186 Biofuels - Status and Perspective

production of alternative fuels or other chemical feedstocks.

**2. World energy supply**

reach dramatically high levels [3].

Biomass is a local resource that can contribute to the diversification of energy supply and potentially create employment for cultivation, harvesting, transport and fuel preparation. The importance of biomass can clearly be seen from the action plan as reported by the European Commission. The commission has targeted to increase the usage of biomass from 289, 000 TJ in 2003 to about 628, 000 TJ in 2010, as reported in their 2005 "Biomass Action Plan". The factors that led to almost double the biomass use was due to some important advantages that have been identified. These include (i) less dependence on short-term weather changes, (ii) low costs, (iii) an alternative source of income for farmers and finally (iv) able to promote regional economic structures [8].

Well-managed biomass yields carbon emission-saving fuels when substituted for fossil fuels. Amongst renewable energy sources, biomass appears to be the most important in terms of technical and economic feasibility. Since the content of both nitrogen and sulfur are low in biomass materials, the formation of NOx and SOx gases during combustion or firing the biomass materials is also low. The carbon dioxide released during combustion is equal to the amount of carbon dioxide intake when the plants grow up and this means produce almost no net carbon dioxide emission after combustion [1, 3, 4]. It is therefore today that biomass is considered a major future energy source for development and industry, arousing growing interest worldwide, not only for use in transport. Thus, the utilization and development of biomass energy could solve not only the energy issues, but could surely reduce the main environment problems such as pollution and greenhouse effects. Food crops containing starch/ sugar/oil can be processed to produce biofuels where the conversion technologies and markets are readily available. Moreover, with the increasing petroleum prices, the commercial opportunity must be quickly taken into consideration.

Huge amount of biomass wastes in Malaysia, especially from rubber plantation are being produced daily. The use of biomass in direct liquefaction with the aim to ease the petroleum importation has been paid a major concern, especially among researchers. However, several drawbacks that affected the direct liquefaction of biomass are actually attributed to the nature of the biomass itself. These include source of biomass being seasonal and biomass normally having a relatively higher distributing area in comparison to its total amount. Eventually, these factors will directly affect the feedstock supply of biomass and of course limit its large-scale utilization.

Energy from biomass is a large untapped energy source and its direct liquefaction is possible [9-15]. Energy that can be derived from biomass actually exists in all three phases, i.e. (i) gas fuels (synthesis gas from gasification), (ii) liquid fuels (biodiesel, bio-oil and bio-ethanol) and (iii) solid fuels (for use in boiler combustion). However, in terms of energy output, commer‐ cially proven technology and versatility in a wide range of processes (biochemical or thermo‐ chemical), energy from biomass is proven to be the most feasible short-term solution to substitute fossil fuels in comparison to other underdeveloped technologies, namely, photo‐ voltaics and fuel cells [16].

### **2.2. Rubber seed oil**

Peninsular Malaysia, compromising 12 of the 14 states in the Malaysian federation is among the world's most important rubber growing area. Rubber tree is also grown in Sabah and Sarawak. Altogether, Malaysia produces almost 20% of the world's natural rubber. More than half of Malaysia's rubber comes from thousands of privately owned small landholdings, which are usually about 2 hectares. The rest is grown on big estates owned by various companies; each can cover over a 1000 hectares. Overall, Malaysia has about 1.7 million hectares of rubber plantation [10]. Rubber tree, or its scientific name is Hevea brasiliensis, belongs to the family Euphorbiaceae and was found to be the most economically important member of the genus Hevea. This is mainly due to the milky latex collected on the daily basis by using special knife tapping from its bark around the tree. In Malaysia, the leaves of the rubber tree fall by end of year, usually from December up to February and refoliate quickly after that, followed by flowering and also producing a large volume of seeds. These seeds, however, were left underutilized [11]. Because of environmental issues, researchers in Malaysia have pursued it quite extensively to evaluate the potential usage and applications of rubber tree wastes (mostly rubber seed, rubber seed pod and rubber wood) through various chemicals and biological determinations. Figure 1 shows the typical scenario of rubber tree plantation in Malaysia and Figure 2 shows the components of rubber tree wastes. Rubber seeds have been found to be rich in oil. Its content in the dried kernel varies from 35 to 45%. It is semi-drying and consists of 17 – 22% saturated fatty acids and 17 – 82% unsaturated fatty acids, and is comparable to drying oils commonly used in surface coating [17]. Rubber seed oil has been found to have potential applications in many areas, which include production of biodiesel as fuel for compression engines [18, 19], foaming agent in latex foam, in the synthesis of alkyd resin used in paints and coatings [17] and several other uses [20]. Thus, the potential of rubber seed to be further utilized in other areas such as co-liquefaction with coal to produce alternative fuels content in the dried kernel varies from 35 to 45%. It is semi-drying and consists of 17 – 22% saturated fatty acids and 17 –

engines [18,19], foaming agent in latex foam, in the synthesis of alkyd resin used in paints and coatings [17] and several

and other useful products provides great opportunity. Table 1 shows the properties of rubber seed oil. other uses [20]. Thus, the potential of rubber seed to be further utilized in other areas such as co-liquefaction with coal to produce alternative fuels and other useful products provides great opportunity. Table 1 shows the properties of rubber seed

Figure 1. Typical rubber tree plantation scenario in Malaysia. **Figure 1.** Typical rubber tree plantation scenario in Malaysia.

**Energy Demand Scenario in Malaysia**

**Characteristics of Mukah Balingian Coal**

**Malaysian Coals**

oil.

Huge amount of biomass wastes in Malaysia, especially from rubber plantation are being produced daily. The use of biomass in direct liquefaction with the aim to ease the petroleum importation has been paid a major concern, especially among researchers. However, several drawbacks that affected the direct liquefaction of biomass are actually attributed to the nature of the biomass itself. These include source of biomass being seasonal and biomass normally having a relatively higher distributing area in comparison to its total amount. Eventually, these factors will directly affect the feedstock supply of biomass and of course limit its large-scale

Energy from biomass is a large untapped energy source and its direct liquefaction is possible [9-15]. Energy that can be derived from biomass actually exists in all three phases, i.e. (i) gas fuels (synthesis gas from gasification), (ii) liquid fuels (biodiesel, bio-oil and bio-ethanol) and (iii) solid fuels (for use in boiler combustion). However, in terms of energy output, commer‐ cially proven technology and versatility in a wide range of processes (biochemical or thermo‐ chemical), energy from biomass is proven to be the most feasible short-term solution to substitute fossil fuels in comparison to other underdeveloped technologies, namely, photo‐

Peninsular Malaysia, compromising 12 of the 14 states in the Malaysian federation is among the world's most important rubber growing area. Rubber tree is also grown in Sabah and Sarawak. Altogether, Malaysia produces almost 20% of the world's natural rubber. More than half of Malaysia's rubber comes from thousands of privately owned small landholdings, which are usually about 2 hectares. The rest is grown on big estates owned by various companies; each can cover over a 1000 hectares. Overall, Malaysia has about 1.7 million hectares of rubber plantation [10]. Rubber tree, or its scientific name is Hevea brasiliensis, belongs to the family Euphorbiaceae and was found to be the most economically important member of the genus Hevea. This is mainly due to the milky latex collected on the daily basis by using special knife tapping from its bark around the tree. In Malaysia, the leaves of the rubber tree fall by end of year, usually from December up to February and refoliate quickly after that, followed by flowering and also producing a large volume of seeds. These seeds, however, were left underutilized [11]. Because of environmental issues, researchers in Malaysia have pursued it quite extensively to evaluate the potential usage and applications of rubber tree wastes (mostly rubber seed, rubber seed pod and rubber wood) through various chemicals and biological determinations. Figure 1 shows the typical scenario of rubber tree plantation in Malaysia and Figure 2 shows the components of rubber tree wastes. Rubber seeds have been found to be rich in oil. Its content in the dried kernel varies from 35 to 45%. It is semi-drying and consists of 17 – 22% saturated fatty acids and 17 – 82% unsaturated fatty acids, and is comparable to drying oils commonly used in surface coating [17]. Rubber seed oil has been found to have potential applications in many areas, which include production of biodiesel as fuel for compression engines [18, 19], foaming agent in latex foam, in the synthesis of alkyd resin used in paints and coatings [17] and several other uses [20]. Thus, the potential of rubber seed to be further utilized in other areas such as co-liquefaction with coal to produce alternative fuels

utilization.

188 Biofuels - Status and Perspective

voltaics and fuel cells [16].

**2.2. Rubber seed oil**

Figure 2. Components of rubber tree wastes: (a) young seeds, (b) ripe seeds, (c) fruit in an opened pod/pericarp and (d) kernel and shell of rubber fruits. **Figure 2.** Components of rubber tree wastes: (a) young seeds, (b) ripe seeds, (c) fruit in an opened pod/pericarp and (d) kernel and shell of rubber fruits.

However, the only coal deposit being mined in Malaysia is from Kapit area, Sarawak.

contains less carbon, liquefaction process is one of the best option thus far to utilize them.

The Malaysian government policy on energy utilization and consumption has approved to increase the coal base generation of electricity from 11% to about 33% by the year 1995 and 2020, respectively [21]. Moreover, the coal reserves in Malaysia, which are mainly located in the states of Sarawak (70% reserves), Sabah (28%) and other states (2% from Selangor, Perak and Perlis), have total reserves of about 1,050 million tonnes of various qualities, ranging from lignite to anthracite [21,22,23].

Since early 1999, Tenaga Nasional Bhd. (TNB), the major electricity provider and Sarawak Electric Supply Co. (SESCO) have purchased 120,000 and 400,000 tonnes per annum (tpa), respectively, from Kapit coal mine [24]. SESCO operates the 100 MW Kapit minemouth coal-fired power station, where two 50 MW units supply electricity to the Sarawak grid. TNB has projected to double to 20 million tpa its coal import once two planned coal-fired plants (total of 1400 MW) are fully commissioned. Moreover, the construction work has started on the 2100 MW Pulau Bunting power station, which will burn 6 million tpa of coal. In order to secure low coal prices and improve the security of coal supply, TNB's long-term plan is to buy 30 to 50% of its annual coal requirement from its Indonesian coal mining subsidiary, TNB Coal International Ltd., which owns the right to mine in five areas in South Kalimantan. Malaysia imported about 2.9 million tonnes of coals in 1999, i.e. 85% were steam coal and 15% anthracite and bituminous coal. This amount of coal was needed to fulfill the requirement for its

Based on the statistics reported in The Eighth Malaysia Plan by the Department of Minerals and Geosciences, Sarawak; Mukah Balingian (MB) was identified as the second largest coal area in Malaysia with reserves of *ca.* 710 km2 [6]. However, most of the known coal areas in the states of Sabah and Sarawak, including Mukah Balingian, are not commercially mined due to poor availability of infrastructure and located far inland [6], and most of the coal types are of low rank, i.e. subbituminous. Thus, the usage of abundant of coal reserves was not optimized. Low rank coals (brown coal, lignite and lower sub-bituminous coals) are the most abundant fossil resources, but they have not been utilized in a large amount because of their low calorific values. This is mainly due to the presence of a large amount of oxygen functional groups in such coals, namely, carboxylic, -COOH; hydroxyl, -OH; carbonyl, -CO; etc. The traits of these coals are low price, relatively large porosity and high reactivity, which benefit their utilization for direct coal liquefaction (DCL) [25]. Owing to the fact that low rank coal

From Table 2, it can be seen that MB coal has relatively high oxygen and volatile matter contents. The petrographic analysis of this coal shows a vitrinite reflectance value of 0.40% and thus can be categorized as a low rank coal, i.e. sub-bituminous C rank [26]. Further, previous work by Ismail et al. [27] using high pressure Temperature Programmed Reduction (TPR) on the pyrite-free MB coal also confirms that this coal is of a low rank by observing the organic sulfur distribution in the coal.

cement and utility industries. Indonesia, Australia, China and South Africa were the major overseas suppliers [23].

**Table 1.** Properties of rubber seed oil [18].


**3. Results**

#### *3.1. Prevalence of Life Satisfaction over Time*

Life satisfaction over time (years 2006 to 2017) is illustrated in Figure 2 and full descriptive statistics can be found in Supplementary Materials (Table S2).

Between 2006–2017 mean life satisfaction varied from a high of 7.61 (*SD* = 1.6) in 2007 to a low of 7.23 (*SD* = 1.73) in 2011; the range in mean changing 0.38 over this time between the high and low.

#### *3.2. Life Satisfaction by Age and Gender*

The results of an independent samples *t*-test showed that women scored significantly higher than men on life satisfaction (*t*(10,771) = −3.763, *p* < 0.001, 95% CI of difference:

−0.186, −0.058, *d* = 0.073), albeit with a very small effect size. Figure 3 shows the distribution of life satisfaction by age and gender for all participants across all years.

**Figure 3.** Life satisfaction by age and gender.

Figure 3 shows that females tend to report being slightly more satisfied with life throughout and over the life course compared to males, with this gender gap being most predominant mid-life. Both females and males on average report slightly decreasing levels of life satisfaction from teenage to mid-life, and then increasing from mid-life onwards.

As a supplementary analysis, we also looked at gender differences in the positive and negative experience indexes we created (composite variables described above). The results of independent samples *t*-tests showed that women scored significantly higher on the negative experience index (*t*(9401.196) = −7.238, *p* < 0.001, 95% CI of difference: −0.054, −0.031, *d* = 0.146), again with a small effect size. No significant gender differences were found for the positive experience index.

#### *3.3. Other Demographic Predictors of Life Satisfaction*

Table 1 presents the results of seven separate ANOVAs, using demographic variables as independent variables (employment, education, location, religious affiliation, relationship status, country of birth, income quintile) explaining life satisfaction.

**Table 1.** ANOVA Results Predicting Life Satisfaction.

For religious affiliation, several categories with very small sample sizes (e.g., "Hinduism" and "Islam") were combined with the "other" category. As indicated in Table 1, the strongest predictor of life satisfaction was income quintile (explaining 3.7% of the variance), followed by employment status (explaining 2.9% of the variance) and relationship status (explaining 2.5% of the variance). Figure 4 presents life satisfaction and employment status.

The self-employed and those who choose to work part-time had the highest levels of life satisfaction and those unemployed experienced the lowest levels of life satisfaction. The results of the Games–Howell test showed that all employment groups were significantly different from each other (*p* < 0.05) except employed full-time for an employer and out of workforce (*p* = 0.074).

Figure 5 presents life satisfaction and relationship status.

**Figure 5.** Life satisfaction and relationship status.

Individuals identifying as married or widowed reported the highest levels of life satisfaction, and those identifying as separated reported the lowest levels of life satisfaction. In summary, and as shown in Figures 4 and 5 and Table 1, the unemployed and separated groups of individuals were in comparison the least satisfied with their lives. The results of the Games–Howell test showed that all marital groups were significantly different from each other (*p* < 0.05) except single and domestic partnership (*p* = 0.717) and domestic partnership and divorced (*p* = 0.856). A separate ANOVA indicated that gender did not moderate the relationship between relationship status and life satisfaction. The results of the Games–Howell test showed that all income groups were significantly different from each other (*p* < 0.05). Education, religious affiliation, and location each explained 0.7% or less of the variance in life satisfaction. Country of birth was not a significant predictor. The results of the Games–Howell test showed that there was a significant difference between people with elementary and tertiary education, and between people with secondary and tertiary education (*p* < 0.01). For religious affiliation, the Games–Howell test showed that all groups were significantly different from each other (*p* < 0.01), whereas for location, the significant differences were between "rural or farm" and all other types of location, as well as between "small town or village" and "Suburb of a large city" (*p* < 0.01).

## *3.4. Regression Analysis*

We included all predictors of life satisfaction along with key demographic variables (the variables are provided in the predictor column of Table 2) in a regression using the standard or simultaneous regression model. A total sample of 6023 participants, of the 10,799 participants (56%), had no missing values on all of the 28 variables and were included in the analysis (see Table 2).

**Table 2.** Comprehensive Regression Analysis.

Note. *B* = unstandardised regression coefficient. Beta = standardised regression coefficient.

The predictors collectively explained 33.1% of the variance in life satisfaction, *F*(27, 5995) = 110.024, *p* < 0.001, *R*2 = 0.331. Based on the results of a separate stepwise regression analysis, household income satisfaction was the strongest predictor explaining 16.8% of the variance. The second strongest predictor was satisfaction with standards of living, contributing an additional 5.4%. Negative experience, city satisfaction, and positive experience were next explaining 3.4%, 1.9%, and 1.7%, respectively. These five variables jointly explained 29.3% of the variance in life satisfaction scores. The other variables collectively added only 3.8% of additional variance. Based on the results of the stepwise regression, perceptions of corruption, donation, religiosity, respect, education, separated, unemployed, and number of children did not add a significant amount of variance beyond the other 19 variables and were excluded.

We also conducted regression analyses separately across age and gender groups. Given the large sample size, the probability of a type 1 error is increased. Therefore, the significance threshold of 0.001 is preferred for assessing significance. Table 3 presents the unstandardised regression coefficients for age and gender groups.

**Table 3.** Unstandardised Regression Coefficients for Age and Gender Groups.

Note. HH income = satisfaction with household income; \*\*\* *p* < 0.001. Given the large sample size, the probability of a type 1 error is increased. Therefore, the significance threshold of 0.001 is preferred for assessing significance.

Satisfaction with healthcare, being separated, and unemployed were removed as they showed no variation in one or more groups. Table 4 presents the regression results across age and gender groups, and also presents the five most important predictors for each group in order of predictive power, based on separate regression analyses using the stepwise procedure for each group.

**Table 4.** Regression Results across Age and Gender Groups.

Note. The *R*2, *F*, and *df* values come from simultaneous regression analyses. The important predictors come from separate regression analyses using the stepwise method. The most important predictors are in order of predictive power. Abbreviations. SWSL = satisfaction with standards of living; HH income = satisfaction with household income; positive = positive experience; negative = negative experience. \*\*\* *p* < 0.001.

For all groups, an important predictor of life satisfaction was satisfaction with standards of living. For males across all age groups and females up to the age of 40 years, positive experiences and satisfaction with household income were also important predictors. Being married was an important predictor for males over 40 years. Feeling satisfied with city was important for females across all ages and for men under 40.

#### *3.5. Relationship between Household Income and Life Satisfaction: A Close Examination*

The relationship between per capita annual household income in International Dollars, e.g., see [44], and life satisfaction is shown in Figure 6.

**Figure 6.** The relationship between annual household income (in International Dollars) and life satisfaction in NZ.

Individuals with incomes over \$100,000 International Dollars were excluded due to their small sample size. As can be seen, the lower income group (under \$15,000 International Dollars, equivalent to about \$23,000 NZD) reported much lower life satisfaction, however, past approximately \$20,000 International Dollars (equivalent to about \$31,000 NZD), there were smaller increases as income increased.


**3. Membrane process and their integration: energy and environmental impact**

In GCC countries, 42% desalinated water is produced by membrane processes. Conventional SWRO processes consume 7–17 kWhpe/m3 primary energy (equivalent to 3–8 kWhelec/m3 ) for seawater desalination and they emit 3.0 kg/m3 CO2 to the environment [112]. Currently, major online SWRO plants in Saudi Arabia and future proposed projects is presented in **Table 3**.

Most of the SWRO plants are operated under saline water conversion cooperation (SWCC), and their overall recovery varies from 17 to 40% depending upon feedwater quality. Four major plants, namely (i) Jeddah, (ii) Rbigh, (iii) Jubail and (iv) Shuqaiq operational data were collected, and analysis results are presented.

#### **3.1. SWRO and hybrid cycle results and discussion**

**Figure 7(a–c)** shows the seawater, retentate and distillate concentration for four mentioned plants. It can be seen that Red seawater feed concentration varies from 37,000 ppm in Jeddah to 40,000 ppm in Jubail. The retentate maximum concentration was observed at Jeddah, 60000 ppm due to better recovery. The distillate concentration met the WHO standard, <500 ppm, except at Rbigh where it can reach to 800 pm and it mixed with thermaldriven processes distillate before distribution to end users.

**Table 3.** Major SWRO plants in operation and future proposed projects in Saudi Arabia. They need extensive pretreatment and still recovery is only up to 40% maximum.

At these four locations, we also analyzed the CO2 emission and chemical rejection in the brine and applied to overall capacity in GCC according to SWRO market share. **Table 4** shows the CO2 emission and chemical rejection per day in the GCC region by SWRO processes only.

biomimetic membranes, isoporous block copolymer membranes and aligned nanotube membranes for energy efficiency [128–135]. In terms of commercialization, most of the proposed materials are farthest (5–10 years) from commercial reality. On the other hand, SWRO processes [136, 137] can be integrated with proposed AD cycle to improve process performance.

**Figure 7.** Six-month results of four major SWRO plants in Saudi Arabia. (a) Seawater feed concentration, (b) SWRO

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Membrane process can be integrated with AD cycle for energy efficiency and to reduce environmental impact. AD cycle can operate at high concentration, almost near crystallization

Both technologies are readily available and can be implemented in near future.

**3.2. Membrane process integration with AD cycle**

retentate concentration and (c) distillate concentration.

The alarming situation, huge amount of CO2 emission to environment and chemical rejection to sea on daily basis can be clearly observed by conventional SWRO process operation. These processes cannot be terminated due to water requirement, but they can be improved.

Impact of SWRO processes can be minimized either by material development or process improvements. The variety of efficient materials have been proposed such as (i) catalytic nanoparticle-coated ceramic membranes, (ii) zeolitic, (iii) inorganic-organic hybrid nanocomposite membranes and (iv) bio-inspired membranes that includes protein-polymer hybrid

**Figure 7.** Six-month results of four major SWRO plants in Saudi Arabia. (a) Seawater feed concentration, (b) SWRO retentate concentration and (c) distillate concentration.

biomimetic membranes, isoporous block copolymer membranes and aligned nanotube membranes for energy efficiency [128–135]. In terms of commercialization, most of the proposed materials are farthest (5–10 years) from commercial reality. On the other hand, SWRO processes [136, 137] can be integrated with proposed AD cycle to improve process performance. Both technologies are readily available and can be implemented in near future.

#### **3.2. Membrane process integration with AD cycle**

At these four locations, we also analyzed the CO2

Rabigh phase (3) 600,000 2019 Alugair 10,000 2019 Omluj 18,000 2020 Yanbu-4 450,000 2020 Jubail phase (3) 330,000 2021

The alarming situation, huge amount of CO2

and still recovery is only up to 40% maximum.

**Plant name Capacity (m3**

104 Desalination and Water Treatment

CO2

Future projects

and applied to overall capacity in GCC according to SWRO market share. **Table 4** shows the

**Table 3.** Major SWRO plants in operation and future proposed projects in Saudi Arabia. They need extensive pretreatment

emission and chemical rejection per day in the GCC region by SWRO processes only.

to sea on daily basis can be clearly observed by conventional SWRO process operation. These

Impact of SWRO processes can be minimized either by material development or process improvements. The variety of efficient materials have been proposed such as (i) catalytic nanoparticle-coated ceramic membranes, (ii) zeolitic, (iii) inorganic-organic hybrid nanocomposite membranes and (iv) bio-inspired membranes that includes protein-polymer hybrid

processes cannot be terminated due to water requirement, but they can be improved.

**/day) Overall recovery (%)**

Umm Lujj 4400 24 1986 SWCC Haql 4400 30 1989 SWCC Duba 4400 31 1989 SWCC Al-Barik 2275 17 1983 SWCC

Barge Raka, 24,981 SWCC [118]

Jeddah phase (4) 400,000 2019 SWCC [122]

Jeddah phase-II 48,848 35 1994 SWCC [113] Rabigh 168,000 40 2009 RAWEC [114] Shuqaiq-II 212,000 40 2010 NOMAC [115] Ras Azzour 307,000 40 2014 SWCC [116] Shuaiba I & II 76,800 40 2003 SEPCO [117] Shuaiba III Extension, 150,000 40 2009 SEPCO [118] Medina-Yanbu Phase II 127,825 35 1995 SWCC [119] North Obhor, Jeddah 12,500 35 2006 SAWACO [120] Jeddah-1 56,800 35 1989 SWCC [121]

emission and chemical rejection in the brine

**Commissioning Operator Ref**

emission to environment and chemical rejection

Membrane process can be integrated with AD cycle for energy efficiency and to reduce environmental impact. AD cycle can operate at high concentration, almost near crystallization

\* SWRO electricity consumption = 3.5 kWhelec/m3 , Power plant conversion efficiency = 47%.

\*\*CO2 emission rate = 0.527 kg/kWhpe.

\*\*\*Pretreatment chemical values are taken from four plants and published literature [123–127].

**Table 4.** Energy consumption, CO2 emission and chemical rejection by all SWRO plants in GCC. The severe impact on environment and marine life can be observed clearly.

enable AD cycle to operate more than 80% recovery, over 250,000 ppm. Experiments were conducted up to 250,000 ppm concentration to investigate salt concentration effect on heat transfer. **Figure 8(a)** shows salt crystallization in evaporator at 250,000 ppm. Soft scale deposition, in the form of white powder, was observed at high concentration that can be easily washed out by spraying as shown in **Figure 8(b)**. **Figure 9** shows concentration effect on heat transfer at different evaporator temperatures. It can be seen that even at high concentration the heat transfer coefficient has reasonable value that shows successful operation of AD cycle

**Parameters SWRO Hybrid cycle % Saving by hybridization (%)**

SO4 3636.4 1348.1 170

**Table 5.** Comparison of SWRO and its hybrid with AD cycle. The superiority of hybrid cycle can be seen clearly from

or AlCl3 1272.7 471.8 170

**Figure 9.** Effect of salt concentration and evaporator temperature on heat transfer coefficient of AD evaporator. The AD

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at highest concentration without fouling and scaling chances.

Total PE consumption (GWhpe/day)\* 81.3 40.9 98.9

Disinfection, NaOCl 36.4 13.4 170

Flocculation, Polyelectrolyte 145.6 53.9 170 Antiscaling, polycarbonic acid 72.8 26.9 170 Dechlorination, NaHSO3 109.2 40.4 170

[137].

emission (ton/day) 42,855.2 21,550.1 98.9

cycle evaporator can operate as low as 7°C.

CO2

\*

Pretreatment chemicals (ton/day)

AD electricity consumption = 1.38kWhelec/m3

Acid for pH adjustment, H2

Coagulation, FeCl3

summary table.

zone, without fouling and corrosion chances due to low temperature operation. In addition to zero chemical injection, it also has minimal impact on environment as it operated with renewable energy. In this way, this hybridization will not only help to reduce CO2 emission but also chemical rejection to the sea.

In proposed integration, the SWRO retentate, at 50,000 to 60,000 ppm, is supplied to AD cycle operating at evaporator temperature of 5–30°C. Both heat inputs, silica gel regeneration and evaporator, are supplied from renewable solar energy. This low evaporator temperature

**Figure 8.** AD cycle evaporator inside view during operation. (a) Salt crystallization at 250,000 ppm at 10°C evaporator temperature and (b) white salt deposition cleared by feed spray jet impingement. It shows AD cycle successful operation at near crystallization zone, over 80% recovery: One of the highest recovery reported up till now.

**Figure 9.** Effect of salt concentration and evaporator temperature on heat transfer coefficient of AD evaporator. The AD cycle evaporator can operate as low as 7°C.

enable AD cycle to operate more than 80% recovery, over 250,000 ppm. Experiments were conducted up to 250,000 ppm concentration to investigate salt concentration effect on heat transfer. **Figure 8(a)** shows salt crystallization in evaporator at 250,000 ppm. Soft scale deposition, in the form of white powder, was observed at high concentration that can be easily washed out by spraying as shown in **Figure 8(b)**. **Figure 9** shows concentration effect on heat transfer at different evaporator temperatures. It can be seen that even at high concentration the heat transfer coefficient has reasonable value that shows successful operation of AD cycle at highest concentration without fouling and scaling chances.

**Table 5.** Comparison of SWRO and its hybrid with AD cycle. The superiority of hybrid cycle can be seen clearly from summary table.

**Figure 8.** AD cycle evaporator inside view during operation. (a) Salt crystallization at 250,000 ppm at 10°C evaporator temperature and (b) white salt deposition cleared by feed spray jet impingement. It shows AD cycle successful operation

zone, without fouling and corrosion chances due to low temperature operation. In addition to zero chemical injection, it also has minimal impact on environment as it operated with renew-

(30–100 ppm) 3636.4 ton/day

(1–35 ppm) 1272.7 ton/day

(3 ppm) 109.2 ton/day

, Power plant conversion efficiency = 47%.

emission and chemical rejection by all SWRO plants in GCC. The severe impact on

In proposed integration, the SWRO retentate, at 50,000 to 60,000 ppm, is supplied to AD cycle operating at evaporator temperature of 5–30°C. Both heat inputs, silica gel regeneration and evaporator, are supplied from renewable solar energy. This low evaporator temperature

emission but also

/day

/day

/day

able energy. In this way, this hybridization will not only help to reduce CO2

**Parameters Quantity Units** Total GCC capacity 26 Mm3

SWRO share (42%) 10.92 Mm3

Total feed (30% recovery) 36.4 mm3

Disinfection, NaOCl or free chlorine (1 ppm) 36.4 ton/day

Flocculation, polyelectrolyte (0.2–4 ppm) 145.6 ton/day Antiscaling, polycarbonic acid (2 ppm) 72.8 ton/day

\*\*\*Pretreatment chemical values are taken from four plants and published literature [123–127].

Total primary energy (PE) consumption\* 81.3 GWh/day

emission\*\* 42,855.2 ton/day

chemical rejection to the sea.

**Table 4.** Energy consumption, CO2

CO2

\*

\*\*CO2

Pre-treatment\*\*\*

Acid for pH adjustment, H2

106 Desalination and Water Treatment

Dechlorination, NaHSO3

Coagulation, FeCl3

SO4

or AlCl3

SWRO electricity consumption = 3.5 kWhelec/m3

environment and marine life can be observed clearly.

emission rate = 0.527 kg/kWhpe.

at near crystallization zone, over 80% recovery: One of the highest recovery reported up till now.

**Table 6.** The comparison of impact of conventional SWRO and proposed hybrid cycle. The hybrid cycle reduced all parameters impact to medium and low.

The proposed AD cycle recovering 51% more from SWRO retentate booting overall recover to 81%. The final reject concentration was observed as 185,000 ppm from AD cycle. This integration will not only help to save overall energy but also environmental pollution. The summary of savings is presented in **Table 5**. It can be noticed that proposed integration can save up to 100% energy and CO2 emission. In addition, it will also help to reduce chemical rejection to sea.

The impact matrix as presented in **Table 1** for conventional SWRO processes can be modified for hybrid cycle as presented in **Table 6**. It can be observed clearly that most of the parameters impact is reduced to medium and low from initial high value. This shows that hybridization will not help to produce more water but also with minimum impact on environment and marine life along with energy efficiency.


**4. Summary and Conclusions**

In summary, a series of Al2O3–Al2TiO5 bulk composites was investigated, with different AT contents (10 and 40 vol.%) and fabricated with different sintering temperature (1450 and 1550 ◦C) in order to develop significantly different microstructural features. The microstructure, crystal structure, and through-thickness residual stress profiles of the samples were obtained.

The main conclusions of the present study are as follows:

**Author Contributions:** Conceptualization, K.F., J.R.-H. and C.B.; methodology, J.R.-H., K.F.; software, W.J.; validation, W.J., S.B. and H.Z.; formal analysis, K.F. and J.R.-H.; investigation, K.F., J.R.-H. and W.J.; resources, J.R.-H., C.B. and S.B.; data curation, K.F.; writing—original draft preparation, K.F. and W.J.; writing—review and editing, K.F. and S.B.; visualization, H.Z.; supervision, P.Y.; project administration, W.F.; funding acquisition, K.F. and W.F. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China, grant number 51805445, 52175209; the Chunhui Plan Cooperative Scientific Research Project of the Ministry of Education of China, grant number 191659; the Opening Foundation of Sichuan Engineering Research Center for Powder Metallurgy, grant number SC-FMYJ2019-04. Beamtime was granted by ISIS ENGIN-X, Exp. No. RB1920330.

**Data Availability Statement:** Some or all data generated or used during the study are available from the corresponding author by request.

**Acknowledgments:** All financial support is greatly appreciated. The ISIS neutron and muon source are thanked for the provision of beamtime for residual strain scanning.

**Conflicts of Interest:** The authors declare no conflict of interest.


**2. Results**

#### *2.1. Preaparation of Bryopsis Plumosa Lectins*

Bryopsis lectin was successfully isolated from the crude extract of Bryopsis plumosa. Combining GalNAc and D-Man affinity chromatography was performed to separate each lectin. Stepwise elution of lectins as different monosaccharides was effective in separating BPL1 and BPL3 (Figure 1). The flow-through fraction contained BPL2, which was successfully isolated using mannose affinity chromatography (Figure 1). The purity of each BPL was more than 95%. All the lectins showed similar hemagglutination activities, as previously reported [22–25].

**Figure 1.** Purification of Bryopsis plumosa lectins (BPLs). M, Molecular weight marker; lane 1, crude extract; lane 2, BPL1; lane 3, BPL2; lane 4, BPL3.

#### *2.2. Cell Viability of Lung Cancer Cells and Non-Cancerous Cells against BPLs*

BPL2 inhibited the viability of lung cancer cell lines, whereas BPL1 and BPL3 did not show the inhibitory activity of the tested cell lines at any concentration (Supplementary Figure S1). Cell viability was dependent on the BPL2 concentration and exposure time. BPL2 activity was most effective in the A549 and H1299 lung cancer cell lines, with cell viability being approximately 40% at 100 μg/mL of BPL2 after exposure for 24 h. However, weak toxicity towards non-cancerous cell lines (MRC5, HEK293T, and HaCaT) was observed at 100 μg/mL (~60–70% viability) (Figure 2A). The increase in the exposure time of BPL2 affected cell viability; cell viability was reduced to approximately 20% after 72 h of exposure (Figure 2B). Based on the cytotoxicity results in non-cancerous cell lines, subsequent experiments were performed at a BPL2 concentration of fewer than 25 μg/mL.

According to the colony-forming assay, BPL2 was effective at low concentrations. All cancer cell lines disappeared after treatment with 20 μg/mL of BPL2. In addition, half of the colonies did not survive at 20 μg/mL BPL2 (Figure 3).

**Figure 3.** Colony-forming assay for the anticancer activity of BPL2. A549, H460, and H1299 cancer cell lines were used for these studies.